Mesh in hernia surgery : aspects on recurrence and pain of different mesh types in groin hernia repair and mesh repair in small umbilical hernias

Abstract: The groin hernia repair is one of the most common surgical procedure in Sweden with nearly 16,000 repairs performed annually. Including a mesh has become standard in the repair and the type of material and weight can influence the two main important postoperative complications; recurrence and pain. Lightweight meshes (LWM) have shown to have improved benefits compared to heavyweight meshes (HWM) in terms of less short-term pain and discomfort following both an open anterior mesh (OAM) groin hernia repair and a laparoscopic totally extraperitoneal (TEP) hernia repair. A lighter mesh with less material could also be beneficial to reduce the risk of chronic pain after surgery. However, concerns exist whether LWM may be associated with higher recurrence rates. Furthermore, compared to groin hernias, small umbilical hernias continue to see a non-standardized practice and mostly limited use of mesh, despite recurrence rates considered to be high with a simple suture repair. In Paper I, the aim was to compare the reoperation rate for recurrences of LWM versus HWM in TEP groin hernia repairs through an observational nationwide population-based cohort. 13,839 hernia repairs between year 2005 and 2013 were collected from the Swedish Hernia Register (SHR) and analyzed with a minimum of a 2-years follow-up. 491 (3.5 %) hernia repairs were reoperated for recurrence and the results demonstrated a significantly associated increased risk of reoperation for recurrence in repairs with LWM (HR 1.56, CI 1.29-1.88) compared to HWM. The risk of recurrence with the use of LWM in indirect and smaller hernia repairs were more comparable to HWM. In Paper II, the aim was to compare the reoperation rate for recurrences of different types of LWMs versus HWM in OAM inguinal hernia repairs through an observational nationwide population-based cohort. Data on 76,495 hernia repairs on male patients undergoing an elective OAM inguinal hernia repair between year 2005 and 2013 was collected from the SHR and analyzed with a minimum of a 2-years follow-up. 1676 (2.1 %) hernia repairs were reoperated for recurrence and the results did not reveal an associated increased risk of reoperation for recurrence for the regular LWM-PP (polypropylene) (HR 1.12, CI 0.96-1.31) compared to HWM. Composite LWM-PP were however associated with an increased risk of recurrence compared to HWM. In Paper III, the aim was to compare the chronic pain rate 1 year after surgery in different LWMs compared to HWM, following an OAM inguinal hernia repair, through an observational nationwide population-based cohort with prospectively assessed patient-reported outcome measures (PROMs). 23,259 male patients via the SHR (response rate 70.6 %) provided answers to the pain questionnaire and were analyzed. Rates of chronic pain were 15.8 % and 15.6 % for the two different LWM groups and the risk of developing significant chronic pain 1 year after surgery did not differ from the repairs with HWM (16.2 %). Younger male patients less than 50 years old had a significant increased risk of reporting chronic pain (19.4 %, OR 1.43, CI 1.29-1.60) compared to elderly patients. In Paper IV, the aim was to investigate the surgical site complications within 30 days after surgery and recurrences of small umbilical hernias ≤ 2 cm that had undergone a repair with a small onlay mesh. Data on 80 elective small umbilical hernia repairs between 2015 and 2019 in a single surgical center at the department of Surgery in Södertälje Hospital (in the region of Stockholm) was collected retrospectively from the hospital’s medical database. Patients were followed at least 4 months after surgery in the outpatient clinic documentation. 4 patients were identified to have had a surgical site complication and no cases of recurrence were registered in the outpatient clinic documentation. In conclusion, while the use of HWM can have advantages to avoid increased recurrence rates in the TEP groin hernia repair, LWM can be recommended for cases of smaller and indirect hernia defects. However, there are no benefits of using HWM in OAM inguinal hernia repairs on male patients, irrespective of the size or the type of the hernia. Whereas recurrence rates in OAM inguinal repair on male patients were low, the chronic pain rates were unsatisfactorily high, particularly in younger patients, and was not found to be influenced by type of mesh used. The best surgical treatment for small umbilical hernia defects is still under research. Repairing small umbilical hernias with a small onlay-mesh seemed however safe with a low surgical site complication rate. Still, randomized controlled trials are warranted to assess whether mesh can reduce recurrences in comparison to a simple suture repair for the repair of umbilical hernias ≤2 cm.