Respect the Middle Lobe: Perioperative Risk of Bilobectomy Compared With Lobectomy and Pneumonectomy.

BACKGROUND: In some cases of right-sided lung cancer, tumor extension, bronchial involvement, or pulmonary artery infiltration may necessitate bilobectomy. Although the middle lobe is believed to represent a fraction of total lung function, the morbidity and mortality associated with bilobectomy is not well described. METHODS: We retrospectively identified patients in The Society of Thoracic Surgeons Database who underwent lobectomy, bilobectomy, or pneumonectomy for lung cancer from 2009 to 2017. The primary outcome was 30-day perioperative mortality. We performed propensity matching by patient demographics, comorbidities, and perioperative variables for each surgical type against bilobectomy and ran Cox proportional hazard models. Secondary outcomes of 30-day morbidity and mortality of upper vs lower bilobectomy were also compared. RESULTS: Within the study period 2911 bilobectomy, 65,506 lobectomy, and 3370 pneumonectomy patients met the inclusion criteria. Patients undergoing pneumonectomy and bilobectomy had fewer comorbidities than lobectomy patients. After propensity matching 30-day mortality of bilobectomy was comparable with left pneumonectomy (hazard ratio [HR], 1.35; 95% CI, 0.95-1.91; P = .09) and significantly worse than left (HR, 0.40; 95% CI, 0.29-0.56; P < .0001) or right (HR, 0.43; 95% CI, 0.31-0.59; P < .0001) lobectomy. Bilobectomy was associated with a survival advantage compared with right pneumonectomy (HR, 2.54; 95% CI, 1.72-3.74; P < .0001). Thirty-day morbidity was higher for bilobectomy compared with lobectomy, and upper bilobectomy had a significant unadjusted 30-day mortality advantage compared with lower bilobectomy (98.3% vs 97%, P = .04). CONCLUSIONS: The morbidity and mortality of bilobectomy is significantly worse than lobectomy and is comparable with left pneumonectomy. The addition of middle lobectomy to a pulmonary resection is not without risk and should be carefully considered during preoperative risk stratification.

Association Between Metastatic Pattern and Prognosis in Stage IV Gastric Cancer: Potential for Stage Classification Reform.

PURPOSE: This study aims to clarify the association between metastatic pattern and prognosis in stage IV gastric cancer, with a focus on patients presenting with metastases limited to nonregional lymph nodes. METHODS: In this retrospective cohort study, the National Cancer Database was used to identify patients ≥ 18 years of age diagnosed with stage IV gastric cancer between 2016 and 2019. Patients were stratified according to pattern of metastatic disease at diagnosis: nonregional lymph nodes only ("stage IV-nodal"), single systemic organ ("stage IV-single organ"), or multiple organs ("stage IV-multi-organ"). Survival was assessed by Kaplan-Meier curves and multivariable Cox models in unadjusted and propensity score-matched samples. RESULTS: Overall, 15,050 patients were identified, including 1,349 (8.7%) stage IV-nodal patients. Most patients in each group received chemotherapy [68.6% of stage IV-nodal patients, 65.2% of stage IV-single organ patients, and 63.5% of stage IV-multi-organ patients (p = 0.003)]. Stage IV-nodal patients exhibited better median survival (10.5 months, 95% CI 9.7-11.9, p < 0.001) than single organ (8.0, 95% CI 7.6-8.2) and multi-organ (5.7, 95% CI 5.4-6.0) patients. In the multivariable Cox model, stage IV-nodal patients also exhibited better survival (HR 0.79, 95% CI 0.73-0.85, p < 0.001) than single organ (reference) and multi-organ (HR 1.27, 95% CI 1.22-1.33, p < 0.001) patients. CONCLUSIONS: Nearly 9% of clinical stage IV gastric cancer patients have their distant disease confined to nonregional lymph nodes. These patients were managed similarly to other stage IV patients but experienced a better prognosis, suggesting opportunities to introduce M1 staging subclassifications.

Real-world abdominal aorta aneurysm screening patterns among patients with new or worsening of symptomatic peripheral artery disease.

