Blue-Blood Pig Thorax Model Increases Residents' Confidence in Internal Mammary Dissection.

BACKGROUND: Preparation of the recipient vessels is a crucial step in autologous breast reconstruction, with limited opportunity for resident training intraoperatively. The Blue-Blood-infused porcine chest wall-a cadaveric pig thorax embedded in a mannequin shell, connected to a saline perfusion system-is a novel, cost-effective ($55) simulator of internal mammary artery (IMA) dissection and anastomosis intended to improve resident's comfort, safety, and expertise with all steps of this procedure. The purpose of this study was to assess the effect of the use of this chest wall model on resident's confidence in performing dissection and anastomosis of the IMA, as well as obtain resident's and faculty's perspectives on model realism and utility. METHODS: Plastic surgery residents and microsurgery faculty at the University of Wisconsin were invited to participate. One expert microsurgeon led individual training sessions and performed as the microsurgical assistant. Participants anonymously completed surveys prior to and immediately following their training session to assess their change in confidence performing the procedure, as well as their perception of model realism and utility as a formal microsurgical training tool on a five-point scale. RESULTS: Every participant saw improvement in confidence after their training session in a minimum of one of seven key procedural steps identified. Of participants who had experience with this procedure in humans, the majority rated model anatomy and performance of key procedural steps as "very" or "extremely" realistic as compared with humans. 100% of participants believed practice with this model would improve residents' ability to perform this operation in the operating room and 100% of participants would recommend this model be incorporated into the microsurgical training curriculum. CONCLUSION: The Blue-Blood porcine chest wall simulator increases trainee confidence in performing key steps of IMA dissection and anastomosis and is perceived as valuable to residents and faculty alike.

Surgical and demographic predictors of free flap salvage after takeback: A systematic review.

BACKGROUND: Microsurgical free tissue transfer (FTT) is a widely employed surgical modality utilized for reconstruction of a broad range of defects, including head and neck, extremity, and breast. Flap survival is reported to be 90%-95%. When FTT fails, salvage procedures aim at establishing reperfusion while limiting ischemia time-with salvage rates between 22% and 67%. There are limited data-driven predictors of successful salvage present in the literature. This systematic review aims to identify predictors of flap salvage. METHODS: A systematic literature review was conducted per PRISMA guidelines. Articles included in the final analysis were limited to those investigating FTT salvage procedures and included factors impacting outcomes. Cohort and case series (>5 flaps) studies up until March 2021 were included. Chi-square tests and linear regression modeling was completed for analysis. RESULTS: The patient-specific factors significantly associated with salvage included the absence of hypercoagulability (p < .00001) and no previous salvage attempts (p < .00001). Case-specific factors significantly associated with salvage included trunk/breast flaps (p < .00001), fasciocutaneous/osteocutaneous flaps (p = .006), venous compromise (p < .00001), and shorter time from index procedure to salvage attempt (R = .746). Radiation in the head and neck population was significantly associated with flap salvage failure. CONCLUSIONS: Given the complexity and challenges surrounding free flap salvage procedures, the goal of this manuscript was to present data helping guide surgical decision-making. Based on our findings, patients without documented hypercoagulability, no previous salvage attempts, fasciocutaneous/osteocutaneous flaps, trunk/breast flaps, and a shorter time interval post-index operation are the best candidates for a salvage attempt.

Local Environment Induces Differential Gene Expression in Regenerating Nerves.

