Miniports versus standard ports for laparoscopic cholecystectomy

  • Conclusions changed
  • Review
  • Intervention

Authors


Abstract

Background

In conventional (standard) port laparoscopic cholecystectomy, four abdominal ports (two of 10 mm diameter and two of 5 mm diameter) are used. Recently, use of smaller ports, miniports, have been reported.

Objectives

To assess the benefits and harms of miniport (defined as ports smaller than the standard ports) laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until February 2013 to identify randomised clinical trials of relevance to this review.

Selection criteria

Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing miniport versus standard port laparoscopic cholecystectomy were considered for the review.

Data collection and analysis

Two review authors collected the data independently. We analysed the data with both fixed-effect and random-effects models using RevMan analysis. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI).

Main results

We included 12 trials with 734 patients randomised to miniport laparoscopic cholecystectomy (380 patients) versus standard laparoscopic cholecystectomy (351 patients). Only one trial which included 70 patients was of low risk of bias. Miniport laparoscopic cholecystectomy could be completed successfully in more than 80% of patients in most trials. The remaining patients were mostly converted to standard port laparoscopic cholecystectomy but some were also converted to open cholecystectomy. These patients were included for the outcome conversion to open cholecystectomy but excluded from other outcomes. Accordingly, the results of the other outcomes are on 343 patients in the miniport laparoscopic cholecystectomy group and 351 patients in the standard port laparoscopic cholecystectomy group, and therefore the results have to be interpreted with extreme caution.

There was no mortality in the seven trials that reported mortality (0/194 patients in miniport laparoscopic cholecystectomy versus 0/203 patients in standard port laparoscopic cholecystectomy). There were no significant differences between miniport laparoscopic cholecystectomy and standard laparoscopic cholecystectomy in the proportion of patients who developed serious adverse events (eight trials; 460 patients; RR 0.33; 95% CI 0.04 to 3.08) (miniport laparoscopic cholecystectomy: 1/226 (adjusted proportion 0.4%) versus standard laparoscopic cholecystectomy: 3/234 (1.3%); quality of life at 10 days after surgery (one trial; 70 patients; SMD -0.20; 95% CI -0.68 to 0.27); or in whom the laparoscopic operation had to be converted to open cholecystectomy (11 trials; 670 patients; RR 1.23; 95% CI 0.44 to 3.45) (miniport laparoscopic cholecystectomy: 8/351 (adjusted proportion 2.3%) versus standard laparoscopic cholecystectomy 6/319 (1.9%)). Miniport laparoscopic cholecystectomy took five minutes longer to complete than standard laparoscopic cholecystectomy (12 trials; 695 patients; MD 4.91 minutes; 95% CI 2.38 to 7.44). There were no significant differences between miniport laparoscopic cholecystectomy and standard laparoscopic cholecystectomy in the length of hospital stay (six trials; 351 patients; MD -0.00 days; 95% CI -0.12 to 0.11); the time taken to return to activity (one trial; 52 patients; MD 0.00 days; 95% CI -0.31 to 0.31); or in the time taken for the patient to return to work (two trials; 187 patients; MD 0.28 days; 95% CI -0.44 to 0.99) between the groups. There was no significant difference in the cosmesis scores at six months to 12 months after surgery between the two groups (two trials; 152 patients; SMD 0.13; 95% CI -0.19 to 0.46).

Authors' conclusions

Miniport laparoscopic cholecystectomy can be completed successfully in more than 80% of patients. There appears to be no advantage of miniport laparoscopic cholecystectomy in terms of decreasing mortality, morbidity, hospital stay, return to activity, return to work, or improving cosmesis. On the other hand, there is a modest increase in operating time after miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy and the safety of miniport laparoscopic cholecystectomy is yet to be established. Miniport laparoscopic cholecystectomy cannot be recommended routinely outside well-designed randomised clinical trials. Further trials of low risks of bias and low risks of random errors are necessary.

Resumen

Minipuertos versus puertos estándar para la colecistectomía laparoscópica

Antecedentes

En la colecistectomía laparoscópica con puertos convencionales (estándar), se utilizan cuatro puertos abdominales (dos de 10 mm de diámetro y dos de 5 mm de diámetro). Recientemente se ha informado el uso de puertos más pequeños o minipuertos.

Objetivos

Evaluar los efectos beneficiosos y perjudiciales de la colecistectomía laparoscópica con minipuertos (definidos como puertos más pequeños que los puertos convencionales) versus la colecistectomía laparoscópica con puertos estándar.

Métodos de búsqueda

Se realizaron búsquedas en el Registro Cochrane Central de Ensayos Controlados (Cochrane Central Register of Controlled Trials, CENTRAL) en The Cochrane Library, MEDLINE, EMBASE y Science Citation Index Expanded hasta febrero de 2013 para identificar ensayos clínicos aleatorios de relevancia para esta revisión.

Criterios de selección

Para la revisión, se consideraron solamente los ensayos clínicos aleatorios (independientemente del idioma, el cegamiento o el estado de publicación) que compararon colecistectomía laparoscópica con minipuertos versus con puertos estándar.

Obtención y análisis de los datos

Dos revisores obtuvieron los datos de forma independiente. Los datos se analizaron con el modelo de efectos fijos y de efectos aleatorios mediante el análisis con RevMan. Para cada resultado, se calculó el cociente de riesgos (CR), la diferencia de medias (DM), o la diferencia de medias estandarizada (DME) con intervalos de confianza (IC) del 95%.

Resultados principales

Se incluyeron 12 ensayos con 734 pacientes asignados al azar a colecistectomía laparoscópica con minipuertos (380 pacientes) versus colecistectomía laparoscópica estándar (351 pacientes). Sólo un ensayo que incluyó a 70 pacientes tuvo bajo riesgo de sesgo. En la mayoría de los ensayos, la colecistectomía laparoscópica con minipuertos pudo completarse con éxito en más del 80% de los pacientes. En los pacientes restantes, hubo necesidad de conversión principalmente a colecistectomía laparoscópica con puertos estándar, pero en algunos también hubo necesidad de conversión a colecistectomía abierta. Estos pacientes se incluyeron en el resultado conversión a colecistectomía abierta, pero se excluyeron de los otros resultados. Por lo tanto, los datos de los otros resultados corresponden a 343 pacientes del grupo de colecistectomía laparoscópica con minipuertos y a 351 pacientes del grupo de colecistectomía laparoscópica con puertos estándar, por lo que los resultados se deben interpretar con mucho cuidado.

No hubo mortalidad en los siete ensayos que la informaron (0/194 pacientes con colecistectomía laparoscópica con minipuertos versus 0/203 pacientes con colecistectomía laparoscópica con puertos estándar). No hubo diferencias significativas entre colecistectomía laparoscópica con minipuertos y colecistectomía laparoscópica estándar en la proporción de pacientes que presentaron eventos adversos graves (ocho ensayos; 460 pacientes; CR 0,33; IC del 95%: 0,04 a 3,08) (colecistectomía laparoscópica con minipuertos: 1/226 [proporción ajustada 0,4%] versus colecistectomía laparoscópica estándar: 3/234 [1,3%]; calidad de vida a los diez días después de la cirugía [un ensayo; 70 pacientes; DME -0,20; IC del 95%: -0,68 a 0,27]; ni en los pacientes en los que hubo necesidad de conversión de la cirugía laparoscópica a la colecistectomía abierta [11 ensayos; 670 pacientes; CR 1,23; IC del 95%: 0,44 a 3,45] [colecistectomía laparoscópica con minipuertos: 8/351 [proporción ajustada 2,3%] versus colecistectomía laparoscópica estándar 6/319 [1,9%]). La colecistectomía laparoscópica con minipuertos demoró cinco minutos más para completarse que la colecistectomía laparoscópica estándar (12 ensayos; 695 pacientes; DM -4,91 minutos; IC del 95%: 2,38 a 7,44). No hubo diferencias significativas entre colecistectomía laparoscópica con minipuertos y colecistectomía laparoscópica estándar en la duración de la estancia hospitalaria (seis ensayos; 351 pacientes; DM -0,00 días; IC del 95%: -0,12 a 0,11); el tiempo para regresar a la actividad (un ensayo; 52 pacientes; DM 0,00 días; IC del 95%: -0,31 a 0,31); ni en el tiempo hasta el regreso del paciente al trabajo (dos ensayos; 187 pacientes; DM 0,28 días; IC del 95%: -0,44 a 0,99) entre los grupos. No hubo diferencias significativas en las puntuaciones estéticas a los seis a 12 meses después de la cirugía entre los dos grupos (dos ensayos; 152 pacientes; DME 0,13; IC del 95%: -0,19 a 0,46).

Conclusiones de los autores

La colecistectomía laparoscópica con minipuertos se puede completar con éxito en más del 80% de los pacientes. No existen ventajas de la colecistectomía laparoscópica con minipuertos en cuanto a reducir la mortalidad, la morbilidad, la estancia hospitalaria, el retorno a la actividad, el retorno al trabajo ni en la mejoría estética. Por otro lado, hay un aumento moderado del tiempo quirúrgico después de la colecistectomía laparoscópica con minipuertos en comparación con la colecistectomía laparoscópica con puertos estándar y se debe establecer la seguridad de la colecistectomía laparoscópica con minipuertos. La colecistectomía laparoscópica con minipuertos no se puede recomendar de forma habitual fuera de ensayos clínicos aleatorios bien diseñados. Se necesitan ensayos adicionales con bajo riesgo de sesgo y bajo riesgo de errores aleatorios.

Plain language summary

Mini keyhole operation versus standard keyhole operation for removal of the gallbladder

About 10% to 15% of the adult western population have gallstones. Between 1% and 4% become symptomatic each year. Removal of the gallbladder (cholecystectomy) is the mainstay treatment for symptomatic gallstones. More than half a million cholecystectomies are performed per year in the United States alone. Laparoscopic cholecystectomy (removal of gallbladder through a key-hole, also known as port) is now the preferred method of cholecystectomy. In standard port laparoscopic cholecystectomy, four ports (two of 10 mm diameter and two of 5 mm diameter) are usually used. Recently, use of smaller ports has been reported (miniport laparoscopic cholecystectomy). However, the safety of miniport laparoscopic cholecystectomy and whether it offers any advantages over standard port laparoscopic cholecystectomy is not known. We sought to answer this question by reviewing the medical literature and obtaining information from randomised clinical trials. When conducted well, such studies provide the most accurate information. Two authors searched the literature and obtained information from the studies thereby minimising errors.

We identified 12 randomised clinical trials involving 734 patients that compared miniport laparoscopic cholecystectomy (380) with standard port laparoscopic cholecystectomy (351). The choice of the treatment that the patients received was determined by a method similar to toss of coin so that both treatments were conducted in patients who were as similar as possible. Most of the trials were of high risk of bias, i.e. there is possibility of arriving at wrong conclusions overestimating benefits or underestimating harms because of study design. Miniport laparoscopic cholecystectomy could be completed successfully in more than 80% of patients in most studies. The remaining patients were mostly converted to standard port laparoscopic cholecystectomy but some patients had to undergo open cholecystectomy. These patients were excluded from the analysis by the study authors and so the results of these trials as well as the present systematic review have to be interpreted with extreme caution. There was no mortality in either group in the seven trials that reported mortality (0/226 patients versus 0/234 patients). There were no significant differences between the two operation types in the proportion of patients who developed serious complications, quality of life at 10 days after operation, or in whom the laparoscopic operation had to be converted to open cholecystectomy. Miniport laparoscopic cholecystectomy took five minutes longer to complete than standard port laparoscopic cholecystectomy. There were no significant differences between the two operation types in the length of hospital stay, the time taken to return to activity, or in the time taken to return to work. There was no significant cosmetic difference at six months to 12 months after surgery between the two groups, in the two trials that reported this outcome.

There appears to be no advantage of miniport laparoscopic cholecystectomy in terms of decreasing surgical complications, hospital stay, return to activity, return to work, or improving cosmesis. On the other hand, there is a modest increase in operating time after miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy. The safety of miniport laparoscopic cholecystectomy is yet to be established. Miniport laparoscopic cholecystectomy cannot be recommended routinely outside well-designed randomised clinical trials. Further well-designed randomised clinical trials are necessary to determine whether miniport laparoscopic cholecystectomy is safe and whether there is any advantage over standard port laparoscopic cholecystectomy.

