Quantifying the cost of laparoscopic inguinal hernia repair

Authors


  • P. Smart MBBS, FRACS; L. Castles, MBBS, FRACS.

Correspondence

Dr Philip Smart, Department of Surgery, Austin Health, 145 Studley Road, Heidelberg, Vic. 3084, Australia. Email: philip.smart@austin.org.au

Abstract

Background

Laparoscopic inguinal hernia repair has been widely adopted. While the clinical advantages and disadvantages are well-quantified, the economic cost is less well-studied.

Methods

A retrospective audit and case review of a single-centre public hospital consecutive case series was performed using data captured from real-time stock usage tracking technology and review of electronic medical records.

Results

Laparoscopic inguinal hernia repair requires 11-min (21%) extra theatre time and costs $1268 (370%) more for single-use disposable equipment and prostheses.

Conclusions

Laparoscopic inguinal hernia repair does not require significantly more theatre time, but has a higher short-term in-hospital cost. Repair technique should be tailored according to patient factors.

Introduction

Over 26 000 inguinal hernia repairs are performed annually in Australia. Of these, 45% are performed laparoscopically, and this proportion has been steadily increasing.[1]

The risks and benefits of laparoscopic inguinal hernia repair are relatively well-studied. A Cochrane meta-analysis demonstrated an equivalent recurrence rate but earlier return-to-work (6 days), albeit at the cost of higher rates of visceral and vascular injury.[2] Chronic pain rates are lower at 1 year,[2, 3] but similar after 4 years.[4] The economic dividend of the early return-to-work has been less well-studied as has the higher cost of single-use disposable equipment.

This study aimed to review the actual equipment usage and in-hospital cost of laparoscopic inguinal hernia repair versus open hernia repair using data from real-time tracking of stock usage, as well as quantifying differences in theatre utilization times.

Methods

All patients undergoing inguinal hernia repair at The Surgery Centre, Austin Health Repatriation Campus, from November 2009 to September 2011 were identified retrospectively.

The Surgery Centre is a dedicated four-theatre facility designed for efficient and streamlined treatment of short-stay elective surgery patients. It was opened in July 2008, and is separate from the main Austin Health campus and Emergency Department. Various novel approaches were utilized in the facility design aimed at maximizing elective surgery efficiency, including the adoption of point-of-use handheld mobile scanning data capture to manage stock usage and other parameters such as theatre usage times (hTrak, hTrak Pty. Ltd., Prahran, Australia). From November 2009, electronic medical records were adopted. These datasets were therefore reviewed and cross-checked for accuracy and completeness in order to perform this audit.

Patients were identified by searching the hTrak database by procedure type. hTrak data are entered using a handheld device at the time of anaesthetic induction by theatre nursing staff. The data are then uploaded to a central, searchable SQL database accessible via web interface. The database contains a customizable dropdown menu for searching procedure types: the terms ‘Inguinal hernia repair’, ‘Inguinal hernia, laparoscopic, unilateral/bilateral’, ‘Laparoscopic bilateral hernia repair’, ‘Laparoscopic hernia repair’ were available and selected. The platform is highly customizable and allows for inclusion of disease and procedure codes; however, these data were not included in the Surgery Centre implementation.

Additional clinical data were obtained by reviewing the electronic medical record for scanned copies of handwritten anaesthetic charts, operation notes and outpatient notes as well as dictated outpatient letters.

Patients with primary, recurrent, unilateral and bilateral herniae were all included. Patients with femoral herniae, or who had additional surgery during the same anaesthetic, were excluded.

Description of procedures

In the study population, surgery was generally performed by consultant surgeons, with the assistance of junior registrars. A small minority of cases were performed by senior registrars or fellows alone. Procedural technique was dictated by surgeon and/or patient preference during the standard operative consent process. In general, laparoscopic repair was not offered to patients with irreducible herniae or those with giant inguinoscrotal herniae. Prior appendicectomy or lower midline laparotomy was not considered a contra-indication to laparoscopic repair. A small number of patients were only offered open repair due to co-morbidities precluding general anaesthesia. Mesh and mesh fixation technique were dictated by surgeon preference. New prostheses and novel disposable equipment require approval by a committee prior to use, thus delaying the available mesh and fixation device choices to some extent as compared to a wider population. For example, absorbable tacking devices were approved for use midway through the study period. Overnight beds were routinely booked as part of the pre-admission process, resulting in an almost universal overnight stay for both laparoscopic and open cases. While many patients may have been suitable for day case surgery, this was not yet routinely adopted during the study period because of the availability of extended evening recovery and re-admission processes.

