Surgical outcomes of VRAM versus gracilis flaps for the reconstruction of pelvic defects following oncologic resection✰.

PURPOSE: Pelvic reconstruction following abdominoperineal resection or pelvic exenteration is associated with signification surgical site morbidity. Immediate pelvic reconstruction with a muscle flap is now the gold standard, associated with reduced perineal morbidity compared to primary closure alone.2,3 The purpose of the present study was to directly compare outcomes of VRAM and gracilis flap pelvic reconstruction following oncologic resection. METHODS: A multicenter retrospective review was performed of 88 patients who underwent abdominoperineal resection or pelvic exenteration and immediate pelvic reconstruction, either with a VRAM (N = 61) or Gracilis flap (N = 27). Electronic medical records were analyzed for patient demographics, intraoperative data, and postoperative outcomes. Mortality, minor complication rate, major complication rate and time to complete wound healing was compared between groups. RESULTS: Overall, there was no significant difference in the minor complication rate (44% gracilis vs 48% VRAM, p = 0.8), major complication rate (19% gracilis vs 13% of VRAM, p = 0.53), 30-day mortality (0% VRAM vs 0% gracilis, p = 1.0) and median time to complete wound healing (68 days vs 67 days, p = 0.19) between the gracilis and VRAM groups. Muscle-only gracilis flaps had a significantly reduced healing time compared to musculocutaneous gracilis flaps (48 days vs 85 days, p = 0.007). CONCLUSIONS: The workhorse flap in pelvic reconstruction remains the VRAM. While previous studies have alluded to the inferiority of thigh based flaps compared to the VRAM, we demonstrate here that pelvic reconstruction with the gracilis flap can be performed with comparable donor and recipient complication rates and similar time to complete wound healing as the VRAM.

Tibial nerve transection - a standardized model for denervation-induced skeletal muscle atrophy in mice.

The tibial nerve transection model is a well-tolerated, validated, and reproducible model of denervation-induced skeletal muscle atrophy in rodents. Although originally developed and used extensively in the rat due to its larger size, the tibial nerve in mice is big enough that it can be easily manipulated with either crush or transection, leaving the peroneal and sural nerve branches of the sciatic nerve intact and thereby preserving their target muscles. Thus, this model offers the advantages of inducing less morbidity and impediment of ambulation than the sciatic nerve transection model and also allows investigators to study the physiologic, cellular and molecular biologic mechanisms regulating the process of muscle atrophy in genetically engineered mice. The tibial nerve supplies the gastrocnemius, soleus and plantaris muscles, so its transection permits the study of denervated skeletal muscle composed of fast twitch type II fibers and/or slow twitch type I fibers. Here we demonstrate the tibial nerve transection model in the C57Black6 mouse. We assess the atrophy of the gastrocnemius muscle, as a representative muscle, at 1, 2, and 4 weeks post-denervation by measuring muscle weights and fiber type specific cross-sectional area on paraffin-embedded histologic sections immunostained for fast twitch myosin.