Visceral obesity is a predictor of surgical site occurrence and hernia recurrence after open abdominal wall reconstruction

The effect of clinically significant weight loss prior to open ventral hernia repair

PURPOSE

The study aim was to assess the impact of clinically significant weight loss (CSWL; ≥5% weight reduction) on postoperative complications following abdominal wall reconstruction with the component separation technique (CST).

METHODS

A retrospective review of patients who underwent open ventral hernia repair (VHR) with CST from November 2008 to January 2022 was performed. Cohorts were stratified by presence of CSWL from baseline weight at preoperative consultation.

RESULTS

Of 180 total patients, 40 (22.2%) achieved CSWL prior to VHR. Mean age was 59.6 ± 11.2 years. Patients in the CSWL cohort represented a higher average body mass index (BMI) (33.6 vs. 31.7 kg/m2, p = 0.076), and were obese more frequently (80.0% vs. 56.4%, p = 0.007). The CSWL cohort had a higher proportion of patients in Ventral Hernia Working Group (VHWG) classification II (82.5% vs. 63.6%) while the non-CSWL cohort had more VHWG classification III/IV (20.0% vs. 10.0%, p = 0.078). Mean follow-up duration was 6.1 ± 13.4 months. Complications, including 30- and 90-day surgical site occurrence (SSO), return to operating room, readmission, and hernia recurrence (CSWL: 5.0% vs. non-CWL 1.4%, p = 0.179), were comparable between cohorts. BMI was an independent predictor of any complication (OR 1.07, p = 0.044) and 90-day SSO (OR 1.10, p = 0.043).

CONCLUSION

Achievement of CSWL prior to open VHR utilizing CST results in similar post-reconstruction outcomes to patients who maintained a comparable BMI at baseline. Higher day-of-surgery BMI was more consequential to postoperative complications than percent weight loss.

Subcutaneous fat thickness predicts postoperative seroma following laparoscopic total extra-peritoneal hernioplasty

PURPOSE

Seroma formation is the most common cause of morbidity associated with laparoscopic inguinal hernia repair. This study aimed to examine the relationship between the thickness of subcutaneous fat (TSF) and the risk of postoperative seroma.

METHODS

We reviewed data from a prospective cohort of 229 male patients who underwent laparoscopic total extra-peritoneal (TEP) hernioplasty for indirect inguinal hernia between August 2018 and July 2021. The TSF was assessed using preoperative ultrasound images. The risk factors for postoperative seroma were determined using univariate and multivariate logistic regression models.

RESULTS

Postoperative seromas occurred in 26 patients (11.4%). The factors associated with postoperative seroma included longer hernia duration, larger hernia defects, extension into the scrotum, and greater TSF (P < 0.05). In multivariate analysis, a greater TSF was independently associated with a greater risk of postoperative seroma (per 1 mm: odd ratio [OR] 1.105, 95% confidence interval [CI] 1.048-1.165, P < 0.001; TSF ≥ 26.0 mm: OR 7.033, 95% CI 2.485-19.901, P < 0.001). Similar results were obtained in the subgroup analysis. The area under the curve of TSF for predicting seroma formation was 0.703 (95% CI 0.601-0.806).

CONCLUSION

Ultrasound-derived TSF may be a promising prognostic factor for postoperative seroma in patients undergoing laparoscopic TEP repair. Further validation is required and then this parameter can be used to improve decision-making process.

Occurrence and prevention of incisional hernia following laparoscopic colorectal surgery

Among minimally invasive surgical procedures, colorectal surgery is associated with a notably higher incidence of incisional hernia (IH), ranging from 1.7% to 24.3%. This complication poses a significant burden on the healthcare system annually, necessitating urgent attention from surgeons. In a study published in the World Journal of Gastrointestinal Surgery, Fan et al compared the incidence of IH among 1614 patients who underwent laparoscopic colorectal surgery with different extraction site locations and evaluated the risk factors associated with its occurrence. This editorial analyzes the current risk factors for IH after laparoscopic colorectal surgery, emphasizing the impact of obesity, surgical site infection, and the choice of incision location on its development. Furthermore, we summarize the currently available preventive measures for IH. Given the low surgical repair rate and high recurrence rate associated with IH, prevention deserves greater research and attention compared to treatment.

