Prevention of Incisional Hernia with Prophylactic Onlay and Sublay Mesh Reinforcement Vs. Primary Suture Only in Midline Laparotomies (PRIMA): Long-Term Outcomes of a Multicentre, Double-Blind, Randomised Controlled Trial.

Background Incisional hernia occurs approximately in 40% of high-risk patients after midline laparotomy. Prophylactic mesh placement has shown promising results, but long-term outcomes are needed. The present study aimed to assess the long-term incisional hernia rates of the previously conducted PRIMA trial with radiological follow-up. Methods In the PRIMA trial, patients with increased risk of incisional hernia formation (AAA or BMI >= 27 kg/m(2)) were randomised in a 1:2:2 ratio to primary suture, onlay mesh or sublay mesh closure in three different countries in eleven institutions. Incisional hernia during follow-up was diagnosed by any of: CT, ultrasound and physical examination, or during surgery. Assessors and patients were blinded until 2-year follow-up. Time-to-event analysis according to intention-to-treat principle was performed with the Kaplan-Meier method and Cox proportional hazard models. Trial registration: NCT00761475 (ClinicalTrials.gov). Findings Between 2009 and 2012, 480 patients were randomized: 107 primary suture, 188 onlay mesh and 185 sublay mesh. Five-year incisional hernia rates were 53.4% (95% CI: 40.4-64.8), 24.7% (95% CI: 12.7-38.8), 29.8% (95% CI: 17.9-42.6), respectively. Compared to primary suture, onlay mesh (HR: 0.390, 95% CI: 0.248-0.614, p < 0.001) and sublay mesh (HR: 0.485, 95% CI: 0.309-0.761, p = 0.002) were associated with a significantly lower risk of incisional hernia development. Interpretation Prophylactic mesh placement remained effective in reducing incisional hernia occurrence after midline laparotomy in high-risk patients during long-term follow-up. Hernia rates in the primary suture group were higher than previously anticipated. Funding B. Braun. Copyright (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).