14th International Headache Congress: clinical highlights

Occipital Nerve Stimulation in Chronic Migraine: The Relationship Between Perceived Sensory Quality, Perceived Sensory Location, and Clinical Efficacy-A Prospective, Observational, Non-Interventional Study

Introduction

Occipital nerve stimulation (ONS) is used to treat therapy-resistant chronic migraine. Clinical use has resulted in a wide intraindividual and interindividual variation of clinical efficacy. The aim of this study was to analyze a potential relationship between sociodemographic variables, headache parameters, perceived sensory quality, perceived sensory location, as well as clinical efficacy.

Methods

Thirty-two subjects (21.9% male, mean age 45.77 years) suffering from chronic migraine refractory to other treatment and therefore treated with ONS were included in this study. We used a computer-based imaging method for mapping the ONS-induced perceived sensory location, the perceived spatial sensory field size, as well as the perceived sensory quality in a long-term course over 21 months in weekly time intervals. Additionally, the effect of ONS on the migraine headache was documented weekly by the participants using a verbal rating scale. Over the observation period, a total of 808 individual weekly data sets were recorded and a potential relationship between ONS-induced perceptions and headache parameters could be analyzed.

Results

We found that 48.9% of stimulation intervals were reported as effective by patients. Women displayed a significantly higher responder rate than men. The reported effectiveness did not differ depending on age, the average number of migraine days per month, the MIDAS score, or the duration of the migraine disorder prior to ONS treatment. Implantation with trial period led to significantly lower responder rates than without the trial period. The most frequently perceived sensory quality of “tingling” was found significantly more frequently in non-responders than in responders. Responders displayed significantly lower pleasantness scores for their reported perceptions than non-responders. Sensations that were spatially perceived above the line connecting the external acoustic meati with the external occipital protuberance (MOP line) led to patients reporting a positive clinical effect significantly more frequently than sensations spatially perceived below the MOP line. Spatially small fields of sensory perception were correlated with a higher responder rate than those covering broader areas.

Conclusions

The ONS-induced sensory location, the size of the spatial sensory field, as well as the sensory quality are significantly correlated with the reported clinical effectiveness. The results suggest that besides surgical technique, the individual and continuous programming of the stimulation parameters is clinically relevant in increasing the therapeutic effectiveness.

Clinical utility of implantable neurostimulation devices in the treatment of chronic migraine

Chronic migraine is a disabling disorder that is costly to individuals and society. Occipital nerve stimulation has been used to treat refractory cases of primary headache disorders including drug-resistant chronic cluster headaches and chronic migraine. The Food and Drug Administration (FDA) off-labeled application of equipment used for peripheral nerve (occipital) stimulation is borrowed from FDA-labeled spinal cord stimulation. Manufacturer-sponsored randomized trials include a feasibility study (ONSTIM-Medtronic) and a safety and efficacy study (St Jude). A non-industry sponsored prospective, randomized crossover study by Serra and Marchiotretto suggests improved quality of life and a significant reduction in medication use. Though preliminary studies suggest occipital nerve stimulation is safe and efficacious in treating chronic migraine headache, complication rates, including lead migration, lead fracture, and surgical site infections remain high. Further studies are needed to demonstrate long-term outcomes, while improved surgical techniques and site-specific equipment are needed to minimize complications.

Innovative delivery systems for migraine: the clinical utility of a transdermal patch for the acute treatment of migraine

Migraine is a disabling, painful primary headache disorder that is associated with various combinations of neurological, gastrointestinal, autonomic and pain symptoms. Gastrointestinal disturbances associated with migraine, including nausea and vomiting, affect a majority of migraineurs and often result in a delay in taking or avoidance of pharmacological intervention. Gastric stasis and vomiting may lead to delayed or inconsistent absorption of orally administered medications. Many migraineurs awake early in the morning with their attack progressing and already associated with nausea and vomiting. As a result, there is a need for a novel, non-invasive, non-oral delivery system for fast and effective acute treatment of migraine. There are two non-oral delivery systems currently available in the US for the acute treatment of migraine: three nasal sprays and two injectable formulations. Although nasal sprays depend partially on nasal mucosal absorption, a significant amount of drug is swallowed, transits the stomach and is absorbed in the small intestine, which is not as rapid or effective a route of delivery for those migraineurs with gastric stasis. Sumatriptan is rapidly absorbed by subcutaneous injection with or without a needle, but the invasiveness and discomfort of the delivery, the high incidence of adverse events and the high recurrence rate all limit its use for many patients. Iontophoretic delivery of medication is a non-invasive transdermal approach that uses small amounts of electrical current to promote rapid movement of the ionized drug through the skin and into the systemic circulation. This delivery bypasses hepatic first-pass metabolism and also avoids gastric transit delay and slowing of small intestinal absorption associated with gastrointestinal stasis in migraineurs. Two pharmacokinetic studies have demonstrated that iontophoretic transdermal delivery of sumatriptan results in rapid and consistent achievement of therapeutic plasma concentrations. These studies also suggest that, by avoiding patient exposure to a rapid rise in and high plasma concentrations of sumatriptan as seen with injectable sumatriptan, transdermal delivery using iontophoresis may significantly reduce typical triptan-related adverse events. A large, randomized, double-blind, placebo-controlled, multicentre clinical trial showed statistically significant efficacy, good tolerability and virtually no triptan-related adverse events. Iontophoretic delivery of sumatriptan, with a novel transdermal patch device, offers patients a migraine-specific medication that is non-invasive and non-oral. Clinically, transdermal delivery provides rapid and effective relief of migraine while bypassing the gastrointestinal tract, with minimal classic triptan-related adverse effects. This unique approach facilitates the rapid absorption of this migraine-specific triptan, which should improve the chances of consistently achieving a therapeutic plasma concentration of sumatriptan, resulting in effective migraine relief.