Selected conditions associated with an increased incidence of incisional hernia: A review of molecular biology

Assessment of myofascial medialization following intraoperative fascial traction (IFT) in a cadaveric model

PURPOSE

Intraoperative fascial traction (IFT) for the treatment of large ventral hernias and loss of domain (LOD) hernias is a promising tool in abdominal wall surgery. However, little is known about the extent of gain in myofascial advancement especially for the anterior rectus sheath. We, therefore, used a cadaveric model to determine the medialization during IFT.

METHODS

4 fresh frozen specimens were used. Retromuscular preparation was carried out followed by IFT with diagonal vertical traction for 30 min. Medial advancement of the anterior rectus sheath was measured after 15 and 30 min as well as traction forces.

RESULTS

Total medialization for anterior rectus sheath after 30 min of IFT was 10.5 cm (mean). The mean traction force was 16.28 kg. Total medialization was significantly higher during the first 15 min of vertical fascial traction (p < 0.05).

CONCLUSIONS

IFT provides significant medialization for the anterior rectus sheath in the cadaveric model. The findings align with results from a retrospective case study. Therefore, we see IFT as a beneficial tool in abdominal wall surgery.

Rectus muscle diastasis in Italian women: determinants of disease severity, and associated disorders

Purpose

Diastasis of rectus abdominis (DRA) refers to a separation of the rectus abdominis from the linea alba, which is common in the female population during pregnancy and in the postpartum period. The present study aimed at investigating DRA severity, risk factors and associated disorders.

Methods

In the present cross-sectional study, a web-based questionnaire was addressed to the 23,000 members of the Women's Diastasis Association. The questionnaire comprised three parts, dedicated respectively to diastasis characteristics, possible risk factors, and related disorders. Faecal and urinary incontinences were assessed using the Wexner and ICIQ-SF score, respectively. Risk factors for diastasis severity (<3, 3-5, >5 cm) were evaluated by a multinomial regression model.

Results

Four thousand six hundred twenty-nine women with a mean age (SD) of 39.8 (6.5) years and a median BMI of 23.7 kg/m2 (range 16.0-40.0) responded to the questionnaire. Proportion of DRA >5 cm increased from 22.8% in norm weight women to 44.0% in severely obese women, and from 10.0% in nulliparous women to 39.3% in women with >3 pregnancies. These associations were confirmed in multivariable analysis. DRA severity was associated with the risk of abdominal hernia and pelvic prolapse, whose prevalence more than doubled from women with DRA <3 cm (31.6% and 9.7%, respectively) to women with DRA >5 cm (68.2% and 20.2%). In addition, most patients reported postural pain and urinary incontinence, whose frequency increased with DRA severity.

Conclusion

The present study confirmed that DRA severity increases with increasing BMI and number of pregnancies. Larger separation between rectal muscles was associated with increased risk of pain/discomfort, urinary incontinence, abdominal hernia and pelvic prolapse. Prospective studies are needed to better evaluate risk factors.

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.

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.

Biomechanical and tissue reaction: the effects of varying sutures size on canine abdominal wall stitching

Objective

Larger diameter sutures can provide sufficient tensile strength to surgical incisions but may exacerbate the inflammatory response caused by the amount of implanted foreign material. This experiment aims to investigate the differences in biomechanical stability and tissue reactivity after suturing canine midline abdominal incisions with different suture sizes.

Method

Assessing the biomechanical differences between USP 2-0, 3-0, and 4-0 PGA sutures using uniaxial tensile testing on ex vivo canine midline skin and fascial muscle tissues using either a simple continuous or simple interrupted technique. mRNA and protein expression levels of inflammatory factors were measured through RT-PCR and ELISA. Tissue reactivity was evaluated using a semi-quantitative scoring system.

