Biofilms and effective porosity of hernia mesh: are they silent assassins? Abstract Purpose The purpose of this paper is to communicate two new concepts with the potential to cause major morbidity in hernia repair, effective porosity and biofilm. These 2 concepts are interrelated and have the potential to result in mesh-related complications. Effective porosity is a term well described in the textile industry. It is best defined as the changes to pore morphology after implantation of mesh in situ. It is heavily dependent on mesh construct and repair technique and has the potential to impact hernia repair by reducing mesh tissue integration and promoting fibrosis. Bacterial biofilm is a well-described condition affecting prosthesis in breast and join replacement surgery with catastrophic consequences. There is a paucity of information on bacterial biofilm in mesh hernia repair. We speculate that bacterial biofilm has the potential to reduce the effective porosity of mesh, resulting in non-suppurative mesh-related complications as well as the potential for late suppurative infections. We describe the aetiology, pathogenesis, diagnosis, treatment and preventative measures to address bacterial biofilm in mesh hernia surgery. Hernia surgeons should be familiar with these two new concepts which have the potential to cause major morbidity in hernia repair and know how to address them. Methods Ovid Medline and PubMed were searched for communications on “effective porosity” and “bacterial biofilm”. Results There is a paucity of information in the literature of these conditions and their impact on outcomes following mesh hernia repair. Conclusions We discuss the two concepts of effective porosity and biofilm and propose potential measures to reduce mesh-related complications. This includes choosing mesh with superior mesh construct and technical nuances in implanting mesh to improve effective porosity. Furthermore, measures to reduce bacterial biofilm and its consequences are suggested.

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

Incidence of arcuate line hernia in patients with abdominal complaints: radiological and clinical features Abstract Introduction Acute abdominal complaints are a frequent cause for consultation in the emergency department, with a large differential diagnosis. One cause is arcuate line herniation, but this entity is little known and rarely considered during initial analysis. The incidence of arcuate line herniation in this population is unknown. Methods A retrospective cohort study was performed. All patients who presented to the emergency department for surgical consultation during an 18-month period with abdominal complaints in who no diagnosis was found after analysis, and who had computed tomography imaging of the abdomen were included. CT scans were reviewed with a focus on abdominal wall pathology and correlated with clinical features. Results Eight hundred and ten patients presented with abdominal complaints, 415 of these had CT scans available for review and were included in the study. In 47 patients (11.3%), an arcuate line anomaly was found, and in 14 patients (3.4%), a frank arcuate line herniation (grades 2 or 3) was found. Retrospective correlation with clinical complaints was found in 50% of these patients. Patients with arcuate line hernia had a significantly higher BMI, and diabetes mellitus and aortic aneurysm were more prevalent in these patients. Conclusion Arcuate line herniation has a higher incidence than previously thought in patients with acute abdominal complaints and should be considered when evaluating these patients.

Survey of patients regarding experience following repair of inguinal hernias Abstract Purpose This study aimed to determine patients’ experiences following inguinal hernia repair at a tertiary hospital and associated cottage hospital in terms of postherniorraphy pain and follow-up. Methods After exclusions, 373 adult patients undergoing inguinal hernia repair at Derriford and Tavistock hospitals during a 1-year period from October 2017 were sent a questionnaire regarding preoperative pain experience, current symptoms, and pain severity at 28 days and other intervals postoperatively. Statistical analysis of responses included unpaired t test to compare means and χ2 test for discrete variables with a p value < 0.05 regarded as statistically significant. Results The survey response rate was 68% (253/373). The mean pain score on visual analogue scale was 1.5 at 28 days postoperatively in those without preoperative pain compared to 3.2 in those with preoperative pain (p = 0.0001). Although 64 (25%) patients complained of pain at a mean follow-up of 47.9 ± 15.6 weeks, pain severity was insignificant after 28 days. Gender, employment status and mesh type did not affect pain scores. Return to normal activity after laparoscopic repair was longer than after open repair (5.4 ± 3.4 versus 4.2 ± 2.2 weeks, respectively; p = 0.0322). Overall, 34.6% thought follow-up was necessary and patients were more likely to agree with a decision not to follow them up. Conclusion This study puts postherniorrhaphy pain in perspective of preoperative pain. Active discussion with patients prior to discharge or telephone follow-up by an appropriate individual may reduce the need for hospital follow-up.

