In this retrospective study, peripheral nerve stimulation reduced mean headache severity on the 11-point Numeric Rating Schedule (NRS) by nearly 50% within one-month post implantation. After 12 months, headache severity scores decreased by at least 50% in 87% (40 of 46) of the patients, with pain decreasing even more substantially the longer the device was in place. Pain intensity scores on the NRS had decreased by 68% as many as 98 months post-implantation.
These findings were consistent with previous studies; however, this study looked for a response rate of ≥ 50% rather than any improvement. This difference in study design may account for higher responses in previous studies.
“Despite long histories of chronic headaches, the majority of patients had significant reductions in pain scores and the number of headache days per month,” wrote study researcher Billy K. Huh, MD, PhD, of the MD Anderson Cancer Center Department of Pain Medicine in Houston, Texas, and colleagues.
There was no correlation between the effectiveness of the peripheral nerve stimulation treatment and the number of years the patients had suffered from headaches, they found.
Huh and colleagues reviewed medical records from 46 patients who had been permanently implanted with Peripheral Nerve Stimulation from January 2005 to January 2012. Patient records and phone interviews were used to measure pain intensity levels, the number of days per month that patients had headaches, and overall patient satisfaction.