Result

For strains below 30% in skin and below 50% in muscle, there were no significant differences among groups. The results of skin biomechanical testing showed that the USP 4-0 PGA suture group demonstrated significantly lower maximum tensile strength compared to the USP 2-0 PGA or USP 3-0 PGA suture groups. However, it remained capable of providing at least 56.3 N (1.03 MPa) tensile strength for canine skin incisions, matching the tensile strength requirements of general canine abdominal wall surgical incisions. In addition, there were no statistically significant differences observed in the maximum tensile strength among different size of sutures according to the data of biomechanical testing in muscle. Larger diameter sutures led to increased levels of inflammatory factors (IL-1β, IL-6, TNF-ɑ) and tissue reactivity. Simple interrupted sutures caused higher levels of inflammatory factors in muscular tissue compared to simple continuous sutures.

Conclusion

USP 4-0 PGA sutures provide sufficient biomechanical stability for suturing canine abdominal skin and linea alba. Suture size significantly influences tissue reactivity after suturing, with smaller gauge sutures reducing early tissue inflammatory response. Thus, USP 4-0 PGA suture has more advantages to suturing canine abdominal surgical incisions.

Incidence, Risk Factors, and Management of Incisional Hernias After Kidney Transplant: A 20-Year Single Center Experience

BACKGROUND

Incisional hernias (IH) constitute a complication after kidney transplant (KT). Patients may be particularly at risk because of comorbidities and immunosuppression. The study aim was to assess the incidence, risk factors, and treatment of IH in patients undergoing KT.

METHODS

This retrospective cohort study included consecutive patients who underwent KT between January 1998 and December 2018. Patient demographics, comorbidities, perioperative parameters, and IH repair characteristics were assessed. Postoperative outcomes included morbidity, mortality, need for reoperation, and length of stay (LOS). Patients who developed IH were compared with those who did not develop one.

RESULTS

Forty-seven patients (6.4%) developed an IH after a median delay of 14 months (IQR, 6-52 months) in 737 KTs. On uni- and multivariate analyses, body mass index (odds ratio [OR], 1.080; P = .020), pulmonary diseases (OR, 2.415; P = .012), postoperative lymphoceles (OR, 2.362; P = .018), and LOS (OR, 1.013; P = .044) were independent risk factors. Thirty-eight patients (81%) underwent operative IH repair, and 37 (97%) were treated with a mesh. The median LOS was 8 days (IQR, 6-11 days). Three patients (8%) developed surgical site infections, and 2 patients (5%) presented hematomas requiring surgical revision. After IH repair, 3 patients (8%) had a recurrence.

CONCLUSIONS

The incidence of IH after KT seems rather low. Overweight, pulmonary comorbidities, lymphoceles, and LOS were identified as independent risk factors. Strategies focusing on the modifiable patient-related risk factors and early detection and treatment of lymphoceles may help to decrease the risk of IH formation after KT.

High Lymphocyte Count as a Significant Risk Factor for Incisional Hernia After Laparoscopic Colorectal Surgery

BACKGROUND

In the era of laparoscopic surgery, incisional hernia (IH) remains a common complication of colorectal surgery. Various risk factors for IH have been evaluated to reduce the incidence, but the impact of nutrition on IH has not been well discussed. The aim of this study is to evaluate the relationship between nutritional status and the development of IH after laparoscopic colorectal surgery.

MATERIALS AND METHODS

We retrospectively evaluated 342 colorectal cancer patients undergoing laparoscopic colectomy or proctectomy between January 2012 and December 2018. Postoperative computed tomography was used to diagnose the IH. Patient characteristics, including preoperative albumin and lymphocyte counts, were evaluated for the risk of development of IH. Further investigations were conducted regarding the impact of nutritional status on the development of IH in each patient of body mass index (BMI) under and over 25.0 kg/m 2 .

