Use of Prophylactic Mesh When Creating a Colostomy Does not Prevent Parastomal Hernia

A Randomized Controlled Trial-STOMAMESH

Christoffer Odensten, MD; Karin Strigård, MD, PhD; Jörgen Rutegård, MD, PhD; Michael Dahlberg, MD, PhD; Ulrika Ståhle, MD; Ulf Gunnarsson, MD, PhD; Pia Näsvall, MD, PhD

Disclosures

Annals of Surgery. 2019;269(3):427-431. 

In This Article

Discussion

This trial, the largest multicenter RCT on stomal surgery in routine healthcare, revealed no difference in PSH rate between procedures incorporating a prophylactic mesh around the stoma and those with no mesh. Complication and reoperation rates did not differ between groups. Compared with previously published trials analyzing the use of mesh in stomal surgery, the current trial was based on a larger population and a systematic follow up including both clinical and CT assessment of PSH. Furthermore, this study was multicenter and thus represents the use of mesh in normal clinical practice using well-established routines. It covers most regions in Sweden, and represents approximately 15% of the population. Furthermore, unlike other studies, this study was blinded to both patient and examiner, which could be an explanation for the diverging results.[18–20,26] This trial also includes different types of hospital and levels of specialization, whereas most previous trials are from single specialist Institutions.[20,22,26,29] The trial reached a de facto power of 91%. The only significant difference found between the 2 treatment arms was a longer operation time (median 38 minutes) for the mesh group corresponding to the time expected for application of the mesh. Interestingly, in a large retrospective study in Sweden including 206 patients, reported from a single institution, it was not possible to show a difference in PSH between procedures with or without mesh.[24] Follow-up assessment in that trial also included both clinical investigation and CT. That trial was carried out at a high-volume single center with top results in the Swedish Rectal Cancer Registry.[4] This center did not participate in the STOMAMESH trial, but had similar results.

We also describe the patient group eligible for inclusion but not taking part, the "not included" group, a procedure rarely performed in previous trials.[18,19,21,22,26,29]

A potential weakness of this study is that we choose to investigate the population of "not included" patients at 3 hospitals (Sunderby, Umeå, and Mora), to get a representative sample, instead of doing this at all participating hospitals. Furthermore, the choice to use routine CT might also be considered a weakness. In some studies, the patients were placed in the supine position or performed the Valsalva maneuver during the examination.[30] This might have increased the sensitivity of CT in this study. The reason not doing this is that abdominal CT scan with the patient in the supine position is standard. An additional CT with Valsalva would have increased radiation exposure and would have demanded extra resources, thus deviating from routine practice. The majority of CT scans were included in routine colorectal cancer follow up at the hospitals participating. It would seem unlikely; however, that this difference in CT follow up should favor one or other of the treatment arms.

The reason for choosing the sublay polypropylene mesh technique was that this had been investigated in a number of previous studies and that laparoscopic surgery had not been accepted as standard practice in Sweden, 2005. Open surgery was thus the natural choice.

Only 1 patient in the STOMAMESH population had emergency surgery whereas 96 (22.4%) in the "not included" population were operated as an emergency. This was a systematic error in the study design but does not entirely explain the differences in ASA and age. One might argue that we should have excluded emergency procedures in the study design. Consequently, we cannot extrapolate the results from elective surgery to those having emergency surgery with a contaminated abdomen.

This study did not investigate or quantify symptoms arising from PSH. It is well known that not all PSHs actually cause symptoms[7] and this has been used as an argument against the use of prophylactic mesh. The PSH rate in our study was more than three times that in a recent review article (29.4% vs 8.9%),[16] implying that results from smaller studies performed at single institutions with a special interest in PSH are difficult to extrapolate to routine clinical practice. The meticulous follow up in this study might well have generated the higher PSH rates. No negative side-effects of prophylactic mesh were detected despite the rather large trial population.

There have been several trials studying PSH, and the majority has shown positive results regardless of which prophylactic mesh is used when forming a colostomy.[16] These authors recommend the use of mesh when creating a colostomy. The results from the current study do not support this conclusion. Comparing our trial with the Dutch trial,[18] which was second largest and the one most similar in design to ours, the Dutch trial did not include routine CT follow up and blinding which could explain the difference in results. In view of the dubious need for prophylactic mesh and the divergent trial results to date, we cannot recommend the use of prophylactic mesh when creating a colostomy. Furthermore, we do not have a clear picture of how many patients who develop a PSH suffer symptoms related to their PSH. The most promising results have been reported using mesh for repair of PSH, including the Sugarbaker procedure.[29,31] Morbidity risk with mesh repair is high and deaths have been reported.[16,32,33] There are reports of long-term complications from mesh implantation in the form of discomfort, pain, and fistula formation.[33–35] Should mesh be used prophylactically on a large scale, the incidence of these complications would likely increase. In fact, long-term follow-up studies on the use of prophylactic parastomal mesh are rare indeed.

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