Objective: To find out whether simultaneous repair of bilateral hernias increases the risk of recurrence compared with unilateral repair.
Design: Prospective study.
Setting: Swedish hospitals participating in the Swedish Hernia Register (SHR).
Interventions: Prospective collection of data from the SHR, 1992-1999 inclusive. The Cox proportional hazard test was used for calculating odds ratio (OR).
Main outcome measures: Hernia repairs were followed up in a life table fashion until re-operation for recurrence or death of the patient.
Results: 33416 unilateral and 1487 bilateral operations on 2974 groin hernias were found. Direct hernias were more common in the bilateral than in the unilateral group, 1,825, 61% compared with 13,336, 40%, (p < 0.0001). A laparoscopic method was used for 1774 (60%) of bilateral and 3285 (10%) unilateral repairs, and 455 bilateral operations (31%) were done as day cases compared with 18376 (55%) unilateral ones (p < 0.0001 for both comparisons). The cumulative incidence of reoperation at three years for groin hernias after bilateral and unilateral repair was 4.1% (95% confidence interval 3.1% to 5.1%) and 3.4% (95% Cl 3.1% to 3.7%, respectively. After adjustment for other risk factors, the OR for reoperation for recurrence after bilateral repair was 1.2 (95% CI 0.9 to 1.5) with unilateral repair as reference. The OR for reoperation after laparoscopic bilateral repair compared with open bilateral repair was 0.9 (95% CI 0.6 to 1.4).
Conclusions: Simultaneous repair of bilateral hernias does not increase the risk of reoperation for recurrence and there is no significant difference in the risk of reoperation after bilateral repair using open or laparoscopic techniques.