Spontaneous incomplete recovery of peroneal palsy after a sealbite

Abstract

Incomplete recovery of peroneal palsy, after a sealbite during swimming has not been reported. A 58-year-old woman was bitten into the right knee by a seal during swimming, resulting in incomplete division of the right profound branch of the peroneal nerve and complete division of the superficial branch of the peroneal nerve. Initial drop-foot, absent foot eversion, and hypaesthesia of the lateral lower leg were followed by almost complete clinical recovery of motor functions within four month by spontaneous re-innervation from the proximal nerve stump, despite severely abnormal electrophysiological findings. Re-evaluation 6 years after the accident revealed only discrete weakness for foot and toe extension, slight distal hypaesthesia, but still increased distal latency, reduced compound muscle action potential, slowed nerve conduction velocity of the right peroneal nerve, and neurogenic electromyography of the right anterior tibial and long peroneal muscles. Nerve conduction studies were hampered by co-innervation of the extensor digitorum brevis muscles by the tibial nerves. This case shows that peroneal palsy from a sealbite may recover spontaneously almost completely, but may go along with residual, subclinical, electrophysiological abnormalities. The later may be enhanced by innervation variants.