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October 15, 2012
1:00:00 PM - 2:30:00 PM
Room 101
Long Term Follow Up of Peripheral Nerve Stimulation (PNS) for Refractory Chronic Headache: A Retrospective Review of Efficacy and Safety of Peripheral Nerve Stimulation
Billy K. Huh, M.D.,Ph.D., Pyung B. Lee, M.D.,Ph.D., Nam-Kha Pham, M.D.
Duke Univeristy Medical Center, Durham, North Carolina, United States
Background: Headache is a common neurological disorder. Approximately 18% of women and 6% of men in the US experience migraine. Significant advances have been made in the treatment of headache over last few decades. However, subsets of patients either do not achieve adequate pain relief or cannot tolerate the side effects of typical migraine medications. An electrical stimulation of the peripheral nerves via an implantable pulse generator appears to be good alternative option for patients with treatment-refractory headaches. The goal of this study is to review efficacy and safety of peripheral nerve stimulation (PNS) for chronic refractory headache.

Methods: A retrospective review was performed on 36 patients who were implanted with PNS for headache at Duke University Medical Center Pain and Palliative Clinic between January 2005 to March 2011. Twenty-three patients received occipital nerve stimulation (ON), 8 received supraorbital (SON), and 4 received both ON and SON, and 1 temporo-auricular stimulation. Pain intensity was scored before and after treatment using a visual analog scale (VAS). The change in pain scores before and after treatment was evaluated for significant decrease using paired t-tests. All tests were 2-tailed. Correlations were also made between the duration of headache prior to the implant to response rate. Long term complications such as infection, device malfunction, or lack of efficacy leading to explanation are documented.

Results: The mean headache severity (HS) decreased from 7.32±1.90 to 2.97±2.01 at 1 month, 2.76±2.56 at 6 month, and 3.32±2.68 at 12 month, respectively (p<0.001. Figure 1) after the PNS implantation. The mean differences between pre and post HS at 1, 6, and 12 month are 4.35, 4.57, 4.19, respectively (p<0.001). The response to stimulation appears to be independent of duration of headache (range 1.5 to 40 years. Mean=9.3 years) prior to the implantation (correlation=0.33). Four patients had post-implant infection requiring explantation; two were subsequently re-implanted. Four had system removed due to lack of efficacy; one patient had resolution of headache after 2 years and had system explanted. Overall 28 patients (78%) were satisfied with PNS experience.

Conclusion: Peripheral nerve stimulation is a safe and effective modality in the management of otherwise treatment-refractory disabling headaches. Although the procedure is minimally invasive, the complication rate is relatively high; revisions may be commonly required. Safety and efficacy results from large prospective, randomized, sham-controlled studies are warranted.
Figure 1

Copyright © 2012 American Society of Anesthesiologists