BACKGROUND: Patients with peripheral artery disease (PAD) have an increased risk of abdominal aortic aneurysms (AAA), but it remains unclear whether practitioners are screening patients for AAA as part of routine PAD management. METHODS: The Patient-centered Outcomes Related to Treatment Practices in Peripheral Arterial Disease (PORTRAIT) Registry is an international prospective registry of patients with new or worsening PAD symptoms presenting to 16 specialty centers in the United States, Netherlands, and Australia, from June 2011 to December 2015. Patients were stratified by AAA screening or AAA positivity. An adjusted median odds ratio was calculated for AAA screening rates across sites. RESULTS: Of the 1275 patients in the study, 871 (68%) were screened for AAA, with 53 (6.1%) having AAA. AAA screening rates did not differ significantly by country (p = 0.36), but there was a large variation across sites for documentation of AAA screening with an adjusted median odds ratio 12.0 (95% CI 4.7-93.1), with AAA screening rates ranging from 7% to 100% across vascular specialty centers. CONCLUSIONS: Among patients with PAD in a multicenter registry, over two-thirds were screened for AAA, with 6% having documented aneurysms. A large variation was seen across clinical sites, suggesting efforts are needed to increase awareness for guideline implementation and establish new benefit-risk evidence inclusive of high-risk populations such as patients with PAD.

Utilization and Outcomes of Radiation in Stage IV Esophageal Cancer.

Introduction: For patients with stage IV esophageal cancer, esophageal radiation may be used selectively for local control and palliation. We aimed to understand patterns of radiation administration among patients with stage IV esophageal cancer and any potential survival associations. Methods: In this retrospective cohort study, the National Cancer Database was queried for patients with metastatic stage IV esophageal cancer diagnosed between 2016 and 2019. Patterns of radiation use were identified. Survival was determined through Kaplan-Meier analysis of propensity score-matched pairs of patients who did and did not receive radiotherapy and time-to-event models. Results: Overall, 12,088 patients with stage IV esophageal cancer were identified, including 32.7% who received esophageal radiation. The median age was 65 (interquartile range [IQR]: 58-73) years, and 82.6% were male. Among the irradiated patients, the median total radiation dose was 35 (IQR: 30-50) Gy administered in a median of 14 (IQR: 10-25) fractions given in 22 (IQR: 14-39) days. Overall, esophageal radiation was not associated with better survival (log-rank p = 0.41). When stratified by radiation dose, a survival advantage (over no radiation) was found in the 1144 patients (29% of the irradiated patients) who received 45 to 59.9 Gy (time ratio = 1.28, 95% confidence interval: 1.20-1.37, p < 0.001) and the 88 patients (2.2%) who received 60 to 80 Gy (time ratio = 1.37, 95% confidence interval: 1.11-1.69, p = 0.003). Conclusions: One-third of the patients with metastatic stage IV esophageal cancer in the National Cancer Database received esophageal radiation. Most received a radiation dose that, although consistent with palliative regimens, was not associated with a survival advantage. Further study is warranted to understand the indications for radiation in stage IV esophageal cancer and potentially reevaluate the most appropriate radiation dose for palliation.

Nonregional Lymph Nodes as the Only Metastatic Site in Stage IV Esophageal Cancer.

