Operational measures

Three invasive treatment strategies for cluster headaches have been proposed:

  • destructive processes,
  • local blockages and
  • neuromodulatory procedures.

Given the numerous and highly effective treatment alternatives available today, surgical interventions should be a last resort. They should only be considered after patients have been thoroughly treated with all relevant pharmacological options in specialized centers.

Less than 1% of cluster headache patients experience treatment-resistant cases. Surgical procedures are generally only an option for patients with chronic cluster headaches, representing approximately 27% of those affected. With roughly 240,000 cluster headache patients in Germany, this equates to about 64,800 individuals. One percent of these patients with treatment-resistant cases comprises approximately 648 patients. If, for example, 50% of these were considered candidates for invasive procedures, such interventions would likely be relevant for approximately 300 people in Germany.

Destructive methods

Transection or decompression of the intermediate nerve or the greater superficial petrosal nerve, as well as direct interventions in the region of the trigeminal nerve, are now only of historical significance due to unsatisfactory long-term results and have been abandoned. Neuromodulatory procedures have moved to the forefront due to improved electronic stimulation options.

Occipital nerve block

The injection of local anesthetics and corticosteroids in the region of the ipsilateral occipital nerve can be therapeutically effective. This procedure was first described by Anthony (1985). More recent open-label studies confirm its efficacy. Effectiveness has also been demonstrated with suboccipital injection of a mixture of short- and long-acting betamethasone: 85% of patients were pain-free within one week. Efficacy can be expected with the use of corticosteroids due to their systemic effects. Whether local application is crucial remains an open question.

Deep brain stimulation

In recent years, it has been suggested that affected individuals should also undergo invasive surgical procedures. Based on structural and functional imaging studies, deep brain stimulation of the posterior hypothalamus has been performed in open-label case series. No convincing effects could be demonstrated. Open-label studies report improvement rates between 50 and 70%. In the only placebo-controlled, double-blind study to date, no significant difference between actual and sham stimulation could be described. Fatal consequences, including fatal intracranial hemorrhages, have occurred. Catastrophic outcomes for individual patients are documented in publicly maintained online diaries. In addition, the procedure is very expensive, costing over €30,000, and requires extensive postoperative care. Based on the current data, neither a theoretical rationale nor a practical justification for the use of deep brain stimulation in cluster headaches can be established. The data available so far do not justify its use in the treatment of cluster headaches.

Occipital nerve stimulation [media id=46] Occipital nerve stimulation is a peripheral invasive nerve stimulation procedure for the treatment of cluster headaches. An electrical stimulation electrode is usually placed horizontally and fixed in the region of the first cervical vertebra after a local incision. A trial stimulation with an external pulse generator can then be performed for several weeks before a pulse generator is permanently implanted. Only small open case series exist for the treatment of chronic cluster headaches using occipital nerve stimulation. Its efficacy appears to be about the same as, or better than, that of deep brain stimulation, with the advantage of fewer serious side effects. Occipital nerve stimulation is less invasive and has fewer complications than deep brain stimulation. In cases of treatment-resistant cluster headaches despite specialized treatment, this experimental procedure may be considered on a case-by-case basis within the framework of a scientific study. Due to its mechanism of action, an indirect pain-modulating effect can be assumed, but no influence on the actual course of the disease is expected. The large spontaneous fluctuation of cluster headaches must also always be taken into account.

When bilateral occipital nerve stimulation is used to treat therapy-resistant chronic cluster headache, an average reduction in attack intensity of 50% can be expected. The required additional acute medication is reduced by an average of 77%. The results show that, unlike other preventive therapies for cluster headaches, this does not result in a complete cessation of the active period, but only a partial reduction in attack intensity and frequency.

Occipital nerve stimulation is not currently a treatment option in the open care setting for patients with cluster headaches. However, it is the preferred option in therapy-resistant cases when invasive treatment is being considered.

Neurostimulation of the sphenopalatine ganglion (GSP)

In 2011, Schoenen introduced neurostimulation of the sphenopalatine ganglion (SGC) for the treatment of cluster headaches. The study (Pathway CH-1), which investigates the safety and efficacy of the ATI neurostimulator, has so far involved 22 participants; a total of approximately 40 patients are planned for the study. Stimulation data from the titration phase are available for 7 of these 22 patients. Pain relief within 15 minutes (the primary endpoint of the study) was achieved in 67% of the treated headache attacks (n=48). Simultaneously, the frequency of headaches decreased in the majority of patients with stimulation; compared to the 4-week period before the start of the study, headache frequency decreased by at least 50% in 70% of patients during the study. The procedure is also to be investigated in the treatment of chronic migraine.

The neurostimulation system, currently in the trial phase, consists of a novel implantable mini-stimulator. About the size of an almond, it was developed for the treatment of severe headaches, including cluster headaches and migraines. This neurostimulator is implanted into the gums without leaving visible scars or cosmetic impairment. The electrode tip of the implant is placed at the sphenopalatine ganglion (SGC) behind the cheekbone. After implantation of the mini-stimulator, the patient can trigger stimulation as needed via an external remote control, similar to a large mobile phone, which then relieves the headache. Once the pain has subsided, the remote control is removed from the cheek, thus deactivating the stimulation therapy.

In the multicenter Pathway CH-1 study, the stimulation parameters are set and adjusted as needed during a titration phase. Subsequently, in an experimental phase, the patients' headaches are treated in a randomized manner with one of three different stimulation doses, including a placebo.