Data collection and calculation of costs

Previous studies have used estimates for calculation of procedural costs.[3, 5] For this study, it was surmised that the main differences in in-hospital costs are due to differences in theatre utilization (i.e. laparoscopic cases take longer) and in the use of single-use disposable equipment. In our institution, general anaesthesia is used almost routinely, and therefore anaesthetic and preoperative work-up costs are equivalent. Patients also routinely stay overnight, regardless of surgery type.

This allows comparison between two relatively hard endpoints: surgery time and actual disposables usage to estimate hospital costs. Theatre and surgery start and finish times are entered into the hTrak mobile handset by theatre nursing staff in real time. Disposables are barcode-scanned by the scout nurse as they are opened and used during a case.

Disposables costs included a comprehensive list of single-use and consumable items ranging from dressings to sutures, disposable drapes, mesh, mesh fixation devices and theatre packs. Disposable ports were used routinely. Other than laparoscopic scissors that were used only occasionally, all other laparoscopic instruments were re-usable.

Statistical analysis

For normally distributed, continuous data, Student's t-test was used to detect statistically significant differences between groups. Categorical data were analysed using Fisher's exact test. All P-values are two-tailed. A P-value <0.05 was considered statistically significant.

Results

A total of 337 consecutive cases were identified. Six patients were excluded where the hernia was found to be femoral. A further 10 cases were excluded where additional surgery such as umbilical hernia repair was performed at the same time.

Of the remaining 321 cases, the breakdown of hernia repair type was as follows:

Totally extraperitoneal (TEP)202(64%)
Lichtenstein59(18%)
Rutkow–Robbins mesh plug55(17%)
Transabdominal preperitoneal5(1.5%)

Although 22 individual surgeons were involved, four surgeons performed 84% of the cases. Most of the 18 remaining surgeons were either hospital surgeons from another campus covering the lists of regular surgeons on leave or were rotating fellows. Patients in the laparoscopic group were 9 years younger on average. Forty-eight per cent of patients in the open group were over 65 years old (i.e. of retirement age) compared to 18% in the laparoscopic group. They were also slightly heavier, but this 3-kg difference is not considered clinically significant (Table 1). The open group had higher co-morbidity: more of these patients had an American Society of Anesthesiologists (ASA) score of 3, fewer had an ASA score of 1. A higher proportion of the laparoscopic group had a bilateral repair, but both groups included similar numbers of recurrent herniae.

Table 1. Baseline characteristics of open and laparoscopic repair groups
 OpenLaparoscopicP-value
  1. ASA, American Society of Anesthesiologists; SD, standard deviation.
Patients (n)114207
Mean age (years) (range; SD)61 (20–90; 16.5)52 (17–83; 15.0)0.0001
Age > 65 (n) (%)54 (48%)37 (18%)0.0001
Gender (M/F)102/12195/120.1276
Weight (kg) (range; SD)76 (49–111; 13)79 (43–137; 11)0.025
ASA 121 (18%)67 (32%)0.0087
ASA 263 (55%)124 (60%)0.4781
ASA 328 (25%)16 (8%)0.0001
ASA 42 (2%)0 (0%)0.1254
Primary hernia103 (90%)187 (90%)1.0000
Recurrent11 (10%)20 (10%)
Right54 (47%)78 (38%)
Left50 (44%)59 (29%)
Bilateral10 (9%)70 (34%)0.0001
General anaesthesia105 (92%)207 (100%)
Local and sedation9 (8%)0 (0%)
Overnight admission111 (97%)194 (94%)

All laparoscopic cases were performed under general anaesthesia, as were most open operations. A few elderly patients had an open operation using local anaesthesia and sedation. Only 10% of cases in both groups were performed as day cases.

