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Fewer-than-four ports versus four ports for laparoscopic cholecystectomy

  1. Kurinchi Selvan Gurusamy1,*,
  2. Jessica Vaughan1,
  3. Michele Rossi2,
  4. Brian R Davidson1

Editorial Group: Cochrane Hepato-Biliary Group

Published Online: 20 FEB 2014

Assessed as up-to-date: 4 SEP 2013

DOI: 10.1002/14651858.CD007109.pub2


How to Cite

Gurusamy KS, Vaughan J, Rossi M, Davidson BR. Fewer-than-four ports versus four ports for laparoscopic cholecystectomy. Cochrane Database of Systematic Reviews 2014, Issue 2. Art. No.: CD007109. DOI: 10.1002/14651858.CD007109.pub2.

Author Information

  1. 1

    Royal Free Campus, UCL Medical School, Department of Surgery, London, UK

  2. 2

    Azienda Ospedaliero-Universitaria Careggi, Endoscopia Chirurgica, Firenze, Firenze, Italy

*Kurinchi Selvan Gurusamy, Department of Surgery, Royal Free Campus, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, NW3 2PF, UK. k.gurusamy@ucl.ac.uk.

Publication History

  1. Publication Status: New
  2. Published Online: 20 FEB 2014

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Summary of findings    [Explanations]

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

 
Summary of findings for the main comparison. Fewer-than-four ports compared with four ports for laparoscopic cholecystectomy

Fewer-than-four ports compared with four ports for laparoscopic cholecystectomy

Patient or population: people undergoing laparoscopic cholecystectomy.
Settings: secondary.
Intervention: fewer-than-four ports.
Comparison: four ports.

OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No of participants
(studies)
Quality of the evidence
(GRADE)

Assumed riskCorresponding risk

Four portsFewer-than-four ports

MortalityThere was no mortality in either groupNot estimable634

(7 studies)
⊕⊝⊝⊝
very low1,2,3





Serious adverse eventsLowRR 3.93
(0.86 to 18.04)
634
(7 studies)
⊕⊝⊝⊝
very low1,2,3

10 per 100039 per 1000
(9 to 180)

Moderate

30 per 1000118 per 1000
(26 to 541)

Quality of life-The mean quality of life in the intervention groups was
0.18 standard deviations higher
(0.05 lower to 0.42 higher)
-510
(4 studies)
⊕⊝⊝⊝
very low1,3,4

Conversion to open cholecystectomy17 per 100012 per 1000
(3 to 40)
RR 0.68
(0.19 to 2.35)
581
(5 studies)
⊕⊝⊝⊝
very low1,2,3

Operating timeThe mean operating time in the control groups was
56 minutes
The mean operating time in the intervention groups was
14.44 higher
(5.95 to 22.93 higher)
-855
(9 studies)
⊕⊝⊝⊝
very low1,5

Hospital stayThe mean hospital stay in the control groups was
2 days
The mean hospital stay in the intervention groups was
0.01 lower
(0.28 lower to 0.26 higher)
-731
(6 studies)
⊕⊝⊝⊝
very low1,3,5

Proportion discharged as day surgery833 per 1000767 per 1000
(583 to 1000)
RR 0.92
(0.7 to 1.22)
50
(1 study)
⊕⊝⊝⊝
very low1,2,3

Return to normal activityThe mean return to normal activity in the control groups was
6.1 days
The mean return to normal activity in the intervention groups was
1.2 lower
(1.58 lower to 0.81 lower)
-325
(2 studies)
⊕⊝⊝⊝
very low1,3,4

Return to workThe mean return to work in the control groups was
12 days
The mean return to work in the intervention groups was
2 lower
(3.31 to 0.69 lower)
-150
(1 study)
⊕⊝⊝⊝
very low1,3

Cosmetic score-The mean cosmetic score in the intervention groups was
0.37 standard deviations higher
(0.1 lower to 0.84 higher)
-317
(2 studies)
⊕⊝⊝⊝
very low3,4

*The basis for the assumed risk was the control group risk across studies in all outcomes other serious adverse events. There were no serious adverse events in the control group and so the information is presented for different control group risks.

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.

 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 It was not possible to explore reporting bias because of the few trials included.
4 The confidence intervals overlapped 0 and minimal clinically important difference (one day for hospital stay, return to activity, and return to work; 15 minutes for operating time; and 0.25 standard deviations for quality of life and cosmesis). The total number of participants in the intervention and control group was fewer than 400.
5 There was severe heterogeneity as noted by the I2 statistic and the lack of overlap of confidence intervals.

 

Background

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms
 

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 one year (NIH 1992; Halldestam 2004). More than half a million cholecystectomies (removal of gallbladder) are performed per year in the United States alone (NIH 1992). Regional differences exist in the cholecystectomy rates (Mjäland 1998). Laparoscopic ('key-hole') cholecystectomy, 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

Traditionally four ports are used to perform laparoscopic cholecystectomy. These include one port for the camera; one port for instruments used to carry out the dissection, diathermy, and clip application; and two ports for manipulation of the gallbladder for adequate exposure of the field of surgery. Two ports are usually 10 mm in size and two ports are usually 5 mm in size (Alponat 2002; Bisgaard 2002). Laparoscopic cholecystectomy has been performed using one, two, or three ports (Poon 2003; Gupta 2005). The technique in performing laparoscopic cholecystectomy with fewer ports, in particular, single-port laparoscopic cholecystectomy varies from conventional four-port method laparoscopic cholecystectomy with regards to the dissection of the gallbladder and the use of roticulating instruments that have articulations with the ability to rotate the tip at the articulation (Roberts 2010).

 

How the intervention might work

The use of fewer ports may decrease the pain (and analgesic requirements) (Gupta 2005). Because of the fewer scars, it may result in better cosmesis (Gupta 2005).

 

Why it is important to do this review

Any new technique has to be evaluated with regards to safety and effectiveness before it can be adopted in routine practice. There are concerns about the safety of using fewer-than-four ports (Hall 2012). The concern about using fewer-than-four ports is about damage to the bile duct or other important structures such as blood vessels supplying the liver because of the fewer ports not allowing adequate vision and sufficient traction on the structures because of the angle at the which the instruments work and because of the fewer instruments that can be used within the body at any given time. The potential advantages include decreased pain and improved cosmesis because of fewer ports being used. There has been no Cochrane systematic review on this topic.

 

Objectives

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

To assess the benefits (such as improvement in cosmesis and earlier return to activity) and harms (such as increased complications) of using fewer-than-four ports (fewer-than-four-ports laparoscopic cholecystectomy) versus four ports in people undergoing laparoscopic cholecystectomy for any reason (symptomatic gallstones, acalculous cholecystitis, gallbladder polyp, or any other condition).

 

Methods

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms
 

Criteria for considering studies for this review

 

Types of studies

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

We excluded quasi-randomised studies (where the method of allocating participants to a treatment were not strictly random (eg, date of birth, hospital record number, alternation), cohort studies, and case-control studies because of the selection bias in such studies. People who were generally considered easy to operate would have undergone laparoscopic cholecystectomy by fewer ports while those who were considered to be difficult to operate would have undergone four-port laparoscopic cholecystectomy. Besides, people in whom the surgery was started as fewer-than-four-ports laparoscopic cholecystectomy and converted to four-port laparoscopic cholecystectomy might have been excluded (as we found was the case even in randomised clinical trials using a similar intervention, ie, smaller size ports or miniport laparoscopic cholecystectomy (Gurusamy 2013)), or would have been included in four-port laparoscopic cholecystectomy making any such comparisons in non-randomised studies meaningless or misleading. However, we recorded any rare harms attributed to fewer-than-four-ports laparoscopic cholecystectomy in such non-randomised studies.

 

Types of participants

People undergoing laparoscopic cholecystectomy (elective or emergency) for any reason (symptomatic gallstones, acalculous cholecystitis, gallbladder polyp, or any other condition).