Resumen en términos sencillos

Cirugía con orificios pequeños versus cirugía con orificios estándar para la extracción de la vesícula biliar

Entre el 10% y el 15% de la población occidental adulta presenta cálculos biliares. Entre el 1% y el 4% se tornan sintomáticos al año. La extracción de la vesícula biliar (colecistectomía) es el tratamiento principal para los cálculos biliares sintomáticos. Se realizan más de medio millón de colecistectomías por año en los Estados Unidos únicamente. La colecistectomía laparoscópica (extracción de la vesícula biliar a través de un pequeño orificio, también conocido como puerto) actualmente es el método preferido para realizar la colecistectomía. En la colecistectomía laparoscópica con puertos estándar, habitualmente se utilizan cuatro puertos (dos de 10 mm de diámetro y dos de 5 mm de diámetro). Recientemente, se ha informado el uso de puertos más pequeños (colecistectomía laparoscópica con minipuertos). Sin embargo, se desconoce la seguridad de la colecistectomía laparoscópica con minipuertos y si ofrece algunas ventajas sobre la colecistectomía laparoscópica con puertos estándar. Se trató de responder a esta pregunta mediante la revisión de la literatura médica y la obtención de información a partir de ensayos clínicos aleatorios. Cuando estos ensayos están bien realizados, proporcionan la información más precisa. Dos revisores buscaron en la literatura y obtuvieron información de los estudios, lo que minimizó los errores.

Se identificaron 12 ensayos clínicos aleatorios con 734 pacientes que compararon colecistectomía laparoscópica con minipuertos (380) con colecistectomía laparoscópica con puertos estándar (351). La elección del tratamiento que los pacientes recibieron fue determinada por un método similar a tirar una moneda para que ambos tratamientos se realizaran en pacientes lo más similares posibles. La mayoría de los ensayos tuvo alto riesgo de sesgo, es decir, existe la posibilidad de establecer conclusiones equivocadas que sobrestimen los efectos beneficiosos o subestimen los efectos perjudiciales debido al diseño del estudio. En la mayoría de los estudios, la colecistectomía laparoscópica con minipuertos se pudo completar con éxito en más del 80% de los pacientes. En los pacientes restantes, hubo necesidad de conversión principalmente a colecistectomía laparoscópica con puertos estándar, pero a algunos pacientes hubo que realizarles colecistectomía abierta. Los revisores excluyeron a estos pacientes del análisis, por lo que los resultados de estos ensayos y la presente revisión sistemática tienen que interpretarse con mucho cuidado. No hubo mortalidad en los grupos de los siete ensayos que la informaron (0/226 pacientes versus 0/234 pacientes). No hubo diferencias significativas entre los dos tipos de cirugía en la proporción de pacientes que desarrollaron complicaciones graves, la calidad de vida a los diez días después de la cirugía, ni en los pacientes en los que hubo necesidad de conversión de cirugía laparoscópica a colecistectomía abierta. La colecistectomía laparoscópica con minipuertos demoró cinco minutos más para completarse que la colecistectomía laparoscópica con puertos estándar. No hubo diferencias significativas entre los dos tipos de cirugías en la duración de la estancia hospitalaria, el tiempo hasta retornar a la actividad ni el tiempo hasta retornar al trabajo. No hubo diferencias significativas en la estética a los seis a 12 meses después de la cirugía entre los dos grupos en los dos ensayos que informaron este resultado.

No existen ventajas de la colecistectomía laparoscópica con minipuertos en cuanto a reducir las complicaciones quirúrgicas, la estancia hospitalaria, el retorno a la actividad, el retorno al trabajo ni en la mejoría estética. Por otro lado, hay un aumento moderado en el tiempo quirúrgico después de la colecistectomía laparoscópica con minipuertos en comparación con la colecistectomía laparoscópica con puertos estándar. Se debe establecer la seguridad de la colecistectomía laparoscópica con minipuertos. La colecistectomía laparoscópica con minipuertos no se puede recomendar de forma habitual fuera de ensayos clínicos aleatorios bien diseñados. Se necesitan ensayos clínicos aleatorios bien diseñados adicionales para determinar si la colecistectomía laparoscópica con minipuertos es segura y si existen ventajas sobre la colecistectomía laparoscópica con puertos estándar.

Notas de traducción

La traducción y edición de las revisiones Cochrane han sido realizadas bajo la responsabilidad del Centro Cochrane Iberoamericano, gracias a la suscripción efectuada por el Ministerio de Sanidad, Servicios Sociales e Igualdad del Gobierno español. Si detecta algún problema con la traducción, por favor, contacte con Infoglobal Suport, cochrane@infoglobal-suport.com.

Summary of findings(Explanation)

Summary of findings for the main comparison. Miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy for patients undergoing laparoscopic cholecystectomy
  1. 1 The trial(s) was (were) of high risk of bias.
    2 The confidence intervals overlapped 1 and either 0.75 or 1.25 or both. The number of events in the intervention and control group was fewer than 300.
    3 The confidence intervals overlapped 0 and minimal clinically important difference. The total number of patients in the intervention and control group was fewer than 400.
    4 The minimal clinically important difference for quality of life and cosmesis was considered to be 0.25 standard deviations.
    5 There was moderate heterogeneity as noted by I-square.
    6 The minimal clinically important difference for hospital stay, return to normal activity and return to work was considered to be one day.

Miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy for patients undergoing laparoscopic cholecystectomy
Patient or population: patients undergoing laparoscopic cholecystectomy.
Settings: secondary care.
Intervention: miniport laparoscopic cholecystectomy.
Comparison: standard port laparoscopic cholecystectomy.
OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No of participants
(studies)
Quality of the evidence
(GRADE)
Assumed riskCorresponding risk
Standard port laparoscopic cholecystectomy Miniport laparoscopic cholecystectomy
Serious adverse events 13 per 1000 4 per 1000
(1 to 39)
RR 0.33
(0.04 to 3.08)
460
(8 studies)
⊕⊝⊝⊝
very low 1,2
Quality of life The mean quality of life in the intervention groups was
0.2 standard deviations lower
(0.68 lower to 0.27 higher)
 69
(1 study)
⊕⊕⊝⊝
low 3,4
Conversion to open cholecystectomy 19 per 1000 23 per 1000
(8 to 65)
RR 1.23
(0.44 to 3.45)
670
(11 studies)
⊕⊝⊝⊝
very low 1,2
Operating timeThe mean operating time in the control groups was
55 minutes
The mean operating time in the intervention groups was
4.91 higher
(2.38 to 7.44 higher)
 695
(12 studies)
⊕⊝⊝⊝
very low 1,5
Hospital stayThe mean hospital stay in the control groups was
3 days
The mean hospital stay in the intervention groups was
0 higher
(0.12 lower to 0.11 higher)
 351
(6 studies)
⊕⊕⊝⊝
low 1,6
Return to activityThe mean return to activity in the control groups was
3 days
The mean return to activity in the intervention groups was
0 higher
(0.31 lower to 0.31 higher)
 52
(1 study)
⊕⊕⊝⊝
low 1,6
Return to workThe mean return to work ranged across control groups from
5 to 10 days
The mean return to work in the intervention groups was
0.28 higher
(0.44 lower to 0.99 higher)
 187
(2 studies)
⊕⊕⊝⊝
low 1,6
Cosmesis The mean cosmesis in the intervention groups was
0.13 standard deviations higher
(0.19 lower to 0.46 higher)
 152
(2 studies)
⊕⊝⊝⊝
very low 1,3,4
*The basis for the assumed risk is the mean control group risk across studies. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio;
GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

Background

Description of the condition

About 10% to 15% of the adult western population have gallstones (Jørgensen 1987; NIH 1992; Muhrbeck 1995; Halldestam 2004). Between 1% and 4% become symptomatic in a year (NIH 1992; Halldestam 2004). More than half a million cholecystectomies are performed per year in the United States alone (NIH 1992). Regional differences exist in the cholecystectomy rates (Mjäland 1998). Laparoscopic cholecystectomy (removal of gallbladder through a key-hole, also known as 'port'), which was introduced in 1987, is now the preferred method of cholecystectomy (NIH 1992; Fullarton 1994; Bakken 2004; Livingston 2004; Keus 2006; David 2008).

Description of the intervention

In standard port laparoscopic cholecystectomy, four ports (two of 10 mm diameter and two of 5 mm diameter) are usually used (Alponat 2002; Bisgaard 2002). Use of smaller ports ('miniports' defined as one or more ports smaller than the standard ports used) has been suggested as an alternative to standard port laparoscopic cholecystectomy (Alponat 2002; Ainslie 2003).

How the intervention might work

The potential advantages of the smaller ports include decreased pain (Bisgaard 2002) and improved cosmesis (Hosono 2007) because of the smaller incisions used for the operation. The smaller ports may also make the operation more complicated, giving rise to more operations with complications and more operations that have to be turned into open operations.

Why it is important to do this review

There is no uniform agreement among surgeons regarding the utility of miniport laparoscopic cholecystectomy. In addition, there have been questions about the safety of miniport laparoscopic cholecystectomy (Gurusamy 2010). With increasing pressure on the surgeons to perform the latest techniques, it is important to have up-to-date information on the safety and effectiveness of the procedure to implement effective procedures and to avoid litigations when the safety has not been established. This is an update of the previous Cochrane review (Gurusamy 2010) and includes revisions of the outcomes into outcomes that are important to patients and healthcare funders.

Objectives

To assess the benefits and harms of miniport laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy.

Methods

Criteria for considering studies for this review

Types of studies

We included only randomised clinical trials irrespective of language, blinding, or publication status.

We excluded quasi-randomised studies (where the method of allocating participants to a treatment are not strictly random (e.g., date of birth, hospital record number, alternation), cohort studies, and case-control studies because of the selection bias in such studies. The patients who are generally considered easy to operate would have been operated by miniport laparoscopic cholecystectomy and patients who would have been considered difficult to operate would have undergone standard port laparoscopic cholecystectomy. Besides, patients in whom the surgery was started as miniport laparoscopic cholecystectomy and converted to standard port laparoscopic cholecystectomy would either have been excluded (as we found was the case in even randomised clinical trials in the previous version of this review) (Gurusamy 2010) or would have been included in standard port laparoscopic cholecystectomy making any such comparisons in non-randomised studies meaningless or misleading. However, we recorded any rare harms attributed to miniport laparoscopic cholecystectomy in such non-randomised studies.

Types of participants

Patients undergoing laparoscopic cholecystectomy for any indication such as symptomatic gallstones, gallbladder polyps, or gallbladder dyskinesia.

Types of interventions

We included trials comparing miniport laparoscopic cholecystectomy (defined as one or more ports smaller than the standard ports used) versus standard port laparoscopic cholecystectomy (laparoscopic cholecystectomy with two 10 mm ports and two 5 mm ports). We excluded trials that did not use the above definition of standard port laparoscopic cholecystectomy.

Types of outcome measures

Primary outcomes
  1. Mortality.

  2. Serious adverse events defined as any event that would increase mortality, is life-threatening, requires inpatient hospitalisation, results in a persistent or significant disability, or any important medical event that might have jeopardised the patient or required intervention to prevent it (ICH-GCP 1997). Complications such as bile duct injury, re-operations, intra-abdominal collections requiring drainage (radiological or surgical), infected intra-abdominal collections, bile leaks requiring drainage, stent, or surgery were classified as serious adverse events. Complications such as wound infections, bile leaks, or abdominal collections that did not require any treatment and settle spontaneously were not considered serious adverse events.

  3. Patient quality of life (however defined by authors).

Secondary outcomes
  1. Conversion to open cholecystectomy.

  2. Operating time.

  3. Hospital stay (length of hospital stay, proportion discharged as day-case laparoscopic cholecystectomy).

  4. Return to activity.

  5. Return to work.

  6. Cosmesis (however defined by authors but at least six months after surgery).

We have reported all the outcomes with at least one trial in the Summary of findings for the main comparison.

Search methods for identification of studies

Electronic searches

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded (Royle 2003), and the World Health Organization International Clinical Trials Registry Platform portal (WHO ICTRP) (http://apps.who.int/trialsearch/) until February 2013. The WHO ICTRP portal allows search of various trial registers including clinicaltrials.gov and ISRCTN among other registers. We have given the search strategies in Appendix 1 with the time span for the searches.

Searching other resources

We also searched the references of the identified trials to identify further relevant trials.

Data collection and analysis

We performed the systematic review according to the recommendations of The Cochrane Collaboration (Higgins 2011) and the Cochrane Hepato-Biliary Group Module (Gluud 2013).

Selection of studies

Review authors KG and JV identified the trials for inclusion independently of each other. KG and JV also listed the excluded trials with the reasons for the exclusion. Any differences in opinion were resolved through discussion.

Data extraction and management

KG and JV extracted the following data independently.

