Sphenopalatine Ganglion Stimulation
The sphenopalatine ganglion (Meckel's ganglion) is an extracranial autonomic ganglion present in the pterygopalatine fossa close to the sphenopalatine foramen. It has connections with the trigeminovascular system, superior salivary nucleus and hypothalamus, and has been targeted by techniques such as anesthetic block, radiosurgery and γ-knife, mainly to treat cluster headache.
An open study on 120 cluster headache cases reported that alcohol injection was effective in 85% with follow-up from 6 months to 4 years. Two more recent studies on patients with chronic cluster headache and intractable migraine used a percutaneous infrazygomatic approach to place a needle at the sphenopalatine ganglion under fluoroscopic guidance during ongoing headache.[79,80] Electrical stimulation at various settings was performed at maximum headache intensity with a temporary stimulating electrode. Complete pain resolution was obtained in 11 of 18 cluster headache patients almost immediately, and 50% relief was obtained in four other patients. Stimulation suppressed or relieved migraine headache in five of ten patients.
In a multicenter study on patients with refractory chronic cluster headache, the efficacy of an implantable on-demand sphenopalatine ganglion neurostimulator was tested as a treatment for acute cluster headache attacks. The experimental period was 30 attacks or a maximum of 8 weeks. Each cluster headache attack was randomly treated with either full, subperception or sham-stimulation. Pain relief at 15 min following stimulation and device- or procedure-related serious adverse events were evaluated. A total of 28 of 32 enrolled patients completed the experimental period. Pain relief was achieved in 67.1% of full stimulation-treated attacks compared with 7.4% of sham-treated and 7.3% of subperception-treated attacks. A pain-free condition was achieved in 34.1% of attacks with full stimulation compared with 1.5% with sham stimulation. At baseline, mean cluster headache attack frequency was 17.4 per week (range: 4–70) which reduced to 12.5 (range: 0–96) over the experimental period. A total of 12 of 28 patients (43%) had a greater than 50% frequency reduction during the experimental period. Altogether, 81% experienced transient, mild/moderate loss of sensation within distinct maxillary nerve regions; 65% of events resolved within 3 months.
Future Neurology. 2013;8(4):457-467. © 2013 Future Medicine Ltd.