 

Types of interventions

Fewer-than-four ports (one, two, or three) versus four ports (two ports of at least 10 mm and two ports of at least 5 mm) in people undergoing laparoscopic cholecystectomy. We considered laparoscopic cholecystectomy using four-port laparoscopic cholecystectomy with two 10-mm ports and two 5-mm ports as standard laparoscopic cholecystectomy. We excluded trials that did not use the above definition of four-port laparoscopic cholecystectomy. The reason for excluding trials in which smaller ports were used in the control group was because of the lack of information on safety in miniport laparoscopic cholecystectomy (Gurusamy 2013).

 

Types of outcome measures

 

Primary outcomes

  1. Mortality.
  2. Serious adverse events defined as any event that would increase mortality, was life-threatening, required hospitalisation, resulted in a persistent or significant disability, or any important medical event that might have jeopardised the person or required intervention to prevent it (ICH-GCP 1997). We classified 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 as serious adverse events. We did not consider complications such as wound infections, bile leaks, or abdominal collections that did not require any treatment and settled spontaneously to be 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).

 

Search methods for identification of studies

 

Electronic searches

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 8, 2013), MEDLINE, EMBASE, Science Citation Index Expanded (Royle 2003), and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) portal (apps.who.int/trialsearch). The WHO ICTRP portal allows search of various trial registers including clinicaltrials.gov and International Standard Randomised Controlled Trial Number (ISRCTN) among other registers to September 2013. We have given the search strategies in Appendix 1 with the time spans for the searches.

 

Searching other resources

We handsearched 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

KG and JV or MR independently identified the trials for inclusion. KG and JV or MR listed the excluded trials with the reasons for the exclusion. We resolved any differences in opinion through discussion.

 

Data extraction and management

KG and JV or MR independently extracted the following data.

  1. Year and language of publication.
  2. Country.
  3. Year of conduct of the trial.
  4. Inclusion and exclusion criteria.
  5. Sample size.
  6. Population characteristics such as age and sex ratio.
  7. Proportion of people who underwent successful fewer-than-four-ports laparoscopic cholecystectomy.
  8. Intra-operative cholangiogram.

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 participants - 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; Savovic 2012; Savovic 2012a), the risk of bias of the trials were assessed based on the following domains.

 

Sequence generation

  • Low risk of bias (the methods used was either adequate (eg, 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 (eg, quasi-randomised studies) was improper and likely to introduce confounding).

 

Allocation concealment

  • Low risk of bias (the method used (eg, 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 (eg, 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 (ie, 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 are unlikely to make treatment effects departure from plausible values, or proper methods have been 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 (eg, complete case estimate) was clearly biased due to the underlying reasons for missingness, and the methods used to handle missing data are 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 had been 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 had been reported or similar).

For this purpose, the trial should have been registered either on the www.clinicaltrials.gov website or a similar register, or there should be a protocol (eg, published in a paper journal). In the case when the trial was run and published in the years when trial registration was not required, we scrutinised all publications reporting on the trial carefully to identify the trial objectives and outcomes and determine whether usable data were provided in the publication's results section on all outcomes specified in the trial objectives.

 

Vested interest bias

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

We classified trials with high risk of bias or uncertain risk of bias in any of the domains as trials with high risk of bias. The trials judged with low risk of bias in all domains were classified as trials with low risk of bias.

 

Measures of treatment effect

For binary outcomes, we calculated the risk ratio (RR) with 95% confidence interval (CI). RR calculations do not include trials in which no events occurred in either group, whereas risk difference calculations do. We planned to report the risk difference 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 might be used).

 

Unit of analysis issues

The unit of analysis were individual participants undergoing fewer-than-four-ports laparoscopic cholecystectomy or four-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 CIs, 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 SMD (Higgins 2011).

 

Assessment of heterogeneity

We explored heterogeneity using the Chi2 test with significance set at P value 0.10 and measured the quantity of heterogeneity using the I2 statistic (Higgins 2002). We also used overlapping of CIs on the forest plot to determine heterogeneity.

 

Assessment of reporting biases

We planned to use visual asymmetry on a funnel plot to explore reporting bias if 10 or more trials were identified (Egger 1997; Macaskill 2001). We also planned to perform linear regression approach described by Egger 1997 to determine the funnel plot asymmetry.

 

Data synthesis

 

Meta-analysis

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 conclusions, we have reported both results in the full text and the more conservative model in the abstract,  Summary of findings for the main comparison, and the plain language summary; otherwise, we have reported the results of the fixed-effect model.

 

Trial sequential analysis

We used 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. If more than one trial was published in a year, we added the trials in alphabetical order according to the last name of the first author. We constructed the trial sequential monitoring boundaries on the basis of the diversity-adjusted required information size (Wetterslev 2008; Wetterslev 2009).

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 primary 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 may be unnecessary) (Brok 2008; Wetterslev 2008; Brok 2009; Thorlund 2009; Wetterslev 2009; Thorlund 2010). For quality of life, 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 if possible, and a minimal clinically relevant difference of 0.25. In trial sequential analyses in which the accrued information size surpassed the diversity-adjusted required information size (DARIS) (ie, days of hospital stay and days of return to normal activity), we post-hoc challenged the accrued information size with trial sequential analyses based on a minimal relevant difference equal to the smallest of the 95% CIs of the meta-analysis.

 

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 to trials with emergency cholecystectomy.
  • Number of ports (one or two or three).

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

 

Sensitivity analysis

We planned to perform 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.

 

Summary of findings table

We have reported all the outcomes with at least one trial in  Summary of findings for the main comparison. This table provides a summary of the number of participants, number of trials, intervention effect estimates, and the quality of evidence for each outcome.

 

Results

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms
 

Description of studies

 

Results of the search

We identified 4780 references through electronic searches of CENTRAL (N = 761), MEDLINE (N = 1240), EMBASE (N = 1086), Science Citation Index Expanded (N = 1663), and WHO ICTRP (N = 30). We identified one further reference on handsearching of reference lists of identified trials. We excluded 1563 duplicates and 3147 clearly irrelevant references through reading abstracts. We retrieved 71 references in full text for further assessment. Three trials were ongoing trials with no interim reports available (Characteristics of ongoing studies). We excluded 58 references of 54 studies or reports. The reasons for exclusion are stated in the Characteristics of excluded studies. In total, we included 10 references of nine completed trials in this review. The reference flow is shown in Figure 1.

 FigureFigure 1. Study flow diagram.

 

Included studies

Nine trials randomised 855 participants to fewer-than-four-ports laparoscopic cholecystectomy (n = 427) and four-port laparoscopic cholecystectomy (n = 428). Four trials included low anaesthetic risk participants undergoing elective laparoscopic cholecystectomy (Kumar 2007; Lirici 2011; Abd Ellatif 2013; Saad 2013). The anaesthetic risk status was not available in the remaining five trials (Cerci 2007; Bucher 2011; Herrero 2012; Sinan 2012; Luna 2013). Seven trials stated that they included people undergoing elective laparoscopic cholecystectomy (Kumar 2007; Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Saad 2013). The information on the inclusion of emergency laparoscopic cholecystectomies was not available in two trials (Cerci 2007; Luna 2013). The mean age ranged between 39 and 50 years in the eight trials that provided this information (Kumar 2007; Cerci 2007; Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Saad 2013). The proportion of females ranged between 23% and 83% in the seven trials that reported this information (Cerci 2007; Kumar 2007; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Saad 2013). In seven trials, a single umbilical port was used (Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Luna 2013; Saad 2013). There were two channels (Abd Ellatif 2013), three channels (Bucher 2011; Lirici 2011; Herrero 2012; Saad 2013), or four channels (Luna 2013) in the single port through which the instruments could be introduced. The number of channels in the single port was not available in one trial (Sinan 2012). The length of the umbilical incision ranged between 15 and 25 mm in the five trials that provided this information (Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Saad 2013). The length of the incision was not reported in the two other trials in which a single port was used (Abd Ellatif 2013; Luna 2013). Two trials included three ports, where one of the subcostal incisions was left out in the intervention group (Cerci 2007; Kumar 2007).