  1. Year and language of publication.

  2. Country.

  3. Year of study.

  4. Inclusion and exclusion criteria.

  5. Sample size.

  6. Size and number of the ports in each group.

  7. Proportion of patients who underwent successful miniport laparoscopic cholecystectomy.

  8. Intra-operative cholangiogram.

  9. Outcomes (mentioned above).

  10. Risk of bias (described below).

We sought any unclear or missing information by contacting the authors of the individual trials. If there was any doubt whether the trials shared the same patients - completely or partially (by identifying common authors and centres) - we planned to contact the authors of the trials to clarify whether the trial report had been duplicated. We resolved any differences in opinion through discussion.

Assessment of risk of bias in included studies

We followed the instructions given in the Cochrane Handbook for Systematic Reviews of Intervention (Higgins 2011) and the Cochrane Hepato-Biliary Group Module (Gluud 2013). According to empirical evidence (Schulz 1995; Moher 1998; Kjaergard 2001; Wood 2008; Lundh 2012; Savović 2012a; Savović 2012b), the risk of bias of the trials were assessed based on the following bias risk domains.

Sequence generation
  • Low risk of bias (the methods used was either adequate (e.g., computer-generated random numbers, table of random numbers) or unlikely to introduce confounding).

  • Uncertain risk of bias (there was insufficient information to assess whether the method used was likely to introduce confounding).

  • High risk of bias (the method used (e.g., quasi-randomised studies) was improper and likely to introduce confounding).

Allocation concealment
  • Low risk of bias (the method used (e.g., central allocation) was unlikely to induce bias on the final observed effect).

  • Uncertain risk of bias (there was insufficient information to assess whether the method used was likely to induce bias on the estimate of effect).

  • High risk of bias (the method used (e.g., open random allocation schedule) was likely to induce bias on the final observed effect).

Blinding of participants, personnel, and outcome assessors

It is impossible to blind the surgeons who performed the surgery. However, by the use of a second surgical team, it is possible to determine whether a patient needs conversion to open cholecystectomy or whether the patient can be discharged from hospital - i.e., the performance bias can be reduced by using a second surgical team to determine patient care.

  • Low risk of bias (blinding was performed adequately, or the outcome measurement was not likely to be influenced by lack of blinding).

  • Uncertain risk of bias (there was insufficient information to assess whether the type of blinding used was likely to induce bias on the estimate of effect).

  • High risk of bias (no blinding or incomplete blinding, and the outcome or the outcome measurement was likely to be influenced by lack of blinding).

Incomplete outcome data
  • Low risk of bias (the underlying reasons for missingness were unlikely to make treatment effects departure from plausible values, or proper methods were employed to handle missing data).

  • Uncertain risk of bias (there was insufficient information to assess whether the missing data mechanism in combination with the method used to handle missing data was likely to induce bias on the estimate of effect).

  • High risk of bias (the crude estimate of effects (e.g., complete case estimate) was clearly biased due to the underlying reasons for missingness, and the methods used to handle missing data were unsatisfactory).

Selective outcome reporting
  • Low risk of bias (the trial protocol was available and all of the trial's pre-specified outcomes that are of interest in the review were reported or similar; if the trial protocol was not available, mortality and morbidity were reported).

  • Uncertain risk of bias (there was insufficient information to assess whether the magnitude and direction of the observed effect was related to selective outcome reporting).

  • High risk of bias (not all of the trial's pre-specified primary outcomes were reported or similar).

Vested interest bias
  • Low risk of bias (the trial was not performed or supported by any parties that might have conflicting interest, e.g., instrument manufacturer).

  • Uncertain risk of bias (any conflicts of interest of the trialist or trial funder was not clear).

  • High risk of bias (the trial was performed or supported by any parties that might have conflicting interest, e.g., instrument manufacturer).

We classified trials at low risk of bias in all domains as those of low risk of bias. In all the remaining cases, the trials were classified as trials with high risk of bias.

Measures of treatment effect

For binary outcomes, we calculated the risk ratio (RR) with 95% confidence interval (CI). Risk ratio calculations do not include trials in which no events occurred in either group, whereas risk difference (RD) calculations do. We planned to report the RD if the conclusions using this association measure were different from RR. For continuous outcomes, we calculated the mean difference (MD) with 95% CI for outcomes such as operating time and hospital stay and the standardised mean difference (SMD) with 95% CI for quality of life (where different scales were used).

Unit of analysis issues

The unit of analysis were patients undergoing miniport laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy.

Dealing with missing data

We sought any unclear or missing information by contacting the authors of the individual trials. We performed an intention-to-treat analysis (Newell 1992) whenever possible. We planned to impute data for binary outcomes using various scenarios such as best-best scenario, worst-worst scenario, best-worst scenario, and worst-best scenario (Gurusamy 2009; Gluud 2013).

For continuous outcomes, we used available-case analysis. We imputed the standard deviation from P values according to the instructions given in the Cochrane Handbook for Systematic Reviews of Intervention (Higgins 2011), and used the median for the meta-analysis when the mean was not available. If it was not possible to calculate the standard deviation from the P value or the confidence intervals, we imputed the standard deviation as the highest standard deviation in the other trials included under that outcome, fully recognising that this form of imputation will decrease the weight of the study for calculation of mean differences and bias the effect estimate to no effect in case of the SMD (Higgins 2011).

Assessment of heterogeneity

We explored heterogeneity by Chi2 with significance set at P value 0.10, and measured the quantity of heterogeneity by I2 (Higgins 2002). We also used overlapping of confidence intervals on the forest plot to determine heterogeneity.

Assessment of reporting biases

We used visual asymmetry on a funnel plot to explore reporting bias and other bias as we have identified 12 trials (Egger 1997; Macaskill 2001). We also performed linear regression approach described by Egger 1997 to determine the funnel plot asymmetry.

Data synthesis

We performed the meta-analyses using the software package Review Manager 5 (RevMan 2012) and following the recommendations of The Cochrane Collaboration (Higgins 2011) and the Cochrane Hepato-Biliary Group Module (Gluud 2013). We used both random-effects model (DerSimonian 1986) and fixed-effect model (DeMets 1987) meta-analyses. In case of discrepancy between the two models resulting in change of significance, we reported both results; otherwise, we reported the results of the fixed-effect model.

Trial sequential analysis

We used the trial sequential analysis to control for random errors due to sparse data and repetitive testing of the accumulating data for the primary outcomes (CTU 2011; Thorlund 2011). We added the trials according to the year of publication, and if more than one trial was published in a year, add the trials in alphabetical order according to the last name of the first author. We planned to construct the trial sequential monitoring boundaries on the basis of the required information size (Brok 2008; Wetterslev 2008; Brok 2009; Thorlund 2009, Wetterslev 2009; Thorlund 2010).   

We applied trial sequential analysis (CTU 2011; Thorlund 2011) using a required sample size calculated from an alpha error of 0.05, a beta error of 0.20, a control group proportion obtained from the results, and a relative risk reduction of 20% for binary outcomes with two or more trials to determine whether more trials are necessary on this topic (if the trial sequential monitoring boundary and the required information size is reached or the futility zone is crossed, then more trials are unnecessary) (Brok 2008; Wetterslev 2008; Brok 2009; Thorlund 2009, Wetterslev 2009; Thorlund 2010). For quality of life, we planned to calculate the required sample size from an alpha error of 0.05, a beta error of 0.20, and based on the variance being estimated from the meta-analysis results of low risk of bias trials, and a minimal clinically relevant difference of 0.25. For operating time, the required sample size was calculated from an alpha error of 0.05, a beta error of 0.20, the variance estimated from the meta-analysis results of low risk of bias trials, and a minimal clinically relevant difference of 15 minutes. For hospital stay and return to work, the required sample size was calculated from an alpha error of 0.05, a beta error of 0.20, the variance estimated from the meta-analysis results of low risk of bias trials, and a minimal clinically relevant difference of one day. We also planned trial sequential analysis for return to activity on the same basis as hospital stay and return to work.

Subgroup analysis and investigation of heterogeneity

We planned to perform the following subgroup analyses.

  • Trials with high-risk of bias compared to trials with low-risk of bias.

  • Elective cholecystectomy compared with emergency cholecystectomy.

  • Different sizes of ports of mini-laparoscopic cholecystectomy.

Of these, we performed only the last subgroup analysis because of the reasons stated in the results section. We used the Chi2 test to identify subgroup differences.

Sensitivity analysis

We performed a sensitivity analysis by imputing data for binary outcomes using various scenarios such as best-best scenario, worst-worst scenario, best-worst scenario, and worst-best scenario in the presence of missing outcome data (Gurusamy 2009; Gluud 2013). We performed a sensitivity analysis by excluding the trials in which the mean and the standard deviation were imputed.

Results

Description of studies

Results of the search

We identified a total of 152 references through electronic searches of The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (n = 19), MEDLINE (n = 33), EMBASE (n = 69), Science Citation Index Expanded (n = 30), and WHO ICTRP (n = 1). We excluded 57 duplicates and 73 clearly irrelevant references through reading abstracts. Twenty-two references were retrieved for further assessment. No references were identified through scanning reference lists of the identified randomised trials. We excluded nine references for the reasons listed under the table 'Characteristics of excluded studies'. Thirteen references of twelve randomised trials involving 735 patients fulfilled the inclusion criteria. The reference flow is shown in Figure 1. All 12 trials were completed trials and could provide data for the analyses. Details about the sample size, patient characteristics; the inclusion and exclusion criteria used in the trials; rate of successful completion of miniport laparoscopic cholecystectomy; details about whether intra-operative cholangiogram was performed; outcomes reported in the trials, and the risk of bias in the trials are shown in the table 'Characteristics of included studies'.

Figure 1.

Study flow diagram.

Included studies

A total of 734 participants who underwent elective laparoscopic cholecystectomy were randomised in 12 trials to miniport laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy. The number of participants in each trial ranged from 21 to 135. Patients undergoing laparoscopic cholecystectomy were randomised to miniport (n = 380) and standard port (n = 351) laparoscopic cholecystectomy. The average age of patients included in the trials ranged from 40 years to 55 years. The proportion of women included in the trials varied between 26% and 85%. Further details of sex ratio, mean age of participants, post-randomisation drop-outs, and the reasons for post-randomisation drop-outs can be found in the table 'Characteristics of included studies'.

In one trial, three groups were used - one standard port laparoscopic cholecystectomy and two groups of varying sizes of miniport laparoscopic cholecystectomy (Huang 2003). The results of the two methods of miniport laparoscopic cholecystectomy were pooled for the main comparison of miniport laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy. In the remaining trials, there were two intervention groups, i.e., miniport laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy.

In 10 trials, at least two ports were 3 mm or smaller (Bisgaard 2000; Schwenk 2000; Alponat 2002; Schmidt 2002; Hsieh 2003; Huang 2003; Sarli 2003; Novitsky 2005; de Carvalho 2013; Saad 2013). In the remaining two trials, at least three ports were larger than 3 mm (Bisgaard 2002; Abbas 2009).

In one trial, one 12 mm port, one 10 mm port, and two 5 mm ports were used as standard operation (Sarli 2003). In the remaining trials, two 10 mm ports and two 5 mm ports were used as control (Bisgaard 2000; Schwenk 2000; Alponat 2002; Bisgaard 2002; Schmidt 2002; Hsieh 2003; Huang 2003; Novitsky 2005; Abbas 2009; de Carvalho 2013; Saad 2013).

In one trial (Hsieh 2003), laparoscopic cholecystectomy was performed during acute cholecystitis. In one trial, it was not clear whether the laparoscopic cholecystectomy was performed during acute cholecystitis (Abbas 2009). In the remaining trials, laparoscopic cholecystectomy was assessed in only elective cholecystectomy (Bisgaard 2000; Schwenk 2000; Alponat 2002; Bisgaard 2002; Schmidt 2002 Huang 2003; Sarli 2003; Novitsky 2005; de Carvalho 2013; Saad 2013).

The indication for laparoscopic cholecystectomy was symptomatic gallstones in nine trials (Bisgaard 2000; Schwenk 2000; Bisgaard 2002; Sarli 2003; Huang 2003; Hsieh 2003; Abbas 2009; de Carvalho 2013; Saad 2013). The reason for laparoscopic cholecystectomy was not clearly stated in the remaining three trials (Alponat 2002; Schmidt 2002; Novitsky 2005).

Risk of bias in included studies

The risk of bias in the included trials is summarised in Figure 2 and Figure 3. Only one trial was of low risk of bias (Saad 2013). The remaining trials were of high risk of bias (Bisgaard 2000; Schwenk 2000; Alponat 2002; Bisgaard 2002; Schmidt 2002; Hsieh 2003; Huang 2003; Sarli 2003; Novitsky 2005; Abbas 2009; de Carvalho 2013).

