Ultrasound guided block of the saphenous neuroma following use of an AFO in a patient with paraplegia: A case report

Abstract

The saphenous nerve is the terminal branch of the femoral nerve and a pure sensory nerve that provide sensation to medial leg. Injury to saphanous nerve following trauma or surgery of the knee can result in formation of a painful neuroma along its distribution. We present a case of saphenous neuroma following use of an ankle-foot orthosis (AFO) in a patient with paraplegia. A 36-year-old patient with paraplegia who was capable of walking independently with his AFO presented to our department with a 3-month history of pain in his left calf. Examination revealed tenderness, paresthesias and positive Tinel sign over the anteromedial aspect of the calf. Ultrasonographic examination of the painful area showed a mass with heterogenous echogenity which was consistent with a saphenous neuroma at the site where fastener band of AFO compressed to skin. We performed a nerve block with steroid and local anesthetic injection under ultrasound guidance to the neuroma. The patient reported pain relief following injection. The use of the AFO may cause a painful saphenous neuroma which is an unusual cause of extremity pain in patients with paraplegia. Ultrasound may be a beneficial diagnostic tool and a guidance for the therapeutic interventions in this condition.