Sphenopalatine Ganglion Stimulation in Neurovascular Headaches.

The interest for the sphenopalatine ganglion (SPG) in neurovascular headaches dates back to 1908 when Sluder presented his work on the role of the SPG in 'nasal headaches', which are now part of the trigeminal autonomic cephalalgias and cluster headache (ICHD-III-beta). Since then various interventions with blocking or lesional properties have targeted the SPG (transnasal injection of lidocaine and other agents, alcohol or steroid injections, radiofrequency lesions, or even ganglionectomy); success rates vary, but benefit is usually transient. Here we briefly review some anatomophysiological characteristics of the SPG and hypotheses about its pathophysiological role in neurovascular headaches before describing recent therapeutic results obtained with electrical stimulation of the SPG. Based on results of a prospective randomized controlled study, SPG stimulation appears to be an effective treatment option for patients with chronic cluster headaches; efficacy data indicate that acute electrical stimulation of the SPG provides significant attack pain relief and in many cases pain freedom compared to sham stimulation. Moreover, in some patients SPG stimulation has been associated with a significant and clinically meaningful reduction in cluster headache attack frequency; this preventive effect of SPG stimulation warrants further investigation. For migraine attacks, the outcome of a proof-of-concept study using a temporary electrode implanted in the pterygopalatine fossa was less encouraging; however, an ongoing multicenter trial is evaluating the efficacy of long-term SPG stimulation against sham stimulation for acute and preventive treatment in patients with frequent migraine.

Stimulation of the sphenopalatine ganglion (SPG) for cluster headache treatment. Pathway CH-1: a randomized, sham-controlled study.

BACKGROUND: The pain and autonomic symptoms of cluster headache (CH) result from activation of the trigeminal parasympathetic reflex, mediated through the sphenopalatine ganglion (SPG). We investigated the safety and efficacy of on-demand SPG stimulation for chronic CH (CCH). METHODS: A multicenter, multiple CH attack study of an implantable on-demand SPG neurostimulator was conducted in patients suffering from refractory CCH. Each CH attack was randomly treated with full, sub-perception, or sham stimulation. Pain relief at 15 minutes following SPG stimulation and device- or procedure-related serious adverse events (SAEs) were evaluated. FINDINGS: Thirty-two patients were enrolled and 28 completed the randomized experimental period. Pain relief was achieved in 67.1% of full stimulation-treated attacks compared to 7.4% of sham-treated and 7.3% of sub-perception-treated attacks ( P < 0.0001). Nineteen of 28 (68%) patients experienced a clinically significant improvement: seven (25%) achieved pain relief in ≥50% of treated attacks, 10 (36%), a ≥50% reduction in attack frequency, and two (7%), both. Five SAEs occurred and most patients (81%) experienced transient, mild/moderate loss of sensation within distinct maxillary nerve regions; 65% of events resolved within three months. INTERPRETATION: On-demand SPG stimulation using the ATI Neurostimulation System is an effective novel therapy for CCH sufferers, with dual beneficial effects, acute pain relief and observed attack prevention, and has an acceptable safety profile compared to similar surgical procedures.

Sphenopalatine ganglion interventions: technical aspects and application.

Recent research has highlighted the important role of the sphenopalatine ganglion (SPG) in cerebrovascular autonomic physiology and in the pathophysiology of cluster and migraine headaches as well as conditions of stroke and cerebral vasospasm. The relatively accessible location of the SPG within the pterygopalatine fossa and the development of options for minimally invasive approaches to the SPG make it an attractive target for neuromodulation approaches. The obvious advantage of SPG stimulation compared to ablative procedures on the SPG such as radiofrequency destruction and stereotactic radiosurgery is its reversibility and adjustable features. The on-going design of strategies for transient and continuous SPG stimulation on as needed basis using implantable SPG stimulators is an exciting new development which is expected to expand the clinical versatility of this technique.