Introduction: Metastatic involvement of at least one nonregional lymph node currently renders patients with esophageal cancer as having stage IV disease. However, the management and outcomes of patients whose sole determinant of stage IV status is nonregional lymph nodes (abbreviated as "stage IV-nodal" disease) have not been fully characterized. Methods: In this retrospective cohort study, the National Cancer Database was queried to identify patients 18 years of age or older who were diagnosed with stage IV esophageal cancer between 2016 and 2019. Survival was assessed by Kaplan-Meier analysis and Cox models in the overall sample and a propensity-matched sample. Patients with "stage IV-nodal" disease were compared with patients with systemic metastases involving a single organ or multiple organs. Results: Overall, 11,589 patients with clinical stage IV esophageal cancer were identified, including 1331 (11.5%) patients with stage IV-nodal disease. Patients with stage IV-nodal disease were more likely to receive chemotherapy (77%) than those with single systemic organ metastases (64%) and multiorgan metastases (63%) (p < 0.0001); patients with stage IV-nodal disease were also more likely to receive radiation (49%) than those with single systemic organ metastases (40%) and multiorgan metastases (39%) (p < 0.0001). Squamous cell carcinoma (OR = 1.58, 95% confidence interval [CI]: 1.34-1.86, p < 0.0001) and academic facility type (OR = 1.24, 95% CI: 1.09-1.4, p = 0.0009) were associated with higher likelihood of the stage IV-nodal presentation. Patients with stage IV-nodal disease experienced superior survival (hazard ratio = 0.72, 95% CI: 0.66-0.78, p < 0.0001) than those with stage IV-single systemic metastases (reference group) and stage IV-multiorgan disease (hazard ratio = 1.30, 95% CI: 1.24-1.37). Conclusions: Approximately 12% of patients with stage IV esophageal cancer lack systemic metastases at presentation. These patients with stage IV-nodal disease are more likely to receive treatment and experience superior survival. Further study of the stage IV-nodal population and consideration of a potential stage IV subclassification system is justified.

Immunotherapy After Chemotherapy and Radiation for Clinical Stage III Lung Cancer.

Importance: The 2017 international PACIFIC trial established a role for immunotherapy after chemoradiation for unresectable stage III non-small cell lung cancer (NSCLC). However, in the US, patients with NSCLC commonly differ from clinical trial populations in terms of age, health, access to care, and treatment course, which may all factor into the efficacy of immunotherapy. Objective: To determine the outcomes of immunotherapy use in unresectable stage III NSCLC in the general US population. Design, Setting, and Participants: This cohort study analyzed the National Cancer Database for patients diagnosed with clinical stage III NSCLC between 2015 and 2017 with follow-up through the end of 2018 who were treated with chemotherapy and radiation. Data were analyzed January 2022. Main Outcomes and Measures: Mortality hazard in a multivariable Cox proportional hazards model and survival among a propensity-matched sample treated with chemotherapy and radiation, with and without immunotherapy. Results: A total of 23 811 patients with clinical stage III NSCLC with median (IQR) age 66 (59-72) years met inclusion criteria (10 454 [43.9%] women; 564 [2.4%] Asian, 2930 [12.3%] Black, 20 077 [84.3%] White patients), including 209 (16.1%) patients with multiple comorbidities and 1297 (5.4%) immunotherapy recipients. Immunotherapy after chemotherapy and radiation was associated with reduced mortality (hazard ratio [HR], 0.74; 95% CI, 0.67-0.82; P < .001). Among a propensity-matched sample, immunotherapy was associated with superior 3-year survival (52% [1297 patients at 0 months, 56 patients at 36 months] vs 44% [2594 patients at 0 months, 173 patients at 36 months]; P < .001). The treatment of 833 patients who received immunotherapy (64.2%) differed from the PACIFIC trial protocol, including 221 patients (17.0%) who received radiation doses outside of the protocol range and 731 patients (56.4%) who started immunotherapy more than 6 weeks after radiation was completed. The survival advantage of immunotherapy persisted when initiated up to 12 weeks after radiation was completed (HR, 0.75; 95% CI, 0.61-0.92). Among patients who received radiation outside the PACIFIC protocol range, the survival advantage of immunotherapy was not significant (HR, 0.87; 95% CI, 0.69-1.01). Conclusions and Relevance: In this cohort study, immunotherapy after chemotherapy and radiation for stage III NSCLC was associated with a survival advantage in the general US population despite two-thirds of patients treated differently than the PACIFIC protocol. The findings suggest there may be flexibility in the timing of immunotherapy initiation after radiation; further study is warranted to clarify the clinical benefits of immunotherapy.

Association Between Food and Drug Administration Approval and Disparities in Immunotherapy Use Among Patients With Cancer in the US.