INTRODUCTION: Approximately 80% of amputations are complicated by neuromas. Methods for neuroma management include nerve translocation into bone and implantation into skeletal muscle grafts, which have also facilitated the development of regenerative neural interfaces to enable fixation of prosthetics with motor and sensory feedback. However, molecular-level differences between nerves in these environments have not been investigated. This study aimed to elucidate the physiology of regenerating nerves in different settings by assessing gene expression. MATERIALS AND METHODS: New Zealand white rabbits underwent transfemoral amputation with sciatic nerve transposition into the femur or tacked to skeletal muscle. At 5 wk, ribonucleic acid (RNA) sequencing of samples of distal nerve terminating in bone or muscle and nerve of the contralateral limb (control) identified differentially expressed genes (DEGs) and biochemical pathways (α = 0.05). RESULTS: Three samples of nerve housed in bone, four of nerve tacked to muscle, and seven naïve controls were analyzed. Relative to controls, nerve housed in bone had little within-group variation and 13,028 DEGs, and nerve tacked to muscle had dramatic within-group variation and 12,811 DEGs. These samples upregulated the following pathways: lysosome, phagosome, antigen processing/presentation, and cell adhesion molecule. Relative to nerve housed in bone, nerve tacked to muscle had 12,526 DEGs, demonstrating upregulation of pathways of B-cell receptor signaling, focal adhesion, natural killer-cell mediated cytotoxicity, leukocyte transendothelial migration, and extracellular matrix-receptor interactions. CONCLUSIONS: Nerve housed in bone has a more predictable molecular profile than does nerve tacked to muscle. Thus, the intramedullary canal may provide a more reliable setting for neuroma prevention and neural interfacing.

The Effect of Tension on Gene Expression in Primary Nerve Repair via the Epineural Suture Technique.

INTRODUCTION: The precise mechanism through which excessive tension confers poor outcomes in nerve gap repair is yet to be elucidated. Furthermore, the effect of tension on gene expression in regenerating nerves has not been characterized. This study investigated differential gene expression in transected nerves repaired under high and minimal tension. METHODS: Male Lewis rats underwent right sciatic nerve transection with either minimal-tension or high-tension repair. Fourteen weeks postoperatively, segments of the right sciatic nerves were harvested along with equal-length segments from the contralateral, healthy nerve to serve as internal controls (naïve nerve). Differentially expressed genes (DEGs) and differentially regulated biochemical pathways between the samples were identified. RESULTS: Seventeen animals were studied. The gene expression profiles of naïve nerve and minimal-tension repair demonstrated minimal within-group variation, whereas that of high-tension repair demonstrated heterogeneity. Relative to naïve nerve, high-tension repair samples had 4276 DEGs (1941 upregulated and 2335 downregulated) and minimal-tension repair samples had 3305 DEGs (1479 upregulated and 1826 downregulated). High-tension repair samples had 360 DEGs relative to minimal-tension repair samples (68 upregulated and 292 downregulated). Upregulated biological pathways in all repaired nerves included steroid biosynthesis, extracellular matrix-receptor interaction, and ferroptosis. Finally, upregulated pathways in high-tension repair samples relative to minimal-tension repair samples included tumor necrosis factor signaling, interleukin-17 signaling, cytokine-cytokine receptor interaction, and mitogen-activated protein kinase signaling. CONCLUSIONS: The improved outcomes achieved with minimal-tension nerve repair may take root in a favorable gene expression profile. Future elucidation of biochemical pathways in nerve regeneration may identify potential therapeutic targets to optimize primary nerve repair outcomes.

Diversity in Plastic Surgery Authorship: A 14-Year Analysis of 2688 Articles Published in Plastic and Reconstructive Surgery.

BACKGROUND: Publication in peer-reviewed journals is a duty and privilege. It is essential to the advancement of evidence-based medicine and often used as a proxy for academic achievement, contributing to decisions around promotion in academia. Within plastic surgery, authors have historically been male surgeons affiliated with academic institutions, lacking representation of women, private practice, medical students, and international collaboration. This study analyzes differences in authors' gender, practice affiliation, degree of education, and international collaboration in articles published in Plastic and Reconstructive Surgery, which was chosen as the representative journal given its high impact factor (3.946) and consistent ranking as the number one journal in plastic surgery worldwide. METHODS: A list of Breast, Cosmetic, and Hand/Peripheral Nerve articles published between 2006 and 2019 was compiled from the online archive of Plastic and Reconstructive Surgery. Demographic author characteristics were recorded, and statistical analyses were performed to identify trends over time. RESULTS: A total of 2688 articles were analyzed. The proportion of articles written by female authors in the Breast category, authors in private practice with academic affiliation in the Cosmetic section, and U.S. collaboration with other countries increased over time (p = 0.038, p = 0.029, p < 0.001, respectively). First authors with bachelor's, master's, and doctorate degrees have also been contributing increasingly. CONCLUSIONS: This analysis revealed increasing demographic heterogeneity of authors in Plastic and Reconstructive Surgery over time, with increasing contributions from women, surgeons in private practice with academic affiliation, medical students, and international collaborations. The Journal is capturing contributions from an increasingly diverse authorship, consistent with the changing demographics of plastic surgeons.

