Accessory deep peroneal nerve - a clinically significant anomaly?
OBJECTIVE
The accessory deep peroneal nerve (ADPN), a variant of the peroneal nerve, may give motor branches to the extensor digitorum brevis muscle (EDB) in 19-28% of the general population and in up to 78% of subjects in familial cases. The aim of our study was to evaluate its significance in the examination of the peroneal nerve.


METHODS
Three groups of patients were analyzed. Group I consisted of 310 patients whose neurography recordings were analyzed retrospectively. Group II consisted of 24 healthy controls and group III consisted of 8 relatives of a healthy control having the ADPN detected. All patients underwent routine neurography of the peroneal nerve with muscular response recorded from the EDB. Groups II and III had additional stimulation behind the lateral malleolus.


RESULTS
On routine neurography, ADPN was found in 7.7% of patients in group I and 12.5% in group II. Stimulation behind the lateral malleolus detected it in 25% of group II and in 50% of group III. The highest CMAP amplitude obtained by stimulation of the ADPN equalled 3.71 mV and was over half of the total EDB response. The presence of the ADPN significantly influences routine neurography of the peroneal nerve in 7.7-12.5% of patients. Stimulation behind the lateral malleolus detected it in 25% of group II and in 50% of the maternal line of the family in group III. In the familial case ADPN was present in 50% of maternally related subjects, reflecting autosomal dominant transmission.


CONCLUSIONS
ADPN may innervate the greater part of the EDB and in cases of peroneal neuropathy may be important for preserving function of the muscle.
Department of Neurology, Medical University of Warsaw, Warsaw, Poland. szowsiak@amwaw.edu.pl
Szymon
S
Owsiak
Anna
A
Kostera-Pruszczyk
Katarzyna
K
Rowińska-Marcińska
D000328:Adult; D004558:Electric Stimulation; D004568:Electrodiagnosis / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D009431:Neural Conduction; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis* / Q000209:etiology; D010543:Peroneal Nerve / Q000033:anatomy & histology* / Q000503:physiopathology*; D012016:Reference Values