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.

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.

Transversus abdominis release with biosynthetic mesh for large ventral hernia repair: a 5-year analysis of clinical outcomes and quality of life.

INTRODUCTION: Transversus abdominis release (TAR) may provide an optimal plane for mesh placement for large ventral hernias requiring medial myofascial flap advancement. Long-term outcomes of TAR for large ventral hernia repair (VHR) remains under-studied. This study aims to assess longitudinal clinical outcomes and quality of life (QoL) following large VHR with TAR and resorbable biosynthetic mesh. METHODS: Retrospective review of clinical outcomes and prospective QoL was performed for patients undergoing VHR with poly-4-hydroxybutyrate mesh and TAR from 2016 to 2021. Patients with ≤ 24 months of follow-up, defects ≤ 150 cm2, and parastomal hernias were excluded. Cost-related data was collected for each patient's hospital course. QoL was compared using paired Wilcoxon signed-rank tests. RESULTS: Twenty-nine patients met inclusion criteria. Median age and BMI were 61 years (53.2-68.1 years) and 31.4 kg/m2 (26.1-35.3 kg/m2). Average hernia defect was 390cm2 ± 152.9 cm2. All patients underwent previous abdominal surgery and were primarily Ventral Hernia Working Group 2 (58.6%). Two hernia recurrences (6.9%) occurred over the median follow-up period of 63.1 months (IQR 43.7-71.3 months), with no cases of mesh infection or explantation. Delayed healing and seroma occurred in 27 and 10.3% of patients, respectively. QoL analysis identified a significant improvement in postoperative QoL (p < 0.005), that continued throughout the 5-year follow-up period, with a 41% overall improvement. Cost analysis identified the hospital revenue generated was approximately equal to the direct costs of patient care. Higher costs were associated with ASA class and length of stay (p < 0.05). CONCLUSION: Large VHR with resorbable biosynthetic mesh and TAR can be performed safely, with a low recurrence and complication rate, acceptable hospital costs, and significant improvement in disease-specific QoL at long-term follow-up.

National epidemiologic trends (2008-2018) in the United States for the incidence and expenditures associated with incisional hernia in relation to abdominal surgery.

PURPOSE: It is unknown whether the trend of rising incisional hernia (IH) repair (IHR) incidence and costs until 2011 currently persists. We aimed to evaluate how the IHR procedure incidence, cost and patient risk-profile have changed over the last decade relative to all abdominal surgeries (AS). METHODS: Repeated cross-sectional analysis of 38,512,737 patients undergoing inpatient 4AS including IHR within the 2008-2018 National Inpatient Sample. Yearly incidence (procedures/1,000,000 people [PMP]), hospital costs, surgical and patient characteristics were compared between IHR and AS using generalized linear and multinomial regression. RESULTS: Between 2008-2018, 3.1% of AS were IHR (1,200,568/38,512,737). There was a steeper decrease in the incidence of AS (356.5 PMP/year) compared to IHR procedures (12.0 PMP/year) which resulted in the IHR burden relative to AS (2008-2018: 12,576.3 to 9,113.4 PMP; trend difference P < 0.01). National costs averaged $47.9 and 1.7 billion/year for AS and IHR, respectively. From 2008-2018, procedure costs increased significantly for AS (68.2%) and IHR (74.6%; trends P < 0.01). Open IHR downtrended (42.2%), whereas laparoscopic (511.1%) and robotic (19,301%) uptrended significantly (trends P < 0.01). For both AS and IHR, the proportion of older (65-85y), Black and Hispanic, publicly-insured, and low-income patients, with higher comorbidity burden, undergoing elective procedures at small- and medium-sized hospitals uptrended significantly (all P < 0.01). CONCLUSION: IH persists as a healthcare burden as demonstrated by the increased proportion of IHR relative to all AS, disproportionate presence of high-risk patients that undergo these procedures, and increased costs. Targeted efforts for IH prevention have the potential of decreasing $17 M/year in costs for every 1% reduction.

Characterizing hernia centers in the United States: what defines a hernia center?