 

Excluded studies

We excluded some studies because they were not randomised trials. We excluded othertrials because the control group was not standard laparoscopic cholecystectomy although the authors stated that the control group was standard laparoscopic cholecystectomy. We considered standard laparoscopic cholecystectomy as that performed with two ports of at least 10 mm in size and two ports of at least 5 mm in size. A few trials were ongoing trials and it is difficult to judge whether these trials will meet the inclusion criteria in future because of the limited information available from interim reports or trial registers. The reasons for exclusion in the individual trials are stated in the 'Characteristics of excluded studies' table.

 

Risk of bias in included studies

The risk of bias is summarised in Figure 2. The risk of bias in individual trials is stated in Figure 3. Only one trial had low risk of bias (Saad 2013). The remaining trials had high risk of bias (Cerci 2007; Kumar 2007; Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Luna 2013).

 FigureFigure 2. Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
 FigureFigure 3. Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

 

Effects of interventions

See:  Summary of findings for the main comparison Fewer-than-four ports compared with four ports for laparoscopic cholecystectomy

Fewer-than-four-ports laparoscopic cholecystectomy was successful in between 90% and 100% of the participants in the seven trials in which it was possible to calculate this (Kumar 2007; Bucher 2011; Lirici 2011; Herrero 2012; Abd Ellatif 2013; Luna 2013; Saad 2013). The remaining participants were mostly converted to four-port laparoscopic cholecystectomy, but some were also converted to open cholecystectomy. The findings are summarised in  Summary of findings for the main comparison.

 

Primary outcomes

 

Mortality

Mortality data were available from seven trials (Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Luna 2013; Saad 2013). There was no mortality in either group in these seven trials (318 participants in fewer-than-four-ports laparoscopic cholecystectomy group and 316 participants in four-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 as before. Instead, we used a proportion of 0.2% in the control group based on data from approximately 30,000 people included in a database in Switzerland (Giger 2011). The proportion of information accrued was only 0.18% of the DARIS and so the trial sequential monitoring boundaries were not drawn (Figure 4). The cumulative Z-curve did not cross the conventional statistical boundaries.

 FigureFigure 4. Trial sequential analysis of mortality

The diversity-adjusted required information size (DARIS) was calculated to 352,564 participants, based on the proportion of participants 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 634 participants in seven trials, only 0.18% 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 (dotted red line) have also not been crossed by the cumulative Z-curve.

 

Surgical morbidity (serious adverse events)

Seven trials reported the proportion of participants with serious adverse events (Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Luna 2013; Saad 2013). There were no serious adverse events in the four-port group. There was no significant difference in the proportion of participants with serious adverse events between the fewer-than-four-ports group and four-port laparoscopic cholecystectomy group using the fixed-effect model (RR 3.93; 95% CI 0.86 to 18.04) ( Analysis 1.1). There were no changes in the results with the random-effects model for the meta-analysis or by using risk difference as the effect measure. Since there were no serious adverse events in the control group, we were unable to use the control group proportion for the calculation of the required information size of the trial sequential analysis as before. Instead, we used a proportion of 0.3% in the control group based on data from approximately 30,000 people included in a database in Switzerland as before (Giger 2011). The proportion of information accrued was only 0.27% of the DARIS and so the trial sequential monitoring boundaries were not drawn (Figure 5). The cumulative Z-curve does not cross the conventional statistical boundaries.

 FigureFigure 5. Trial sequential analysis of serious adverse events

The diversity-adjusted required information size (DARIS) was calculated to 234,831 participants, based on the proportion of participants in the control group with the outcome of 0.3%, 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 634 participants in seven trials, only 0.27% 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 (dotted red line) have also not been crossed by the cumulative Z-curve.

 

Quality of life

Four trials reported this outcome (Bucher 2011; Lirici 2011; Abd Ellatif 2013; Saad 2013). The quality of life was measured between 10 days and one month after surgery in these trials (Bucher 2011; Lirici 2011; Abd Ellatif 2013; Saad 2013). The scales used included EQ-5D (Abd Ellatif 2013), Gastrointestinal Quality of Life Index (GIQLI) (Saad 2013), Short Form - 12 (SF-12) (Bucher 2011), and Short Form - 36 (Lirici 2011). Quality of life was significantly better with fewer-than-four-ports than four-port laparoscopic cholecystectomy with the fixed-effect model (SMD 0.21; 95% CI 0.03 to 0.38). There was no significant difference between the two treatments with the random-effects model (SMD 0.18; 95% CI -0.05 to 0.42) ( Analysis 1.2). Trial sequential analysis was not performed since the software does not allow calculation of SMD.

 

Secondary outcomes

 

Conversion to open cholecystectomy

Five trials reported the proportion of participants in whom the laparoscopic cholecystectomy had to be converted to open cholecystectomy (Cerci 2007; Kumar 2007; Bucher 2011; Lirici 2011; Abd Ellatif 2013). There was no significant difference in the proportion of participants in whom the laparoscopic cholecystectomy had to be converted to open cholecystectomy between the two groups using the fixed-effect model (RR 0.68; 95% CI 0.19 to 2.35) ( Analysis 1.3). Using the random-effects model or risk difference did not alter the conclusions. Trial sequential analysis revealed that the proportion of information accrued was only 1.42% of the DARIS and so the trial sequential monitoring boundaries were not drawn (Figure 6). The cumulative Z-curve did not cross the conventional statistical boundaries.

 FigureFigure 6. Trial sequential analysis of conversion to open cholecystectomy

The diversity-adjusted required information size (DARIS) was calculated to 40,918 participants, based on the proportion of patients in the control group with the outcome of 1.7%, 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 581 participants in five trials, only 1.42% 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 (dotted red line) have also not been crossed by the cumulative Z-curve.

 

Operating time

All the trials reported operating time. The fewer-than-four-ports laparoscopic cholecystectomy took seven minutes longer to complete than the four-ports laparoscopic cholecystectomy using the fixed-effect model (MD 14.44 minutes; 95% CI 5.95 to 22.93) ( Analysis 1.4). There was no change in the results by using the random-effects model. Trial sequential analysis revealed that the trial sequential boundaries were crossed suggesting that the operating time was likely to be longer in the fewer-than-four-ports group than four-ports group with low risk of random errors (Figure 7).

 FigureFigure 7. Trial sequential analysis of operating time

The diversity-adjusted required information size (DARIS) was 1124 participants based on a minimal relevant difference (MIRD) of 15 minutes, a variance (VAR) of 385.03, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 95.2%.The cumulative Z-curve (blue line) crosses the conventional boundary (dotted red line) and the trial sequential monitoring boundaries (continuous red line) after the seventh trial. Although the DARIS has not been reached after accrual of 855 participants in nine trials, the results suggest that operating time is longer with fewer-than-four-ports laparoscopic cholecystectomy as compared with four-ports laparoscopic cholecystectomy with low risk of random errors.

 

Hospital stay

Six trials reported the length of hospital stay (Cerci 2007; Kumar 2007; Bucher 2011; Lirici 2011; Abd Ellatif 2013; Saad 2013). Hospital stay was significantly longer in the fewer-than-four-ports group than four-ports group using the fixed-effect model (MD 0.14 days; 95% CI 0.02 to 0.26). There was no significant difference in the hospital stay between the groups by using the random-effects model (MD -0.01 days; 95% CI -0.28 to 0.26) ( Analysis 1.5). One trial reported the proportion of participants discharged as day-surgery laparoscopic cholecystectomy (Herrero 2012). There was no significant difference in the proportion of participants who underwent day-surgery laparoscopic cholecystectomy between the groups (RR 0.92; 95% CI 0.70 to 1.22) ( Analysis 1.6). Trial sequential analysis revealed that the DARIS has been reached and the conventional boundaries were not crossed (Figure 8). This suggests that there is unlikely to be a difference in the length of hospital stay between the groups with low risk of random errors. Trial sequential analysis after changing the minimal relevant difference (MIRD) to the smallest limit of the 95% CI of the meta-analysis showed that the proportion of information accrued was only 26.09% of the DARIS and that neither the trial sequential monitoring boundaries nor the conventional boundaries were crossed (Figure 9).

