Non-invasive trial testing for trigeminal branch stimulation to treat refractory trigeminal neuropathic pain: A technical note

Abstract

Objective: Trigeminal neuropathic pain can be debilitating and extremely difficult to treat. Trigeminal branch stimulation is a minimally invasive treatment that has shown benefit in earlier series. However, there is currently no widely accepted method to predict response. We propose an office-based, non-invasive trial to assess potential pain relief before the final decision for electrode implantation in patients with refractory trigeminal neuropathic pain. Methods: We retrospectively reviewed patients undergoing transcutaneous trigeminal branch nerve stimulation testing before moving on to electrode implantation between 2009 and 2017. Testing was done using an Ojeman Cortical Stimulator (OCS1) or a Grass S-88 Nerve/Muscle Stimulator via two SIU-7 CC isolators over the painful area. Frequency, pulse width and amplitude were set at values consistent with implanted electrode settings. Patients reporting more than 50% relief after up to 2 h of stimulation, and loss of relief after stimulation was discontinued, were deemed appropriate candidates and subsequently underwent implantation. Results: We identified 7 patients undergoing testing and subsequent implantation. Follow-up ranged from 2 months to 8 years. During last follow-up, 4 patients were still using their systems. Electrode removal was necessary because of loss of efficacy or infection. Three patients still using their systems required revision. Initial visual analogue pain score (VAS) ranged between 8 and 10. Patients with systems still in use reported VAS 1–4 on last follow-up, with pain relief of about 70%. Conclusions: Transcutaneous office-based testing is a simple and cost-effective method to gauge response to trigeminal branch stimulation in patients with refractory trigeminal neuropathic pain.

Keywords

• Trigeminal neuropathic pain
• Trigeminal nerve
• Stimulation