PURPOSE: A universal definition for what constitutes a hernia center does not exist. The purpose of this study was to characterize hernia centers in the United States by analyzing hernia centers and their non-hernia center counterparts. METHODS: A web-based search was conducted to identify defining features of hernia centers including faculty demographics and composition, research output, research funding, clinical trials, and website content. Hernia centers and non-hernia centers were compared. RESULTS: Most hernia centers (n = 36) are in urban areas (89%) and distributed evenly across regions of the United States. Hernia centers are associated with University program types (p = 0.001) while non-hernia centers are associated with University-Affiliate (p = 0.001) and Community (p = 0.02) program types. Hernia centers are associated with Abdominal Core Health Quality Collaborative participation (p = 0.01) and Center of Excellence by the Surgical Review Corporation certification (p = 0.005). Hernia centers are associated with presence of active clinical trials (p < 0.001) and number of clinical trials (p < 0.001). Hernia centers are associated with industry-sponsored trials (p < 0.001) but are not associated with NIH-sponsored trials. Fifty percent of hernia centers have PRS faculty. The vast majority of hernia center websites describe hernias treated (92%) and repair techniques (89%). The majority of hernia center mission statements emphasize an individualized care plan (61%) and multidisciplinary care (57%). Only 39% of websites and 17% of mission statements mention research. CONCLUSION: In the United States, hernia centers are clinically oriented, multidisciplinary surgical teams at predominantly urban, University programs that may use this title to attract patient referrals and industry sponsorship of clinical trials.

The Abdominal Hernia-Q: a critical analysis of the components that impact quality-of-life.

PURPOSE: Ventral hernias (VH) are a common surgical problem associated with significant morbidity. While assessment tools have examined quality-of-life (QoL), the relative change in specific domains of hernia-related QoL measures from pre- to post-operative period has yet to be comprehensively examined. Using the Abdominal Hernia-Q (AHQ), this study aims to assess the impact of ventral hernia repair (VHR) on key components of QoL. METHODS: A retrospective chart review was conducted of patients undergoing VHR between September 2017 and September 2019 who had completed at least one pre- and post-operative AHQ. Post-operative intervals were created to capture AHQ responses around standard follow-up visits (< 1.5 months, 1.5-4.5 months, 4.5-11 months, and 11 + months) and scores were statistically analyzed. RESULTS: A total of 136 patients were included, with an average age of 54.8 years at the time of VHR. Compared to the pre-operative period, the appearance score increased significantly (p < 0.05). The physical domain score increased from < 1.5 month to the 1.5-4.5 month period (p = 0.03) and remained significantly higher in later time period. The appearance score decreased from the 1.5-4.5 month to 4.5-11 month period (p = 0.05). CONCLUSIONS: VHR leads to a sustained multi-dimensional increase in hernia-specific QoL measures during the post-operative course driven by early positive changes in appearance and sustained physical functioning. The initial increase in QoL is mainly driven by an improvement in appearance, while the sustained increase may be due to restored physical function.

Influence of osteoporosis on the compressive properties of femoral cancellous bone and its dependence on various density parameters.

Data collection of mechanical parameters from compressive tests play a fundamental role in FE modelling of bone tissues or the developing and designing of bone implants, especially referring to osteoporosis or other forms of bone loss. A total of 43 cylindrical samples (Ø8 × 16 mm) were taken from 43 freshly frozen proximal femora using a tenon cutter. All femora underwent BMD measurement and additionally apparent- and relative- and bulk density (ρapp, ρr, ρb) were determined using samples bordering the compressive specimen on the proximal and distal regions. All samples were classified as "normal", "osteopenia" and "osteoporosis" based on the DEXA measurements. Distal apparent density was most suitable for predicting bone strength and BMD. One novel aspect is the examination of the plateau stress as it describes the stress at which the failure of spongious bone progresses. No significant differences in mechanical properties (compressive modulus E; compressive stress σmax and plateau stress σp) were found between osteopenic and osteoporotic bone. The results suggest that already in the case of a known osteopenia, actions should be taken as they are applied in the case of osteoporosis A review of the literature regarding extraction and testing methods illustrates the urgent need for standardized biomechanical compressive material testing.

An evaluation of clinical and quality of life outcomes after ventral hernia repair with poly-4-hydroxybutyrate mesh.