 FigureFigure 8. Trial sequential analysis of hospital stay
The diversity-adjusted required information size (DARIS) was 222 participants based on a minimal relevant difference (MIRD) of 1 day, a variance (VAR) of 1.29, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 81.55%. Seven hundred and thirty-one participants were accrued in six trials. The cumulative Z-curve (blue line) crosses the DARIS after the third trial (vertical red line). However, it does not cross the conventional boundaries (dotted red line). This suggests that there is no significant difference in the length of hospital stay between fewer-than-four-ports laparoscopic cholecystectomy versus four-ports laparoscopic cholecystectomy with low risk of random errors.
 FigureFigure 9. Trial sequential analysis of hospital stay with smallest confidence interval used as minimal relevant difference

The diversity-adjusted required information size (DARIS) was 2802 participants based on a minimal relevant difference (MIRD) of 0.28 days, a variance (VAR) of 1.29, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 81.55%. After accruing 731 participants in six trials, only 26.09% of the DARIS has been reached. Accordingly, the trial sequential analysis does not show the futility area. As shown, the cumulative Z-curve (blue line) does not cross the trial sequential boundaries (red line). Conventional boundaries (dotted red line) have also not been crossed by the cumulative Z-curve.

 

Return to activity and work

Two trials reported the time taken to return to activity (Kumar 2007; Abd Ellatif 2013). The time taken to return to normal activity was significantly shorter in the fewer-than-four-ports group than the four-ports group using the fixed-effect model (MD -1.20 days; 95% CI -1.58 to -0.81) ( Analysis 1.7). There was no change in the results between the two groups using the random-effects model. Trial sequential analysis revealed that the trial sequential boundaries were crossed suggesting that the time taken to return to activity was likely to be shorter in the fewer-than-four-ports group than four-ports group with low risk of random errors (Figure 10). The trial sequential analysis results did not change by changing the MIRD to the smallest of the 95% CI of the meta-analysis (Figure 11).

 FigureFigure 10. Trial sequential analysis of return to normal activity

The diversity-adjusted required information size (DARIS) was 200 participants based on a minimal relevant difference (MIRD) of 1 day, a variance (VAR) of 6.35, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 0%. Three hundred and twenty-five participants were accrued in two trials. The cumulative Z-curve crosses the trial sequential monitoring boundaries (continuous red lines) and the conventional boundaries (dotted red line) after the second trial. The results are compatible with significantly fewer days to return to normal activity in the fewer-than-four-ports group with four-ports group with low risk of random errors.
 FigureFigure 11. Trial sequential analysis of return to normal activity with smallest confidence interval used as minimal relevant difference

The diversity-adjusted required information size (DARIS) was 304 participants based on a minimal relevant difference (MIRD) of 0.81 day, a variance (VAR) of 6.35, an alpha (a) of 5%, a beta (b) of 20%, and a diversity (D2) of 0%. Three hundred and twenty-five participants were accrued in two trials. The cumulative Z-curve crosses the trial sequential monitoring boundaries (continuous red lines) and the conventional boundaries (dotted red line) after the second trial. The results are compatible with significantly fewer days to return to normal activity in the fewer-than-four-ports group with four-ports group with low risk of random errors.

One trial reported the time taken to return to work (Bucher 2011). The time taken to return to work was shorter by two days in the fewer-than-four-ports group compared with four-port laparoscopic cholecystectomy (MD -2.00 days; 95% CI -3.31 to -0.69) ( Analysis 1.8). Since this was the only trial, the issue of fixed-effect versus random-effects meta-analysis does not arise and trial sequential analysis was not performed.

 

Cosmesis

Two trials reported cosmesis at multiple time points (Abd Ellatif 2013; Saad 2013). We obtained the values at six months and one year since wound remodelling can take place even one year after surgery (Gurtner 2008). The cosmesis scores were significantly better in the fewer-than-four-ports group than four-ports group using the fixed-effect model (SMD 0.46; 95% CI 0.24 to 0.69). There was no significant difference in the cosmesis scores between the groups using the random-effects model (SMD 0.37; 95% CI -0.10 to 0.84) ( Analysis 1.9). Trial sequential analysis cannot be performed when SMD is calculated.

 

Subgroup analysis

Two planned subgroup analyses (trials with high risk of bias versus low risk of bias and elective cholecystectomy versus 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 had a possible inclusion of emergency laparoscopic cholecystectomy (Cerci 2007)). Such a subgroup analysis is prone to error.

We performed a subgroup analysis based on the number of ports. We compared whether the results were different between the trials that used a single port versus those that used three ports. The Chi2 test for subgroup differences was not statistically significant for any of the outcomes in which the two subgroups were represented (conversion to open cholecystectomy ( Analysis 1.3; P value = 0.62), hospital stay ( Analysis 1.5; P value = 0.67), return to normal activity ( Analysis 1.7; P value = 0.89) except operating time ( Analysis 1.4; P value = 0.001). For operating time, the operating time was longer for one-port than four-ports group (MD 21.04 minutes; 95% CI 10.45 to 31.62) while there was no significant difference in the operating time between three-port and four-port groups (MD -5.32 minutes; 95% CI -17.38 to 6.73) ( Analysis 1.4).

 

Sensitivity analysis

We did not perform the planned 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). This was because there were no post-randomisation drop-outs in six of the nine included trials (Cerci 2007; Kumar 2007; Bucher 2011; Lirici 2011; Abd Ellatif 2013; Saad 2013). In the remaining three trials, it was not clear whether there were any post-randomisation drop-outs (Herrero 2012; Sinan 2012; Luna 2013).

We performed a sensitivity analysis by excluding the trials in which either the mean or the standard deviation or both were imputed. This was only possible for quality of life ( Analysis 2.1), operating time ( Analysis 2.2), hospital stay ( Analysis 2.3), and return to normal activity ( Analysis 2.4). There was no change in the conclusions by performing this sensitivity analysis for operating time, hospital stay, and return to normal activity. However, there was no significant difference in the quality of life between the groups when the trials in which either the mean or the standard deviation or both were imputed (SMD 0.14; 95% CI -0.08 to 0.36).

Of the remaining continuous outcomes, there was no imputation of mean or standard deviation of cosmetic score in the two trials that reported this outcome (Abd Ellatif 2013; Saad 2013). Although the mean and the standard deviation were imputed for return to work, we did not perform a sensitivity analysis since only one trial reported this outcome ( Analysis 1.8).

 

Funnel plot

We did not explore reporting bias using funnel plot because this review included nine trials only.

 

Discussion

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms
 

Summary of main results

In this review, we did not find any difference in mortality or morbidity between fewer-than-four-ports laparoscopic cholecystectomy versus four-port laparoscopic cholecystectomy. There were no deaths in the seven trials that reported this outcome (Bucher 2011; Lirici 2011; Herrero 2012; Sinan 2012; Abd Ellatif 2013; Luna 2013; Saad 2013). Mortality after laparoscopic cholecystectomy is approximately 0.2% (Giger 2011). Most of the trials included in this review randomised people with low anaesthetic risk and undergoing elective laparoscopic cholecystectomy. Therefore, it is not surprising that there was no mortality in either group. There was no significant difference in the proportion of people who developed serious adverse events. However, it is unsure if this was because there was no difference in the proportion of people who develop serious adverse events between fewer-than-four-ports laparoscopic cholecystectomy and four-port laparoscopic cholecystectomy or whether this is because of lack of evidence of a difference between the groups. This is because of wide CI values that overlapped no effect (RR of 1) and a 25% relative risk reduction or increase (0.75 or 1.25). It should be noted that the proportion of people with serious adverse events was higher in the fewer-than-four-ports group (6/318 (1.9%)) versus four-port laparoscopic cholecystectomy (0/318 (0%)). This could have happened by chance, but there is also a possibility that this was a true difference. Until further trials demonstrate the safety of fewer-than-four-ports laparoscopic cholecystectomy, it cannot be recommended routinely particularly because it does not seem to offer any significant benefits in terms of improved quality of life or decreased length of hospital stay. Although the fewer-than-four-ports group returned to normal activity and work significantly earlier compared to the four-port laparoscopic cholecystectomy group, it must be noted that the trials appeared to lack blinding, which may have a significant influence on these outcomes.

