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.