PURPOSE: Despite continued efforts, recurrence after ventral hernia repair (VHR) remains a common problem. Biosynthetic Phasix™ (Poly-4-Hydroxybutyrate, P4HB) mesh combines the durability of synthetic mesh with the bio-resistance of biologics. P4HB has shown promising early outcomes, but long-term data are lacking. We examine patients following VHR with P4HB with at least 3 years of follow-up to assess clinical and patient reported outcomes (PROs). METHODS: Adult patients (≥ 18 years old) undergoing VHR with P4HB mesh between 10/2015 and 01/2018 by a single surgeon were retrospectively identified. Patients with < 36 months of follow-up were excluded unless they had a documented recurrence. Clinical outcomes and quality of life using the Hernia-Related Quality of Life Survey (HerQLes) were assessed. RESULTS: Seventy-one patients were included with a median age and body mass index of 61.2 and 31 kg/m2, respectively. Mesh was placed in the retromuscular (79%) and onlay (21%) planes with 1/3 of patients having hernias repaired in contaminated fields. There were no mesh infections, enterocutaneous fistulas, or mesh explantations. Nine patients (12.7%) developed recurrence at a median follow-up of 43.1 months [38.2-49.1]. Mesh plane, fixation technique, and Ventral Hernia Working Group were not associated with recurrence. Significant improvement in disease-specific PROs was observed and maintained at 3-year follow-up. CONCLUSION: Longitudinal clinical and quality of life outcomes after clean and contaminated VHR with P4HB are limited. Here, we conclude that P4HB is an effective and versatile mesh option for use in abdominal wall reinforcement.

The incisional hernia epidemic: evaluation of outcomes, recurrence, and expenses using the healthcare cost and utilization project (HCUP) datasets.

BACKGROUND: Incisional hernias (IH) following abdominal surgery persist as morbid, costly, and multi-disciplinary surgical challenges. Using longitudinal, multi-state, administrative claims data (HCUP State Inpatient Databases (SID)); (HCUP State Ambulatory Surgery and Services Databases (SASD)), we aimed to characterize the epidemiology, outcomes, recurrence, and costs of IH. STUDY DESIGN: 529,108 patients undergoing abdominal surgery in 2010 across six specialties (colorectal, general/bariatric, hepatobiliary, obstetrics/gynecology, urology, and vascular) were identified within inpatient and ambulatory databases for Florida (FL), Iowa (IA), Nebraska (NE), New York (NY), and Utah (UT). IH repairs, complications, and expenditures were assessed through 2014. Predictive regression modeling was validated using a training set of 1000 bootstrapped repetitions. RESULTS: 16,169 (3.1%) patients developed hernias requiring repair (4.3-year mean follow-up), 3176 (20%) underwent recurrent repair, and 731 (23%) underwent re-recurrent repair. Patients with IH had increased readmissions (6.6 vs. 2.4), morbidity (39 vs. 8% surgical and 22 vs. 7% medical), and costs ($46,000 vs. $25,000) when compared to patients without IH (p < 0.001). IH expenditures totaled $875 million: initial ($687 million), recurrent ($155 million), and re-recurrent hernias ($33 million). IH predominated in colorectal (10%), hepatobiliary (8%), and vascular (5%) procedures. Of 31 significant independent IH risk factors (p < 0.001), obesity, age, smoking, open surgery, and prior surgery were pervasive across surgical specialties. CONCLUSION: IH represents an unremitting surgical epidemic associated with considerable morbidity, costs, and features consistent with a chronic disease state. We define critical pervasive risk factors (obesity, age, smoking open surgery, and prior surgery) independently associated with IH across surgical disciplines. With failed repairs, subsequent success becomes less likely, increasing morbidity and costs-underscoring the critical importance of optimal treatment and prevention.

Risk factors, outcomes, and complications associated with combined ventral hernia and enterocutaneous fistula single-staged abdominal wall reconstruction.

PURPOSE: To compare two cohorts of patients; those with isolated ventral hernias (VH) and those with VH and enterocutaneous fistulas (ECF). Risk factors for surgical complications (including recurrent ECF) and outcomes during single-stage VH with ECF surgical reconstruction were analyzed. METHODS: A retrospective review was performed from 2008 to 2019. We compared two cohorts of patients with single-stage VH repairs: (1) ventral hernia repair alone (hernia alone), and (2) combined VH repair and ECF repair (hernia plus ECF). Inclusion criteria were patients ≥ 18 years of age with pre-operative VH either with or without an ECF, who underwent open hernia repair and ECF repair in a single-stage operation, with a minimum follow-up of 12 months. Patient risk factors, operative characteristics, outcomes and surgical-site complications were compared using univariate and multivariate analyses. RESULTS: We included 442 patients (hernia alone = 401; hernia plus ECF = 41) with a median follow-up of 22 months (12-96). Hernia plus ECF patients were more likely to have inflammatory bowel disease (IBD)(OR 4.4, 95% CI 1.1-17.5, p = 0.037), a history of abdominal wound infections (OR 3.4, 95% CI 1.5-7.9, p = 0.004), reoperations (OR 4.9, 95% CI 1.6-15.4, p = 0.006), superficial soft tissue infections (OR 2.5, 95% CI 1.1-6.1, p = 0.044) and hematomas (OR 8.4, 95% CI 1.2-58.8, p = 0.031), compared to hernia alone patients. ECF recurrence was associated with diabetes mellitus (DM) (n = 8, 73% vs. n = 6, 20%; p = 0.003) and surgical-site complications (n = 10, 91% vs. n = 16, 53%; p = 0.048), compared to ECF resolution. CONCLUSION: Risk factors for developing ECF were IBD and history of abdominal wound infections. Single-staged combined ECF reconstruction was associated with reoperations, soft tissue infections and hematomas. DM and surgical-site complications were associated with ECF recurrence.