Importance: Clinical trials and compassionate use agreements provide selected patients with access to potentially life-saving treatments before approval by the Food and Drug Administration (FDA). Approval from the FDA decreases a number of access barriers; however, it is unknown whether FDA approval is associated with increases in the equitable use of novel therapies and reductions in disparities in use among patients with cancer in the US. Objective: To assess the association between FDA drug approval and disparities in the use of immunotherapy across health, sociodemographic, and socioeconomic strata before and after approval of the first checkpoint inhibitors for the treatment of patients with cancer in the US. Design, Setting, and Participants: This cohort study used data from the National Cancer Database to examine the use of immunotherapy across health, sociodemographic, and socioeconomic strata before and after FDA approval of the first checkpoint inhibitor therapies. A total of 402 689 patients 20 years or older who were diagnosed with stage IV non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), or melanoma of the skin between January 1, 2007, and December 31, 2018 (specific years varied by tumor type), were included. Exposures: Patient health (Charlson-Deyo comorbidity score and age), sociodemographic characteristics (sex, race, and ethnicity), and socioeconomic (insurance status and household income based on zip code of residence) characteristics. Main Outcomes and Measures: The association of patient characteristics with receipt of immunotherapy was evaluated in the 4 years before and the 3 years immediately after FDA approval using multivariable logistic regression modeling. Results: Among 402 689 patients (median [IQR] age, 68 [60-76 years]; 225 081 men [55.9%]), 347 233 had NSCLC, 43 714 had RCC, and 11 742 patients had melanoma. A total of 47 527 patients (11.8%) were Black, 15 763 (3.9%) were Hispanic, 375 874 (93.3%) were non-Hispanic, 335 833 (83.4%) were White, and 16 553 (4.1%) were of other races. Before FDA approval, 6271 patients (3.2%) with NSCLC, 1155 patients (4.8%) with RCC, and 504 patients (8.6%) with melanoma received immunotherapy compared with 23 908 patients (15.6%) with NSCLC, 3890 patients (19.7%) with RCC, and 1143 patients (19.3%) with melanoma after FDA approval. Before FDA approval, sociodemographic and socioeconomic characteristics were associated with variable immunotherapy administration by tumor type. For example, among those with NSCLC, Black patients were less likely to receive immunotherapy than White patients (odds ratio [OR], 0.78; 95% CI ,0.71-0.85; P < .001); among those with RCC, uninsured patients were less likely to receive immunotherapy than privately insured patients (OR, 0.31; 95% CI, 0.20-0.48; P < .001). After FDA approval, most disparities persisted, but several narrowed (eg, Black patients with NSCLC: OR, 0.87 [95% CI, 0.83-0.91; P < .001]; uninsured patients with RCC: OR, 0.60 [95% CI, 0.48-0.75; P < .001]). Although many disparities remained, some gaps across socioeconomic characteristics appeared to widen (eg, patients with NSCLC in the lowest vs highest income quartile: OR, 0.80; 95% CI, 0.76-0.83; P < .001), and new gaps emerged (eg, Black patients with RCC: OR, 0.82; 95% CI, 0.72-0.93; P = .003). Conclusions and Relevance: In this cohort study, disparities in immunotherapy use existed across a number of sociodemographic and socioeconomic characteristics among patients with NSCLC, RCC, and melanoma before FDA approval, including during the important period when clinical trials were accruing patients. Although FDA approval was associated with a significant increase in the use of immunotherapy, gaps persisted, suggesting that FDA approval may not eliminate disparities in the use of novel therapies.

Revisiting Indications for Brain Imaging During the Clinical Staging Evaluation of Lung Cancer.

Introduction: Available guidelines are inconsistent as to whether patients with newly diagnosed clinical stage II NSCLC should receive routine brain imaging. Methods: The National Cancer Database was queried for the prevalence of isolated brain metastases among patients with newly diagnosed NSCLC in 2016 and 2017. Patients with metastases in locations other than the brain were excluded. The prevalences were then stratified by clinical T and N classifications and further stratified into a summary stage, which was calculated based on T and N classifications. The summary stage represents the clinical stage that would have been available at the time of decision for brain imaging. Results: A total of 6,949 of 149,958 patients (4.6%) with clinical stages I, II, III, or brain-limited stage IV NSCLC had dissemination limited to the brain. As T and N stages increased, prevalence of brain metastases generally increased. Among patients with node-negative (N0) NSCLC, the prevalence of brain-only metastases increased from 1.2% in patients with T1a to 3.8% among patients with T4 (p < 0.001). Among patients with T1a, the prevalence of brain-only metastases increased from 1.2% for patients with N0 to 7.9% for patients with N3 (p < 0.001). The prevalence of brain-limited metastases generally increased with increasing summary stage. The prevalence of brain-only metastases among patients with stage IA was 1.7% whereas that among patients with stage IIIA was 6.7% (p < 0.001). Of note, the prevalence of brain-limited metastases was approximately 6% for both summary stages II and III. Conclusions: Considering the similarity in prevalence of isolated brain metastases and the potential hazards associated with brain imaging in early stage NSCLC, practitioners may consider a more liberal use of brain imaging when interpreting conflicting guidelines.