Figure 2.

Methodological quality graph: review authors' judgements about each methodological quality item presented as percentages across all included studies.

Figure 3.

Methodological quality summary: review authors' judgements about each methodological quality item for each included study.

Miniport laparoscopic cholecystectomy could be completed successfully in more than 80% of patients in most of the trials. The remaining patients were mostly converted to standard port laparoscopic cholecystectomy but some were also converted to open cholecystectomy. These patients were included for the outcome conversion to open cholecystectomy but excluded from other outcomes as this information was not available from the trials. The trials did not report the other outcomes for patients who required conversion to open cholecystectomy in the standard port laparoscopic cholecystectomy. Therefore, the results of the other outcomes are on 343 patients in miniport laparoscopic cholecystectomy group and 351 patients in standard port laparoscopic cholecystectomy group and so the results have to interpreted with extreme caution.

Effects of interventions

See: Summary of findings for the main comparison Miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy for patients undergoing laparoscopic cholecystectomy

Miniport laparoscopic cholecystectomy was successful in between 61.5% and 100% of the patients who were randomised to miniport laparoscopic cholecystectomy in the 10 trials in which it was possible to calculate this (Bisgaard 2000; Schwenk 2000; Alponat 2002; Bisgaard 2002; Huang 2003; Sarli 2003; Novitsky 2005; Abbas 2009; de Carvalho 2013; Saad 2013). The remaining patients were mostly converted to standard port laparoscopic cholecystectomy, but some were also converted to open cholecystectomy. Further information about these patients who underwent conversion to open cholecystectomy was not available in most trials. Therefore, these patients were included only for the outcome 'conversion to open cholecystectomy' and not for any of the other outcomes. Most trials also excluded patients who were converted to standard port laparoscopic cholecystectomy for most of the other outcomes. Thus, we had to use 'per-protocol' analysis for most comparisons. The findings are summarised in the Summary of findings for the main comparison.

Primary outcomes

Mortality

Seven trials reported on this outcome (Bisgaard 2000; Alponat 2002; Hsieh 2003; Sarli 2003; Abbas 2009; de Carvalho 2013; Saad 2013). There was no mortality in either group in these seven trials (194 patients in miniport laparoscopic cholecystectomy group and 203 patients in standard port laparoscopic cholecystectomy group). Since there was no mortality in either group, we were unable to use the control group proportion for the calculation of the required information size of the trial sequential analysis. Instead, we used a proportion of 0.2% in the control group based on data from approximately 30,000 patients included in a database in Switzerland (Giger 2011). The proportion of information accrued was only 0.11% of the diversity-adjusted required information size and so the trial sequential monitoring boundaries were not drawn (Figure 4).

Figure 4.

Trial sequential analysis of mortality
The diversity-adjusted required information size (DARIS) was calculated to 352,564 patients, based on the proportion of patients in the control group with the outcome of 0.2%, a relative risk reduction of 20%, an alpha of 5%, a beta of 20%, and a diversity of 0%. To account for zero event groups, a continuity correction of 0.01 was used in the calculation of the cumulative Z-curve (blue line). After accruing a total of 397 patients in seven trials, only 0.12% of the DARIS has been reached. Accordingly, the trial sequential analysis does not show the required information size and the trial sequential monitoring boundaries. As shown, the conventional boundaries have also not been crossed by the cumulative Z-curve.

Surgical morbidity (serious adverse events)

Serious adverse events were reported in eight trials (Schwenk 2000; Bisgaard 2000; Schmidt 2002; Alponat 2002; Hsieh 2003; Sarli 2003; de Carvalho 2013; Saad 2013). There were serious adverse events in only one trial (Sarli 2003). There were no serious adverse events in either group in the remaining seven trials (Schwenk 2000; Bisgaard 2000; Schmidt 2002; Alponat 2002; Hsieh 2003; de Carvalho 2013; Saad 2013). However, it must be noted that one cannot be sure that there were no serious advents in four of these seven trials as the authors did not report the serious adverse events adequately to be sure about the absence of serious adverse events (Schwenk 2000; Schmidt 2002; Alponat 2002; Hsieh 2003). Overall, there was no significant difference in the proportion of patients who developed serious adverse events between the groups (risk ratio (RR) 0.33; 95% confidence interval (CI) 0.04 to 3.08) (Analysis 1.1). There was no change in conclusions by calculating the risk difference. Trial sequential analysis revealed that the proportion of information accrued was only 0.87% of the diversity-adjusted required information size and so the trial sequential monitoring boundaries were not drawn (Figure 5).

Figure 5.

Trial sequential analysis of serious adverse events
The diversity-adjusted required information size (DARIS) was calculated to 52,796 patients, based on the proportion of patients in the control group with the outcome of 1.28%, a relative risk reduction of 20%, an alpha of 5%, a beta of 20%, and a diversity of 0%. To account for zero event groups, a continuity correction of 0.01 was used in the calculation of the cumulative Z-curve (blue line). After accruing a total of 460 patients in eight trials, only 0.87% of the DARIS has been reached. Accordingly, the trial sequential analysis does not show the required information size and the trial sequential monitoring boundaries. As shown, the conventional boundaries have also not been crossed by the cumulative Z-curve.

Imputation of patients with missing outcome data by various scenarios did not alter the conclusions for best-best scenario, worst-worst scenario, and best-worst scenarios (Analysis 2.1). However, the worst-best scenario resulted in a significantly higher proportion of patients who developed serious adverse events in the miniport laparoscopic cholecystectomy group compared with the standard port laparoscopic cholecystectomy group (RR 3.31; 95% CI 1.18 to 9.29) (Analysis 2.1), demonstrating the potential impact of post-randomisation drop-outs on serious adverse events.

Quality of life

Only one trial reported this outcome (Saad 2013). There was no significant difference in the quality of life at 10 days after surgery using the gastrointestinal quality of life index (GIQLI) scale (standardised mean difference (SMD) -0.20; 95% CI -0.68 to 0.27) (Analysis 1.2). Trial sequential analysis was not performed since there was only one trial that reported quality of life.

Secondary outcomes

Conversion to open cholecystectomy

Eleven trials reported conversion to open cholecystectomy (Bisgaard 2000; Alponat 2002; Bisgaard 2002; Schmidt 2002; Hsieh 2003; Huang 2003; Sarli 2003; Novitsky 2005; Abbas 2009; Saad 2013; de Carvalho 2013). There was no significant difference in the proportion of patients in whom the laparoscopic operation had to be converted to open cholecystectomy (RR 1.23; 95% CI 0.44 to 3.45) (Analysis 1.3). Using the random-effects model or risk difference did not alter the conclusion. Although most of the excluded patients could be included for conversion to open cholecystectomy as the trials reported this information, one of the trials did not report the outcome of excluded patients (Novitsky 2005). Imputation of patients with missing outcome data by various scenarios did not alter the conclusion for best-best scenario, worst-worst scenario, and best-worst scenarios (Analysis 2.2). However, the worst-best scenario resulted in a significantly higher proportion of patients who had to undergo conversion to open cholecystectomy in the miniport group compared with the standard port laparoscopic cholecystectomy group (RR 3.23; 95% CI 1.39 to 7.50) (Analysis 2.2), demonstrating the potential impact of post-randomisation drop-outs on conversion to open cholecystectomy. The trial sequential analysis revealed that the proportion of information accrued was only 0.87% of the diversity-adjusted required information size and so the trial sequential monitoring boundaries were not drawn (Figure 6).

Figure 6.

Trial sequential analysis of conversion to open cholecystectomy
The diversity-adjusted required information size (DARIS) was calculated to 36,124 patients, based on the proportion of patients in the control group with the outcome of 1.88%, a relative risk reduction of 20%, an alpha of 5%, a beta of 20%, and a diversity of 0%. To account for zero event groups, a continuity correction of 0.01 was used in the calculation of the cumulative Z-curve (blue line). After accruing a total of 670 patients in 11 trials, only 1.85% of the DARIS has been reached. Accordingly, the trial sequential analysis does not show the required information size and the trial sequential monitoring boundaries. As shown, the conventional boundaries have also not been crossed by the cumulative Z-curve.

Operating time

All the trials reported this outcome. The miniport laparoscopic cholecystectomy took five minutes longer to complete (mean difference (MD) 4.91 minutes; 95% CI 2.38 to 7.44) (Analysis 1.4). Using the random-effects model showed no alteration in results. Either the mean or the standard deviation or both were imputed in seven trials (Bisgaard 2000; Schwenk 2000; Bisgaard 2002; Schmidt 2002 Huang 2003; Sarli 2003; Abbas 2009). Excluding these seven trials did not alter the results (MD 4.91 minutes; 95% CI 1.37 to 8.45) (Analysis 2.3). The trial sequential analysis showed that the trial sequential monitoring boundary favouring standard laparoscopic cholecystectomy was crossed by the cumulative Z-curve (Figure 7), suggesting that new trials are unlikely to dispute the finding that the operating time is significantly longer in the miniport laparoscopic cholecystectomy group compared with the standard laparoscopic cholecystectomy group.

Figure 7.

Trial sequential analysis of operating time
Trial sequential analysis of operating time showing that the accumulative Z-curve crosses the trial sequential monitoring boundary after the fourth trial. The diversity-adjusted required information size (DARIS) was 189 participants based on a minimal relevant difference (MIRD) of 15 minutes, a variance (VAR) of 509.29, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 61.91%. The results are compatible with significantly higher operating time in the miniport laparoscopic cholecystectomy group compared with standard laparoscopic cholecystectomy group without risk of random errors.

Hospital stay

Six trials reported this outcome (Bisgaard 2002; Schmidt 2002; Hsieh 2003; Huang 2003; de Carvalho 2013; Saad 2013). There was no significant difference in the hospital stay between the groups (MD -0.00 days; 95% CI -0.12 to 0.11) (Analysis 1.5). Using the random-effects model showed no alteration in results. Either the mean or the standard deviation or both were imputed in four trials (Bisgaard 2002; Schmidt 2002; Huang 2003; de Carvalho 2013). Exclusion of these four trials did not alter the results (MD 0.00 days; 95% CI -0.12 to 0.12) (Analysis 2.4). The trial sequential analysis showed that the trial sequential monitoring boundaries could not be drawn since the information fraction from the first trial was greater than 100% (Figure 8). So, we performed a post hoc trial sequential analysis with a minimal clinically relevant difference of 0.2 days. The cumulative Z-curve does not cross the conventional statistical boundaries and lies in the futility area (Figure 9) suggesting that it is unlikely that future trials are unlikely to detect a difference in hospital stay as small as 0.2 days between miniport laparoscopic cholecystectomy and standard laparoscopic cholecystectomy irrespective of the sample size. Although a difference of 0.2 days is not clinically significant, this analysis demonstrates that a clinically relevant difference of one day is even more unlikely to be demonstrated in future trials irrespective of sample size.

Figure 8.

Trial sequential analysis of length of hospital stay
The diversity-adjusted required information size (DARIS) was 20 participants based on a minimal relevant difference (MIRD) of 1 day, a variance (VAR) of 0.61 (we used the variance from all the trials rather than the variance of low bias-risk trial since the variance from the low bias risk trial was 0.13 which will further reduce the required sample size), an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 0%. Trial sequential boundaries were not drawn since the information fraction exceeded the required sample size after one trial. The Z-curve does not cross the conventional boundary suggesting that there is no significant difference in the length of hospital between miniport laparoscopic cholecystectomy and standard laparoscopic cholecystectomy.

Figure 9.

Trial sequential analysis of length of hospital stay (post hoc analysis)
The diversity-adjusted required information size (DARIS) was 479 participants based on a minimal relevant difference (MIRD) of 0.2 days, a variance (VAR) of 0.61, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 0%. This was a post hoc decision.After accruing 351 participants in six trials, the cumulative Z-curve (blue line) lies in the futility area. The conventional statistical boundaries were not crossed by the cumulative Z-curve. This suggests that future trials are unlikely to detect a difference as small as 0.2 days in the length of hospital between miniport laparoscopic cholecystectomy and standard laparoscopic cholecystectomy irrespective of the sample size in those trials.

None of the trials reported on the number of patients eligible to be discharged as day-surgery laparoscopic cholecystectomy.

Return to activity and work

One trial reported the time taken to return to activity (Bisgaard 2002). There was no significant difference in the time taken to return to activity between the two groups (MD 0.00 days; 95% CI -0.31 to 0.31) (Analysis 1.6). Since this was the only trial, the issues of fixed-effect versus random-effects meta-analysis or sensitivity analyses do not arise although the standard deviation was imputed. Trial sequential analysis was not performed since there was only one trial.