Obesity increases the surgical complexity and risk of recurrence after midline primary ventral hernia repair: results on 2307 patients from the French Society of hernia surgery (SFCP-CH) registry database

PURPOSE

Obesity is a known risk factor of recurrence after hernia surgery, but available data often concern pooled cases of primary and incisional hernia, with short follow-up. We aimed to analyze the impact of severe obesity (BMI ≥ 35 kg/m2) on the results of midline primary ventral hernia repair (mPVHR), in comparison with non-severely obese patients.

METHODS

Data were extracted from a multicentric registry, in which patients' data are consecutively and anonymously collected. We conducted a retrospective comparative study on patients with severe obesity (sOb) versus non-severely obese patients (non-sOb), who underwent surgery, with a minimal 2-year follow-up after their mPVHR.

RESULTS

Among 2307 patients, 267 sOb and 2040 non-sOb matched inclusion criteria. Compared with non-sOb, sOb group gathered all the worse conditions and risk factors: more ASA3-4 (39.3% vs. 10.2%; p < 0.001), symptomatic hernia (15.7% vs. 6.8%; p < 0.001), defect > 4 cm in diameter (24.3% vs. 8.8%; p < 0.001), emergency surgery (6.1% vs. 2.5%; p = 0.003), and Altemeir class > 1 (9.4% vs. 2.9%; p < 0.001). Laparoscopic IPOM was used more often in sOb patients (40% vs. 32%; p = 0.016), but with smaller Hauters' ratio (46 vs. 73; p < 0.001). Compared with the non-sOb, the rate of day-case surgery was lower (48% vs. 68%; p < 0.001), the surgical site occurrences were significantly more frequent (6.4 %vs. 2.5%; p < 0.001). The main outcome, 2-year recurrence, was 5.9% in the sOb vs. 2.1% (p = 0.008), and 2-year reoperations was 3% vs. 0.3% (p = 0.006). In the adjusted analysis, severe obesity was an independent risk factor for recurrence [OR = 2.82, (95%CI, 1.45; 5.22); p = 0.003].

CONCLUSION

In patients with severe obesity, mPVHR is technically challenging and recurrence rate is three times higher than that of non-severely obese patients.

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.

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.

Outcomes of Complex Abdominal Wall Reconstruction with Biologic Mesh in Patients with 8 Years of Follow-Up

BACKGROUND

While many studies evaluated outcomes of abdominal wall reconstruction with biologic mesh, long-term data is lacking. In this study, we sought to analyze the outcomes of complex AWR with biologic mesh in a robust cohort of patients with a mean follow up of 8 years.

METHODS

We conducted a longitudinal study of AWR patients from 2005 to 2019. Hernia recurrence was the primary outcome, and surgical site occurrence was the secondary outcome. Predictive/protective factors were identified using a Cox proportional hazards regression models.

RESULTS

We identified 109 consecutive patients who met the inclusion criteria. Patient's mean (± SD) age was 57.5 ± 11.8 years, mean body mass index was 30.7 ± 7.2 kg/m2, and mean follow-up time was 96.2 ± 15.9 months. Fifty-six percent had clean defects, 34% had clean-contaminated defects, and 10% had contaminated/infected defects. Patients had a mean defect size of 261 ± 199.6 cm2 and mean mesh size of 391.3 ± 160.2 cm2. Nineteen patients (17.4%) developed HR at the final follow-up date. Obesity was independently associated with a four-fold higher risk of HR (hazard ratio, 3.98; 95%CI, 1.34 to 14.60, p = 0.02). SSOs were identified in 24.8% of patients. A prior hernia repair was associated with a three-fold higher risk of SSOs (Odds ratio, 3.13; 95%CI, 1.10 to 8.94, p = 0.03). No patient developed mesh infection.