Vestibular and oculomotor abnormalities among HIV-infected and HIV-uninfected men and women: A pilot study.

OBJECTIVE: To determine if middle-aged and aging men and women with HIV disease (HIV+) should be screened for vestibular and oculomotor dysfunction. METHODS: Age- and sociodemographically matched HIV+ and HIV- men and women were tested on vestibular evoked myogenic potential (VEMP), bi-thermic caloric testing, Dix-Hallpike maneuvers and saccades. RESULTS: HIV+ men had more caloric weakness than HIV- men. HIV+ subjects had more saccade abnormalities than HIV- subjects. A saccade abnormality was positively associated with being HIV+. Among the HIV+ sample, abnormalities were associated with increasing age, being male, ever taking monotherapy, and having an undetectable viral load. Only being male and having an undetectable viral load were statistically significant. Unilateral caloric weakness had a decreased prevalence with age per 10 years, and being HIV+ showed an increased prevalence. In HIV+ subjects only, these abnormalities decreased with age and being male but increased with undetectable viral load and ever taking antiretroviral monotherapy. No statistically significant differences were found. CONCLUSION: Women are at greater risk of vestibular and oculomotor abnormalities than men. HIV+ adults are at greater risk than HIV- adults. Physicians who care for HIV+ men and women should monitor the symptoms of vestibular and oculomotor impairment.

Modern Treatment Trends and Outcomes of Pulmonary Embolism With and Without Hemodynamic Significance.

BACKGROUND: Pulmonary embolism is common, but the benefit of surgical embolectomy remains unclear. National trends in embolectomy have been described to 2008. Recent data are lacking. We characterized the national trends in incidence, management, and outcomes of pulmonary embolisms, along with the population-level outcomes. METHODS: The National Inpatient Sample was queried by International Classification of Diseases-9th Revision codes for pulmonary embolisms from 2011 to 2014. Saddle embolisms, shock, and interventions, including systemic thrombolysis, catheter-directed therapy, extracorporeal membrane oxygenation, and pulmonary embolectomy, were identified. Predictors of in-hospital death were identified by logistic regression. RESULTS: We identified 1,283,063 embolism records, including 34,040 (2.6%) with saddle embolism, 31,057 (2.4%) with shock, and 1768 (0.14%) had saddle embolism with shock. Embolectomy and catheter-directed therapies were associated with reduced death in saddle embolism with shock (n = 1768; embolectomy: odds ratio [OR], 0.30; 95% confidence interval [CI], 0.19-0.48; catheter-directed therapies: OR, 0.68; 95% CI, 0.49-0.96). Systemic thrombolytics were not associated with a in-hospital death difference (OR, 1.10; 95% CI, 60.87-1.38). Extracorporeal membrane oxygenation was associated with increased death (OR, 2.07; 95% CI, 1.09-3.92). The number needed to treat for in-hospital death of saddle embolisms with shock was 4.7 (95% CI, 3.9-6.9). CONCLUSIONS: In this contemporary nationally representative sample, surgical embolectomy and catheter-directed therapies were associated reduced in-hospital death for saddle pulmonary embolism with shock, and systemic thrombolytics were not associated with in-hospital death.

United States national trends in comorbidity and outcomes of adult cardiac surgery patients.

