RISK FACTORS OF LONG-TERM INCISIONAL HERNIA AFTER OPEN SURGERY FOR ABDOMINAL AORTIC ANEURYSM: A BICENTRIC STUDY

Linking factors to incisional hernia following pancreatic surgery: a 14-year retrospective analysis

BACKGROUND

Incisional hernias (IH) are a significant postoperative complication with profound implications for patient morbidity and healthcare costs. The relationship between IH and perioperative factors in pancreatic surgery, with particular attention to preoperative biliary stents and pancreatic fistulas requires further exploration.

METHODS

This retrospective observational study examined adult patients who underwent open pancreatic surgeries via midline incision at a high-volume tertiary hepatopancreatobiliary center from January 2008 to December 2021. The study focused on IH incidence and associated risk factors, with particular attention to preoperative biliary stents and pancreatic fistulas.

RESULTS

In a cohort of 620 individuals undergoing pancreatic surgery, 351 had open surgery with at least one-year follow-up. Within a median follow-up of 794 days (IQR 1694-537), the overall incidence of IH was 17.38%. The highest frequency of IH was observed among patients who had a Pancreaticoduodenectomy (PD). Significant predictors for the development of IH within the entire study population in a multivariable analysis included perioperative biliary stenting (OR 2.05; 95% CI 1.06-3.96; p = 0.03), increased age at diagnosis (OR 2.05; 95% CI 1.06-3.96; p = 0.01), and BMI (OR 1.08; 95% CI 1.01-1.15; p = 0.01). In the subset of patients who underwent Pancreaticoduodenectomy (PD), although the presence of biliary stents was associated with a heightened occurrence of SSIs, it did not demonstrate a direct correlation with an increased incidence of incisional hernias (IH). The development of pancreatic fistulas did not show a significant correlation with IH in either the Distal Pancreatectomy with Splenectomy (DPS) or the PD patient groups.

CONCLUSIONS

The study underscores a notable association between biliary stent placement and increased IH risk after PD, mediated by elevated SSI incidence. Pancreatic fistulas were not directly correlated with IH in the studied cohorts. Further research is necessary to validate these findings and guide clinical practice.

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.

Optimal computed tomography-based biomarkers for prediction of incisional hernia formation

PURPOSE

Unstructured data are an untapped source for surgical prediction. Modern image analysis and machine learning (ML) can harness unstructured data in medical imaging. Incisional hernia (IH) is a pervasive surgical disease, well-suited for prediction using image analysis. Our objective was to identify optimal biomarkers (OBMs) from preoperative abdominopelvic computed tomography (CT) imaging which are most predictive of IH development.

METHODS

Two hundred and twelve rigorously matched colorectal surgery patients at our institution were included. Preoperative abdominopelvic CT scans were segmented to derive linear, volumetric, intensity-based, and textural features. These features were analyzed to find a small subset of OBMs, which are maximally predictive of IH. Three ML classifiers (Ensemble Boosting, Random Forest, SVM) trained on these OBMs were used for prediction of IH.

RESULTS

Altogether, 279 features were extracted from each CT scan. The most predictive OBMs found were: (1) abdominopelvic visceral adipose tissue (VAT) volume, normalized for height; (2) abdominopelvic skeletal muscle tissue volume, normalized for height; and (3) pelvic VAT volume to pelvic outer aspect of body wall skeletal musculature (OAM) volume ratio. Among ML prediction models, Ensemble Boosting produced the best performance with an AUC of 0.85, accuracy of 0.83, sensitivity of 0.86, and specificity of 0.81.

CONCLUSION

These OBMs suggest increased intra-abdominopelvic volume/pressure as the salient pathophysiologic driver and likely mechanism for IH formation. ML models using these OBMs are highly predictive for IH development. The next generation of surgical prediction will maximize the utility of unstructured data using advanced image analysis and ML.

Preoperative Computed Tomography Morphological Features Indicative of Incisional Hernia Formation After Abdominal Surgery

OBJECTIVE

To investigate key morphometric features identifiable on routine preoperative computed tomography (CT) imaging indicative of incisional hernia (IH) formation following abdominal surgery.

BACKGROUND

IH is a pervasive surgical disease that impacts all surgical disciplines operating in the abdominopelvic region and affecting 13% of patients undergoing abdominal surgery. Despite the significant costs and disability associated with IH, there is an incomplete understanding of the pathophysiology of hernia.

METHODS

A cohort of patients (n=21,501) that underwent colorectal surgery was identified, and clinical data and demographics were extracted, with a primary outcome of IH. Two datasets of case-control matched pairs were created for feature measurement, classification, and testing. Morphometric linear and volumetric measurements were extracted as features from anonymized preoperative abdominopelvic CT scans. Multivariate Pearson testing was performed to assess correlations among features. Each feature's ability to discriminate between classes was evaluated using 2-sided paired t testing. A support vector machine was implemented to determine the predictive accuracy of the features individually and in combination.

RESULTS

Two hundred and twelve patients were analyzed (106 matched pairs). Of 117 features measured, 21 features were capable of discriminating between IH and non-IH patients. These features are categorized into three key pathophysiologic domains: 1) structural widening of the rectus complex, 2) increased visceral volume, 3) atrophy of abdominopelvic skeletal muscle. Individual prediction accuracy ranged from 0.69 to 0.78 for the top 3 features among 117.

CONCLUSIONS

Three morphometric domains identifiable on routine preoperative CT imaging were associated with hernia: widening of the rectus complex, increased visceral volume, and body wall skeletal muscle atrophy. This work highlights an innovative pathophysiologic mechanism for IH formation hallmarked by increased intra-abdominal pressure and compromise of the rectus complex and abdominopelvic skeletal musculature.