CONCLUSION

These longitudinal data demonstrate that complex AWR with biologic mesh provides long-term durable outcomes with acceptable HR and SSO rates despite high contamination levels, patients complexity, and large defect size.

Preoperative Optimization for Abdominal Wall Reconstruction

Patients requiring abdominal wall reconstruction may have medical comorbidities and/or complex defects. Comorbidities such as smoking, diabetes, obesity, cirrhosis, and frailty have been associated with an increased risk of postoperative complications. Prehabilitation strategies are variably associated with improved outcomes. Large hernia defects and loss of domain may present challenges in achieving fascial closure, an important part of restoring abdominal wall function. Prehabilitation of the abdominal wall can be achieved with the use of botulinum toxin A, and preoperative progressive pneumoperitoneum.

Correlation between abdominal visceral volume measured by a simple procedure and bulging at the abdominal free flap donor site for breast reconstruction

BACKGROUND

Breast reconstructions using autologous abdominal tissue result in breasts with a natural shape and consistency. One of the major complications is abdominal bulging. Because of the increased abdominal wall tension, high visceral volume (not visceral fat alone) may increase the occurrence rate of abdominal bulging. A simple procedure involving CT imaging was used to assess this relationship in patients undergoing an abdominal free flap for unilateral breast reconstruction.

METHODS

A total of 278 patients were enrolled in this study. The patients' demographics, the thicknesses of visceral volume were compared (Bulging (+) vs. Bulging (-)). Visceral volume was investigated based on the horizontal thickness, which was measured at the thickest part at the level of the umbilical fossa between both sides under the transverse abdominis muscles.

RESULTS

Bulging (+) consisted of 39 patients (14.0%), whereas Bulging (-) included 239 patients. Patients with Bulging (+) were significantly older, had higher gestational history rate, and had thin rectus abdominis muscle. In terms of visceral volume, the Bulging (+) group had significantly higher horizontal thicknesses (median 233 mm vs. 219 mm, P < 0.001). No significant differences were observed with respect to other factors (age, BMI, history of laparotomy, and operative details). The multivariate logistic regression analysis revealed that the thickness of the rectus abdominis muscle, horizontal visceral volume, and gestational history were independently significant predictors.

CONCLUSIONS

Not only the patients with thin rectus abdominis muscle but also patients with a thick horizontal visceral volume may have a higher risk of abdominal bulging.

Visceral obesity as a risk factor of incisional hernia after single-port laparoscopic gynecologic surgery

OBJECTIVE

We aimed to evaluate associations between abdominal fat distribution (AFD) parameters and incisional hernia (IH) in patients who underwent transumbilical single-port laparoscopic surgery (SPLS) for gynecological disease.

METHODS

Medical records of 2116 patients who underwent SPLS for gynecological disease at Daejeon St. Mary's Hospital between March 2014 and February 2021 were reviewed. Among 21 (1.0%) patients who developed IH requiring surgical treatment after SPLS, 18 had preoperative abdominopelvic computed tomography (CT) images. As a control group, we randomly selected 72 patients who did not develop IH and who had undergone preoperative abdominopelvic CT scan, matched to test patients by type of surgery. Total fat area (TFA), visceral fat area (VFA), subcutaneous fat area (SFA), visceral-to-subcutaneous fat ratio (VSR), and waist circumference (WC) were measured at the level of the third lumbar vertebral body on the preoperative abdominopelvic CT images, using National Institutes of Health (NIH) ImageJ version 1.53 k.

RESULTS

Receiver operating curve analysis showed that VFA has the highest predictive value for IH among AFD parameters (AUC = 0.749, 95% CI 0.630-0.869, p < 0.001). Univariate analysis showed that age, BMI, hypertension, dyslipidemia, TFA, VFA, VSR and WC were significant factors for IH. In multivariate analysis, only high VFA was identified as an independent risk factor for IH (HR 6.18, 95% CI 1.13-33.87, p = 0.04), whereas BMI, TFA, SFA, VSR, and WC failed to show statistical significance.

