Peripheral Nerve Stimulation for Painful Mononeuropathy Secondary to Leprosy: A 12-Month Follow-Up Study.

OBJECTIVE: Leprosy affects approximately 10-15 million patients worldwide and remains a relevant public health issue. Chronic pain secondary to leprosy is a primary cause of morbidity, and its treatment remains a challenge. We evaluated the feasibility and safety of peripheral nerve stimulation (PNS) for painful mononeuropathy secondary to leprosy that is refractory to pharmacological therapy and surgical intervention (decompression).

METHODS: Between 2011 and 2013 twenty-three patients with painful mononeuropathy secondary to leprosy were recruited to this prospective case series. All patients were considered to be refractory to optimized conservative treatment and neurosurgical decompression. Pain was evaluated over the course of the study using the neuropathic pain scale and the visual analog scale for pain. In the first stage, patients were implanted with a temporary electrode that was connected to an external stimulator, and were treated with PNS for seven days. Patients with 50% or greater pain relief received a definitive implantation in the second stage. Follow-ups in the second stage were conducted at 1, 3, 6, and 12 months.

RESULTS: After seven days of trial in the first stage, 10 patients showed a pain reduction of 50% or greater. At 12-month follow-up in the second stage, 6 of the 10 patients who underwent permanent device implantation showed a pain reduction of 50% or greater (75% reduction on average), and two patients showed a 30% reduction in pain. Two patients presented with electrode migration that required repositioning during the 12-month follow-up period.

CONCLUSIONS: Our data suggest that PNS might have significant long-term utility for the treatment of painful mononeuropathy secondary to leprosy. Future studies should be performed in order to corroborate our findings in a larger population and encourage the clinical implementation of this technique.