Given the low incidence of complications in four-port laparoscopic cholecystectomy, it is unlikely that the trials assessing the fewer ports can be powered to measure a reduction in the complications after laparoscopic cholecystectomy. Use of pain as one of the primary outcomes can also be misleading, as the clinical significance of reduction in pain scores measured by visual analogue scale is unknown for laparoscopic cholecystectomy. Future trials assessing fewer-than-four ports could use the length of hospital stay or the proportion of people discharged as day-surgery laparoscopic cholecystectomy as the outcome based on which sample size calculations are performed to decrease type I and type II errors. This has significant cost benefits to the healthcare funder. Any cost savings can be used to fund other treatments or other socially beneficial projects in a state-sponsored health scheme.

It is important that the participants and outcome assessors are blinded to the groups if discharge following day-procedure laparoscopic cholecystectomy is used as primary outcome in such trials, as the decision to discharge a participant following day procedure is subjective. Quality of life is another outcome that should be measured in such trials as they have implications in cost-effectiveness analysis. Cosmesis is only one aspect of quality of life and cannot be used in any economic health evaluation. However, it is an important patient outcome. Wound remodelling occurs even at one year after surgery (Gurtner 2008). Trials should follow participants for at least one year if cosmesis is assessed. It is important to perform intention-to-treat analyses so that the mean clinical efficacy and cost-effectiveness of the intervention (fewer-than-four ports) can be easily determined and used in economic evaluation.

 

Overall completeness and applicability of evidence

This review is applicable only to elective laparoscopic cholecystectomy performed in low anaesthetic risk participants as most trials included such participants. Most of the trials excluded moderately obese (Herrero 2012; Abd Ellatif 2013; Luna 2013), severely obese (Lirici 2011; Saad 2013), or very severely obese participants undergoing laparoscopic cholecystectomy (Sinan 2012). Therefore, the findings of the review are applicable only in non-obese people undergoing laparoscopic cholecystectomy.

 

Quality of the evidence

Only one trial was of low risk of bias (Saad 2013). There was moderate to severe inconsistency in some of the outcomes, such as hospital stay and operating time. Overall, the evidence is of very low quality as shown in  Summary of findings for the main comparison. However, it must be noted that this is the best level of evidence available.

 

Potential biases in the review process

We imputed the mean from median and standard deviation based on guidance from the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). This might have introduced bias in the review process.

 

Agreements and disagreements with other studies or reviews

Several reviews exist on fewer-than-four ports (mostly single-port laparoscopic cholecystectomy) versus conventional laparoscopic cholecystectomy in people undergoing laparoscopic cholecystectomy for various indications such as symptomatic gallstones and gallbladder polyps. Some reviews suggested that single-port laparoscopic cholecystectomy was safe (Markar 2012; Song 2012) and effective (Garg 2012a; Pisanu 2012), and can be offered as alternatives to conventional laparoscopic cholecystectomy while other reviews suggested that there was no benefit with single-port laparoscopic cholecystectomy or that there was a balance between benefits and harms and suggested a more cautious approach (Sun 2009; Hall 2012; Wang 2012). We have recommended that using fewer-than-four ports should be reserved to well-designed randomised clinical trials. Some of the reasons for our disagreements with other researchers are that the other researchers included trials in which the control group was not necessarily four ports with at least two 10-mm ports and two 5-mm ports, misinterpretation between lack of evidence of harm and lack of harm, and use of very early cosmesis scores that are ultimately of no clinical significance.

 

Authors' conclusions

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

 

Implications for practice

The safety profile of using fewer-than-four ports is yet to be established and fewer-than-four-ports laparoscopic cholecystectomy should be reserved to well-designed randomised clinical trials. We found very low quality evidence on clinical outcomes to support the use of fewer-than-four-ports laparoscopic cholecystectomy. The shorter time taken to return to normal activity and time taken to return to work associated with using fewer-than-four ports comes from evidence of very low quality.

 
Implications for research

Further well-designed randomised clinical trial with low risk of random and systematic errors are necessary. Such trials should be designed according to the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) statement and reported according to the CONSORT (CONsolidated Standards Of Reporting Trials) statement (Moher 2010; Chan 2013).

 

Acknowledgements

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

To the Cochrane Hepato-Biliary Group for the support that they have provided.

Peer reviewers: Stefano Trastulli, Italy; Giorgakis Emmanouil, UK.
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

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms
Download statistical data

 
Comparison 1. Fewer-than-four ports versus four ports

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Serious adverse events7634Risk Ratio (M-H, Fixed, 95% CI)3.93 [0.86, 18.04]

    1.1 One port
7634Risk Ratio (M-H, Fixed, 95% CI)3.93 [0.86, 18.04]

 2 Quality of life4510Std. Mean Difference (IV, Random, 95% CI)0.18 [-0.05, 0.42]

    2.1 One port
4510Std. Mean Difference (IV, Random, 95% CI)0.18 [-0.05, 0.42]

 3 Conversion to open cholecystectomy5581Risk Ratio (M-H, Fixed, 95% CI)0.68 [0.19, 2.35]

    3.1 One port
3360Risk Ratio (M-H, Fixed, 95% CI)0.33 [0.01, 7.72]

    3.2 Three ports
2221Risk Ratio (M-H, Fixed, 95% CI)0.79 [0.20, 3.14]

 4 Operating time9855Mean Difference (IV, Random, 95% CI)14.44 [5.95, 22.93]

    4.1 One port
7634Mean Difference (IV, Random, 95% CI)21.04 [10.45, 31.62]

    4.2 Three ports
2221Mean Difference (IV, Random, 95% CI)-5.32 [-17.38, 6.73]

 5 Hospital stay6731Mean Difference (IV, Random, 95% CI)-0.01 [-0.28, 0.26]

    5.1 One port
4510Mean Difference (IV, Random, 95% CI)0.02 [-0.32, 0.37]

    5.2 Three ports
2221Mean Difference (IV, Random, 95% CI)-0.09 [-0.47, 0.30]

 6 Proportion discharged as day-surgery150Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.70, 1.22]

    6.1 One port
150Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.70, 1.22]

 7 Return to normal activity2325Mean Difference (IV, Fixed, 95% CI)-1.20 [-1.58, -0.81]

    7.1 One port
1250Mean Difference (IV, Fixed, 95% CI)-1.20 [-1.59, -0.81]

    7.2 Three ports
175Mean Difference (IV, Fixed, 95% CI)-0.90 [-5.08, 3.28]

 8 Return to work1150Mean Difference (IV, Random, 95% CI)-2.0 [-3.31, -0.69]

    8.1 One port
1150Mean Difference (IV, Random, 95% CI)-2.0 [-3.31, -0.69]

 9 Cosmetic score2317Std. Mean Difference (IV, Random, 95% CI)0.37 [-0.10, 0.84]

    9.1 One port
2317Std. Mean Difference (IV, Random, 95% CI)0.37 [-0.10, 0.84]

 
Comparison 2. Fewer-than-four ports versus four ports (sensitivity analysis)

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Quality of life2320Std. Mean Difference (IV, Fixed, 95% CI)0.14 [-0.08, 0.36]

    1.1 One port
2320Std. Mean Difference (IV, Fixed, 95% CI)0.14 [-0.08, 0.36]

 2 Operating time7665Mean Difference (IV, Fixed, 95% CI)7.40 [5.48, 9.31]

    2.1 One port
5444Mean Difference (IV, Fixed, 95% CI)9.45 [7.34, 11.57]

    2.2 Three ports
2221Mean Difference (IV, Fixed, 95% CI)-2.03 [-6.56, 2.50]

 3 Hospital stay3466Mean Difference (IV, Random, 95% CI)0.21 [0.08, 0.35]

    3.1 One port
2320Mean Difference (IV, Random, 95% CI)0.21 [0.02, 0.41]

    3.2 Three ports
1146Mean Difference (IV, Random, 95% CI)0.15 [-0.34, 0.64]

 4 Return to normal activity1250Mean Difference (IV, Fixed, 95% CI)-1.20 [-1.59, -0.81]

    4.1 One port
1250Mean Difference (IV, Fixed, 95% CI)-1.20 [-1.59, -0.81]

 