RESULTS

IH was observed in 37 patients (10.8%), with a median follow-up period of 48.5 months. Female [odds ratio (OR)=3.43, P <0.01], BMI ≥25 kg/m 2 (OR=2.9, P <0.01), lymphocyte count ≥1798/µL (OR=3.37, P <0.01), and operative time ≥254 minutes (OR=3.90, P <0.01) had statistically significant relationships to IH in multivariate analysis. Low albumin was related to IH in BMI ≥25 kg/m 2 ( P =0.02), but was not in BMI<25 kg/m 2 ( P =0.21). On the other hand, a high lymphocyte count was related to IH regardless of BMI (BMI ≥25 kg/m 2 : P =0.01, BMI<25 kg/m 2 : P =0.04).

CONCLUSIONS

A high preoperative lymphocyte count is an independent risk factor for IH, whereas a low albumin count is limited regarding predicting IH.

Role of fibroblast plasticity and heterogeneity in modulating angiogenesis and healing in the diabetic foot ulcer

Chronic diabetic foot ulcers (DFUs) are an important clinical issue faced by clinicians despite the advanced treatment strategies consisting of wound debridement, off-loading, medication, wound dressings, and keeping the ulcer clean. Non-healing DFUs are associated with the risk of amputation, increased morbidity and mortality, and economic stress. Neo-angiogenesis and granulation tissue formation are necessary for physiological DFU healing and acute inflammation play a key role in healing. However, chronic inflammation in association with diabetic complications holds the ulcer in the inflammatory phase without progressing to the resolution phase contributing to non-healing. Fibroblasts acquiring myofibroblasts phenotype contribute to granulation tissue formation and angiogenesis. However, recent studies suggest the presence of five subtypes of fibroblast population and of changing density in non-healing DFUs. Further, the association of fibroblast plasticity and heterogeneity with wound healing suggests that the switch in fibroblast phenotype may affect wound healing. The fibroblast phenotype shift and altered function may be due to the presence of chronic inflammation or a diabetic wound microenvironment. This review focuses on the role of fibroblast plasticity and heterogeneity, the effect of hyperglycemia and inflammatory cytokines on fibroblasts, and the interaction of fibroblasts with other cells in diabetic wound microenvironment in the perspective of DFU healing. Next, we summarize secretory, angiogenic, and angiostatic phenotypes of fibroblast which have been discussed in other organ systems but not in relation to DFUs followed by the perspective on the role of their phenotypes in promoting angiogenesis in DFUs.

Prevention of incisional hernia after single-port sleeve gastrectomy (PRISM): a prospective non-randomized controlled study

BACKGROUND

SPSG carries a risk of incisional hernia, particularly in patients with high body mass index. Prophylactic mesh placement with either permanent or absorbable mesh could decrease the occurrence of incisional hernia, with uncertainty on other postoperative parietal complications.

METHODS

This is a non-randomized monocentric single-blinded prospective study. High-risk patients (body mass index ≥ 45 kg/m²) underwent either 3 strategies of parietal closure (suture with or without permanent or absorbable mesh) during SPSG. The primary outcome was the occurrence of radiologically defined incisional hernia during the first postoperative year. Secondary outcomes included surgical site infection rates and postoperative pain.

RESULTS

Between November 2018 and November 2019, 255 patients were included (85 in each group). All patients reached one-year postoperative follow-up. Significantly more incisional hernias were observed in the no mesh group in comparison with permanent and absorbable mesh groups, respectively (20% vs. 7.1% vs. 5.1%, P = 0.005). No difference was observed in mesh groups. No difference was observed regarding other parietal complications. One patient in the absorbable mesh group presented a superficial surgical site infection and required surgical drainage without mesh removal and one patient in the permanent mesh group presented a parietal hematoma and required surgical drainage with mesh removal. Twenty-six (92.8%) asymptomatic patients presented incisional hernia discovered on the one-year CT-scan.

CONCLUSIONS

Prophylactic mesh placement during SPSG decreases the occurrence of postoperative incisional hernia. Routine permanent mesh placement could be proposed in high-risk patients.