Ventral hernia repair with synthetic mesh in a contaminated field: a systematic review and meta-analysis.

PURPOSE: The use of mesh in ventral hernia repair becomes especially challenging when associated with a contaminated field. Permanent synthetic mesh use in this setting is currently debated and this discussion is yet to be resolved clinically or in the literature. We aim to systematically assess postoperative outcomes of non-absorbable synthetic mesh (NASM) used in ventral hernia repair in the setting of contamination. METHODS: A literature search of PubMed, Embase, Scopus, Cinahl, and Cochrane Library identified all articles from 2000-2020 that examined the use of NASM for ventral hernia repair in a contaminated field. Postoperative outcomes were assessed by means of pooled analysis and meta-analysis. Qualitative analysis was completed for all included studies using a modified Newcastle-Ottawa scale. RESULTS: Of 630 distinct publications and 104 requiring full review, this study included 17 articles published between 2007 and 2020. Meta-analysis demonstrated absorbable mesh was associated with more HR (OR 1.89, 1.15-3.12, p = 0.008), SSO (OR 1.43, 0.96-2.11, p = 0.087), SSI (OR 2.84, 1.85-4.35, p < 0.001), and unplanned reoperation (OR 1.99, 1.19-3.32, p = 0.009) compared to NASM. CONCLUSION: The use of NASM for ventral hernia repair in a contaminated field may be a safe alternative to absorbable mesh, as evidenced by lower rates of postoperative complications. This review counters the current clinical paradigm, and additional prospective randomized controlled trials are warranted.

Cutting through the fat: a retrospective analysis of clinical outcomes, cost, and quality of life with the addition of panniculectomy to ventral hernia repair in overweight patients.

BACKGROUND: Due to the increased prevalence of overweight patients with ventral hernia, abdominal wall reconstruction combining ventral hernia repair (VHR) with panniculectomy (VHR-PAN) in overweight patients is increasingly considered. We present a retrospective comparison between VHR-PAN and VHR alone in overweight patients by examining costs, clinical outcomes, and quality of life (QoL). METHODS: Patients with body mass index (BMI) > 25.0 kg/m2 underwent VHR-PAN or VHR alone between September 2015 and May 2017 with a single surgeon and were matched into cohorts by BMI and age (n = 24 in each cohort). QoL was assessed using the Hernia-related Quality of Life Survey (HerQLes). Cost was assessed using billing data. Statistical analyses were performed using Fisher's exact tests, Mann-Whitney U tests, and regression modeling. RESULTS: Hernia defect size (p = 0.127), operative time (p = 0.140), mesh placement (p = 0.357), and recurrence rates (p = 0.156) did not vary significantly between cohorts at average follow up of one year. 60% of patients completed QoL surveys, with 61% net improvement in VHR-PAN postoperatively (p = 0.042) vs 36% in VHR alone (p = 0.054). Mean total hospitalization costs were higher for VHR alone (p = 0.019). Regression modeling showed no significant independent contribution of procedure performed due to differences in cost, wound complications, or hernia recurrence. CONCLUSIONS: At mean follow up of 2 years, VHR-PAN patients reported a comparable increase in QoL to those who received VHR alone without significantly different cost and complication rates. Concurrent VHR-PAN may therefore be a safe approach for overweight patients presenting with hernia and excess abdominal skin.

Hernia prevention: practice patterns and surgeons' attitudes about abdominal wall closure and the use of prophylactic mesh.

