Peroneus Tertius as a Target in Targeted Muscle Reinnervation for the Management of Neuropathic Pain in the Leg: A Cadaveric Study

INTRODUCTION: Targeted muscle reinnervation is increasingly being utilized to prevent or manage neuropathic pain in both amputees and non-amputees. The motor entry points (MEP) to the peroneus tertius provide ideal targets, as they are accessible but deep, and expendable with no donor morbidity. However, there has been no prior study of the neural anatomy of the peroneus tertius in this setting. This study aimed to evaluate the distribution of motor entry points (MEP) to the peroneus tertius, providing an anatomic roadmap to guide its use in targeted muscle reinnervation. METHODS: The branches of the deep peroneal nerve to the peroneus tertius were dissected in 12 cadaveric adult lower limbs. The number of MEP, diameter of the terminal branches and distance of each MEP from the tip of the lateral malleolus was recorded, as was the overall length of the fibula. A ratio of the distance of the MEP from the lateral malleolus to the overall length of the fibula was calculated. RESULTS: A mean of 1.9 ± 0.7 [range: 1-3] MEP innervated each peroneus tertius, with the terminal nerve 1.0 ± 0.5 mm [range: 0.5-2] in diameter, located a mean of 144.4 ± 29.1 mm [range: 90-188] cranial to the tip of the lateral malleolus (40.0% ± 8.8% [range: 26.0-56.3] of total fibular length). All specimens had at least a single MEP in the zone spanning 31.4% to 52.2% of the fibular length, located in the plane between the peroneus tertius and extensor digitorum longus. CONCLUSION: The peroneus tertius has MEP at a consistent location and plane and may be considered an optimal target for targeted muscle reinnervation around the foot and ankle.