Burns B et al. (2008) Treatment of hemicrania continua by occipital nerve stimulation with a bion device: long-term follow-up of a crossover study. Lancet. Neurol 7: 1001–1012

Occipital nerve stimulation (ONS) is an effective treatment for primary headache. However, current methods of ONS involve electrodes placed across the occipital nerve that are connected to a battery pack situated in the chest wall or abdomen; migration of the connecting leads is, therefore, a common complication that can require repeat surgery. Burns et al. used a self-contained miniature implantable neurostimulator, called a bion, to deliver ONS to six patients with hemicrania continua, a rare unilateral form of primary headache.

The bion, a 27 × 3.3 mm telemetrically programmable neurostimulator with an integrated electrode and battery rechargeable with an external device, was implanted close to the occipital nerve ipsilateral to the headache site. The six patients were aged 37–64 years with a median 14-year history of hemicrania continua. The implant was activated for 3 months from the day of activation, switched off for the fourth month, and then reactivated for long-term follow-up (range 6–21 months).

Four of the six patients reported substantial improvement (80–95%) in their headache symptoms, and one patient reported a 30% improvement. The sixth patient reported a 20% worsening in his headache at 6 months' follow-up. Although the authors recognize the possibility of a placebo effect in the successful outcomes, the delays (of days to weeks) experienced by some patients between activation or deactivation of the implant and subsequent changes in headache symptoms make a placebo effect less probable.