Pulsed Radiofrequency of the Median Nerve under Ultrasound Guidance

Abstract

Neuropathy of the median nerve within the carpal tunnel (carpal tunnel syndrome) has an age adjusted incidence of 105 cases per 100,000 person years. Treatment of carpal tunnel syndrome ranges from conservative management with medication and exercise to surgical release of the median nerve. Conservative treatment accounts for a significant portion of resources utilized and includes splinting, nerve gliding, ultrasound, and carpal bone mobilization. Recurrent symptoms of carpal tunnel syndrome have been shown to occur in 0% to 19% of patients following carpal tunnel release, with up to 12% requiring re-exploration. Prognosis for re-exploration is not as good as for primary carpal tunnel release, with a high recurrence rate in some populations. Ultrasound has seen increasing use in regional anesthesia and has been shown to improve the quality of regional anesthetic blocks. Pulsed radiofrequency was developed with the goal of providing reduction in pain from the use of electrical fields in the absence of neural injury. The use of ultrasound guidance for positioning radiofrequency probes over peripheral nerves has not been reported. This case report describes the use of ultrasound guided pulsed radiofrequency in the treatment of recurrent carpal tunnel syndrome. Following revision carpal tunnel surgery, the patient in this report was unable to obtain relief of pain in either hand with medication therapy alone. After a successful diagnostic median nerve block at the cubital fossa, pulsed radiofrequency of the median nerve was performed on the left side at the cubital fossa, under ultrasound guidance. Radiofrequency probe adjustment around the nerve was conducted under live ultrasound guidance and multiple pulsed treatments were applied at anatomically distinct sites over the nerve. A 70% reduction in pain was reported over the follow up period of 12 weeks. Key words: Pulsed radiofrequency, carpal tunnel, ultrasound, median nerve.