BACKGROUND: Comorbidity profiles of cardiac surgery patients are known to have changed over time, but modern national trends in these comorbidities and outcomes are not described. This study describes comorbidity trends over time for common adult cardiac surgery procedures. METHODS: A retrospective, cross-sectional analysis of the National Inpatient Sample was conducted for years 2005-2014. Hospitalizations with coronary artery bypass grafting (CABG), aortic valve replacement (AVR), and mitral valve repair/replacement (MVRR), as well as combined CABG/valve operations, were identified by ICD-9 procedure codes. Comorbidities were defined based on ICD-9 codes to discriminate between comorbidities and complications. Surgical volume, patient age, in-hospital mortality, and length of stay trends over time were evaluated by linear regression. RESULTS: Incidence increased for AVR, MVRR, and CABG + AVR and declined for CABG and CABG + MVRR (P < .001). The mean number of comorbidities across all surgeries increased from 1.4 to 1.9 (P < .001). Length of stay declined for AVR, CABG + AVR, and CABG + MVRR (P < .001) with an overall decline from 10.1 to 9.7 days (P = .003). In-hospital mortality decreased in all categories over time (P < .001). Overall, in-hospital mortality decreased from 2.9% to 2.3% (P < .001). CONCLUSIONS: Despite increasing comorbidity in cardiac surgery, operations are being conducted with fewer in-hospital mortalities across all types of surgery and decreasing length of stay for most types of surgery, which should inform the frequency of risk model updates and raise questions of the applicability of earlier studies in cardiac surgery to the modern population.

Impact of early reoperation on graft survival after liver transplantation: Univariate and multivariate analysis.

BACKGROUND: Data on rate, risk factors, and consequences of early reoperation after liver transplantation are still limited. STUDY DESIGN: Single-center retrospective analysis of data of 428 patients, who underwent liver transplantation in period between January 2009 and December 2014. Univariate and multivariate analysis were used to study the risk factors of early reoperation and its impact on graft survival. RESULTS: Of 428 patients, 74 (17.3%) underwent early reoperation. Of them, 46 (62.2%) underwent reoperation within the first week and 28 (37.8%) underwent reoperation later than 1 week after transplantation. With multivariate analysis, significant risk factors of early reoperation included pretransplant ICU admission, previous abdominal surgery and diabetes. Early reoperation itself was not found to be an independent predictor of graft loss. However, early reoperation later than 7 days from transplant was found to be independent predictor of graft loss (odds ratio [OR] = 5.125; 95% CI, 1.358-19.552; P = .016). In our series, other independent predictors of graft loss were MELD score (P = .010) and operative time (P = .048). CONCLUSIONS: This analysis demonstrates that early reoperations later than a week appear to negatively impact the graft survival. The timing of early reoperation should be a focus of additional studies.

Remodeling characteristics and collagen distribution in biological scaffold materials explanted from human subjects after abdominal soft tissue reconstruction: an analysis of scaffold remodeling characteristics by patient risk factors and surgical site classifications.

OBJECTIVE: The study purpose was to evaluate the associations between patient characteristics or surgical site classifications and the histologic remodeling scores of biologic meshes biopsied from abdominal soft tissue repair sites in the first attempt to generate a multivariable risk-prediction model of nonconstructive remodeling. BACKGROUND: Host characteristics and surgical site assessments may predict remodeling degree for biologic meshes used to reinforce abdominal tissue repair sites. METHODS: Biologic meshes were biopsied from the abdominal tissue repair sites of n = 40 patients during an abdominal reexploration, stained with hematoxylin and eosin, and evaluated according to a semi-quantitative scoring system for remodeling characteristics (cell types, cell infiltration, extracellular matrix deposition, scaffold degradation, fibrous encapsulation, and neovascularization) and a mean composite score. Biopsies were stained with Sirius Red and Fast Green and analyzed to determine the collagen I:III ratio. On the basis of univariate analyses between subject clinical characteristics or surgical site classification and the histologic remodeling scores, cohort variables were selected for multivariable regression models using P ≤ 0.200. RESULTS: The model selection process for cell infiltration score yielded 2 variables: age at mesh implantation and mesh classification (C statistic = 0.989). For the mean composite score, the model selection process yielded 2 variables: age at mesh implantation and mesh classification (r = 0.449). CONCLUSIONS: These preliminary results constitute the first steps in generating a risk-prediction model that predicts the patients and clinical circumstances most likely to experience nonconstructive remodeling of abdominal tissue repair sites with biologic mesh reinforcement.

