Prophylactic mesh reinforcement for midline incisional hernia prevention: systematic review and updated meta-analysis of randomized controlled trials

Prophylactic Mesh Reinforcement Versus Primary Suture for Abdominal Wall Closure after Elective Abdominal Aortic Aneurysm Repair with Midline Laparotomy Incision: Updated Systematic Review Including Time-To-Event Meta-Analysis and Trial Sequential Analysis of Randomized Controlled Trials

BACKGROUND

Patients undergoing open abdominal aortic aneurysm (AAA) repair have a high risk of incisional hernia. Heterogeneity in recommendations regarding prophylactic mesh reinforcement between scientific society guidelines reflects the lack of sufficient data, with the Society for Vascular Surgery making no recommendation on methods for abdominal wall closure. We aimed to synthesize the most current evidence on mesh versus primary suture abdominal wall closure after open AAA repair.

METHODS

A systematic review was conducted on randomized controlled trials (RCTs) comparing mesh reinforcement with primary abdominal wall closure for patients who underwent elective AAA repair with a midline laparotomy incision. Dichotomous and time-to-event data were pooled using random effects models, applying the Mantel-Haenszel or inverse variance statistical method. The revised Cochrane tool and Grades of Recommendation, Assessment, Development, and Evaluation framework were used to assess the risk of bias and certainty of evidence, respectively. Trial sequential analysis assumed alpha = 5% and power = 80%.

RESULTS

Five RCTs were included reporting a total of 487 patients (260 in the mesh group and 227 in the primary suture group). Patients who had mesh closure had statistically significantly lower odds of developing incisional hernia after open AAA repair than those with primary suture closure (odds ratio (OR) 0.20, 95% confidence interval (CI) 0.09-0.43). Time-to-event analysis confirmed that the hazard of incisional hernia was statistically significantly lower in patients who had mesh closure (P < 0.05). Meta-analysis found statistically significantly lower odds of reoperation for incisional hernia in the mesh group (OR 0.23, 95% CI 0.06-0.93), but there was no statistically significant difference in wound infection (risk difference 0.02, 95% CI -0.03-0.08). The overall risk of bias was low in one study, high in 2 studies, "some concerns" in 2 studies for incisional hernia and reoperation for incisional hernia, and high in all studies reporting wound infection. The certainty of evidence was judged to be low for all outcomes. Trial sequential analysis confirmed a benefit of mesh reinforcement in reducing the risk of incisional hernia.

CONCLUSIONS

Meta-analysis of the highest-level data demonstrated a benefit of prophylactic mesh reinforcement, with trial sequential analysis confirming no additional RCTs required. This provides compelling evidence to support the use of mesh for midline laparotomy closure in patients undergoing open AAA repair.

Impact of body fat location and volume on incisional hernia development and its outcomes following repair

BACKGROUND

Obesity is known to increase the likelihood of developing abdominal wall hernias, body mass index (BMI) alone does not provide detailed information about the amount and location of body fat. The aim of this study was to investigate the link between various adipose tissue parameters and the incidence of incisional hernias (IHs), as well as the outcomes of hernia repair.

METHODS

We conducted a comprehensive review of the existing literature to examine the relationship between various body fat parameters and the occurrence of IHs after abdominal surgeries, as well as the outcomes of hernia repair.

RESULTS

Thirteen studies were included for analysis. Eight trials evaluated the IH development after abdominal surgeries via specific fat parameters, and five studies evaluated the postoperative outcomes after IH repair. The findings of this study suggest that an increase in visceral fat volume (VFA or VFV) and subcutaneous fat (SFA or SFV) are linked to a higher incidence of IHs after abdominal surgeries. Higher levels of VFV or VFA were associated with more challenging fascia closure and greater postoperative recurrence rates following repair. Whereas BMI did not demonstrate a significant association.

CONCLUSION

Measuring visceral and subcutaneous fat composition preoperatively can be a useful tool for assessing the risk of IH, and is more reliable than BMI. Elevated levels of these fat parameters have been linked to increased recurrence of IH following hernia repair, as well as the use of complex surgical techniques during repair.