Is there a role for prophylactic mesh in abdominal wall closure after emergency laparotomy? A systematic review and meta-analysis Abstract Background Incisional hernias are a common complication of emergency laparotomy and are associated with significant morbidity. Recent studies have found a reduction in incisional hernias when mesh is placed prophylactically during abdominal closure in elective laparotomies. This systematic review will assess the safety and efficacy of prophylactic mesh placement in emergency laparotomy. Methods A systematic review was performed according to the PROSPERO registered protocol (CRD42018109283). Papers were dual screened for eligibility, and included when a comparison was made between closure with prophylactic mesh and closure with a standard technique, reported using a comparative design (i.e. case–control, cohort or randomised trial), where the primary outcome was incisional hernia. Bias was assessed using the Cochrane risk of bias in non-randomised studies tool. A meta-analysis of incisional hernia rate was performed to estimate risk ratio using a random effects model (Mantel–Haenszel approach). Results 332 studies were screened for eligibility, 29 full texts were reviewed and 2 non-randomised studies were included. Both studies were biased due to confounding factors, as closure technique was based on patient risk factors for incisional hernia. Both studies found significantly fewer incisional hernias in the mesh groups [3.2% vs 28.6% (p < 0.001) and 5.9% vs 33.3% (p = 0.0001)]. A meta-analysis of incisional hernia risk favoured prophylactic mesh closure [risk ratio 0.15 (95% CI 0.6–0.35, p < 0.001)]. Neither study found an association between mesh and infection or enterocutaneous fistula. Conclusion This review found that there are limited data to assess the effect or safety profile of prophylactic mesh in the emergency laparotomy setting. The current data cannot reliably assess the use of mesh due to confounding factors, and a randomised controlled trial is required to address this important clinical question.

Predictors of discharge destination after complex abdominal wall reconstruction Abstract Background Complex ventral hernia repair is a common operation performed in a diverse population. Post-operatively, patients may have a prolonged length of stay pending facility placement. With increasing in-patient volumes, the authors aim to identify risk factors for non-home discharge to expedite placement applications and decrease length of stay. Methods The ACS-NSQIP database was queried for all ventral hernia repairs with separation of components performed between 2005 and 2016, excluding patients that left against medical advice or expired. Multivariate logistic regression was performed to identify independent risk factors for discharge to a facility as well as the risk for post-discharge complications following discharge to a facility after univariate analysis to compare demographics, comorbidities, and complications. Independent sample t test was done to compare mean age, body mass index and length of stay. Results 4549 patients met inclusion criteria. Pre-operative factors significantly associated with non-home discharge on multivariate analysis were female gender, history of diabetes, history of hypertension, older age (60+), presence of pre-operative wound infection/contaminated wound, sepsis, and dependent functional status. Intra-operative factors included ASA classification of 3 or 4 and longer operative time. Conclusion Our study was able to identify several predictive factors, mostly pre-operative, that increase the likelihood that a patient will require discharge to a facility after complex ventral hernia repair. Identification of these factors can expedite patient discharge disposition resulting in decreased length of stay, less hospital-acquired conditions, and minimized health care costs.

Total extraperitoneal endoscopic hernioplasty (TEP) versus Lichtenstein hernioplasty: a systematic review by updated traditional and cumulative meta-analysis of randomised-controlled trials Abstract Background–purpose Totally extraperitoneal (TEP) endoscopic hernioplasty and Lichtenstein hernioplasty are the most commonly used approaches for inguinal hernia repair. However, current evidence on which is the preferred approach is inconclusive. This updated meta-analysis was conducted to track the accumulation of evidence over time. Methods Studies were identified by a systematic literature search of the EMBASE, PubMed, Cochrane Library, and Google Scholar databases. Fixed- and random-effects models were used to cumulatively assess the accumulation of evidence over time. Results The TEP cohort showed significantly higher rates of recurrences and vascular injuries compared to the Lichtenstein cohort; [Peto Odds ratio (OR) = 1.58 (1.22, 2.04), p = 0.005], [Peto OR = 2.49 (1.05, 5.88), p = 0.04], respectively. In contrast, haematoma formation rate, time to return to usual activities, and local paraesthesia were significantly lower in the TEP cohort compared to the Lichtenstein cohort; [Peto OR = 0.26 (0.16, 0.41), p ≤ 0.001], [mean difference = − 6.32 (− 8.17, − 4.48), p ≤ 0.001], [Peto OR = 0.26 (0.17, 0.40), p ≤ 0.001], respectively. Conclusions This study, which is based on randomised-controlled trials (RCTs) of high quality, showed significantly higher rates of recurrences and vascular injuries in the TEP cohort than in the Lichtenstein cohort. In contrast, rate of postoperative haematoma formation, local paraesthesia, and time to return to usual activities were significantly lower in the TEP cohort than in the Lichtenstein cohort. Future multicentre RCTs with strict adherence to the standards recommended in the Consolidated Standards of Reporting Trials guidelines will shed further light on the topic.

Primary ventral hernia: where are we at?

Correction to: Pure tissue repairs: a timely and critical revival In the original publication, author group, abstract text, position of Figure 1, Figure 5 legend, Figure 6 (duplication of figure panels) and the conflict of interest statement were incorrectly published. The corrected text and the figures are given here.

Robotic transabdominal preperitoneal approach for repair of primary, uncomplicated ventral hernias