Preemer Trial - Prophylactic Mesh Versus no Mesh in the Midline Emergency Laparotomy Closure for Prevention of Incisional Hernia: a Multi Center, Double-blind, Randomized Controlled Trial

Incisional hernia (IH) is a common complication of abdominal wall surgery. Its' incidence varies greatly (2-30 %) among studies. The incisional hernia incidence is influenced by several factors, such as closing technique, follow-up time and the modality of radiological investigations, patient characteristics and co-morbidities as well as indication and type for surgery.

European Hernia Society (EHS) guideline strongly recommends to utilise a non-midline approach to a laparotomy whenever possible to decrease the incidence of incisional hernia. However, this is clearly not an option in an emergency laparotomy, as midline incision is the fastest and the best visualizing opening to explore the whole abdominal cavity in an emergency setting.

For elective midline incisions, evidence-based recommendation is to perform a continuous suturing technique with slowly absorbable monofilament suture when closing the incision. Suturation should be done performing a single layer aponeurotic closure technique without separate closure of the peritoneum. A small bites technique with a suture to wound length (SL/WL) ratio at least 4:1 is the current recommended method of fascial closure.

Prophylactic mesh augmentation in a non-emergency setting appears effective and safe and can be suggested for high-risk patients. However, no recommendations can be given on the optimal technique to close emergency laparotomy incisions because of lack of evidence. This problem should be emphasized on due to high rates of IH after emergency laparotomy. All this makes the use of prophylactic mesh in the emergency setting an interesting proposition, as it may decrease the rate of IHs. However, there are concerns over potential mesh related complications including infection, chronic pain, seromas and bowel fistulas especially in emergency situations like peritonitis and intestinal obstruction. There is preliminary evidence published about the safety and efficiency of the prevention of IHs using meshes in the emergency laparotomy closure even in contaminated conditions.

In the resent systematic review and meta-analysis, only results of 2 studies and altogether 299 patients were eligible for the analysis. Swiss case-control study reported an IH rate of 3,2% (2/63) in the mesh group and 28,6% (20/70) in the control group. Spanish study group had the same kind of results in their retrospective cohort; IH rate of 5,9% (3/50) in the mesh group and 33,3% (33/100) in the control group. There was no statistically significant difference in the incidence of surgical site infection or other complications when prophylactic mesh group was compared to standard closure group. SSI rate in Swiss study was 60% and respectively only 17% in the Spanish study. This may reflect differences in the patient selection, therefore the safety profile of the prophylactic mesh in the emergency setting has not been adequately described. Neither of the studies included in meta-analysis were not randomized controlled trials. There were also many methodological differences including patient selection, used mesh, and mesh placement. Thus, the conclusion of the systematic review paper was that there are limited data to assess the effect or safety of the use of prophylactic mesh in the emergency laparotomy setting. Randomized control trials are required to address this important clinical question. EHS guideline group resulted the same conclusion in their recommendation report.

There are about 1650 patients are operated in Finland because of IH every year. According to the European study, the estimated cost for IH surgery is 6450 euros. The corresponding costs in Sweden were even higher reaching 9060 euros per treatment. Extrapolated to Finland, this means that operative treatment of IHs cause more than 10 million expenses to the Finnish health care sector in a year. Some of these costs may be avoidable by using the prophylactic mesh during the closure of midline emergency laparotomies in the patients with IH risk factors.