MRI anatomical preoperative evaluation of distally based peroneus brevis muscle flap in reconstructive surgery of the lower limb

Background The distally based peroneus brevis muscle flap has proved to be a simple solution for small- to moderate-sized wounds of the lower limb. The length of the muscle belly suitable for coverage is a crucial parameter. In this study, we evaluated the capability of 3D MRI of the lower limb to measure it preoperatively. Methods Between 2008 and 2017, 32 patients with lower limb defects underwent preoperative MRI to measure the peroneus brevis muscle length. All patients underwent reconstruction, and the muscle was measured again intraoperatively during surgical dissection. Surgical measurements were then compared to the MRI ones. Results MRI measures of the peroneus brevis muscle belly ranged from 9 to 21 cm (μ = 14.44 ± 3.43 cm), and intraoperative measures ranged from 9 to 20 cm (μ = 14.2 ± 2.3 cm). Thirty of 32 intraoperative measures corresponded to the MRI ones (variation = ± 1 cm, r = 0.92, p = 0.002). One patient showed an intraoperative muscle length 3 cm shorter than the MRI measure, and another patient had intraoperative muscle length 3 cm longer than the MRI one. All flaps survived, and no secondary local flap coverage was required, with no flap-related complication, limited donor site morbidity, and acceptable patient discomfort. Conclusions The reverse peroneus brevis muscle flap is a versatile alternative to free flap reconstruction in small- to moderate-sized defects of the lower limb. Preoperative 3D MRI is accurate to evaluate the anatomy of the muscle when performed by an expert radiologist. In our experience, it should become part of preoperative workup before performing a peroneus brevis flap procedure.