Superficial Peroneal Nerve Entrapment Neuropathy

Superficial peroneal nerve (SPN) branches from common peroneal nerve at longus peroneal muscle, penetrates fascia approximately 10 cm from lateral malleolus, and reaches to dorsum of foot. It is a mainly sensory branch in lower lateral shin and instep. SPN entrapment neuropathy is relatively rare and not well understood. It can be attributable to trauma, compression due to incarceration of muscle at fascial defect, and mass lesions; it can be idiopathic. Idiopathic SPN entrapment neuropathy involves entrapment at site where nerve penetrates fascia and overall compression below fascia. Diagnostic symptoms are numbness and pain at lower shin and instep, excluding deep peroneal nerve region; intermittent claudication may occur. A Tinel-like sign at single or multiple sites along SPN is diagnostically useful as is analgesic effect of nerve blocks. Patients may have a history of common peroneal nerve surgery. Those with an identified cause of their SPN are candidates for surgery. In patients with idiopathic SPN entrapment neuropathy, extensive opening and decompression is recommended to prevent re-entrapment by residual fascia.