Most repairs in the laparoscopic group were performed using contoured polypropylene mesh (Bard 3D max, Bard Medical, Covington, GA, USA; n = 116), followed by partially absorbable lightweight composite mesh (Ultrapro, Ethicon, Somerville, NJ, USA; n = 70). In 16 cases, the repair was performed using with standard polypropylene (Surgipro, Covidien, Dublin, Ireland), 3 using dual mesh (Proceed, Ethicon) and 2 with polyester (Parietex, Covidien). All mesh was fixed, initially using 5-mm titanium tacks (Pro Tack, Covidien; n = 90) then once available mostly with absorbable synthetic polyester copolymer tacks (AbsorbaTack, Covidien; n = 101). Fibrin glue (Tisseel, Baxter, Deerfield, IL, USA) was used for mesh fixation in 16 cases.

For open surgery, herniae were repaired with a preformed polypropylene plug (Bard PerFix Plug, Bard Medical; n = 48) where the Rutkow–Robbins technique was used. Either standard polypropylene (Surgipro, Covidien; n = 28) or partially absorbable lightweight composite mesh (Ultrapro, Ethicon; n = 38) was used for the Lichtenstein technique. Most mesh inserted at open surgery was fixed with sutures (n = 96); however, 5-mm titanium tacks (Stat Tack, Covidien; n = 18) were used in some cases.

Open cases were completed in 52 min on average, 11 min quicker than laparoscopic cases, which took 63 min (Table 2). Given the higher number of bilateral laparoscopic cases, unilateral and bilateral subgroups were then analysed separately. Unilateral open cases were completed in an average of 50 min, only 8 min faster than the laparoscopic repairs. Bilateral herniae were repaired 5 min faster using an open approach; however, given the low numbers of open cases, this did not reach statistical significance.

Table 2. Cost of disposables and operating times
 OpenLaparoscopicDifference (95% CI)P-value
  1. CI, confidence interval; SD, standard deviation.
Surgery time: all cases (min)5263110.0001
(range; SD)(23–129; 21)(30–150; 21)(6–15)
Surgery time: bilateral herniae (min)727750.5
(range; SD)(79–132; 20)(43–150; 25)(−19–9)
Surgery time: unilateral herniae (min)505880.0009
(range; SD)(23–129; 18)(31–124; 20)(3–13)
Total theatre usage time (min)10896130.0001
(range; SD)(53–192; 28)(31–211; 26)(6–19)
Disposables cost ($AUD)$343$1611$12680.0001
(range; SD)(176–964; 122)(794–3188; 430)(1186–1350)

Total theatre usage time reflected the longer surgery times alone: laparoscopic cases took only 13 min longer than open cases in total. This is the expected result given the almost universal use of general anaesthesia and serves to validate reliability of the data.

Average cost of single-use and consumable equipment was $1611 for the laparoscopic group and $343 for the open group: a mean difference of $1268. Most of the cost difference was due to the use of laparoscopic tackers and fibrin fixation, as well as the cost of disposable distension and structural balloons for establishing and maintaining the TEP space. This cost was stable over the 2-year study period: mean cost for the first 50 cases was $1586, for the last 50 mean cost was $1623 (P = 0.63).

Discussion

This study has some limitations. It is a retrospective single institution review of public hospital cases; therefore, the conclusions are not necessarily universally applicable. It is possible that some patients were missed in the database search as the operation descriptions are somewhat arbitrary and overlapping. For example, a case may be misclassified as an incisional hernia repair rather than inguinal hernia repair. This could be remedied by classifying the cases by procedure code in the database.

The open and laparoscopic groups contained heterogeneity within them with regard to surgery type and style. We did not analyse these subgroups separately as we preferred to gain a broadly applicable overview of the open versus laparoscopic groups as a whole. In addition, the costs and time differences of the various styles of open repair were not felt to be significant.

The cost calculations in this study rely on the accuracy of the underlying database. In one instance, barcode scanning of a distension balloon recorded the use of a box of five balloons rather than one single balloon, thereby inflating the cost significantly. This was corrected in the analysis, but there may be other instances that were missed. On the other hand, it is possible that some disposables were not scanned: in a busy theatre with many disposable items used, it is almost certain than some were missed, resulting in an underestimate of the true underlying cost.

