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Background: The effect of different modalities of anaesthesia in microvascular free flap surgery has been a topic of ongoing debate. Comparative data to study the effect of general anaesthesia and regional anaesthesia in the form of peripheral nerve blocks (PNBs) on lower extremity free flap survival is lacking to date. This study aims to elucidate the effect of regional anaesthesia on flap survival in lower extremity free flap reconstructions. Methods: A retrospective cohort study of all patients who underwent free vascularised flap reconstruction of the lower extremities between 2012 and 2021 at the Amsterdam University Medical Centre (UMC), The Netherlands, and between 2019 and 2021 at the Radboud UMC, Nijmegen, The Netherlands. In this cohort, we analysed partial and total flap failures. Results: In this cohort, 87 patients received a total of 102 microvascular free flap reconstructions of the lower extremity. In 20.5% of these operations, patients received a supplemental PNB. Total flap failure was 23.8% in the regional anaesthesia group compared to 21% in the group with general anaesthesia only (p = 0.779). Operation time was longer for patients with regional anaesthesia (p = 0.057). Length of stay was on average 2 days shorter for patients with supplemental regional anaesthesia (p = 0.716). Discussion: This is the largest cohort comparing flap survival in patients receiving general anaesthesia to general anaesthesia with a PNB in lower extremity reconstructions to date. We cannot attribute a significant beneficial or detrimental effect of regional anaesthesia to flap survival. High failure rates stress the need for future studies. How to cite this article: Koster ITS, den Os MM, Rutten MVH, et al. The Effect of Regional Anaesthesia on Free Flap Survival in Lower Extremity Reconstructions. Strategies Trauma Limb Reconstr 2024;19(1):15-20.
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Background: Free flap reconstructions are an important reconstructive option for soft tissue defects in mangled lower extremities. Microsurgery facilitates soft tissue coverage of defects that otherwise would result in amputation. However, the success rates of traumatic lower extremity free flap reconstructions remain lower than those in other locations. Nevertheless, post-free flap failure salvage strategies have rarely been addressed. Therefore, the current review aims to provide an overview of post-free flap failure strategies in lower extremity trauma and their subsequent outcomes. Methods: A search of Pubmed, Cochrane, and Embase databases was performed on June 9, June 2021 using the following medical subject headings (MeSH) search terms: 'lower extremity', 'leg injuries', 'reconstructive surgical procedures', 'reoperation', 'microsurgery' and 'treatment failure'. This review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Partial and total free flap failures after traumatic reconstruction were included. Results: Twenty-eight studies with a total of 102 free flap failures fulfilled the eligibility criteria. Following the total failure, a second free flap is the predominant reconstructive strategy (69%). In comparison to the failure rate of a first free flap (10%), the fate of a second free flap is less favorable with a failure rate of 17%. The amputation rate following flap failure is 12%. The risk of amputation increases between primary and secondary free flap failures. After partial flap loss, the preferred strategy is a split skin graft (50%). Conclusion: To our knowledge, this is the first systematic review on the outcome of salvage strategies after free flap failure in traumatic lower extremity reconstruction. This review provides valuable evidence to take into consideration in the decision-making regarding post-free flap failure strategies.
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In a microarray-based screen for genes that are involved in tissue separation downstream of Paraxial Protocadherin (PAPC) and Frizzled-7 (Fz7)-mediated signaling we identified xGit2 and xRhoGAP 11A, two GTPase-activating proteins (GAP) for small GTPases. xGit2 and xRhoGAP 11A are expressed in the dorsal ectoderm, and their transcription is downregulated in the involuting dorsal mesoderm by PAPC and Fz7. Overexpression of xGit2 and xRhoGAP 11A inhibits Rho activity and impairs convergent extension movements as well as tissue separation behaviour. We propose that Rho activity in the involuting mesoderm is enhanced through inhibition of xGit2 and xRhoGAP 11A transcription by PAPC and Fz7. By this mechanism xRhoGAP 11A and xGit2 are restricted to the dorsal ectoderm, while Rho signaling is inhibited.
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Proteínas Activadoras de GTPasa/metabolismo , Gástrula/metabolismo , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica , Receptores Acoplados a Proteínas G/metabolismo , Proteínas de Xenopus/metabolismo , Animales , Biología Evolutiva/métodos , Ectodermo/metabolismo , Proteínas Activadoras de GTPasa/genética , Proteínas Fluorescentes Verdes/metabolismo , Mesodermo/metabolismo , Modelos Biológicos , Transducción de Señal , Transcripción Genética , Proteínas de Xenopus/genética , Xenopus laevisRESUMEN
Xenopus Paraxial Protocadherin (xPAPC) has signaling functions that are essential for convergent extension (CE) movements and tissue separation during gastrulation. PAPC modulates components of the planar cell polarity (PCP) pathway, but it is not clear how PAPC is connected to beta-catenin-independent Wnt-signaling. By yeast two-hybrid screen, we found that the intracellular domain of PAPC interacts with Sprouty (Spry), an inhibitor of CE movements. Upon binding to PAPC, Spry function is inhibited and PCP signaling is enhanced. Our data indicate that PAPC promotes gastrulation movements by sequestration of Spry and reveal a novel mechanism by which protocadherins modulate beta-catenin-independent Wnt-signaling.