Prevalence of the accessory deep peroneal nerve: A cadaveric study and meta-analysis.

OBJECTIVES: The accessory deep peroneal nerve (ADPN) is a common anatomical variant arising from the superficial peroneal nerve (SPN) and, when present, is often responsible for partial or complete innervation of the extensor digitorum brevis muscle (EDBM). The nerve lies posterior to the peroneus brevis muscle, traveling posterior to the lateral malleolus to terminate in the ankle by giving off sensory branches to the ankle and joints. Although the EDBM is usually supplied by the deep peroneal nerve (DPN), in the presence of an ADPN, electrodiagnostic procedures may be complicated. Due to the lack of detailed anatomical knowledge on the topography of the ADPN, its presence posterior to the lateral malleolus can be iatrogenically injured during surgical procedures on the ankle using a lateral approach. Therefore, this meta-analysis aimed to provide a comprehensive, evidence-based assessment of the anatomical characteristics of the ADPN, supplemented with data from our own cadaveric dissection.

PATIENTS AND METHODS: A comprehensive search of all major electronic databases, including Pubmed, Embase, Scopus, Web of Science, ScienceDirect, SciELO, and BIOSIS was performed. All articles with data on prevalence, symmetry and innervation of the EDBM by the ADPN were included. The anatomical data was then extracted and pooled into a meta-analysis using MetaXL 2.0. In addition, we dissected 21 cadavers (n=42 lower limbs) bilaterally to find the ADPN.

RESULTS: A total of 19 studies (n=6070 lower limbs) were included in the meta-analysis. The pooled prevalence of the ADPN was 18.8% (95%CI:14.2-24.0) with a 39.3% prevalence rate for cadaveric studies. The ADPN was present more commonly unilaterally (67.0%) and when it was present, provided branches to the EDBM in 79.5% of cases. In our cadaveric study, the ADPN was identified in 5 of the 42 lower limbs dissected (11.9%); on the right side in 3 lower limbs and on the left side in 2 lower limbs.

CONCLUSIONS: The ADPN is a clinically important nerve and has been inculpated in unexplained cases of chronic ankle pain and EDBM atrophy. The variability in detection of the ADPN using electrophysiological techniques can lead to misdiagnoses of peroneal nerve lesions and increase the risk for iatrogenic injury to the ADPN, especially in laterally approaching ankle procedures and sural nerve biopsies.