Introduction Collagen and human amniotic membrane (hAM) are Food and Drug Administration (FDA)-approved biomaterials that can be used as nerve wraps or conduits for repair of peripheral nerve injuries. Both biomaterials have been shown to reduce scarring and fibrosis of injured peripheral nerves. However, comparative advantages and disadvantages have not been definitively shown in the literature. The purpose of this systematic review is to comprehensively evaluate the literature regarding the roles of hAM and collagen nerve wraps and conduits on peripheral nerve regeneration in preclinical models.
Methods The MEDLINE database was queried using the PubMed search engine on July 7, 2019, with the following search strategy: (“amniotic membrane” OR “amnion”) OR (“collagen conduit” OR “nerve wrap”)] AND “nerve.” All resulting articles were screened by two independent reviewers. Nerve type, lesion type/injury model, repair type, treatment, and outcomes were assessed.
Results Two hundred and fifty-eight articles were identified, and 44 studies remained after application of inclusion and exclusion criteria. Seventeen studies utilized hAM, whereas 27 studies utilized collagen wraps or conduits. Twenty-three (85%) of the collagen studies utilized conduits, and four (15%) utilized wraps. Six (35%) of the hAM studies utilized conduits and 11 (65%) utilized wraps. Two (9%) collagen studies involving a conduit and one (25%) involving a wrap demonstrated at least one significant improvement in outcomes compared with a control. While none of the hAM conduit studies showed significant improvements, eight (73%) of the studies investigating hAM wraps showed at least one significant improvement in outcomes.
Conclusion The majority of studies reported positive outcomes, indicating that collagen and hAM nerve wraps and conduits both have the potential to enhance peripheral nerve regeneration. However, relatively few studies reported significant findings, except for studies evaluating hAM wraps. Preclinical models may help guide clinical practice regarding applications of these biomaterials in peripheral nerve repair.
Background Perineal reconstruction following salvage APR’s for squamous cell carcinoma of the anus (SCCA) are scant with conflicting results from large and single center studies. We analyzed these techniques taking into account sociodemographic and oncologic variables. Methods This is a retrospective cohort study from 2016-2019 using a targeted ACS/NSQIP database stratified into primary closure (PC), abdominal myocutaneous (AM), lower extremity (LE), and omental pedicled (OP) flaps. We analyzed major and wound complications through univariate and multivariate regression analysis. Results A total of 766 patients were analyzed, 512 (67%) had PC, 196 (25%) AM, 36 (5%) OP and 22 (3%) LE. Rates of chemotherapy and radiation within 90 days were similar between the groups. Having 2 or more additional organs resected was more common for the AM group (AM 4.1%, PC 1.6%, OP 3.3%, LE 0%). Overall, major complication rate was 41% (n = 324). Primary closure had 35.0%, OP 47.2%, AM 52.6%, and LE 45.5%. Wound complication rate was highest in AM with 11.7%, followed by OP 8.3%, PC 5.9%, and LE 0%. The multivariate regression analysis demonstrated none of the closure techniques to be associated with increasing or decreasing the probability of having a major or wound complication. Morbidity probability was the sole predictor of major complication (OR 1.07, 95% CI 1.04-1.1) Conclusions Myocutaneous and omental flaps are associated with comparable wound and major complications when taking into account the baseline, oncologic and perioperative variables that drive the clinical decision making when selecting a perineal reconstruction.
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