Sensory Potentials and Ultrasonography in Common Peroneal Mononeuropathy

Common peroneal mononeuropathy at the fibular neck (CPN) is one of the most frequent mononeuropathies of the lower extremities. The common peroneal nerve sub serves sensation to the dorsum of the foot and toes. In CPN motor fibers of the deep peroneal nerve are more frequently affected than those of the superficial peroneal nerve. Fascicles of the deep branch of the common peroneal nerve are more anteriorly located and more vulnerable to injury than those of the superficial peroneal branch. The clinical and electrodiagnostic findings in CPN resemble the anatomical structure of the common peroneal nerve, indeed fibers for the deep peroneal nerve and the superficial peroneal nerve are bounded in separate fascicles along the course of the nerve. Superficial peroneal nerve sensory potential (SPSP) should be performed to localize the site of injury. Electrodiagnostic testing is used widely to evaluate the function of the common peroneal nerve. SPSP have been examined in CPN with conflicting results. A loss in amplitude of this response implies some axonal loss affecting either the common peroneal nerve or its superficial branch. Prominent axonal loss is the hallmark of most CPN lesions and suggested that abnormalities in sensory nerves mirror those in motor nerves. Moreover, assessment of the structure of the common peroneal nerve is likely to improve the diagnostic yield" by using high-resolution ultrasonography. Ultrasound imaging is painless, does not expose the patient to radiation, and has several advantages compared with magnetic resonance imaging in the laboratory setting, including reduced cost, accessibility, ability to image the entire length of the nerve in a single study, and the ability to image both statically and dynamically. This study was conducted to evaluate the superficial peroneal sensory potential and high-resolution ultrasonography role in confirmation of common peroneal mononeuropathy at the fibular neck.