Short-term outcomes of a multicentre prospective study using a "visible" polyvinylidene fluoride onlay mesh for the prevention of midline incisional hernia

INTRODUCTION

Prophylactic meshes in high-risk patients prevent incisional hernias, although there are still some concerns about the best layer to place them in, the type of fixation, the mesh material, the significance of the level of contamination, and surgical complications. We aimed to provide answers to these questions and information about how the implanted material behaves based on its visibility under magnetic resonance imaging (MRI).

METHOD

This is a prospective multicentre observational cohort study. Preliminary results from the first 3 months are presented. We included general surgical patients who had at least two risk factors for developing an incisional hernia. Multivariate logistic regression was used. A polyvinylidene fluoride (PVDF) mesh loaded with iron particles was used in an onlay position. MRIs were performed 6 weeks after treatment.

RESULTS

Between July 2016 and June 2022, 185 patients were enrolled in the study. Surgery was emergent in 30.3% of cases, contaminated in 10.7% and dirty in 11.8%. A total of 5.6% of cases had postoperative wound infections, with the requirement of stoma being the only significant risk factor (OR = 7.59, p = 0.03). The formation of a seroma at 6 weeks detected by MRI, was associated with body mass index (OR = 1.13, p = 0.02).

CONCLUSIONS

The prophylactic use of onlay PVDF mesh in midline laparotomies in high-risk patients was safe and effective in the short term, regardless of the type of surgery or the level of contamination. MRI allowed us to detect asymptomatic seromas during the early process of integration.

STUDY REGISTRATION

 This protocol was registered at ClinicalTrials.gov (NCT03105895).

Protocol for an independent patient data meta-analysis of prophylactic mesh placement for incisional hernia prevention after abdominal aortic aneurysm surgery: a collaborative European Hernia Society project (I-PREVENT-AAA)

INTRODUCTION

Incisional hernia (IH) is a prevalent and potentially dangerous complication of abdominal surgery, especially in high-risk groups. Mesh reinforcement of the abdominal wall has been studied as a potential intervention to prevent IHs. Randomised controlled trials (RCTs) have demonstrated that prophylactic mesh reinforcement after abdominal surgery, in general, is effective and safe. In patients with abdominal aortic aneurysm (AAA), prophylactic mesh reinforcement after open repair has not yet been recommended in official guidelines, because of relatively small sample sizes in individual trials. Furthermore, the identification of subgroups that benefit most from prophylactic mesh placement requires larger patient numbers. Our primary aim is to evaluate the efficacy and effectiveness of the use of a prophylactic mesh after open AAA surgery to prevent IH by performing an individual patient data meta-analysis (IPDMA). Secondary aims include the evaluation of postoperative complications, pain and quality of life, and the identification of potential subgroups that benefit most from prophylactic mesh reinforcement.

METHODS AND ANALYSIS

We will conduct a systematic review to identify RCTs that study prophylactic mesh placement after open AAA surgery. Cochrane Central Register of Controlled Trials, MEDLINE Ovid, Embase, Web of Science Core Collection and Google Scholar will be searched from the date of inception onwards. RCTs must directly compare primary sutured closure with mesh closure in adult patients who undergo open AAA surgery. Lead authors of eligible studies will be asked to share individual participant data (IPD). The risk of bias (ROB) for each included study will be assessed using the Cochrane ROB tool. An IPDMA will be performed to evaluate the efficacy, with the IH rate as the primary outcome. Any signs of heterogeneity will be evaluated by Forest plots. Time-to-event analyses are performed using Cox regression analysis to evaluate risk factors.

ETHICS AND DISSEMINATION

No new data will be collected in this study. We will adhere to institutional, national and international regulations regarding the secure and confidential sharing of IPD, addressing ethics as indicated. We will disseminate findings via international conferences, open-source publications in peer-reviewed journals and summaries posted online.

