Prevention of incisional hernia using different suture materials for closing the abdominal wall: a comparison of PDS, Vicryl and Prolene in a rat model.

PURPOSE: An incisional hernia occurs frequently after a midline incision with an incidence of 12.8%. The choice in suture material used for abdominal wall closure is not straightforward and the conflicting literature focuses on clinical outcomes. This study compares a non-absorbable, slow-absorbable and fast-absorbable suture in a rat model, focusing on histological outcomes predicting better fascia healing. METHODS: 33 male Wistar rats, divided over three groups, each received two separate 1 cm incisions closed with either Prolene 4/0, PDS 4/0 or Vicryl 4/0. At 7 days and 21 days, one of the incisions was explanted. Tissue was semi-quantitatively scored regarding inflammatory cells and collagen fibres present. Using qPCR macrophage polarisation, fibroblast activity and vascularisation were evaluated. Data were analysed by Kruskal-Wallis test with Mann-Whitney U post hoc test. A p value of 0.017 was considered significant after Bonferroni correction. RESULTS: All animals recovered without complications and completed the 21 days of follow-up. The Vicryl group showed a higher presence of macrophages after 21 days in comparison with Prolene (p = 0.003) and PDS (p = 0.006) and more foreign body giant cells compared to Prolene at 7 days (p = 0.010) and PDS at 21 days (p < 0.001). qPCR showed 2.5-fold higher expression of clec10A in PDS compared to Prolene after 7 days (p = 0.007). CONCLUSIONS: The results of this study carefully support the use of PDS suture, compared to Prolene and Vicryl, in abdominal wall closure based on a favourable macrophage response. The heterogeneity and variability in the data might be explained by the spectrum of the macrophage subtype paradigm.

Comparison of coated meshes for intraperitoneal placement in animal studies: a systematic review and meta-analysis.

PURPOSE: Laparoscopic intraperitoneal onlay mesh in hernia repair can result in adhesions leading to intestinal obstruction and fistulation. The aim of this systematic review is to compare the effects of mesh coatings reducing the tissue-to-mesh adhesion in animal studies. METHODS: Pubmed and Embase were systematically searched. Animal experiments comparing intraperitoneally placed meshes with coatings were eligible for inclusion. Only studies with comparable follow-up, measurements, and species were included for data pooling and subsequent meta-analysis. RESULTS: A total of 131 articles met inclusion criteria, with four studies integrated into one comparison and five studies integrated into another comparison. Compared to uncoated polypropylene (PP) mesh, PP mesh coated with hyaluronic acid/carboxymethyl cellulose (HA/CMC) showed significantly reduced adhesion formation at follow-up of 4 weeks measured with adhesion score of extent (random effects model, mean difference,- 0.96, 95% CI - 1.32 to - 0.61, P < 0.001, I2 = 23%; fixed effects model, mean difference,- 0.94, 95% CI - 1.25 to - 0.63, P < 0.001, I2 = 23%). Compared to PP mesh, polyester mesh coated with collagen (PC mesh) showed no significant difference at follow-up of 4 weeks regarding percentage of adhesion-area on a mesh, using random effects model (mean difference - 11.69, 95% CI - 44.14 to 20.76, P = 0.48, I2 = 92%). However, this result differed using fixed effects model (mean difference - 25.55, 95% CI - 33.70 to - 7.40, P < 0.001, I2 = 92%). CONCLUSION: HA/CMC coating reduces adhesion formation to PP mesh effectively at a follow-up of 4 weeks, while the anti-adhesive properties of PC mesh are inclusive comparing all study data.

Laparotomy closure techniques: Do surgeons follow the latest guidelines? Results of a questionnaire.

PURPOSE: Incisional hernias after laparotomy are associated with significant morbidity and increased costs. Recent research on prevention of incisional hernia formation suggests that a laparotomy closure technique using a slowly absorbable monofilament suture with small fascial steps and bites in a continuous, single layer with a suture length to wound length (SL/WL) ratio of at least 4:1 is effective in lowering morbidity. Little is known about application of this evidence in daily practice. Therefore, a survey was performed among Dutch surgeons. METHODS: All members of the Dutch Surgical Society were invited to participate in a 24-question online survey on techniques and materials used for abdominal wall closure after midline laparotomy. Subgroup analysis was performed based on surgical subspecialty, type of hospital and experience. RESULTS: Response rate was 26% (402 respondents), representing 97% of all Dutch surgical departments. More than 90% of participants closed the abdominal wall in a single mass layer, using a slowly absorbable monofilament running suture The SL/WL ratio of >4:1 is practiced by only 35% of participants and preferred suture size was variable among participants. Risk factors for incisional hernia development were generally identified correctly but more than half of the participants were unaware of the incidence and time of occurrence of incisional hernia. Subgroup analysis found that gastrointestinal and oncologic surgeons preferred smaller diameter sutures and higher suture-length to wound-length ratios. Trauma, vascular and pediatric surgeons had lower estimates of incidence of incisional hernia than other subspecialties. Surgeons employed in academic hospitals were more likely to use small fascial steps and smaller suture sizes than their colleagues in non-academic hospitals. Correct estimates of incisional hernia incidence decreased when surgeons perform less than 10 laparotomies annually. CONCLUSION: Implementation of the latest evidence regarding closure techniques of the abdominal wall is not widespread. Only 35% of surgeons close the abdominal fascia using a suture length to wound length ratio of 4:1, which is recommended based on the latest evidence. Surgical trainees, gastrointestinal and oncological surgeons are most familiar with the recommended technique and use it in their daily practice. Efforts should be directed at improving spreading of this technique.

Prophylactic mesh placement to avoid incisional hernias after stoma reversal: a systematic review and meta-analysis.