Appendices

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms
 

Appendix 1. Search strategies


DatabasePeriod of searchSearch strategy

Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane LibraryIssue 8, 2013#1 minilaparoscopic OR mini-laparoscopic OR minisite OR mini-site OR miniport OR mini-port OR one OR two OR three OR transumbilical OR trans-umbilical
#2 MeSH descriptor Miniaturization explode all trees
#3 MeSH descriptor Microsurgery explode all trees
#4 (#1 OR #2 OR #3)
#5 (laparoscop* OR celioscop* OR coelioscop* OR abdominoscop* OR peritoneoscop*) AND (cholecystecto* OR colecystecto*)
#6 MeSH descriptor Cholecystectomy, Laparoscopic explode all trees
#7 (#5 OR #6)
#8 (#4 AND #7)

MEDLINE (PubMed)1987 to September 2013(minilaparoscopic OR mini-laparoscopic OR minisite OR mini-site OR miniport OR mini-port OR one OR two OR three OR transumbilical OR trans-umbilical OR "Miniaturization"[MeSH] OR "Microsurgery"[MeSH]) AND (((laparoscop* OR celioscop* OR coelioscop* OR abdominoscop* OR peritoneoscop*) AND (cholecystecto* OR colecystecto*)) OR "cholecystectomy, laparoscopic"[MeSH]) AND (((randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized controlled trials [mh] OR random allocation [mh] OR double-blind method [mh] OR single-blind method [mh] OR clinical trial [pt] OR clinical trials [mh] OR ("clinical trial" [tw]) OR ((singl* [tw] OR doubl* [tw] OR trebl* [tw] OR tripl* [tw]) AND (mask* [tw] OR blind* [tw])) OR (placebos [mh] OR placebo* [tw] OR random* [tw] OR research design [mh:noexp]) NOT (animals [mh] NOT human [mh]))))

EMBASE (Ovid SP)1987 to September 20131 exp CROSSOVER PROCEDURE/
2 exp DOUBLE BLIND PROCEDURE/
3 exp SINGLE BLIND PROCEDURE/
4 exp RANDOMIZED CONTROLLED TRIAL/
5 (((RANDOM* or FACTORIAL* or CROSSOVER* or CROSS) and OVER*) or PLACEBO* or (DOUBL* and BLIND*) or (SINGL* and BLIND*) or ASSIGN* or ALLOCAT* or VOLUNTEER*).af.
6 1 or 2 or 3 or 4 or 5
7 (minilaparoscopic or mini-laparoscopic or minisite or mini-site or miniport or mini-port or one or two or three or transumbilical OR trans-umbilical).af.
8 exp microsurgery/
9 7 or 8
10 (laparoscop* or celioscop* or coelioscop* or abdominoscop* or peritoneoscop*).af.
11 exp laparoscopic surgery/ or exp laparoscopy/
12 10 or 11
13 (cholecystect* or colecystect*).af.
14 exp cholecystectomy/
15 13 or 14
16 6 and 9 and 12 and 15

Science Citation Index Expanded (apps.isiknowledge.com)1987 to September 2013#1 TS=( minilaparoscopic OR mini-laparoscopic OR minisite OR mini-site OR miniport OR mini-port OR one OR two OR three OR transumbilical OR trans-umbilical)
#2 TS=(laparoscop* OR celioscop* OR coelioscop* OR abdominoscop* OR peritoneoscop*)
#3 TS=(cholecystecto* OR colecystecto*)
#4 TS=(random* OR rct* OR crossover OR masked OR blind* OR placebo* OR meta-analysis OR systematic review* OR meta-analys*)
#5 #4 AND #3 AND #2 AND #1

World Health Organization International Clinical Trials Registry Platform Portal (apps.who.int/trialsearch/)September 2013port AND laparoscopic cholecystectomy



 

Contributions of authors

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

KSG selected trials, extracted data, and wrote the review.

JV or MR independently assessed the trials for inclusion and extracted the data.

BRD critically commented on the review and provided advice for improving the review.

 

Declarations of interest

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

None known.

 

Sources of support

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms
 

Internal sources

  • None, Not specified.

 

External sources

  • None, Not specified.

 

Differences between protocol and review

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

  1. The control group has been defined very clearly now.
  2. The outcomes have been divided into primary and secondary. Important patient outcomes have been used. The assessment of the risk of bias has been revised in line with the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).
  3. S Junnarkar was unable to perform the data extraction as per the protocol. J Vaughan or M Rossi performed the data extraction instead.

 

Notes

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Notes
  17. Index terms

There are changes in the review authors' team; the review has been prepared by KS Gurusamy, J Vaughan, M Rossi, and BR Davidson. The protocol was prepared by KS Gurusamy, S Junnarkar, and BR Davidson.

* Indicates the major publication for the study

References

References to studies included in this review

  1. Top of page
  2. AbstractRésumé scientifique
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Notes
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
Abd Ellatif 2013 {published data only}
  • Abd Ellatif ME, Askar WA, Abbas AE, Noaman N, Negm A, El-Morsy G, et al. Quality-of-life measures after single-access versus conventional laparoscopic cholecystectomy: a prospective randomized study. Surgical Endoscopy 2013;27(6):1896-906.
Bucher 2011 {published data only}
Cerci 2007 {published data only}
Herrero 2012 {published data only}
  • Herrero E, Cugat E, García-Domingo MI, Camps J, Porta R, Carvajal F, et al. A randomised prospective comparative study between laparoscopic cholecystectomy and single port cholecystectomy in a major outpatient surgery unit. Cirugia Espanola 2012;90(10):641-6.
Kumar 2007 {published data only}
  • Kumar M, Agrawal CS, Gupta RK. Three-port versus standard four-port laparoscopic cholecystectomy: A randomized controlled clinical trial in a community-based teaching hospital in eastern Nepal. Journal of the Society of Laparoendoscopic Surgeons 2007;11(3):358-62.
Lirici 2011 {published data only}
  • Lirici MM, Califano AD, Angelini P, Corcione F. Laparo-endoscopic single site cholecystectomy versus standard laparoscopic cholecystectomy: results of a pilot randomized trial. American Journal of Surgery 2011;202(1):45-52.
Luna 2013 {published data only}
  • Luna RA, Nogueira DB, Varela PS, De ORNE, Norton MJR, Do Carmo BRL, et al. A prospective, randomized comparison of pain, inflammatory response, and short-term outcomes between single port and laparoscopic cholecystectomy. Surgical Endoscopy 2013;27(4):1254-9.
Saad 2013 {published data only}
  • Saad S, Strassel V, Martin C, Sauerland S. Single port-versus mini-versus conventional laparoscopic cholecystectomy-a blinded randomized controlled trial. Surgical Endoscopy 2013;27(Suppl 1):S14.
  • Saad S, Strassel V, Sauerland S. Randomized clinical trial of single-port, minilaparoscopic and conventional laparoscopic cholecystectomy. British Journal of Surgery 2013;100(3):339-49.
Sinan 2012 {published data only}
  • Sinan H, Demirbas S, Ozer MT, Sucullu I, Akyol M. Single-incision laparoscopic cholecystectomy versus laparoscopic cholecystectomy: a prospective randomized study. Surgical Laparoscopy, Endoscopy and Percutaneous Techniques 2012;22(1):12-6.