CONCLUSION

We could find high VFA as an independent risk factor of IH in patients who underwent SPLS for gynecologic disease.

Prediction models in hernia repair: a systematic review

BACKGROUND

Hernias can present with unique challenges when it comes to management and repair. Prediction models can be a useful tool for clinicians to better anticipate and understand the severity of a hernia, the type of surgical technique, or presurgical planning that may be required to treat the patient, and the risk of complications. Our goal is to evaluate and consolidate prediction models in hernia repair present in the literature for which physicians can reference to best improve patient outcomes and postoperative management.

METHODS

We performed a literature search in PubMed using keywords, "rectus width to defect width ratio," "predicting myofascial release," "computed tomography hernia repair prediction," "component separation radiology prediction hernia," "fat volume and hernia repair," "body morphometrics and Query hernia repair," "body morphometrics and reherniation," "computed tomography findings and risk of emergency hernia repair," "loss of domain and hernia radiology," and "volumetry and hernia repair." We searched for publications that used radiographic parameters to predict hernia severity, interventions, and outcomes.

RESULTS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), we found twenty-three studies related to prediction models in hernia repair published between 2000 and 2021. We summarized studies pertaining to predicting acute care, predicting operative planning with loss of domain and component separation, predicting complications, paraesophageal hernia predictions, and predicting postoperative respiratory complications.

CONCLUSION

Radiographic prediction models can be an objective and efficient way for surgeons to analyze hernias and better understand a patient's situation so that they can inform patients about the best treatment options and the risk of complications.

Body mass index and the risk of abdominal hernia: a Mendelian randomization study

PURPOSE

Abdominal hernia (AH) is one of the most common clinical diseases. A large number of observational studies have found that obesity is an important risk factor for AH. However, the causal relationship between obesity and AH cannot be determined because of the clinical studies on AH induced by obesity are relatively few and only have some small- or medium-scale observational studies. Observational studies have so many confounding factors and reverse causality due to their shortcomings. From an evidence-based medicine perspective, they are not sufficiently convincing. Therefore, there is still a lack of high-quality, evidence-based medical evidence supporting a causal relationship between obesity and AH. A causal relationship between obesity and AH is also almost impossible to confirm by randomized controlled trials (RCTs). Our study based on Mendelian randomization (MR) may provide a higher level of evidence-based medical support for the relationship between obesity and AH. Body mass index (BMI) is the most common measure used for defining obesity. Finally, we employed two-sample Mendelian randomization (TSMR) to explore the causal relationship between BMI and AH.

METHODS

AH-related single nucleotide polymorphisms (SNPs) data were obtained from the FinnGen Biobank (FB), and BMI-related single nucleotide polymorphisms (SNPs) data were obtained from the UK Biobank (UKB). Genetic loci are used as instrumental variables (IVs), methods such as inverse variance weighted (IVW) were used for two-sample Mendelian randomization analysis, and the odds ratio (OR) value was used to evaluate the causal relationship between BMI and AH.

RESULTS

The results of the horizontal pleiotropy test were calculated by Egger-intercept method: p = 0.34 > 0.05. The Cochran Q test of MR-Egger method and IVW method showed heterogeneity P = 0.03 < 0.05, so the IVW random effect model was used as the gold standard. We found a genetically determined 1-standard deviation (SD) increment of BMI causally increased a 66.0% risk of AH (N = 371 SNPs, OR = 1.66, 95% CI 1.46-1.89, p = 1.55E-14) based on the IVW random effect model which was almost consistent with the results of other seven methods.

CONCLUSIONS

Our MR found genetic evidence for BMI and AH. The risk of developing AH increases with the number of BMI. This finding provides further evidence that maintaining a healthy BMI can prevent the development of AH. In addition, clinicians may need to focus on the potential risk of AH on some high-BMI patients.

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.