PURPOSE: To provide an overview of the available literature on prevention of incisional hernias after stoma reversal, with the use of prophylactic meshes. METHODS: A literature search of Pubmed, MEDLINE and EMBASE was performed. Search terms for stoma, enterostomy, mesh, prophylaxis and hernia were used. Search was updated to December 31th 2018. No time limitations were used, while English, Geman, Dutch and French were used as language restrictions. The primary outcome was the incidence of incisional hernia formation after stoma reversal. Secondary outcomes were mesh-related complications. Data on study design, sample size, patient characteristics, stoma and mesh characteristics, duration of follow-up and outcomes were extracted from the included articles. RESULTS: A number of 241 articles were identified and three studies with 536 patients were included. A prophylactic mesh was placed in 168 patients to prevent incisional hernias after stoma reversal. Follow-up ranged from 10 to 21 months. The risk of incisional hernia in case of prophylactic mesh placement was significantly lower in comparison to no mesh placement (OR 0.10, 95% CI 0.04-0.27, p < 0.001, I2 = 0%, CI 0-91.40%). No differences in surgical site infections were detected between the groups. CONCLUSIONS: The use of a prophylactic mesh seems to reduce the risk on incisional hernias after stoma reversal and therefore mesh reinforcement should be considered after stoma reversal.

Meta-analysis of postoperative pain using non-sutured or sutured single-layer open mesh repair for inguinal hernia.

Background: Chronic postoperative pain occurs in up to 21·7 per cent of patients undergoing open inguinal hernia repair. Several mesh fixation techniques using glue or self-gripping meshes have been developed to reduce postoperative pain. The aim of this meta-analysis was to evaluate RCTs comparing adhesional/self-gripping and sutured single-layer open mesh fixations in the repair of inguinal herniation, with postoperative pain as endpoint. Methods: PubMed, Embase and Cochrane CENTRAL databases were searched systematically for RCTs according to the PRISMA guidelines; the study was registered at PROSPERO (CRD42017056373). Different fixation methods were analysed. The primary outcome, chronic pain, was defined as a postoperative visual analogue scale (VAS) score of at least 3 at 12 months. Secondary outcomes were mean VAS score at 1 week and at 1 month after surgery. Results: Twenty-three studies including 5190 patients were included in the meta-analysis. Adhesional (self-adhering or glued) or self-gripping fixation methods were associated with a significantly lower VAS score at 1 week (mean difference -0·49, 95 per cent c.i. -0·81 to -0·17; P = 0·003) and at 1 month (mean difference -0·31, -0·58 to -0·04; P = 0·02) after surgery than suture fixation, but the incidence of chronic pain after 12 months was similar in the two groups (odds ratio 0·70, 95 per cent c.i. 0·30 to 1·66). Differences in recurrences and complications between groups did not reach statistical significance. Conclusion: There was no difference in the incidence of chronic pain 12 months after different mesh repair fixation techniques despite significant reductions in short-term postoperative pain favouring a non-sutured technique. There were no differences in recurrence rates or in rates of other complications at 1 year.

Pitfalls and clinical recommendations for the primary lumbar hernia based on a systematic review of the literature.

PURPOSE: The lumbar abdominal wall hernia is a rare hernia in which abdominal contents protrude through a defect in the dorsal abdominal wall, which can be of iatrogenic, congenital, or traumatic origin. Two anatomical locations are known: the superior and the inferior lumbar triangle. The aim of this systematic review is to provide a clear overview of the existing literature and make practical clinical recommendations for proper diagnosis and treatment of the primary lumbar hernia. METHODS: The systematic review was conducted according to the PRISMA guidelines. A systematic search in PubMed, MEDLINE, and EMBASE was performed, and all studies reporting on primary lumbar hernias were included. No exclusion based on study design was performed. Data regarding incarceration, recurrence, complications, and surgical management were extracted. RESULTS: Out of 670 eligible articles, 14 were included and additional single case reports were analysed separately. The average quality of the included articles was 4.7 on the MINORS index (0-16). Risk factors are related to increased intra-abdominal pressure. CT scanning should be performed during pre-operative workup. Available evidence favours laparoscopic mesh reinforcement, saving open repair for larger defects. Incarceration was observed in 30.8% of the cases and 2.0% had a recurrence after surgical repair. Hematomas and seromas are common complications, but surgical site infections are relatively rare. CONCLUSION: The high risks of incarceration in lumbar hernias demand a relatively fast elective repair. The use of a mesh is recommended, but the surgical approach should be tailored to individual patient characteristics and risk factors.

Critical overview of all available animal models for abdominal wall hernia research.

PURPOSE: Since the introduction of the first prosthetic mesh for abdominal hernia repair, there has been a search for the "ideal mesh." The use of preclinical or animal models for assessment of necessary characteristics of new and existing meshes is an indispensable part of hernia research. Unfortunately, in our experience there is a lack of consensus among different research groups on which model to use. Therefore, we hypothesized that there is a lack of comparability within published animal research on hernia surgery due to wide range in experimental setup among different research groups. METHODS: A systematic search of the literature was performed to provide a complete overview of all animal models published between 2000 and 2014. Relevant parameters on model characteristics and outcome measurement were scored on a standardized scoring sheet. RESULTS: Due to the wide range in different animals used, ranging from large animal models like pigs to rodents, we decided to limit the study to 168 articles concerning rat models. Within these rat models, we found wide range of baseline animal characteristics, operation techniques, and outcome measurements. Making reliable comparison of results among these studies is impossible. CONCLUSION: There is a lack of comparability among experimental hernia research, limiting the impact of this experimental research. We therefore propose the establishment of guidelines for experimental hernia research by the EHS.