1. 2015;18;505-516Peripheral Nerve Stimulation for the Treatment of Chronic Intractable Headaches: Long-term Efficacy and Safety Study
   Retrospective Review
   Francis S Nahm, MD, PhD, Christian Horazeck, MD, Pyung Bok Lee, MD, and Billy K. Huh, MD, PhD.

BACKGROUND: Despite the various modalities available for treating headaches, typical therapy does not provide adequate pain relief for some patients.

OBJECTIVES: This study explored the efficacy and safety of long-term peripheral nerve stimulation (PNS) for intractable chronic headaches.

STUDY DESIGN: Retrospective study of refractory headache patients at academic pain center.

METHODS: The medical records of all patients (N = 46) permanently implanted with PNS between January 2005 and January 2012 were reviewed retrospectively. Patient records and phone interviews were used to quantify the levels of pain intensity, headache days per month, and overall patient satisfaction with treatment. The correlation between headache duration and effectiveness of PNS was also assessed.

RESULTS: Pain intensity on the 11-point Numeric Rating Scale decreased from 7.60 ± 1.73 before implantation to 3.78 ± 2.41, 3.32 ± 2.67, 3.42 ± 2.74, and 2.04 ± 2.27 at one, 6, 12, and > 12 (19 – 98) months after implantation, respectively (P < .001). The mean number of headache days per month decreased by about 14 days from the base line. No correlation (r = -.33) was found between the number of years the patients had suffered from headaches and the efficacy of treatment.

LIMITATIONS: Due to the limitation of a retrospective study, the data collected via chart reviews and phone interviews are susceptible to selection and information biases.

CONCLUSIONS: PNS is an effective modality in the long-term management of intractable chronic headaches. Despite long histories of chronic headaches, the majority of patients had significant reductions in pain scores and the number of headache days per month. The outcomes were not dependent on the number of years the patients had suffered from headaches before PNS treatment.