PURPOSE: The penetration of hernia prevention techniques into surgical practice remains unknown. METHODS: A survey about knowledge/attitudes on hernia prevention was sent to the members of hernia societies. RESULTS: The 497 respondents were mostly from the US (47%) or Europe (40%). Most reported practicing, but not measuring their suture-to-wound length closure of > 4:1 (63%) and practicing but not measuring the number of stitches (58%). Reasons for not using short stitch closure were: does not apply to patient population (19%), not familiar enough with methods to correctly execute (25%), takes too long (13%), not reimbursed (4%), concerned about closure-related complications (27%), and other (22%). Regarding prophylactic mesh, respondents stated they were not familiar with literature (11%), familiar with literature but would not use (24%), familiar with literature and interested in use (45%), familiar with literature and using (15%), and other (5%). CONCLUSIONS: There appears to be some application of hernia prevention principles related to fascial closure; however, the use of prophylactic mesh still appears to be controversial.

First application of a transcutaneous optical single-port glucose monitoring device in patients with type 1 diabetes mellitus.

The combination of continuous glucose monitoring (CGM) and continuous subcutaneous insulin infusion can be used to improve the treatment of patients with diabetes. The aim of this study was to advance an existing preclinical single-port system for clinical application by integrating the sensors of a phosphorescence based CGM system into a standard insulin infusion set. The extracorporeal optical phase fluorimeter was miniaturised and is now comparable with commercial CGM systems regarding size, weight and wear comfort. Sensor chemistry was adapted to improve the adhesion of the sensor elements on the insulin infusion set. In-vitro tests showed a linear correlation of R2=0.998 between sensor values and reference glucose values in the range of 0-300mg/dl. Electrical and cytotoxicity tests showed no negative impact on human health. Two single-port devices were tested in each of 12 patients with type 1 diabetes mellitus in a clinical set-up for 12h. Without additional data processing, the overall median absolute relative difference (median ARD) was 22.5%. For some of the used devices the median ARD was even well below 10%. The present results show that individual glucose sensors performance of the single-port system is comparable with commercial CGM systems but further improvements are needed. The new system offers a high extent of safety and usability by combining insulin infusion and continuous glucose measurement in a single-port system which could become a central element in an artificial pancreas for an improved treatment of patients with type 1 diabetes mellitus.

Acute kidney injury after open ventral hernia repair: an analysis of the 2005-2012 ACS-NSQIP datasets.

PURPOSE: Acute kidney injury (AKI) is a serious postoperative complication, negatively impacting mortality rates, extending length of stay, and raising hospital costs. The purpose of this study was to examine AKI following open ventral hernia repair (OVHR) using a large, heterogeneous database to determine the incidence and identify risk factors for this complication. METHODS: Using the 2005-2012 ACS-NSQIP database, patients undergoing open ventral hernia repair were identified by CPT codes. Patients with acute kidney injury within 30 days of surgery were compared to controls by multivariate logistic regression across preoperative and intraoperative characteristics. RESULTS: Of 48,629 open ventral hernia repair patients identified in the dataset, AKI developed in 1.4% (681 patients). Multivariate logistic regression determined a number of factors associated with AKI. These include WHO Class III obesity (OR = 2.57, p < 0.001), history of cardiovascular disease (OR = 1.81, p < 0.001), diabetes (OR = 1.29, p = 0.028), hypoalbuminemia (OR = 1.42, p = 0.004), and chronic kidney disease (for a baseline GFR of 60-89 mL/min/1.73 m2, OR = 1.62, p = 0.001; for 30-59 mL/min/1.73 m2, OR = 2.25, p < 0.001; for 15-29 mL/min/1.73 m2, OR = 4.96, p < 0.001). Intraoperative factors include prolonged operative time (for ≥1 SD above the mean, OR = 1.68, p = 0.002; for ≥2SD above the mean, OR = 2.76, p < 0.001) and intraoperative transfusion (OR = 2.44, p < 0.001). CONCLUSIONS: Patients with a history of obesity, chronic kidney disease, cardiovascular history, diabetes, and hypoalbuminemia are at increased risk for AKI when undergoing OVHR. Intraoperative variables such as prolonged operative times and blood transfusions may also suggest increased risk. Preoperative identification of patients with these characteristics and perioperative hemodynamic stabilization are important first steps to minimize this complication.

Wound risk assessment in ventral hernia repair: generation and internal validation of a risk stratification system using the ACS-NSQIP.