Remodeling characteristics and collagen distribution in synthetic mesh materials explanted from human subjects after abdominal wall reconstruction: an analysis of remodeling characteristics by patient risk factors and surgical site classifications.

BACKGROUND: The purpose of this study was to evaluate the associations between patient characteristics or surgical site classifications and the histologic remodeling scores of synthetic meshes biopsied from their abdominal wall repair sites in the first attempt to generate a multivariable risk prediction model of non-constructive remodeling. METHODS: Biopsies of the synthetic meshes were obtained from the abdominal wall repair sites of 51 patients during a subsequent abdominal re-exploration. Biopsies were stained with hematoxylin and eosin, and evaluated according to a semi-quantitative scoring system for remodeling characteristics (cell infiltration, cell types, extracellular matrix deposition, inflammation, fibrous encapsulation, and neovascularization) and a mean composite score (CR). Biopsies were also stained with Sirius Red and Fast Green, and analyzed to determine the collagen I:III ratio. Based on univariate analyses between subject clinical characteristics or surgical site classification and the histologic remodeling scores, cohort variables were selected for multivariable regression models using a threshold p value of ≤0.200. RESULTS: The model selection process for the extracellular matrix score yielded two variables: subject age at time of mesh implantation, and mesh classification (c-statistic = 0.842). For CR score, the model selection process yielded two variables: subject age at time of mesh implantation and mesh classification (r (2) = 0.464). The model selection process for the collagen III area yielded a model with two variables: subject body mass index at time of mesh explantation and pack-year history (r (2) = 0.244). CONCLUSION: Host characteristics and surgical site assessments may predict degree of remodeling for synthetic meshes used to reinforce abdominal wall repair sites. These preliminary results constitute the first steps in generating a risk prediction model that predicts the patients and clinical circumstances for which non-constructive remodeling of an abdominal wall repair site with synthetic mesh reinforcement is most likely to occur.

Differentiation of biologic scaffold materials through physicomechanical, thermal, and enzymatic degradation techniques.

OBJECTIVE: The objective of this study was to characterize the physicomechanical, thermal, and degradation properties of several types of biologic scaffold materials to differentiate between the various materials. BACKGROUND: As more biologic scaffold materials arrive on the market, it is critical that surgeons understand the properties of each material and are provided with resources to determine the suitability of these products for specific applications such as hernia repair. METHODS: Twelve biologic scaffold materials were evaluated, including crosslinked and non-crosslinked; those of bovine, human, and porcine origin; and derivatives of pericardium, dermis, and small intestine submucosa. Physicomechanical, thermal, and degradation properties were evaluated through biomechanical testing, modulated differential scanning calorimetry, and collagenase digestion assays, respectively. Biomechanical testing included suture retention, tear strength, uniaxial tensile, and ball burst techniques. RESULTS: All scaffolds exhibited suture retention strengths greater than 20 N, but only half of the scaffolds exhibited tear resistance greater than 20 N, indicating that some scaffolds may not provide adequate resistance to tearing. A wide range of burst strengths were observed ranging from 66.2 ± 10.8 N/cm for Permacol to 1,028.0 ± 199.1 N/cm for X-Thick AlloDerm, and all scaffolds except SurgiMend, Strattice, and CollaMend exhibited strains in the physiological range of 10% to 30% (at a stress of 16 N/cm). Thermal analysis revealed differences between crosslinked and non-crosslinked materials with crosslinked bovine pericardium and porcine dermis materials exhibiting a higher melting temperature than their non-crosslinked counterparts. Similarly, the collagenase digestion assay revealed that crosslinked bovine pericardium materials resisted enzymatic degradation significantly longer than non-crosslinked bovine pericardium. CONCLUSIONS: Although differences were observed because of cross-linking, some crosslinked and non-crosslinked materials exhibited very similar properties. Variables other than cross-linking, such as decellularization/sterilization treatments or species/tissue type also contribute to the properties of the scaffolds.