Evaluation of Racial Disparities in Postoperative Outcomes Following Breast Reconstruction at a Single Institution in Wisconsin.

INTRODUCTION: Breast cancer is the most common cancer in women in Wisconsin. Evidence demonstrates that non-White racial minorities in the United States exhibit a higher mortality rate and more advanced or aggressive presentations of the disease than their White counterparts. Postmastectomy breast reconstruction remains essential to the treatment and recovery of these patients; however, racial disparities in the receipt of reconstruction are evident. This study evaluates the presence of racial disparities in postoperative outcomes of breast reconstruction at a single institution in Wisconsin. METHODS: An institutional review board-exempt retrospective study of postoperative outcomes was performed using a single institution's National Surgical Quality Improvement Program Registry to identify patients who underwent autologous or prosthesis-based breast reconstruction following mastectomy. Patient demographic, preoperative, operative, and postoperative variables were recorded. Postoperative outcomes in relation to self-reported race were evaluated using univariate analysis and propensity score matching. RESULTS: A total of 1,140 patients were included (1,092 White vs 48 non-White), with fewer non-White patients undergoing reconstruction. Patients of non-White race demonstrated a higher incidence of morbid obesity (4.4% White vs 12.5% non-White, P = 0.010) and bleeding disorders (0.3% White vs 4.2% non-White, P < 0.001). No association between self-reported race and postoperative complication was found. CONCLUSION: This study did not reveal racial disparities in postoperative outcomes of breast reconstruction at a single institution in Wisconsin; however, non-White patients were less likely to undergo reconstruction. Further research into the underlying causes of unequal access to care, influence of insurance, effect of structural racism, and impact of physician- and patient-associated factors is warranted.

The Blue-Blood Porcine Chest Wall: A Novel Microsurgery Training Simulator for Internal Mammary Vessel Dissection and Anastomosis.

BACKGROUND: Preparation of the internal mammary artery (IMA) is a critical step in autologous breast reconstruction. Intraoperatively, there is limited opportunity for residents to practice this skill. Porcine models provide highly realistic simulation for vascular surgery; however, use of live laboratory pigs is expensive, inconvenient, and offers limited opportunity for repetitive training. We aimed to develop an inexpensive and effective training model for IMA preparation. This article describes creation of a novel microsurgical model using cadaveric chest walls of Wisconsin Miniature Swine embedded in a modified mannequin thorax and augmented with a blue-blood perfusion system. METHODS: Anatomic comparison: five porcine chest walls were dissected, and various anatomic measurements were made for anatomic comparison to existing human data in the literature. Model assembly: the chest wall is prepared by cannulating the proximal and distal ends of the internal mammary vessels with angiocatheters, which are then connected to the blue-blood perfusion system. The model is assembled in four layers including: (1) a mannequin thorax with a window removed to expose the first to fourth intercostal spaces, bilaterally, (2) a layer of foam simulating fat, (3) the perfused pig chest wall, and (4) a second mannequin shell placed posteriorly for support. RESULTS: The porcine chest walls are similar to humans with regards to vessel size and location. This model can be assembled quickly, with a one-time approximate cost of $55.00, and allows for six training sessions per specimen. The model allows residents to practice the key steps of IMA preparation including dissection, elevation of perichondria, and vascular anastomosis while working at a depth that closely simulates the human thorax. Continuous blue-blood perfusion provides immediate feedback on anastomosis quality. CONCLUSION: Overall, this novel model can provide inexpensive and realistic simulation of internal mammary vessel preparation and anastomosis.