PROSPERO REGISTRATION NUMBER

CRD42022347881.

The enigma of incisional hernia prediction unraveled: external validation of a prognostic model in colorectal cancer patients

PURPOSE

Accurate prediction of hernia occurrence is vital for surgical decision-making and patient management, particularly in colorectal surgery patients. While a hernia prediction model has been developed, its performance in external populations remain to be investigated. This study aims to validate the existing model on an external dataset of patients who underwent colorectal surgery.

METHODS

The "Penn Hernia Calculator" model was externally validated using the Hughes Abdominal Repair Trial (HART) data, a randomized trial comparing colorectal cancer surgery closure techniques. The data encompassed demographics, comorbidities, and surgical specifics. Patients without complete follow-up were omitted. Model performance was assessed using key metrics, including area under the curve (AUC-ROC and AUC-PR) and Brier score. Reporting followed the TRIPOD consensus.

RESULTS

An external international dataset consisting of 802 colorectal surgery patients were identified, of which 674 patients with up to 2 years follow-up were included. Average patient age was 68 years, with 63.8% male. The average BMI was 28.1. Prevalence of diabetes, hypertension, and smoking were 15.7%, 16.3%, and 36.5%, respectively. Additionally, 7.9% of patients had a previous hernia. The most common operation types were low anterior resection (35.3%) and right hemicolectomy (34.4%). Hernia were observed in 24% of cases by 2-year follow-up. The external validation model revealed an AUC-ROC of 0.66, AUC-PR of 0.72, and a Brier score of 0.2.

CONCLUSION

The hernia prediction model demonstrated moderate performance in the external validation. Its potential generalizability, specifically in those undergoing colorectal surgery, may suggest utility in identifying and managing high-risk hernia candidates.

Effect of Functionalization of Texturized Polypropylene Surface by Silanization and HBII-RGD Attachment on Response of Primary Abdominal and Vaginal Fibroblasts

Soft tissue defects, such as incisional hernia or pelvic organ prolapse, are prevalent pathologies characterized by a tissue microenvironment rich in fragile and dysfunctional fibroblasts. Precision medicine could improve their surgical repair, currently based on polymeric materials. Nonetheless, biomaterial-triggered interventions need first a better understanding of the cell-material interfaces that truly consider the patients' biology. Few tools are available to study the interactions between polymers and dysfunctional soft tissue cells in vitro. Here, we propose polypropylene (PP) as a matrix to create microscale surfaces w/wo functionalization with an HBII-RGD molecule, a fibronectin fragment modified to include an RGD sequence for promoting cell attachment and differentiation. Metal mold surfaces were roughened by shot blasting with aluminum oxide, and polypropylene plates were obtained by injection molding. HBII-RGD was covalently attached by silanization. As a proof of concept, primary abdominal and vaginal wall fasciae fibroblasts from control patients were grown on the new surfaces. Tissue-specific significant differences in cell morphology, early adhesion and cytoskeletal structure were observed. Roughness and biofunctionalization parameters exerted unique and combinatorial effects that need further investigation. We conclude that the proposed model is effective and provides a new framework to inform the design of smart materials for the treatment of clinically compromised tissues.

Incisional Hernia: A Surgical Complication or Medical Disease?

Incisional hernia (IH) is a frequent complication following abdominal surgery. The development of IH could be more sophisticated than a simple anatomical failure of the abdominal wall. Reported IH incidence varies among studies. This review presented an overview of definitions, molecular basis, risk factors, incidence, clinical presentation, surgical techniques, postoperative care, cost, risk prediction tools, and proposed preventative measures. A literature search of PubMed was conducted to include high-quality studies on IH. The incidence of IH depends on the primary surgical pathology, incision site and extent, associated medical comorbidities, and risk factors. The review highlighted inherent and modifiable risk factors. The disorganisation of the extracellular matrix, defective fibroblast functions, and ratio variations of different collagen types are implicated in molecular mechanisms. Elective repair of IH alleviates symptoms, prevents complications, and improves the quality of life (QOL). Recent studies introduced risk prediction tools to implement preventative measures, including suture line reinforcement or prophylactic mesh application in high-risk groups. Elective repair improves QOL and prevents sinister outcomes associated with emergency IH repair. The watchful wait strategy should be reviewed, and options should be discussed thoroughly during patients' counselling. Risk stratification tools for predicting IH would help adopt prophylactic measures.