Two trials reported the time taken to return to work (Bisgaard 2002; Sarli 2003). There was no significant difference in the time taken to return to work between the groups (MD 0.28 days; 95% CI -0.44 to 0.99) (Analysis 1.7). Using the random-effects model showed no alteration in results. Either the mean or the standard deviation or both were imputed in both the trials and so a sensitivity analysis was not performed. Trial sequential analysis revealed that the information from was too small (27.91%) to draw the futility area and the trial sequential boundaries for benefits or harms of miniports were not crossed (Figure 10).

Figure 10.

Trial sequential analysis of return to work
The diversity-adjusted required information size (DARIS) was calculated to 670 patients, based on on a minimal relevant difference (MIRD) of 1 day, a variance (VAR) of 12.51, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 41.35%. After accruing 187 patients in two trials, only 27.91% of the DARIS has been reached. Accordingly, the futility area was not drawn. Neither the conventional statistical boundaries nor the trial sequential monitoring boundaries for benefits or harms of miniports versus standard ports were crossed by the cumulative Z-curve (blue line).

Cosmesis

Two trials reported this outcome (Huang 2003; Saad 2013). In one trial, the cosmesis was reported at six months after surgery (Huang 2003) and in the other trial, it was reported one year after the surgery (Saad 2013). Although the second trial reported the cosmesis at six months after surgery also, we obtained the values at one year since wound remodelling may last even for a year (Gurtner 2008). There was no significant difference in the cosmesis scores between the two groups (SMD 0.13; 95% CI -0.19 to 0.46) (Analysis 1.8). Using the random-effects model showed no alteration in results. The mean and standard deviation were imputed in one trial (Huang 2003). Excluding this trial did not show alteration in the results (SMD 0.29; 95% CI -0.19 to 0.77) (Analysis 2.5).

Subgroup analysis

Two planned subgroup analyses (trials with high-risk of bias compared to trials with low-risk of bias) and (elective cholecystectomy compared to emergency cholecystectomy) were not performed because one of the subgroups had only one trial (only one trial was of low risk of bias (Saad 2013) and only one trial included patients with acute cholecystitis (Hsieh 2003)). Such subgroup analyses are prone to errors.

We performed a subgroup analysis based on the size of the port. We compared whether the results were different between the trials that used less than 3 mm port for at least two of the ports versus those that did not use less than 3 mm port for at least two ports. The only outcome with sufficient trials to allow a subgroup analysis was operating time. The Chi2 test for subgroup differences was not statistically significant (P = 0.27).

Funnel plot

Visual inspection of the funnel plot did not reveal any bias for conversion to open cholecystectomy (Figure 11) and operating time (Figure 12), the only outcomes with 10 or more trials. Although 11 trials were included for the outcome 'conversion to open cholecystectomy', eight trials (Bisgaard 2000; Alponat 2002; Schmidt 2002; Huang 2003; Novitsky 2005; Abbas 2009; de Carvalho 2013; Saad 2013) did not have any events (conversion to open cholecystectomy) in either group and so were not included in the funnel plot. Thus, this funnel plot has to be interpreted with caution. Egger's linear regression analysis could not be performed for conversion to open cholecystectomy because of the few trials with data. Egger's linear regression analysis was not statistically significant for operating time (P = 0.39).

Figure 11.

Funnel plot of comparison: 1. Miniport laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy, outcome: 1.6 Conversion to open cholecystectomy. Five trials did not have any event (conversion to open cholecystectomy) in any of the groups and were not included in this funnel plot. So, this funnel plot has to be interpreted with caution.

Figure 12.

Funnel plot of comparison: 1 Miniport laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy, outcome: 1.4 Operating time [minutes].

Discussion

Summary of main results

This meta-analysis has shown that there is no evidence of any benefit from miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy. The proportion of patients with successful operations was more than 80% in most of the trials in the miniport laparoscopic cholecystectomy group. Most of the patients not completing miniport laparoscopic cholecystectomy underwent standard port laparoscopic cholecystectomy. However, some patients underwent conversion to open cholecystectomy. Further information about the patients who underwent conversion to open cholecystectomy was not available in most trials. Most trials did not report morbidity adequately, even in patients who completed miniport laparoscopic cholecystectomy successfully. As a result of this, the potential for bias due to incomplete outcome data (lack of intention-to-treat analysis) and selective outcome reporting bias is very high, and we were accordingly unable to determine the safety of miniport laparoscopic cholecystectomy. We did not identify any specific harm attributable to miniport laparoscopic cholecystectomy from any of the excluded studies identified.

The safety of the procedure should take precedence over any measures of effectiveness in recommending miniport laparoscopic cholecystectomy because of the availability of a very effective method of removal of gallbladder, i.e., standard port laparoscopic cholecystectomy. Because of this reason, miniport laparoscopic cholecystectomy should be confined to appropriately designed randomised clinical trials, which assess the safety and effectiveness of miniport laparoscopic cholecystectomy. Alternatively, an informed consent from the patients explaining that they are willing to undergo a potentially unsafe procedure in spite of the availability of a safe and effective alternative, i.e., standard port laparoscopic cholecystectomy, should be obtained.

While it is appropriate to perform a sensitivity analysis of including and excluding patients who were converted to open cholecystectomy, it is inappropriate to exclude the conversions from miniport to standard port laparoscopic cholecystectomy. By excluding these patients from cosmesis and operating time, the impact of conversion from miniport to standard port laparoscopic cholecystectomy on these outcomes cannot be assessed. Thus, in this review, it is not possible to assess the miniport technology adequately due to insufficient reporting in the trials. Our results are only applicable to patients who underwent successful completion of miniport laparoscopic cholecystectomy, which was between 80% and 97% in most trials.

There was no significant difference in the quality of life between patients even at 10 days after surgery in the only trial which reported the quality of life (Saad 2013).

The operating time was longer in the miniport than in the standard port laparoscopic cholecystectomy group by about five minutes. The operating time in the individual trials is different in both groups, and individual centres have to assess the difference in the operating time for cost calculations. There was no significant differences in mortality, the length of hospital stay, return to normal activity, or return to work between the two interventions groups. Trial sequential analyses demonstrated that we have only accrued a small fraction of the required information size so far to assess these outcomes appropriately.

Although the early cosmesis following miniport laparoscopic cholecystectomy was better (Gurusamy 2010), there was no significant difference in cosmesis when trials that assessed cosmesis at least six months after surgery were included. Wound remodelling may last even for a year (Gurtner 2008) and it is appropriate to assess the cosmesis after at least six months after surgery rather than early cosmesis. None of the trials used a validated scale for measurement of cosmesis. Furthermore, blinding was unclear in one of the two trials that reported cosmesis after at least six months (Huang 2003).

For performing miniport laparoscopic cholecystectomy, a new set of instruments has to be purchased. However, the standard instruments should also be available because of the significant risk of failure of miniport laparoscopic cholecystectomy. The operating time is also longer with miniport laparoscopic cholecystectomy (even when the patients with conversions to standard port laparoscopic cholecystectomy were excluded). The impact of miniport laparoscopic cholecystectomy on day-case laparoscopic cholecystectomy has not been reported. Thus, from the current evidence, there appears to be no economic benefit in performing miniport laparoscopic cholecystectomy.

Overall completeness and applicability of evidence

Only one trial included patients with acute cholecystitis (Hsieh 2003). There was no significant differences between the groups in any of the outcomes in this trial. Most of the remaining trials in this review clearly state that they included only elective laparoscopic cholecystectomies. The proportion of patients with acute cholecystitis was low in the remaining trials. Thus, the results of this review may only be considered for elective laparoscopic cholecystectomy. Most of the included patients were of low anaesthetic risk. So, the review is applicable only for such patients.

We did not assess acute or chronic pain. A number of the trials assessed acute pain (Schwenk 2000; Bisgaard 2000; Alponat 2002; Bisgaard 2002; Schmidt 2002; Sarli 2003; Huang 2003; Novitsky 2005; Abbas 2009; de Carvalho 2013; Saad 2013) and some reported that pain following the miniport operation was reduced (Sarli 2003; Novitsky 2005). Pain is of course important, but it is a complication that can be handled with pain reducing treatments. Furthermore, pain may be considered a surrogate for quality of life, earlier return to normal activity, or earlier return to work. We considered the latter outcomes and found no significant advantage of miniport laparoscopic cholecystectomy compared with standard laparoscopic cholecystectomy.

Quality of the evidence

The quality of the evidence is generally low or very low as shown in Summary of findings for the main comparison. Blinding was unclear or inadequate in most of the trials. Imputation of missing data under different scenarios showed that the results were vulnerable to post-randomisation drop-outs. Morbidity was not described adequately in many of the trials. However, this is the best quality of evidence available.

Potential biases in the review process

We performed a thorough search of literature. At least two review authors independently identified trials for inclusion and extracted data, thus minimising errors. However, we imputed the mean and standard deviation when these were not available. The alternative was to present the data without imputing these values which would have been even more confusing. Besides, the results of the operating time and hospital stay did not change after exclusion of trials in which mean or standard deviation or both had been imputed.

Agreements and disagreements with other studies or reviews

We identified two systematic reviews on this topic (McCloy 2008; Thakur 2011). Neither of these systematic reviews recommended miniport laparoscopic cholecystectomy routinely.

Authors' conclusions

Implications for practice

Miniport laparoscopic cholecystectomy can be completed successfully in more than 80% of patients. There appears to be no advantage of miniport laparoscopic cholecystectomy in terms of decreasing mortality, morbidity, hospital stay, return to activity, return to work or improving cosmesis. On the other hand, there is a modest increase in operating time after miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy and the safety of miniport laparoscopic cholecystectomy is yet to be established. Miniport laparoscopic cholecystectomy cannot be recommended outside well-designed randomised clinical trials.

Implications for research

  1. Further randomised clinical trials are necessary to evaluate miniport cholecystectomy in the emergency and in the elective set-up.

  2. Future randomised clinical trials should minimise the risk of bias to lack of blinding (by blinding the patients and outcome assessors), and incomplete outcome data (by measuring all the outcomes in all patients recruited into the trial).

  3. Future trials should include the proportion of patients discharged as day-case laparoscopic cholecystectomy as one of the primary outcomes.

  4. Future trials need to be designed according to the SPIRIT guidelines (http://www.spirit-statement.org/) and conducted and reported according to the CONSORT Statement (www.consort-statement.org).

Acknowledgements

To The Cochrane Hepato-Biliary Group for the support that they have provided.
To the authors of the trials who replied to the queries related to their trials.
To K Samraj, who contributed to the first version of the review.

Peer Reviewers: Hamid Mofid, Germany; Dirk Bulian, Germany.
Contact Editor: Christian Gluud, Denmark.

This project was funded by the National Institute for Health Research.
Disclaimer of the Department of Health: 'The views and opinions expressed in the review are those of the authors and do not necessarily reflect those of the National Institute for Health Research (NIHR), National Health Services (NHS), or the Department of Health'.

Data and analyses

Download statistical data

Comparison 1. Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Serious adverse events8460Risk Ratio (M-H, Fixed, 95% CI)0.33 [0.04, 3.08]
2 Quality of life1 Std. Mean Difference (IV, Fixed, 95% CI)Totals not selected
3 Conversion to open cholecystectomy11670Risk Ratio (M-H, Fixed, 95% CI)1.23 [0.44, 3.45]
4 Operating time12695Mean Difference (IV, Fixed, 95% CI)4.91 [2.38, 7.44]
5 Hospital stay6351Mean Difference (IV, Fixed, 95% CI)-0.00 [-0.12, 0.11]
6 Return to activity1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
7 Return to work2187Mean Difference (IV, Fixed, 95% CI)0.28 [-0.44, 0.99]
8 Cosmesis2152Std. Mean Difference (IV, Fixed, 95% CI)0.13 [-0.19, 0.46]
Analysis 1.1.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 1 Serious adverse events.

Analysis 1.2.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 2 Quality of life.

Analysis 1.3.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 3 Conversion to open cholecystectomy.

Analysis 1.4.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 4 Operating time.

Analysis 1.5.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 5 Hospital stay.

Analysis 1.6.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 6 Return to activity.

Analysis 1.7.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 7 Return to work.

Analysis 1.8.

Comparison 1 Mini-laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy, Outcome 8 Cosmesis.