References to studies excluded from this review

  1. Top of page
  2. AbstractRésumé scientifique
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Notes
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
Allemann 2012 {published data only}
  • Allemann P. Safety and cost-effectiveness study of single port laparoscopic cholecystectomies (SPoCOT), 2012. clinicaltrials.gov/show/NCT00974194 (accessed 13 February 2014).
Asakuma 2011 {published data only}
  • Asakuma M. Randomized controlled trial to evaluate the superiority of the Single Port Cholecystectomy (SPC) on reduction of postoperative pain, compared with the conventional laparoscopic cholecystectomy at the single institution, 2011. www.umin.ac.jp/ctr/index.htm (accessed 13 February 2014).
Bansal 2012 {published data only}
  • Bansal VK. A prospective randomized control trial comparing the outcome of the two modalities of treatment of gall stone disease viz. single incision laparoscopic cholecystectomy with standard 4 port laparoscopic cholecystectomy, 2012. www.ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=5253 (accessed 13 February 2014).
Barugola 2011 {published data only}
  • Barugola G. Single port laparoscopic cholecystectomy versus four port laparoscopic cholecystectomy: impact on postoperative pain, 2011. clinicaltrials.gov/show/NCT01348620 (accessed 13 February 2014).
Bingener-Casey 2012 {published data only}
  • Bingener-Casey J. Comparative effectiveness of novel minimally invasive procedures, 2012. clinicaltrials.gov/show/NCT01489436 (accessed 13 February 2014).
Bresadola 1999 {published data only}
Broeders 2010 {published data only}
Brown 2013 {published data only}
  • Brown KM, Moore BT, Sorensen GB, Boettger CH, Tang F, Jones PG, et al. Patient-reported outcomes after single-incision versus traditional laparoscopic cholecystectomy: a randomized prospective trial. Surgical Endoscopy 2013;27(9):3108-15.
Cao 2011 {published data only}
  • Cao ZG, Cai W, Qin MF, Zhao HZ, Yue P, Li Y. Randomized clinical trial of single-incision versus conventional laparoscopic cholecystectomy: short-term operative outcomes. Surgical Laparoscopy, Endoscopy and Percutaneous Techniques 2011;21(5):311-3.
Chang 2013 {published data only}
  • Chang SK, Wang YL, Shen L, Iyer SG, Shaik AB, Lomanto D. Interim report: A randomized controlled trial comparing postoperative pain in single-incision laparoscopic cholecystectomy and conventional laparoscopic cholecystectomy. Asian Journal of Endoscopic Surgery 2013;6(1):14-20.
Chen 2002 {published data only}
  • Chen TW, Hsieh CB, Huang SH, Yu JC, Liu YC, Monduzzi Editore MEME. Learning curves of an inexperienced surgeon for three-port microlaparoscopic cholecystectomy and four-port laparoscopic cholecystectomy. XXXIII World Congress of the International College of Surgeons - ICS 2002. 2002:99-103.
Cockbain 2013 {published data only}
Dam 2011 {published data only}
  • Dam DAV. Single Incision, MiniPort or convEntional Laparoscopic surgery for uncomplicated sympthomatic cholecystolithiasis (SIMPEL-trial), 2011. www.trialregister.nl/trialreg/admin/rctview.asp?TC=3100 (accessed 13 February 2014).
de Carvalho 2013 {published data only}
  • de Carvalho LFA, Fierens K, Kint M. Mini-laparoscopic versus conventional laparoscopic cholecystectomy: a randomized controlled trial. Journal of Laparoendoscopic & Advanced Surgical Techniques 2013;23(2):109-16.
Garg 2012 {published data only}
  • Garg P, Thakur JD, Singh I, Nain N, Mittal G, Gupta V. A prospective controlled trial comparing single-incision and conventional laparoscopic cholecystectomy: caution before damage control. Surgical Laparoscopy, Endoscopy and Percutaneous Techniques 2012;22(3):220-5.
Gupta 2005 {published data only}
  • Gupta A, Shrivastava UK, Kumar P, Burman D. Minilaparoscopic versus laparoscopic cholecystectomy: a randomised controlled trial. Tropical Gastroenterology 2005;26(3):149-51.
Hansen 2011 {published data only}
  • Hansen P. A randomized trial of single port laparoscopic cholecystectomy versus four port laparoscopic cholecystectomy, 2011. clinicaltrials.gov/show/NCT00892879 (accessed 13 February 2014).
Hauters 2013 {published data only}
  • Hauters P, Auvray S, Cardin JL, Papillon M, Delaby J, Dabrowski A, et al. Comparison between single-incision and conventional laparoscopic cholecystectomy: a prospective trial of the Club Coelio. Surgical Endoscopy 2013;27(5):1689-94.
Hu 2005 {published data only}
  • Hu H. Clinical application and study on three-port-looping laparoscopic cholecystectomy. China Journal of Endoscopy 2005;11:552.
Hu 2010 {published data only}
Jorgensen 2010 {published data only}
  • Jorgensen LN. Efficacy of transumbilical versus standard laparoscopic cholecystectomy on postoperative pain, 2010. clinicaltrials.gov/show/NCT01268748 (accessed 13 February 2014).
Khorgami 2011 {published data only}
  • Khorgami Z. Comparison of perioperative outcomes following four port, three port and single incision laparoscopic cholecystectomy in patients of Shariati hospital in 2011. www.irct.ir/searchresult.php?id=2982&number=4 (accessed 13 February 2014).
Kim 2009 {published data only}
  • Kim SS, Kim SH, Mun SP. Should subcostal and lateral trocars be used in laparoscopic cholecystectomy? A randomized, prospective study. Journal of Laparoendoscopic and Advanced Surgical Techniques. Part A 2009;19(6):749-53.
Lai 2011 {published data only}
  • Lai EC, Yang GP, Tang CN, Yih PC, Chan OC, Li MK. Prospective randomized comparative study of single incision laparoscopic cholecystectomy versus conventional four-port laparoscopic cholecystectomy. American Journal of Surgery 2011;202(3):254-8.
Lee 2010 {published data only}
Leung 2011 {published data only}
  • Leung D, Denham W, Salabat M, Butt Z, Barrera E, Ujiki M. Single-incision laparoscopic cholecystectomy results in similar short-term post-operative pain and quality of life scores when compared to multi-incision: A prospective randomized blinded comparison. Surgical Endoscopy and Other Interventional Techniques 2011;25(1 Suppl):S239.
Limberger 2005 {published data only}
  • Limberger A, Pluszcyk T, Schilling M. [Laparoscopic cholecystectomy. Preliminary results of a comparison of 2 and 3 trocar operation techniques]. Chirurgische Praxis 2005;64(1):35-40.
Ma 2011 {published data only}
  • Ma J, Cassera MA, Spaun GO, Hammill CW, Hansen PD, Aliabadi-Wahle S. Randomized controlled trial comparing single-port laparoscopic cholecystectomy and four-port laparoscopic cholecystectomy. Annals of Surgery 2011;254(1):22-7.
Madureira 2013 {published data only}
  • Madureira FA, Manso JE, Madureira Filho D, Iglesias AC. Inflammation in laparoendoscopic single-site surgery versus laparoscopic cholecystectomy. Surgical Innovation 2013; Vol. Epub ahead of print.
  • Madureira FAV, Manso JEF, Fo DM, Iglesias ACG. Randomized clinical study for assessment of incision characteristics and pain associated with LESS versus laparoscopic cholecystectomy. Surgical Endoscopy 2013;27(3):1009-15.
  • Madureira FAV, Manso JEF, Madureira D, Iglesias ACG. Inflammation in less versus laparoscopic cholecystectomy. Surgical Endoscopy 2013;27:S444.
Marks 2011 {published data only}
  • Marks J, Tacchino R, Roberts K, Onders R, Denoto G, Paraskeva P, et al. Prospective randomized controlled trial of traditional laparoscopic cholecystectomy versus single-incision laparoscopic cholecystectomy: report of preliminary data. American Journal of Surgery 2011;201(3):369-72.
Marks 2012 {published data only}
  • Marks J. Prospective randomized controlled trial of traditional laparoscopic cholecystectomy versus SILS™ port laparoscopic cholecystectomy, 2012. clinicaltrials.gov/show/NCT00832767 (accessed 13 February 2014).
Marks 2013 {published data only}
  • Marks JM, Phillips MS, Tacchino R, Roberts K, Onders R, DeNoto G, et al. Single-incision laparoscopic cholecystectomy is associated with improved cosmesis scoring at the cost of significantly higher hernia rates: 1-year results of a prospective randomized, multicenter, single-blinded trial of traditional multiport laparoscopic cholecystectomy vs single-incision laparoscopic cholecystectomy. Journal of the American College of Surgeons 2013;216(6):1037-47.
McGregor 2011 {published data only}
  • McGregor CG, Sodergren MH, Aslanyan A, Wright VJ, Purkayastha S, Darzi A, et al. Evaluating systemic stress response in single port vs. multi-port laparoscopic cholecystectomy. Journal of Gastrointestinal Surgery 2011;15(4):614-22.
Moran 2011 {published data only}
  • Moran M, Gundogdu E, Dizen H, Akgun AE, Ozmen MM. Single vs two vs three vs four incision laparoscopic cholecystectomy: a randomized controlled clinical trial. Surgical Endoscopy and Other Interventional Techniques 2011;25(1 Suppl):S34.
Mosca 2012 {published data only}
  • Mosca F, Cuschieri A. EndoCone single port versus conventional multi-port laparoscopic approach, 2012. clinicaltrials.gov/show/NCT01709877 (accessed 13 February 2014).
Ng 1999 {published data only}
Noguera 2012 {published data only}
  • Noguera JF, Cuadrado A, Dolz C, Olea JM, Garcia JC. Prospective randomized clinical trial comparing laparoscopic cholecystectomy and hybrid Natural Orifice Transluminal Endoscopic Surgery (NOTES) (NCT00835250). Surgical Endoscopy 2012;26(12):3435-41.
Ospanov 2013 {published data only}
  • Ospanov OB, Khassenov RE. Length of the wound and postoperative scar after using single port laparoscopic cholecystectomy. Surgical Endoscopy 2013;27(Suppl 1):S74.
Ostlie 2013 {published data only}
  • Ostlie DJ, Adibe David Juang OO, Iqbal CW, Sharp SW, Snyder CL, Andrews WS, et al. Single incision versus standard 4-port laparoscopic cholecystectomy: a prospective randomized trial. Journal of Pediatric Surgery 2013;48(1):209-14.
  • Ostlie DJ, Sharp NE, Thomas P, Sharp SW, Holcomb GW, Peter SD. Patient scar assessment after single-incision versus four-port laparoscopic cholecystectomy: long-term follow-up from a prospective randomized trial. Journal of Laparoendoscopic and Advanced Surgical Techniques. Part A 2013;23(6):553-5.
Pappas-Gogos 2010 {published data only}
  • Pappas-Gogos G. Study of oxidative stress in standard laparoscopic vs single port cholecystectomy for uncomplicated cholelithiasis (LAP vs SILS), 2010. clinicaltrials.gov/show/NCT01211743 (accessed 13 February 2014).
Pathania 2013 {published data only}
  • Pathania BS. A comparative clinical evaluation of single incision laparoscopic cholecystectomy with single and multiport access versus conventional mufti -port laparoscopic cholecystectomy. European Surgical Research 2013;50:13-4.
Patricia 2010 {published data only}
  • Patricia YCL. Prospective randomized trial of single port laparoscopic cholecystectomy versus four ports laparoscopic cholecystectomy in patients with gallbladder stones, 2010. www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12610000006044 (accessed 13 February 2014).
Phillips 2012 {published data only}
  • Phillips MS, Marks JM, Roberts K, Tacchino R, Onders R, DeNoto G, et al. Intermediate results of a prospective randomized controlled trial of traditional four-port laparoscopic cholecystectomy versus single-incision laparoscopic cholecystectomy. Surgical Endoscopy 2012;26(5):1296-303.
  • Phillips MS, Marks JM, Tacchino R, Roberts K, Onders R, De Noto G, et al. Prospective randomized controlled trial of traditional four port laparoscopic cholecystectomy versus single incision laparoscopic cholecystectomy. Surgical Endoscopy 2011;25:S217.
Poon 2003 {published data only}
Sasaki 2012 {published data only}
  • Sasaki A, Ogawa M, Tono C, Obara S, Hosoi N, Wakabayashi G. Single-port versus multiport laparoscopic cholecystectomy: a prospective randomized clinical trial. Surgical Laparoscopy, Endoscopy and Percutaneous Techniques 2012;22(5):396-9.
Soroush 2011 {published data only}
  • Soroush M. The comparison between result of single port laparoscopic cholecystectomy with 4 ports cholecystectomy, 2011. www.irct.ir/searchresult.php?id=6359&number=1 (accessed 13 February 2014).
Steinemann 2011 {published data only}
  • Steinemann DC, Raptis DA, Lurje G, Oberkofler CE, Wyss R, Zehnder A, et al. Cosmesis and body image after single-port laparoscopic or conventional laparoscopic cholecystectomy: a multicenter double blinded randomised controlled trial (SPOCC-trial). BMC Surgery 2011;11:24.
Tacchino 2011 {published data only}
  • Tacchino R, Marks J, Onders R, DeNoto G, Paraskeva B, Rivas H, et al. Conventional 4-port laparoscopic cholecystectomy versus SILS port laparoscopic cholecystectomy. The first prospective randomized sham controlled trial. Surgical Endoscopy and Other Interventional Techniques 2011;25(1 Suppl):S35.
Trichak 2003 {published data only}
Tsimogiannis 2010 {published data only}
  • Tsimogiannis K. Study of the inflammatory reaction in standard vs single port cholecystectomy for uncomplicated cholelithiasis, 2010. clinicaltrials.gov/show/NCT01116492 (accessed 13 February 2014).
Tsimoyiannis 2010 {published data only}
  • Tsimoyiannis EC, Tsimogiannis KE, Pappas-Gogos G, Farantos C, Benetatos N, Mavridou P, et al. Different pain scores in single transumbilical incision laparoscopic cholecystectomy versus classic laparoscopic cholecystectomy: a randomized controlled trial. Surgical Endoscopy 2010;24(8):1842-8.
Umit Ugurlu 2013 {published data only}
  • Umit Ugurlu M, Tahir Oruc M. Comparison of single-incision laparoscopic cholecystectomy with standard laparoscopic approach. Surgical Endoscopy 2013;27(Suppl S1):S457.
Vezakis 2010 {published data only}
  • Vezakis A, Polymeneas G. A randomised comparison between single incision laparoscopic cholecystectomy and standard laparoscopic cholecystectomy, 2010. clinicaltrials.gov/show/NCT01094379 (accessed 13 February 2014).
Vilallonga 2012 {published data only}
  • Vilallonga R, Barbaros U, Sumer A, Demirel T, Fort J, Gonzalez O, et al. Single-port transumbilical laparoscopic cholecystectomy: a prospective randomised comparison of clinical results of 140 cases. Journal of Minimal Access Surgery 2012;8(3):74-8.

