A case report of wireless peripheral nerve stimulation for complex regional pain syndrome type-I of the upper extremity: 1 year follow up.

BACKGROUND

Complex regional pain syndrome (CRPS) is a chronic disabling painful disorder with limited options to achieve therapeutic relief. CRPS type I which follows trauma, may not show obvious damage to the nervous structures and remains dubious in its pathophysiology and also its response to conservative treatment or interventional pain management is elusive. Spinal cord and dorsal root ganglion stimulation (SCS, DRGS) provide good relief, mainly for causalgia or CRPS I of lower extremities but not very encouraging for upper extremity CRPS I. we reported earlier, a case of CRPS I of right arm treated successfully by wireless peripheral nerve stimulation (WPNS) with short term follow up. Here we present 1-year follow-up of this patient.

OBJECTIVE

To present the first case of WPNS for CRPS I with a year follow up. The patient had minimally invasive peripheral nerve stimulation (PNS), without implantable pulse generator (IPG) or its accessories.

CASE REPORT

This was a case of refractory CRPS I after blunt trauma to the right forearm of a young female. She underwent placement of two Stimwave electrodes (Leads: FR4A-RCV-A0 with tines, Generation 1 and FR4A-RCV-B0 with tines, Generation 1) in her forearm under intraoperative electrophysiological and ultrasound guidance along radial and median nerves. This WPNS required no IPG. At high frequency (HF) stimulation (HF 10 kHz/32 μs, 2.0 mA), patient had shown remarkable relief in pain, allodynia and temperature impairment. At 5 months she started driving without opioid consumption, while allodynia disappeared. At 1 year follow up she was relieved of pain [visual analogue scale (VAS) score of 4 from 7] and Kapanji Index (Score) improved to 7-8. Both hands look similar in color and temperature. She never made unscheduled visits to the clinic or visited emergency room for any complications related to the WPNS.

CONCLUSIONS

CRPS I involving upper extremity remain difficult to manage with conventional SCS or DRGS because of equipment related adverse events. Minimally invasive WPNS in this case had shown consistent relief without any complications or side effects related to the wireless technology or the technique at the end of 1 year.

IMPLICATIONS

This is the first case illustration of WPNS for CRPS I, successfully treated and followed up for 1 year.