Comparison 2. Subgroup and sensitivity analysis
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Serious adverse events8 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
1.1 Best-best scenario8475Risk Ratio (M-H, Fixed, 95% CI)0.33 [0.04, 3.08]
1.2 Worst-worst scenario8475Risk Ratio (M-H, Fixed, 95% CI)2.36 [0.95, 5.88]
1.3 Best-worst scenario8475Risk Ratio (M-H, Fixed, 95% CI)0.25 [0.04, 1.47]
1.4 Worst-best scenario8475Risk Ratio (M-H, Fixed, 95% CI)3.31 [1.18, 9.29]
2 Conversion to open cholecystectomy11 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
2.1 Best-best scenario11681Risk Ratio (M-H, Fixed, 95% CI)1.23 [0.44, 3.45]
2.2 Worst-worst scenario11681Risk Ratio (M-H, Fixed, 95% CI)1.63 [0.87, 3.07]
2.3 Best-worst scenario11681Risk Ratio (M-H, Fixed, 95% CI)0.61 [0.26, 1.43]
2.4 Worst-best scenario11681Risk Ratio (M-H, Fixed, 95% CI)3.23 [1.39, 7.50]
3 Operating time (sensitivity analysis)5281Mean Difference (IV, Fixed, 95% CI)4.91 [1.37, 8.45]
4 Hospital stay2134Mean Difference (IV, Fixed, 95% CI)0.00 [-0.12, 0.12]
5 Cosmesis168Std. Mean Difference (IV, Fixed, 95% CI)0.29 [-0.19, 0.77]
6 Operating time (subgroup analysis)12695Mean Difference (IV, Fixed, 95% CI)4.91 [2.38, 7.44]
6.1 At least 2 ports < 3 mm10616Mean Difference (IV, Fixed, 95% CI)5.91 [2.82, 9.00]
6.2 Other trials (at least 3 ports > 3 mm)279Mean Difference (IV, Fixed, 95% CI)2.88 [-1.53, 7.30]
Analysis 2.1.

Comparison 2 Subgroup and sensitivity analysis, Outcome 1 Serious adverse events.

Analysis 2.2.

Comparison 2 Subgroup and sensitivity analysis, Outcome 2 Conversion to open cholecystectomy.

Analysis 2.3.

Comparison 2 Subgroup and sensitivity analysis, Outcome 3 Operating time (sensitivity analysis).

Analysis 2.4.

Comparison 2 Subgroup and sensitivity analysis, Outcome 4 Hospital stay.

Analysis 2.5.

Comparison 2 Subgroup and sensitivity analysis, Outcome 5 Cosmesis.

Analysis 2.6.

Comparison 2 Subgroup and sensitivity analysis, Outcome 6 Operating time (subgroup analysis).

Appendices

Appendix 1. Search Strategies

DatabasePeriod of SearchSearch Strategy
Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Wiley)Issue 1, 2013.#1 (minilaparoscopic OR mini-laparoscopic OR microlaparoscopic OR micro-laparoscopic OR needlescopic OR microinvasive OR micro-invasive OR micropuncture OR micro-punture OR minisite OR mini-site OR miniport OR mini-port OR microport OR micro-port )
#2 MeSH descriptor Miniaturization explode all trees
#3 MeSH descriptor Microsurgery explode all trees
#4 MeSH descriptor Punctures explode all trees
#5 (#1 OR #2 OR #3 OR #4)
#6 (laparoscop* OR celioscop* OR coelioscop* OR abdominoscop* OR peritoneoscop*) AND (cholecystecto* OR colecystecto*)
#7 MeSH descriptor Cholecystectomy, Laparoscopic explode all trees
#8 (#6 OR #7)
#9 MeSH descriptor Pain explode all trees
#10 MeSH descriptor Cicatrix explode all trees
#11 pain OR scar OR scars OR cicatrix OR cicatrices
#12 #9 OR #10 OR #11
#13 (#5 AND #8 AND #12)
MEDLINE (Pubmed)1987 to February 2013.(minilaparoscopic OR mini-laparoscopic OR microlaparoscopic OR micro-laparoscopic OR needlescopic OR microinvasive OR micro-invasive OR micropuncture OR micro-punture OR minisite OR mini-site OR miniport OR mini-port OR microport OR micro-port OR "Miniaturization"[MeSH] OR "Microsurgery"[MeSH] OR "Punctures"[MeSH]) AND (((laparoscop* OR celioscop* OR coelioscop* OR abdominoscop* OR peritoneoscop*) AND (cholecystecto* OR colecystecto*)) OR "cholecystectomy, laparoscopic"[MeSH]) AND ("pain"[MeSH] OR "cicatrix"[MeSH] OR pain OR scar OR scars OR cicatrix OR cicatrices) AND (randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized [tiab] OR placebo [tiab] OR drug therapy [sh] OR randomly [tiab] OR trial [tiab] OR groups [tiab]) NOT (animals [mh] NOT (humans [mh] AND animals [mh]))
EMBASE (OvidSP)1987 to February 2013.1 random:.tw. or clinical trial:.mp. or exp health care quality/
2 (minilaparoscopic or mini-laparoscopic or microlaparoscopic or micro-laparoscopic or needlescopic or microinvasive or micro-invasive or micropuncture or micro-punture or minisite or mini-site or miniport or mini-port or microport or micro-port).af.
3 exp Microsurgery/
4 exp Puncture/
5 2 or 3 or 4
6 (laparoscop* or celioscop* or coelioscop* or abdominoscop* or peritoneoscop*).af.
7 exp Laparoscopic Surgery/
8 exp Laparoscopy/
9 6 or 7 or 8
10 (cholecystecto* or colecystecto*).af.
11 exp Cholecystectomy/
12 10 or 11
13 1 and 5 and 9 and 12
Science Citation Index Expanded (Web of Knowledge)1987 to February 2013.#1 TS=(minilaparoscopic OR mini-laparoscopic OR microlaparoscopic OR micro-laparoscopic OR needlescopic OR microinvasive OR micro-invasive OR micropuncture OR micro-punture OR minisite OR mini-site OR miniport OR mini-port OR microport OR micro-port)
#2 TS=(laparoscop* OR celioscop* OR coelioscop* OR abdominoscop* OR peritoneoscop*)
#3 TS=(cholecystecto* OR colecystecto*)
#4 TS=(pain OR scar OR scars OR cicatrix OR cicatrices)
#5 TS=(random* OR blind* OR placebo* OR meta-analysis)
#6 #5 AND #4 AND #3 AND #2 AND #1
World Health Organization International Clinical Trials Registry Platform Portal (http://apps.who.int/trialsearch/)February 2013port AND laparoscopic cholecystectomy

What's new

DateEventDescription
13 February 2013AmendedAuthor list: Kurinchi Selvan Gurusamy, Jessica Vaughan, Rajarajan Ramamoorthy, Giuseppe Fusai, Brian R Davidson.
13 February 2013New citation required and conclusions have changedThe methods were revised (please see Differences between protocol and review), and the conclusions changed because of the change in the methods. The conclusions were changed from "Miniport laparoscopic cholecystectomy can be completed successfully in more than 85% of patients. Patients in whom elective miniport laparoscopic cholecystectomy was completed successfully had lower pain than those who underwent standard port laparoscopic cholecystectomy. However, because of the lack of information on its safety, miniport laparoscopic cholecystectomy cannot be recommended outside well-designed, randomised clinical trials" to "Miniport laparoscopic cholecystectomy can be completed successfully in more than 80% of patients. There appears to be no advantage of miniport laparoscopic cholecystectomy in terms of decreasing mortality, morbidity, hospital stay, return to activity, return to work, or improving cosmesis. On the other hand, there is a modest increase in operating time after miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy, and the safety of miniport laparoscopic cholecystectomy is yet to be established. Miniport laparoscopic cholecystectomy cannot be recommended routinely outside well-designed clinical trials. Further trials of low risk of bias and random errors are necessary".
6 February 2013New search has been performedSearches were updated February 6, 2013, and three new trials were included.

Contributions of authors

KS Gurusamy wrote the review and assessed the trials for inclusion, and extracted data on included trials. J Vaughan independently identified the trials for inclusion and extracted data on the included trials for the current update. R Ramamoorthy independently assessed the trials for inclusion and extracted data on included trials for the previous version. G Fusai and BR Davidson critically commented on the review and provided advice for improving the previous version of the review.

Declarations of interest

None known.

Sources of support

Internal sources

  • None, Not specified.

External sources

  • None, Not specified.

Differences between protocol and review

The outcomes have been divided into primary and secondary outcomes. Three new outcomes - return to activity, return to work, and patient quality of life - have been added as these are important outcomes in the assessment of cost-effectiveness. The outcomes have been ordered according to their clinical and economic importance. The assessment of methodological quality has been updated in line with the updated version of the Cochrane Handbook for Systematic Reviews of Intervention (Higgins 2011).

Changes in the first version of the review

A subgroup analysis of standard port laparoscopic cholecystectomy (four ports with two ports of at least 10 mm ports and two ports of at least 5 mm) was performed following user feedback. The results and discussion were modified to reflect the changes in the subgroup analysis.

Changes in this update (2013)

  1. We excluded any trials that did not compare miniport laparoscopic cholecystectomy and which did not meet the definition of standard port laparoscopic cholecystectomy.

  2. We used the ICH-GCP definition of serious adverse events to define the surgical morbidity.

  3. We changed quality of life to a primary outcome.

  4. We moved conversion to open cholecystectomy to the secondary outcomes as the decision to use miniport or standard port laparoscopic cholecystectomy should be based on mortality, morbidity, and quality of life, and if there are no differences in these outcomes (which are now the primary outcomes), the decision to use miniport or standard port laparoscopic cholecystectomy will depend upon whether there was any difference in the conversion to open cholecystectomy, operating time, length of hospital stay, return to work, return to normal activity, and long-term cosmesis (at six months or beyond). These are the outcomes considered to be important for patients and healthcare funders.

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Abbas 2009

MethodsRandomised clinical trial
Participants

Country: United Kingdom.

Number randomised: 27.

Post-randomisation drop-outs: not stated.

Revised sample size: 27.

Average age: not stated.

Females: not stated.

Inclusion criteria

  1. Nonmorbidly obese patients (BMI lower than 40 kg/m2) aged 16 years or older.

  2. Patients scheduled for laparoscopic cholecystectomy for small calculi (5 mm or less) and non-thick walled gallbladder on ultrasonography.

Exclusion criteria

  1. Patients with insufficient information on abdominal ultrasonography regarding the thickness of the gallbladder wall and size of gallstones.

  2. Those scheduled for laparoscopic cholecystectomy ± bile duct exploration.

  3. Patients who took oral analgesia on regular basis for other medical reasons.  

Interventions

Participants were randomly assigned to two groups.
Group 1: miniport (n = 13).
Further details: size of port in mm: 5 + 5 + 5 + 5.
Successful completion of miniport laparoscopic cholecystectomy in 10 (76.9%) patients.

Group 2: standard (n = 14).
Further details: size of port in mm: 10 + 10 + 5 + 5.

Other details:

Intra-operative cholangiogram: not stated.

OutcomesThe outcomes reported were mortality, conversion to open cholecystectomy, and operating time.
NotesAttempts made to contact the authors in February 2013 were unsuccessful.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: "Randomization was performed by referral to computer-generated randomization lists, and was conducted by referral to sealed envelopes in theater.".
Allocation concealment (selection bias)Unclear riskQuote: "Randomization was performed by referral to computer-generated randomization lists, and was conducted by referral to sealed envelopes in theater.".
Comment: Further details were not available.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskQuote: "The patients and the investigator were blinded to the randomization group, and the patients’ wounds were concealed by standard-size nontransparent dressings".
Comment: No information as to whether a second surgical team was involved in decision making
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskComment: This information was not available.
Selective reporting (reporting bias)High riskComment: Morbidity was not reported for patients who underwent laparoscopic cholecystectomy separately.
Free from vested interest bias?Unclear riskComment: This information was not available.

Alponat 2002

MethodsRandomised clinical trial
Participants

Country: Turkey.
Number randomised: 44.
Post-randomisation drop-outs: 5 (11.9%).

Revised sample size: 39
Mean age: 40 years.
Females: 33 (84.6%).

Inclusion criteria:

  1. Elective laparoscopic cholecystectomy.

  2. ASA I.

Exclusion criteria:

  1. Acute biliary complications.

  2. Known endocrine, metabolic, renal, or hepatic disease.

  3. Risk factors associated with long-term pneumoperitoneum (not stated what these are).

  4. Dense adhesions.

  5. Thick-walled gallbladder.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 22).

Further details: size of ports in mm: 10 + 2 + 2 + 2
Successful completion of miniport laparoscopic cholecystectomy in 17 (77.3%) patients.

Group 2: standard (n = 22).

