In this study, the prophylactic effect of simultaneous placement of mesh beside the stoma during CRC radical resection to prevent PSH seemed beneficial rather than routine sigmoidostomy in prolonging time to recurrence for PSH. Our findings are in line with previous studies wherein the incidence rate for recurrence for PSH in patients was significantly lower than in patients without the mesh. Going by the estimates, the recurrence rate has been shown to be almost nine times higher without mesh (15,16). Pioneering reports on using mesh for repairs was published by Hopkins and Trento (16), however the technique was limited in its clinical use in light of intestinal erosions and infections (16,17). However, effectiveness and safety of this procedure still remains controversial.
In a prospective study involving 344 patients undergoing PSH repair using mesh, the recurrence rate was a mere 2.1%, and no complications were reported during the follow up, which could be attributed to the mesh (18). On contrary, results from a retrospective cohort involving ventral hernia repair showed frequent occurrence of intestinal obstruction secondary to adhesions with PVDF than when with Parietex mesh (19). Thus, it is of foremost importance and necessary to standardize the surgical method and approach while taking in long-term outcomes to understand the exact benefits of mesh use (20,21).
The risk of PSH increases substantially when the stoma is created, because the abdominal wall, which was otherwise undamaged, now becomes defective (22). Advanced age, obesity, smoking, ostomy size, ostomy location, malnutrition, diabetes, lung disease, hormone drug use is all high-risk factors for postoperative PSH. For every increase in the patient age, the risk of developing PSH increases by 4% (23). Studies have shown that BMI (kg/m2) greater than 25 can increase the incidence of parastomal hernia, and gender is an independent risk factor for the occurrence and development of parastatal hernia (24,25).
The level of stability provided by underlying structure of the muscles of the abdomen which, when applied in creating the stoma, can lower the potential for hernias to develop (22). Reduction in PSH risk can be achieved through careful and sufficient preparation prior to surgery, opting an optimal stoma location, and identifying patients who are at the greatest risk of PSH (22). During follow up, although these procedures have promised lower incidence of PSH when compared to a non-prophylactic method, but due to the limitations of methodology and absence of any standardization, it is necessary to remain cautious when interpreting any results thus far (26–29).
The prophylactic use of a mesh when the stoma is created is demonstrated in several studies; nonetheless this does not support the fact of using this approach to prevent PSH. To date, various randomized controlled trials have assessed these comparisons (30–41). These studies utilized a wide variety of meshes and surgical methods, using open and laparoscopic procedures to place various mesh styles in different positions. Thus, because of a lack of consistency in the other variables involved, it can be difficult to draw conclusions when comparing particular factors.
In our study, the fact that the incidence rate of severe postoperative PSH was different between the two groups (41.7% vs. 71.9%) show that placement of mesh can reduce the probability of second operation in the future, reduce trauma, cost, and surgical risk. While compared with previous reports of 10-20% hernia incidence, our overall incidence was high due to inclusion of H1 and H2 types). Nevertheless, in previous PSH studies, the main study was the H2 type with abdominal mass, which was basically the same as the incidence of type H2(12.5%) in our experimental group (42). We analyzed that a considerable number of patients had H1 type hernia that progressed to H2 type hernia over time. This rate of progression was lower in the patients belonging to experimental group (49.28%) compared to those in the control group was high (60.86%). However, a considerable number of patients with H1 mild PSH hernia go undetected during the course of diagnosis and corresponding preventive measures are not taken to avoid further aggravation. These patients can be distinguished through our classification, and a series of measures can be taken in the future to slow their progress.
At the same time, our study has been to an extent successful in showcasing the benefits of placing a prophylactic mesh during the surgical resection in significantly prolonging the time for PSH recurrence (48 months vs. 10 months). It is noteworthy to mention that the onset time of 48 months in the current experimental group was higher than the median survival of 29.4 months after CRC surgery (43). This may also implicate that a considerable number of patients may not be affected by PSH in their future life. The 10-year recurrence rate of incisional hernia is estimated to be 63% for conventional meshless suture repair and 32% for prosthetic mesh repairs (44). Because of the variability and poor-quality evidence in the previous studies, it is now suggested that although prophylactic mesh can be helpful in preventing PSH, it is important to discuss the risks and benefits prior to surgery with patients. In future it will also be useful to establish techniques which can be performed easily by novice surgeons within a fair additional operative time and without unnecessary complexity (20).
A strength of our study is defining strict inclusion and exclusion criteria that allowed comparison between groups of patients undergoing surgery for the same indication by the same operating surgeons, using a uniform technique. In addition, the long follow-up time period (the longest follow-up time of the experimental group is 63 months with median follow-up time of 32.5 months; the longest follow-up time of the control group is 58 months with median follow-up time of 20.19 months), enabled us to represents the general state of most patients after this type of surgery, and thus can reflect the influence of the preset patch on the incidence of PSH. However, limitations are small sample size, loss to follow up and study design that is used to assess this approach. These might limit the extrapolation of these clinical findings.
In future, more studies with sufficient sample size and longer follow-up period along with clinical correlation would be useful in assessing the long-term effectiveness and safety of prophylactic mesh in preventing PSH development. Efforts must be made in using prophylactic mesh in patients at high risk of post-operative PSH in routine clinical practice.