BACKGROUND: There is a need for validated risk models to better stratify surgical site occurrences (SSO) following open ventral hernia repair (OVHR). The addition of more generalizable and validated risk models will serve to improve perioperative care in OVHR patients. METHODS: We reviewed the 2005-2011 ACS-NSQIP databases identifying encounters for OVHR. The dependent outcome measure of interest was SSO, defined as superficial surgical site infection, deep infection, organ space infection, or wound dehiscence. Multivariate logistic regression of independently associated factors was performed and internally validated using a bootstrap technique. A composite risk score, the Hernia Wound Risk Assessment Tool (HW-RAT) was created using weighted beta coefficients. The HW-RAT was compared to existing models from the literature. RESULTS: A total of 60,187 patients who met inclusion criteria were identified in the 2005-2011 ACS-NSQIP databases. The incidence of SSO in the study was 6.2% (N = 3,732). SSO risk factors were broken down based on rounded risk scores into the following groups: mild, intermediate, moderate, and severe risk. Severe risk factors related to operative time and degree of wound contamination. Moderate risk factors included class III obesity, component separation, dependent functional status, and inpatient hernia surgery. Patient stratification was performed based on total risk score into HW-RAT risk groups 1 through 5 which demonstrated significant discrimination between and across each group (P < 0.01, C-statistic = 0.71) with an incidence of SSO that ranged from 3.3 to 26.5%. CONCLUSION: We present an internally validated risk model of SSO in OVHR (HW-RAT), which complements and builds upon current risk models. LEVEL OF EVIDENCE: Prognostic/risk category, level II.

A comparison of outcomes and cost in VHWG grade II hernias between Rives-Stoppa synthetic mesh hernia repair versus underlay biologic mesh repair.

BACKGROUND: The current literature is void of evidence-based guidelines regarding optimal choice of mesh. We aim to perform a comparative outcome analysis of synthetic mesh and acellular dermal matrix (ADM) in Ventral Hernia Working Grade (VHWG) grade II hernias with primary fascial closure. METHODS: A retrospective review of patients undergoing ventral hernia repair (VHR) by the senior author (S.J.K.) from 2007 to 2012 was performed. Patients undergoing VHR with primary fascial closure were risk stratified using the VHWG defined grading system. RESULTS: Seventy-two patients met the abovementioned inclusion criteria with 45 receiving synthetic mesh and 27 receiving ADM. The mean length of follow-up was 12.1 ± 9.1 months. Patients were, on average, 53.2 ± 11.6 years of age with a BMI of 33.9 ± 10.6 kg/m(2). The overall incidence of surgical site occurrence (SSO) in the cohort was 41.7 % and the incidence of hernia recurrence was 5.6 %. 30-day mortality was 1.2 %. Bivariate analysis demonstrated that obesity (P = 0.038) and number of comorbidities (P = 0.043) were associated with SSO. Bivariate analysis demonstrated that prior failed hernia, use of ADM, and operative time were associated with higher rates of hernia recurrence; however, adjusted multivariate regression found only prior failed hernia (OR = 4.1, P = 0.03) and biologic mesh (OR = 3.4, P = 0.046) to be independently associated with recurrent hernia. Comparison of mesh types revealed few differences in preoperative or operative characteristics between synthetic mesh and acellular dermal matrices (ADM). The rate of hernia recurrence was significantly higher with ADM (14.8 % vs. 0.0 %, P = 0.017). Patients receiving ADM repairs incurred significantly greater cost ($56,142.1 ± 54,775.5 vs. $30,599.8 ± 39,000.8, P < 0.001). CONCLUSIONS: These data suggest synthetic mesh is indicated in higher risk VHWG grade II repairs. In comparison to ADM, synthetic mesh was associated with significantly fewer hernia recurrences and lower cost utilization at 1-year. LEVEL OF EVIDENCE: Prognostic/risk category, level III.

Ablation of neural tissue by short-pulsed lasers--a technical report.

The basis for most laser applications in neurosurgery is the conversion of laser light into heat when the incident laser beam is absorbed by the tissue. Irradiation of neural tissue with laser light therefore leads to its thermal damage. However, due to the diffusion of heat energy into the surrounding tissue, often there is thermal damage to neural tissue outside the area of the target volume. These are the characteristics of thermal laser/tissue interaction. In this paper we discuss how we used three different short-pulsed lasers to achieve non-thermal ablation of neural tissue. Three different short-pulsed lasers were used to generate ultrashort laser pulses in the picosecond to femtosecond range. The interaction of such laser pulses with tissue was predicted to be nonthermal. The short-pulsed lasers were used for the ablation of neural tissue using an in vitro calf brain model. The histopathological examination of the lesions revealed that the neural tissue had been removed very precisely without any sign of thermal damage to the surrounding tissue.