References to ongoing studies

  1. Top of page
  2. AbstractRésumé scientifique
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Notes
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
Mosca 2013 {published data only}
  • Mosca F. EndoCone single port versus conventional multi-port laparoscopic approach, 2013. clinicaltrials.gov/show/NCT01709877 (accessed 13 February 2014).
Soroush 2013 {published data only}
  • Soroush M. The comparison between result of single port laparoscopic cholecystectomy with 4 ports cholecystectomy, 2013. www.irct.ir/searchresult.php?id=6359&number=1 (accessed 13 February 2014).
Takada 2013 {published data only}
  • Takada Y. Randomized study comparing quality of life after single-port versus conventional 4-port laparoscopic cholecystectomy, 2013. www.umin.ac.jp/ctr/index.htm (accessed 13 February 2014).

Additional references

  1. Top of page
  2. AbstractRésumé scientifique
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Notes
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
Alponat 2002
  • Alponat A, Cubukcu A, Gonullu N, Canturk Z, Ozbay O. Is minisite cholecystectomy less traumatic? Prospective randomized study comparing minisite and conventional laparoscopic cholecystectomies. World Journal of Surgery 2002;26(12):1437-40.
Bakken 2004
  • Bakken IJ, Skjeldestad FE, Mjåland O, Johnson E. Cholecystectomy in Norway 1990-2002 [Kolecystektomi i Norge i 1990-2002]. Tidsskrift for den Norske Laegeforening 2004;124(18):2376-8.
Bisgaard 2002
  • Bisgaard T, Klarskov B, Trap R, Kehlet H, Rosenberg J. Microlaparoscopic vs conventional laparoscopic cholecystectomy: a prospective randomized double-blind trial. Surgical Endoscopy 2002;16(3):458-64.
Brok 2008
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Brok 2009
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Chan 2013
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David 2008
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Garg 2012a
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Higgins 2011
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Mjäland 1998
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Moher 1998
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Moher 2010
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Pisanu 2012
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RevMan 2012
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Roberts 2010
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