Parastomal hernias have an incidence of up to 50%, or even more if diagnosed radiologically. End colostomy is the most likely ostomy to develop these hernias. After their repair there is a huge difference in the rate of relapse among the different techniques after a 12-month follow-up.
Interest in their prevention has increased in the past decades, to the point that there are more meta-analyses than randomized controlled trials of parastomal hernias.
After a Robin test, we can say that mesh works for this prevention but we cannot say which is the best mesh and position. Dr. López-Cano talks about the network meta-analysis, an extension of the classical meta-analysis, that combines both direct and indirect evidence in multiple treatment comparison.
He presents a network meta-analysis using ten meta-analyses and including 8 synthetical meshes, 2 biological meshes and the retromuscular and laparoscopic intraperitoneal onlay mesh (IPOM) positions. All of the studies included were related to end-colostomy hernia repair.
So far, we can say, on the basis of evidence, that using a synthetic non-absorbable flat mesh is better than using none, and therefore its use is justified. We do not know whether a biological mesh is better than a synthetic mesh because we only have indirect comparisons regarding this question which show no differences, and so we cannot justify its use.
In the same way, we only have a direct comparison between a retromuscular mesh and no mesh at all, which shows that the first option is more beneficial. No direct comparison exists between a retromuscular mesh and IPOM, so we cannot justify the latter position.
More research on the use of biological meshes versus the synthetic meshes as well as on their position is needed. Dr. López-Cano concludes that research into parastomal hernia repair has just begun.