Low incisional hernia incidence using a large-bite, low-tension technique for celiotomy closure

Background

Incisional herniae (IH) are reported in 5->20 % of patients undergoing open celiotomy, and can be linked to closure technique. The STITCH randomized trial favors a small bite technique for midline celiotomy closure with a 1-year IH rate of 13 % over larger bites (23 %).

Methods

A continuous musculofascial mass closure with absorbable looped #1 PDS suture with 2-cm bite size was used for all open celiotomies. IH frequency and associated clinicopathologic factors were retrospectively analyzed from prospective data in 336 consecutive patients undergoing visceral resections by a single surgeon.

Results

The study population included 192 men and 144 women, 81 % of whom had a cancer diagnosis, who underwent hepatobiliary, pancreatic, gastroesophageal, and colorectal resections, or a combination. The majority of patients (84 %) had subcostal incisions, and 10 % received a midline incision. At a median follow-up of 19.5 months, the overall IH rate was 3.3 %. Hernia rates were 2.5 % for subcostal margin, 2.9 % for midline, and 5.5 % for other incisions (p = 0.006). Median time to hernia detection was 492 days. Factors associated with IH were increased weight, abdominal depth/girth, male sex, spleen size, visceral fat, and body height (p ≤ 0.04 for all), but not type of resection, prior operations, underlying diagnosis, weight loss, adjuvant chemotherapy or radiation, incision length or suture to incision ratio.

Conclusions

The described technique leads to a low IH rate of <3 % in subcostal or midline incisions, and can be recommended for routine use. The observed results appear superior to those of the STITCH trial, even for the smaller midline incision cohort.

What is the ideal mesh location for incisional hernia prevention during elective laparotomy? A network meta-analysis of randomized trials

BACKGROUND

Incisional hernia (IH) represents an important complication after surgery. Prophylactic mesh reinforcement (PMR) with different mesh locations [onlay (OL), retromuscular (RM), preperitoneal (PP), and intraperitoneal (IP)] has been described to possibly reduce the risk of postoperative IH. However, data reporting the 'ideal' mesh location are sparse. The aim of this study was to evaluate the optimal mesh location for IH prevention during elective laparotomy.

METHODS

Systematic review and network meta-analysis of randomized controlled trials (RCTs). OL, RM, PP, IP, and no mesh (NM) were compared. The primary aim was postoperative IH. Risk ratio (RR) and weighted mean difference (WMD) were used as pooled effect size measures, whereas 95% credible intervals (CrI) were used to assess relative inference.

RESULTS

Fourteen RCTs (2332 patients) were included. Overall, 1052 (45.1%) had no mesh (NM) while 1280 (54.9%) underwent PMR stratified in IP ( n =344 pts), PP ( n =52 pts), RM ( n =463 pts), and OL ( n =421 pts) placement. Follow-up ranged from 12 months to 67 months. RM (RR=0.34; 95% CrI: 0.10-0.81) and OL (RR=0.15; 95% CrI: 0.044-0.35) were associated with significantly reduced IH RR compared to NM. A tendency toward reduced IH RR was noticed for PP versus NM (RR=0.16; 95% CrI: 0.018-1.01), while no differences were found for IP versus NM (RR=0.59; 95% CrI: 0.19-1.81). Seroma, hematoma, surgical site infection, 90-day mortality, operative time and hospital length of stay were comparable among treatments.

CONCLUSIONS

RM or OL mesh placement seems associated with reduced IH RR compared to NM. PP location appears promising; however, future studies are warranted to corroborate this preliminary indication.