The cost estimates in this series do not take into account the additional capital expenditure required for laparoscopic equipment purchase and maintenance. Laparoscopic instrument trays are generally more time consuming to clean and sterilize. These factors would, of course, result in an underestimate of the true cost to the hospital of laparoscopic cases. On the other hand, laparoscopic cases may be cheaper in facilities where day case surgery is widely adopted, as these patients are likely to go home earlier.

The time difference may have also been underestimated. Patients in the open group were older, heavier and sicker, all of which would lengthen operation times. In addition, the open group almost certainly included more patients with large inguinoscrotal herniae deemed not suitable for laparoscopic repair. These cases would also take longer and result in an underestimation of the extra surgical time needed for laparoscopic cases. In a randomized trial, the time difference demonstrated in this study would likely be larger: indeed, in a meta-analysis of 7161 patients, the difference was 15 min in favour of open surgery.[2]

This study highlights the potential power of the implementation of information technology into clinical service areas. While this study examined two limited parameters (disposables cost and operating time), these can be easily broadened to capture unlimited endpoints. Dedicated data managers can be made obsolete as, with the correct implementation, automated data collection can now be integrated into normal clinical workflows. Clinical benchmarks, identification of outlying performance, sentinel events and even trial data could potentially be gathered freely, as well as monitored and published in real time. These benefits, however, can be accrued only with clinician involvement in the software design phase. A stock usage tracking system, with some customization, might be altered to aid identification of best surgical practice.

Although not designed to do so, chart review of this case series also highlighted the higher rates of serious morbidity in the laparoscopic group. In this case series alone, it was noted that one patient required an emergency Hartmann's procedure for a sigmoid colon injury, one required emergency laparotomy to control bleeding from an iliopubic vein, two patients had a vas deferens division, one patient had an injury to the lateral cutaneous nerve of the thigh and two patients had a recurrent hernia within 30 days requiring re-operation. There were no major vascular or bladder injuries. These events are highly pertinent to cost analyses, as a serious complication would obliterate the cost benefit of many other uncomplicated procedures. A more robust cost analysis would therefore require a comprehensive analysis of all complications and re-admission rates.

In contrast among the open group, one patient who had had a previous paediatric herniotomy suffered a delayed thrombosis of the testicular veins, resulting in testicular ischaemia and atrophy. Another patient with a large inguinoscrotal hernia required orchidectomy at index hernia repair, and one patient in the open group required referral to a pain specialist for the management of chronic post-operative groin pain. No other major morbidity was noted in this older and frailer group and there were no early returns to theatre. These findings are consistent with the reported literature. Open hernia repair is safer but at the cost of higher rates of chronic pain.

In 2009, the European Hernia Society published comprehensive guidelines on the management of adult inguinal hernia based on an extensive literature review.[4] It was noted that although the in-hospital costs were higher for laparoscopic repair, from a socio-economic perspective, laparoscopic repair was ‘probably the most cost-effective approach for patients who participate in the labour market, especially for bilateral hernias’.

Recommended repair technique should be in accordance with the published guidelines. Laparoscopic repair is recommended for bilateral hernias, recurrent hernias after previous anterior repair, for patients in whom chronic pain is more likely or for working-age patients. It is safer to treat older or non-working patients with primary unilateral inguinal hernia by open or anterior technique.

It is pleasing to note that this case series adhered to these recommendations in that patients in the laparoscopic group were younger and more often had bilateral herniae. In our series, the bilateral open repairs were generally performed in patients not fit for general anaesthesia, and the recurrent herniae repaired via open technique either had a previous laparoscopic repair or were old and frail.

Aside from early return-to-work, the other benefit over open repair is a reduction in the prevalence of chronic pain. Risk factors for the development of chronic pain have been delineated and include recurrent hernia repair, the presence of preoperative pain, day case surgery, delayed onset of symptoms, high pain scores in the first week after surgery, young age, preoperative anxiety level and occurrence of any post-operative complication.[6-8] These risk factors should prompt consideration of laparoscopic over open repair.

Conclusion

Laparoscopic inguinal hernia repair costs $1268 more than open repair for disposable and single-use equipment, but only 11-min additional operating time on average. Laparoscopic repair is recommended in patients fit for general anaesthesia with bilateral hernias, recurrent hernias after previous anterior repair, for patients in whom chronic pain is more likely or for working-age patients.

Ancillary