Ultrasound-guided therapeutic injections for neural pathology about the foot and ankle: a 4 year retrospective review.

OBJECTIVE: To describe a 4-year clinical experience with ultrasound-guided therapeutic perineural injections of peripheral nerves about the foot and ankle.

MATERIALS AND METHODS: Retrospective analysis of foot and ankle perineural injections performed between January 2012 and August 2016. Demographics, clinical indications, presence of structural pathology, immediate and interval pain relief, as well as complications were recorded.

RESULTS: Fifty-nine therapeutic injections were performed among 46 patients, accounting for multiple injections in a single visit or multiple visits [mean age = 43 years (range 18-75), 31 female (67%) and 15 male (33%)]. Most commonly, perineural injections involved the hallux branch of the medial plantar nerve (n = 17, 22%). Least commonly, perineural injections involved the saphenous nerve (n = 3, 4%). Other injections in our series include sural (10), superficial (11) and deep (7) peroneal, medial (5) and lateral (3) plantar nerves, and the posterior tibial nerve (3). Ultrasound evaluation revealed structural abnormality associated with the nerve in 30 cases (51%)-most commonly thickening with perineural scarring (n = 14). Of 45 injections with complete documentation, immediate relief of symptoms was reported in 43 (96%) cases. Interval symptom relief was achieved in 23 injections [short term (n = 12), intermediate (n = 6), and long term (n = 5)] out of 38 for which follow-up was available (61%). Complications are rare, occurring in only one case.

CONCLUSION: Ultrasound-guided perineural injections about the foot and ankle are safe and provide lasting symptomatic relief for many indications. Concomitant sonographic evaluation identifies structural abnormalities that may contribute to neuropathic symptoms, allowing targeting of injection or clinical therapy.