Further details: size of ports in mm: 10 + 10 + 5 + 5.
Other details:
Intra-operative cholangiogram: not stated.

OutcomesThe main outcome measures were mortality, surgical morbidity, conversion to open cholecystectomy, operating time, and hospital stay.
NotesFive patients were withdrawn after randomisation (all in the miniport group who were converted to standard port laparoscopic cholecystectomy; none of these patients required conversion to open cholecystectomy and were included for this outcome. But these patients were not included for the other outcomes).
Attempts made to contact the authors in March 2007 were unsuccessful.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskComment: This information was not available.
Allocation concealment (selection bias)Unclear riskComment: This information was not available.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskComment: This information was not available.
Incomplete outcome data (attrition bias)
All outcomes
High riskComment: Five patients were withdrawn after randomisation (all in the miniport group who were converted to standard port laparoscopic cholecystectomy; none of these patients required conversion to open cholecystectomy and were included for this outcome. But these patients were not included for the other outcomes).
Selective reporting (reporting bias)High risk

Quote: "There were no wound infections, no late complications, and no deaths from either of the procedures".

Comment: The surgical morbidity was not adequately reported i.e. it was not clear whether the patients developed any other complications such as bile duct injury or bile leak.

Free from vested interest bias?Unclear riskComment: This information was not available.

Bisgaard 2000

MethodsRandomised clinical trial
Participants

Country: Denmark.
Number randomised: 26.
Post-randomisation drop-outs: 5 (19.2%).

Revised sample size: 21.

Mean age: 50 years.
Females: 14 (53.8%).

Inclusion criteria:
ASA I or II.

Exclusion criteria:

  1. Estimated abdominal wall layer of > 10 cm.

  2. Patients having papillotomy by endoscopic retrograde cholangiopancreatography (ERCP) < 1 month before operation.

  3. Chronic pain diseases other than gallstone disease.

  4. Received opioids or tranquillisers > 1 week before surgery.

  5. History of alcohol or drug abuse.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 13).
Further details: size of ports in mm: 10 + 2 + 2 + 2.

Successful completion of miniport laparoscopic cholecystectomy in 8 (61.5%) patients.

Group 2: standard (n = 13).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Other details:
Intra-operative cholangiogram: not performed.

OutcomesThe main outcome measures were morbidity and operating time.
Notes

Five patients were withdrawn after randomisation (all in the miniport group who were converted to standard port laparoscopic cholecystectomy; the outcomes of these patients were not reported. These patients were included for the operating time but were excluded from morbidity.

Replies related to risk of bias items and pain scores were obtained from the authors (Dr T Bisgaard) in March 2007 and September 2009.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: "The envelope method based on a computer-generated list" (author replies).
Allocation concealment (selection bias)Low riskQuote: "we used opaque, sealed, consecutively numbered envelopes" (author replies).
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote: "The surgeon randomised patients to micro-laparoscopic cholecystectomy or laparoscopic cholecystectomy by the envelope method after anesthesia was induced and did not attend to the patient or the two observers who recorded pain at any time after the operation. The starting time of the operation was blinded to the two observers. At the end of the operation, the incisions were blinded with waterproof standard dressings. Prior to the operation, the patients were instructed to keep the dressings for the 1st postoperative week."
Incomplete outcome data (attrition bias)
All outcomes
High riskComment: Five patients were withdrawn after randomisation (all in the miniport group who were converted to standard port laparoscopic cholecystectomy; the outcomes of these patients were not reported. These patients were included for the operating time but were excluded from morbidity).
Selective reporting (reporting bias)Low riskMortality and morbidity were reported (authors replied that there was no surgery-related morbidity in either group)
Free from vested interest bias?Low riskQuote: "This work was supported by grants from the University of Copenhagen and the Danish Medical Research Council (journal no. 9601607) and the King Christian X Foundation."

Bisgaard 2002

MethodsRandomised clinical trial
Participants

Country: Denmark.
Number randomised: 60.
Post-randomisation drop-outs:8 (13.3%).

Revised sample size: 52

Mean age: 48 years.
Females: 42 (80.8%).

Inclusion criteria:
ASA I or II.

Exclusion criteria:

  1. Age > 75 years.

  2. Patients having papillotomy by endoscopic retrograde cholangiopancreatography (ERCP) < 1 month before operation.

  3. Chronic pain diseases other than gallstone disease.

  4. Received opioids or tranquillisers > 1 week before surgery.

  5. Mental disorder.

  6. History of alcohol or drug abuse.

  7. Spoke a foreign language.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 30).

Further details: size of ports in mm: 10 + 3.5 + 3.5 + 3.5.
Successful completion of miniport laparoscopic cholecystectomy in 28 (93.3%) patients.

Group 2: standard (n = 30).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Intra-operative cholangiogram: ( 4 patients in miniport group and 8 in standard group).

OutcomesThe main outcome measures were conversion to open cholecystectomy, operating time, hospital stay, return to normal activity, and return to work.
Notes

Eight patients were withdrawn after randomisation (conversion to open cholecystectomy 1 in each arm; additional trocar in miniport group 1; conversion to standard port laparoscopic cholecystectomy from miniport laparoscopic cholecystectomy 1; common bile duct stone on intra-operative cholangiography 1 in each arm; pancreatitis in miniport group 1; intra-abdominal bleeding drained in standard group 1). We have included these patients under conversion to open cholecystectomy and conversion to standard port laparoscopic cholecystectomy but have excluded them from other outcomes (as the other outcomes for these patients have not been reported).

Replies related to pulmonary functions were obtained from the authors (Dr T Bisgaard) in March 2007 and September 2009. This information was not used in the review.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: "After anesthesia was induced, the surgeon randomised patients to 3.5-mm laparoscopic cholecystectomy or laparoscopic cholecystectomy by the sealed-envelope method (based on a block- randomised computer-generated list)."
Allocation concealment (selection bias)Low riskQuote: "we used opaque, sealed, consecutively numbered envelopes."
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote: "The patients were instructed to keep the dressings on for the 1st postoperative week. The surgeon did not participate in the postoperative assessment, which was done by two observers who were blinded to the type of surgical procedure and the starting time of the operation."
Incomplete outcome data (attrition bias)
All outcomes
High riskComment: Eight patients were withdrawn after randomisation (conversion to open cholecystectomy 1 in each arm; additional trocar in miniport group 1; conversion to standard port laparoscopic cholecystectomy from miniport laparoscopic cholecystectomy 1; common bile duct stone on intra-operative cholangiography 1 in each arm; pancreatitis in miniport laparoscopic cholecystectomy group 1; intra-abdominal bleeding drained in standard group 1).
Selective reporting (reporting bias)High riskComment: Surgical morbidity was not adequately described.
Free from vested interest bias?High riskAcknowledgments. This work was supported by grants from the University of Copenhagen and the Danish Medical Research Council (journal no. 9902757). We thank DEMA A/S. Copenhagen, Denmark, for supplying the 3.5-mm Richard Wolf Endoscopy System.

de Carvalho 2013

MethodsRandomised clinical trial
ParticipantsCountry: Belgium.
Number randomised: 41.
Post-randomisation drop-outs: not stated.
Revised sample size: 41.
Average age: 50 years.
Females: 34 (82.9%).

Inclusion criteria
Patients with chronic cholecystitis or symptomatic cholecystolithiasis requiring an elective cholecystectomy.

Exclusion criteria
1. Presence of complicated gallstone disease that could be assessed by preoperative blood analysis, ultrasonographic findings, and clinical features.
2. Previous upper abdominal surgery.
3. BMI > 30 kg/m2.
4. Antecedents of psychiatric disorder.
5. Very high risk for general anaesthesia (ASA Grade IV).
6. Pregnancy.
7. Coagulation disorders.
8. Suspected or proven malignancy.
9. History of alcohol or drug abuse.
Interventions

Participants were randomly assigned to two groups.
Group 1: miniport (n = 18).
Further details: size of port in mm: 10 + 5 + 2.8 + 2.8.
Successful completion of miniport laparoscopic cholecystectomy in 15 (83.3%) patients.

Group 2: standard (n = 23).
Further details: size of port in mm: 10 + 10 + 5 + 5.

Other details:

Intra-operative cholangiogram: not stated.

OutcomesThe outcomes reported were mortality, morbidity, conversion to open cholecystectomy, operating time, and hospital stay.
NotesReplies related to risk of bias items were obtained from the authors (Luis Carvalho) in February 2013.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: "I shuffled the envelopes" (author replies).
Allocation concealment (selection bias)Low riskQuote: "Patients were randomly assigned by the envelope method to either the miniport laparoscopic cholecystectomy group or the standard port laparoscopic cholecystectomy group"; "The envelopes were opaque and it was not possible to read their content. They were kept in a box in the office of the head of department. The envelopes were opened according to the pre-established sequence, at the operation room, just before the start of the operation" (author replies).
Blinding (performance bias and detection bias)
All outcomes
High riskQuote: "The patients were only told which operation they had undergone after a period of 24 hours during which the pain scores were obtained"; "The health care providers were not blinded" (author replies).
Incomplete outcome data (attrition bias)
All outcomes
Low riskQuote: "The patients received information about the study at the preoperative consultation but they were only included in the study just before the operation began. It was also at this moment that the randomization-envelope was opened, and the patient was assigned to one of the study-arms. Therefore, we have no drop-outs" (author replies).
Selective reporting (reporting bias)Low riskComment: Mortality and morbidity were reported
Free from vested interest bias?Low riskQuote: "There was no funding" (author replies).

Hsieh 2003

MethodsRandomised clinical trial
Participants

Country: Taiwan.
Number randomised: 69.
Post-randomisation drop-outs: 5 (7.2%).
Revised sample size: 64.

Mean age: 55 years.
Females: 34 (53.1%).

Inclusion criteria:
Acute cholecystitis.

Exclusion criteria:

  1. Previous upper abdominal surgery.

  2. Critically ill with unstable haemodynamic status due to profound sepsis.

  3. Concurrent disease such as liver abscess or severe acute pancreatitis.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 38).

Further details: size of ports in mm: 10 + 3 + 3 + 3.
Successful completion of miniport laparoscopic cholecystectomy: not stated.

Group 2: standard (n = 31).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Other details:
Intra-operative cholangiogram: not stated.

OutcomesThe main outcome measures were mortality, surgical morbidity, conversion to open cholecystectomy, operating time, and hospital stay.
Notes

Five patients were withdrawn after randomisation (3 from miniport group and 2 from standard port because of conversion to open cholecystectomy). These patients were included for conversion to open cholecystectomy but were excluded from other outcomes as the other outcomes were not reported in these patients.

Attempts made to contact the authors in March 2007 were unsuccessful.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskComment: This information was not available.
Allocation concealment (selection bias)Unclear riskComment: This information was not available.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskComment: This information was not available.
Incomplete outcome data (attrition bias)
All outcomes
High riskComment: Five patients were withdrawn after randomisation (3 from miniport group and 2 from standard port because of conversion to open cholecystectomy). These patients were included for conversion to open cholecystectomy but were excluded from other outcomes as the other outcomes were not reported in these patients.
Selective reporting (reporting bias)High riskComment: Important outcomes such as pain scores were not reported.
Free from vested interest bias?Unclear riskComment: This information was not available.

Huang 2003

MethodsRandomised clinical trial
Participants

Country: Taiwan.
Number randomised: 90.
Post-randomisation drop-outs: 6 (6.7%).
Revised sample size: 84.

Mean age: 49 years.
Females: 55 (61.1%).

Inclusion criteria:

  1. Symptomatic gallstones.

  2. Elective laparoscopic cholecystectomy.

Interventions

Participants were randomly assigned to three groups.

Group 1: miniport type 1 (n = 30).

Further details: size of ports in mm: 10 + 2 + 2 + 2.
Successful completion of miniport laparoscopic cholecystectomy in 25 (83.3%) patients.

Group 2: miniport type 2 (n = 30).

Further details: size of ports in mm: 5 + 5 + 2 + 2.
Successful completion of miniport laparoscopic cholecystectomy in 29 (96.7%) patients.

Group 3: standard (n = 30).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Other details:
Intra-operative cholangiogram: not stated.

OutcomesThe main outcome measures were surgical morbidity, conversion to open cholecystectomy, operating time, hospital stay, and cosmesis.
Notes

Six patients (one from miniport type 1 and 5 from miniport type 2) were excluded from analysis as they were converted to standard port laparoscopic cholecystectomy. None of these patients underwent conversion to open procedure. So, these patients were included for conversion to open cholecystectomy but could not be included for the remaining outcomes as these outcomes were not reported.

