Necessary duration of follow-up to assess complications of mesh in hernia surgery: a time-lapse study based on 460 explants.

Purpose: Risk of complications following hernia repair is the key parameter to assess risk/benefit ratio of a technique. As mesh devices are permanent, their risks are life-long. Too many reports in the past assessed mesh safety prematurely after short follow-ups. We aimed to explore what length of follow up would reveal the full extent of complications.

Methods: Time lapses between implantation and excision were analyzed in 460 cases of meshes excised for complications after hernia repair. Patterns of percentage growth and time lapses at 50th and 95th percentiles were used to compare groups of different hernia type, age, gender and reason for excision.

Results: The 50th and 95th case percentiles in the dataset were at 3.75 and 15.0 years between mesh implantation and excision. For hernia types, the longest time lapses were for groin hernias (4.0 and 16.11 years at 50th and 95th percentiles). The shortest were for umbilical hernias (2.16 and 9.68 years). Males had later excisions than females (4.11 and 16.1 vs. 2.47 and 9.79 years). Younger patients (< 45 y.o.) had later excisions than older patients (4.12 and 17.68 vs. 3.37 and 10.0 years). Out of all subgroups, the longest time lapses were for groin hernias in younger males (4.77 and 18.89 years) and for mesh erosion into organs (4.67 and 17.0 years).

Conclusions: Follow-up of more than 15 years is needed to fully assess complications after mesh hernia repair. Especially longer periods are needed to detect mesh erosion into organs and complications in younger males. Presently, short observations and lack of reporting standard in the literature prohibit accurate assessment of complication risks. We propose to use cumulative incidence for standardized risk reporting (y% risk at x years). This will show time-dependent patterns and allow comparisons between different techniques and studies of variable duration. Standardization will also help to predict long-term risks beyond shorter (practical) follow-ups and facilitate real-time monitoring during surveillance.