This review concluded that laparoscopic inguinal hernia repair was associated with earlier discharge from hospital, quicker return to normal activity and work and fewer postoperative complications than open inguinal hernia repair. Operating time was longer. Publication and language biases were possible, most studies were of poor quality and there was significant heterogeneity, so the authors' conclusions may not be reliable.

To compare laparoscopic inguinal hernia repair (LIHR) and open inguinal hernia repair (OIHR).

MEDLINE, EMBASE, Science Citation Index and Current Contents were searched for studies published in English in peer-reviewed journals between January 1990 and October 2000. Abstracts presented at national and international meetings were excluded. Unpublished studies were excluded. Search terms were reported. Bibliographies of relevant papers were searched for additional articles.

Randomised controlled trials (RCTs) of any size that compared LIHR with any type of OIHR and reported at least three outcome variables (or outcomes that could be obtained from the authors) were eligible for inclusion. The outcomes considered most suitable for analysis were: operating time; time to discharge from hospital, return to normal activity and return to work; postoperative complications; and hernia recurrence rate. Other outcomes (such as postoperative pain, analgesia requirements and hospital costs) were excluded.

The included studies were of laparoscopic repair: transabdominal pre-peritoneal (TAPP) was the most common; totally extra-peritoneal (TEP) and intra-peritoneal onlay mesh repair were also used. Laparoscopic repair was compared with open inguinal repair (using a variety of tension-creating and tension-free techniques). Mean follow-up duration was from one to 41 months (where reported).

The number of reviewers who selected studies for inclusion was not reported.

Methodological quality was assessed using the five-point Jadad scale for assessment of RCTs on the basis of randomisation, blinding and withdrawals.

Data to calculate odds ratios (ORs) and mean differences and associated 95% confidence intervals (CIs) were extracted by three reviewers. Authors were contacted for additional information if necessary.

Odds ratios and mean differences were pooled using a random-effects model to obtain pooled odds ratios and weighted mean differences (WMDs). Duration of operation and recurrence were analysed by the number of hernias (not the number of patients). Heterogeneity was assessed using Χ². A random-effects meta regression model was used to investigate whether heterogeneity was explained by year of study, length of follow-up and study size.

Subgroup analyses of the two methods of LIHR that were assessed by more than one study (TAPP and TEP) and OIHR (tension free and tension creating) were performed. A sensitivity analysis was performed to investigate the effect of excluding poor-quality studies (Jadad score 1).

Twenty-nine RCTs were included (n=5,588 patients and 5,989 hernia repairs). Study quality was described as poor (mostly due to inadequate description of randomisation, lack of blinding and lack of reperting of withdrawals and drop-outs) with a mean score of 2 (range zero to 3).

LIHR was associated with a significantly longer operating time (WMD 15.20 minutes, 95% CI 7.78 to 22.63; 28 studies, 5,877 hernias) than OIHR. There was a non-significant increase in the odds of short-term recurrence after LIHR compared with OIHR (OR 1.51, 95% CI 0.81 to 2.79; 29 studies, 5,682 hernias). LIHR was associated with a significant reduction in complications (OR 0.62, 95% CI 0.46 to 0.84; 28 studies), reduction in hospital stay (WMD -3.43 hours, 95% CI -6.50 to -0.35; 25 studies), reduction in time to return to normal activities (WMD -4.73 days, 95% CI -5.96 to -3.51; 24 studies) and reduction in time to return to work (-6.96 days, 95% CI -8.57 to -5.34; 23 studies). These analyses were all associated with significant heterogeneity.

The meta-regression analysis found a significant association between length of follow-up and return to normal activities.

The direction of effect remained the same in all subgroup analyses except one: subgroup analysis of TAPP and TEP on the outcome of hospital discharge showed no significant difference between procedures.

Sensitivity analysis of higher-quality studies provided similar results.

LIHR was associated with earlier discharge from hospital, quicker return to normal activity and work, and significantly fewer postoperative complications than OIHR. However, operating time for LIHR was significantly longer and there was a trend towards an increase in the relative odds of recurrence after laparoscopic repair.

The research question was supported by inclusion criteria for study design, outcomes and intervention and broad criteria for participants. Inclusion was restricted to studies published in English, so publication and language biases could not be ruled out. Study quality was assessed and taken into consideration in the analyses. The evidence base consisted mostly of poor-quality studies. Validity assessment and data extraction were performed by multiple reviewers, which reduced risks of error and bias; it was not reported whether similar steps were taken for study selection. The analyses were all associated with significant heterogeneity that was largely unexplained when explored.

Publication and language biases were possible, most studies were of poor quality and there was significant heterogeneity, so the authors' conclusions may not be reliable.

Practice: The authors did not state any implications for practice.

Research: The authors stated that the increased short-term recurrence rate with LIHR needed to be addressed in further large randomised trials.

One author was supported by the University Hospitals of Leicester NHS Trust, UK.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.