Atypical deep peroneal neuropathy in the setting of an accessory deep peroneal nerve

Abstract

We report a case of deep peroneal neuropathy resulting in foot drop with preserved toe extension. These unexpected findings were the result of the presence of an accessory deep peroneal nerve that provided total innervation of the extensor digitorum brevis. We review the literature on total innervation of the extensor digitorum brevis by the accessory deep peroneal nerve with and without an associated deep peroneal nerve lesion. Muscle Nerve 40: 313-315, 2009.

Prevalence of accessory deep peroneal nerve in referred patients to an electrodiagnostic medicine clinic

“…In our study there is no difference between female and male in distribution of APN. Other issue that was detected and explained in our study is detection of EDB agenesis that was not shown and mentioned in other studies [2,12].…”

“…This difference could be due to some genetic issues and/or techniques used that needs further studies to be confirmed. Also Kayal and et al described this difference" the reported evidence is higher in studies that routinely applied stimulation behind the lateral malleolus during the performance of peroneal motor conduction studies" [ 2 ].…”

“…Accessory Deep Peroneal Nerve (ADPN) is an anatomic variation which can potentially disturb electrodaignostic studies [ 1 , 2 ]. This nerve is separated from Superficial Peroneal Nerve (SPN) and then turns around lateral malleolus to innervate all or part of Extensor Digitorum Brevis(EDB)[ 3 , 4 ] (figure 1 ).…”

“…If this anomaly exists among patients with peroneal nerve lesion, atypical presentations could be seen in their electrodiagnostic study (EDX) [ 5 ]. In case of Deep Peronel Nerve (DPN) lesion, denervation in all of DPN innervated muscles could be seen except for EDB [ 2 , 4 ]. In case of Superficial Peroneal Nerve (SPN) lesion at distal part of leg there is only impaired sensory SPN response, however in case of APN variation, denervation of EDB is also present.…”

Neurological Complications of Foot and Ankle Surgery

“…The lateral terminal branch supplies the extensor digitorum brevis muscle, and it provides interosseous branches that innervate the tarsal and metatarsophalangeal joints of the middle three toes. 12 The proximal segment of the DPN is equally well seen on US and MRN, whereas the distal branches are difficult to identify unless they are abnormal. We favor MRN for DPN evaluation because it better shows the nerve signal intensity changes as well as the related muscle denervation changes.…”