Replies related to risk of bias were obtained from the authors (Dr MT Huang) in March 2007.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: " We used a random table to generate the random numbers."
Allocation concealment (selection bias)Low riskQuote: "...., the allocation of the specific surgical procedure was determined by the random selection of a sealed envelope by the patient."
Blinding (performance bias and detection bias)
All outcomes
Unclear risk

Quote: "The patient was still unaware of which type of surgery would be performed before receiving anesthesia."

Comment: It is not clear whether patients were told about the procedure after the completion of surgery. The outcome assessors were also not blinded.

Incomplete outcome data (attrition bias)
All outcomes
High riskComment: Six patients (one from miniport type 1 and 5 from miniport type 2) were excluded from analysis as they were converted to standard port laparoscopic cholecystectomy. None of these patients underwent conversion to open procedure. So, these patients were included for conversion to open cholecystectomy but could not be included for the remaining outcomes as these outcomes were not reported.
Selective reporting (reporting bias)Low riskComment: All the primary outcomes were reported.
Free from vested interest bias?Unclear riskComment: This information was not available.

Novitsky 2005

MethodsRandomised clinical trial
Participants

Country: USA.
Number randomised: 79.
Post-randomisation drop-outs: 20 (25.3%).
Revised sample size: 59.

Mean age: 44 years.
Females: 45 (67.2%).

Inclusion criteria:
ASA I or II.

Exclusion criteria:

  1. More than 70 years old.

  2. Liver disorder.

  3. Coagulation disorders.

  4. Morbid obesity.

  5. Previous major abdominal surgical procedures.

  6. Acute cholecystitis.

  7. Intraoperative evidence of choledocholithiasis.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 38).

Further details: size of ports in mm: 10 + 5 + 2 + 2.
Successful completion of miniport laparoscopic cholecystectomy in 30 (78.9%) patients.
Group 2: standard (n = 41).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Other details:
Intra-operative cholangiogram: 3 in miniport group and 7 in standard group.

OutcomesThe main outcome measures were conversion to open cholecystectomy, and operating time.
Notes

Twenty patients were withdrawn after randomisation. Reasons for withdrawal were: acute cholecystitis (2 miniport; 4 standard), CBD exploration (1 in each group), unable to perform surgery (2 in each group), and conversion to standard port laparoscopic cholecystectomy (8 in miniport group). The eight patients who were converted from miniport to standard port laparoscopic cholecystectomy were included for conversion to open cholecystectomy and operating time but were excluded for other outcomes.

Replies related to risk of bias were obtained from the authors (Dr Y Novitsky) in March 2007.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: "Patients were randomly assigned to either the C-laparoscopic cholecystectomy group or the M-laparoscopic cholecystectomy group by a study nurse on the basis of a block-randomized computer generated list."
Allocation concealment (selection bias)Low riskQuote: "We had a "third-party" nurse who kept all the randomisation documentation."
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote: "The patients and the study nurse remained blinded to the type of instrumentation used until the study was finished."; "Postoperatively, all the patient had similar occlusive dressings for 48 hours."
Incomplete outcome data (attrition bias)
All outcomes
High riskComment: Twenty patients were withdrawn after randomisation. Reasons for withdrawal were: acute cholecystitis (2 miniport; 4 standard), CBD exploration (1 in each group), unable to perform surgery (2 in each group), and conversion to standard port laparoscopic cholecystectomy (8 in miniport group). The eight patients who were converted from miniport to standard port laparoscopic cholecystectomy were included for conversion to open cholecystectomy and operating time but were excluded for other outcomes.
Selective reporting (reporting bias)High riskComment: Surgical morbidity was not adequately reported.
Free from vested interest bias?Unclear riskComment: This information was not available.

Saad 2013

MethodsRandomised clinical trial
Participants

Country: Germany.

Number randomised: 70.

Post-randomisation drop-outs: 0 (0%).

Revised sample size: 70.

Average age: 47 years.

Females: 18 (25.7%).

Inclusion criteria

  1. Age at least 18 years.

  2. Indication for elective cholecystectomy.

  3. Uncomplicated, symptomatic cholecystolithiasis.

Exclusion criteria

  1. Age over 80 years.

  2. BMI exceeding 30 kg/m2.

  3. Acute cholecystitis.

  4. Gallbladder empyema.

  5. Pancreatitis or other complications.

  6. ASA grade IV or V.

  7. Previous upper abdominal laparotomy with suspicion of peritoneal adhesions.

  8. Allergy to paracetamol or piritramide.

  9. History of pain medication or alcohol abuse.

  10. Neuromuscular disease.

  11. Pregnancy or lactation. 

Interventions

Participants were randomly assigned to two groups.
Group 1: miniport (n = 35).
Further details: size of port in mm: 10 + 3 + 3 + 3.
Successful completion of miniport laparoscopic cholecystectomy in 35 (100%) patients.

Group 2: standard (n = 35).
Further details: size of port in mm: 10 + 10 + 5 + 5.

Other details:

Intra-operative cholangiogram: not stated.

Another group in which laparoscopic cholecystectomy was performed using a single port was excluded from this review.

OutcomesThe outcomes reported were mortality, surgical morbidity, quality of life, conversion to open cholecystectomy, operating time, hospital stay, and cosmetic scores  .
NotesOne patient was lost to follow-up on day 7 and another by 1 year in the miniport group. These patients were included for operative outcomes but not for quality of life (1 patient) and cosmesis (2 patients).
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: "A sequence with block sizes of three and six in random order was generated by computer (http://www.randomization. com).".
Allocation concealment (selection bias)Low riskQuote: "Patients were randomized to CL, ML or SP cholecystectomy by drawing sequentially numbered, opaque, sealed envelopes that had been prepared earlier by a third party. ".
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote: "After completion of cholecystectomy, all patients received non-transparent waterproof dressings at four sites on the abdomen, reflecting the incisions necessary for CL cholecystectomy. This ensured that patients, ward doctors and nurses responsible for the postoperative evaluation and care of patients were unaware of which procedure had actually been performed. The operating surgeons and operating room staff were excluded from postoperative treatment and evaluation. ".
Incomplete outcome data (attrition bias)
All outcomes
Low riskComment: All patients were included for operative outcomes. Two patients were lost to follow-up and so the quality of life and cosmetic scores may be at high risk of bias. However, mortality and morbidity are at low risk of bias.
Selective reporting (reporting bias)Low riskComment: Mortality and morbidity were reported
Free from vested interest bias?Low riskQuote: "This study was funded partly by the German Federal Ministry of Education and Research: grant numbers 01GH0605 and 01GH1001E (CHIR-Net)".

Sarli 2003

MethodsRandomised clinical trial
Participants

Country: Italy.
Number randomised: 138.
Post-randomisation drop-outs: 3 (2.2%).
Revised sample size: 135.

Mean age: 44 years.
Females: 71 (52.6%).

Inclusion criteria:

  1. Symptomatic chronic calculous cholecystitis.

  2. Elective laparoscopic cholecystectomy.

  3. ASA I to III.

Exclusion criteria:

  1. Pregnancy.

  2. Cirrhosis.

  3. Coagulation disorders.

  4. Suspected or proven malignancy.

  5. Failed endoscopic treatment of bile duct stones.

  6. Concomitant surgery not related to cholecystectomy.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 68).

Further details: size of ports in mm: 3 + 12 + 3 + 3.
Successful completion of miniport laparoscopic cholecystectomy in 64 (94.1%) patients.
Group 2: standard (n = 67).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Other details:
Intra-operative cholangiogram: 3 in miniport laparoscopic cholecystectomy group and 2 in standard port laparoscopic cholecystectomy group.

OutcomesThe main outcome measures were surgical morbidity, conversion to open cholecystectomy, operating time, hospital stay, and return to work.
Notes

Three patients were withdrawn after randomisation as they were unwilling to have the pain scored. The group to which these patients belonged was not stated.

Attempts made to contact the authors in March 2007 were unsuccessful.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskComment: This information was not available.
Allocation concealment (selection bias)Unclear risk

Quote: "Patients were randomised by means of a blind envelope system just before surgery."

Comment: Further details were not available.

Blinding (performance bias and detection bias)
All outcomes
High risk

Quote: "Patients were not informed of the type of surgery they had undergone until 24 h after surgery".

Comment: The outcome assessors were not blinded.

Incomplete outcome data (attrition bias)
All outcomes
High riskComment: Three patients were withdrawn after randomisation as they were unwilling to have the pain scored. The group to which these patients belonged was not stated.
Selective reporting (reporting bias)Low riskComment: Surgical mortality and morbidity were reported.
Free from vested interest bias?High riskQuote: "The authors thank Dr Giovanni Bader (Pfizer) for his support with the statistical evaluation."

Schmidt 2002

MethodsRandomised clinical trial
Participants

Country: Germany.
Number randomised: 40.
Post-randomisation drop-outs: 0 (0%)
Revised sample size: 40.

Mean age: 52 years.
Females: 22 (55%).

Inclusion criteria:
Laparoscopic cholecystectomy.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 20).

Further details: size of ports in mm: 10 + 1.7 + 1.7 + 1.7.
Successful completion of miniport laparoscopic cholecystectomy: not stated.
Group 2: standard (n = 20).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Other details:
Intra-operative cholangiogram: not stated.

OutcomesThe main outcome measures were surgical morbidity, conversion to open cholecystectomy, and operating time.
NotesAttempts made to contact the authors in March 2007 were unsuccessful.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskComment: This information was not available.
Allocation concealment (selection bias)Unclear riskComment: This information was not available.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskComment: This information was not available.
Incomplete outcome data (attrition bias)
All outcomes
Low riskComment: There were no post-randomisation drop-outs.
Selective reporting (reporting bias)High riskComment: Important outcomes such as surgical morbidity were not adequately reported.
Free from vested interest bias?Unclear riskComment: This information was not available.

Schwenk 2000

  1. a

    > = more than, or greater than.
    < = less than.
    ASA = American Society of Anesthesiologists.
    BMI = body mass index.
    CBD = common bile duct.
    h = hour.

MethodsRandomised clinical trial
Participants

Country: Germany.
Number randomised: 50.
Post-randomisation drop-outs: not stated.
Revised sample size: 50.

Mean age: 46 years.
Females: 35 (70%).

Inclusion criteria:

  1. Symptomatic cholelithiasis.

  2. Elective cholecystectomy.

  3. ASA I to III.

Exclusion criteria:

  1. Acute cholecystitis.

  2. BMI > 32 kg/m2.

  3. Coagulopathy.

  4. Thrombocytopenia.

  5. Alcohol or drug addiction.

Interventions

Participants were randomly assigned to two groups.

Group 1: miniport (n = 25).

Further details: size of ports in mm: 5 + 5 + 2 + 2.
Successful completion of miniport laparoscopic cholecystectomy in 24 (96%) patients.
Group 2: standard (n = 25).

Further details: size of ports in mm: 10 + 10 + 5 + 5.

Other details:
Intra-operative cholangiogram: not stated.

OutcomesThe main outcome measures were conversion to open cholecystectomy, pain, operating time, cosmesis, and pulmonary functions.
NotesAttempts made to contact the authors in March 2007 were unsuccessful.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskComment: This information was not available.
Allocation concealment (selection bias)Unclear riskComment: This information was not available.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskComment: This information was not available.
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskComment: This information was not available.
Selective reporting (reporting bias)High risk

Quote: "There was one wound infection in each group at the 10-mm trocar site, both were treated successfully with antibiotics. There were no deaths, no conversions, no episodes of postoperative bleeding, and no secondary complications, due to the additional diagnostic method".

Comment: Important outcomes such as surgical morbidity were not reported adequately. While the authors mention that there were no complications due to the additional diagnostic method (neurometer values, an outcome not included for this review), there is no indication as to whether there was any surgery related morbidity in either group.

Free from vested interest bias?Unclear riskComment: This information was not available.

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Ainslie 2003The size of ports in control were not stated. The references cited for the control include four ports which do not meet the criteria for standard port laparoscopic cholecystectomy.
Cabral 2008Not a randomised clinical trial.
Cheah 2001The size of ports in control did not meet the criteria for standard port laparoscopic cholecystectomy.
Dam 2011In this ongoing trial, it is not clear whether the control group was standard port laparoscopic cholecystectomy as defined in this review.
Gupta 2005Four port versus three port laparoscopic cholecystectomy.
Leggett 2000The control group has only three ports.
Look 2001The size of ports in control did not meet the criteria for standard port laparoscopic cholecystectomy.
Pring 2001Comment on an excluded trial (Cheah 2001). Does not contain any new trial.
Yorganci 2001Comment on an excluded trial (Cheah 2001). Does not contain any new trial.

Ancillary