Implantation of a sphenopalatine ganglion stimulation device for chronic cluster headache

5.1 Lead revision or explantation of the device was needed for 16% (5/32) of patients, between 30 days and 1 year after the procedure, in a randomised sham‑controlled crossover trial of 32 patients who randomly had full stimulation, sub‑perception stimulation or sham stimulation during each cluster headache attack.

5.2 Lead revision, due to improper or suboptimal lead positioning, was needed in 13% (13/98) of patients in a case series of 98 patients. No further details were provided. In the same study, device explantation was needed in 6% (6/98) of patients due to dislodgement of an incorrectly sized neurostimulator (n=1), dysaesthesia/neurotic pain in the maxillary nerve (n=3), improper placement of the lead in the maxillary sinus (n=1), and infection within the surgical incision site (n=1).

5.3 Sensory disturbances (including localised loss of sensation, hypoaesthesia, paraesthesia, dysaesthesia and allodynia) were reported in 81% (26/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in 58% (15/26) of these patients. Sensory disturbances were reported in 16% (5/32) of patients between 30 days and 1 year after the procedure; symptoms resolved in 60% (3/5) of these patients.

5.4 Pain (facial, cheek, gum, temporomandibular joint, nose, incision site or periorbital) was reported in 38% (12/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients. Severity of pain was not described and symptoms resolved in all of these patients. Pain was reported in 19% (6/32) of patients between 30 days and 1 year after the procedure: symptoms resolved in 50% (3/6) of these patients.

5.5 Headaches, that were not cluster headaches, were reported in 9% (3/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in all of these patients. Headaches, that were not cluster headaches, were reported in 9% (3/32) of patients between 30 days and 1 year after the procedure; symptoms resolved in 1 of these patients.

5.6 Unspecified swelling was reported in 22% (7/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in 86% (6/7) of these patients.

5.7 Trismus was reported in 16% (5/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in 80% (4/5) of these patients.

5.8 Dry eye was reported in 9% (3/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in 1 of these patients. Dry eye was reported in 1 patient between 30 days and 1 year after the procedure; no further details were provided.

5.9 Mild paresis of the muscles around the nasolabial fold was reported in 6% (2/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in 1 of these patients.

5.10 Infection was reported in 6% (2/32) of patients within 30 days of device implantation in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in all patients following treatment with antibiotics. Infection was reported in 1 patient between 30 days and 1 year after the procedure; symptoms resolved following treatment with antibiotics.

5.11 Epistaxis, facial asymmetry, lacrimation, vomiting, lead migration and a maxillary sinus puncture (no details were provided) were each reported as occurring on single occasions in different patients within 30 days of device implantation, in the randomised sham‑controlled crossover trial of 32 patients; symptoms resolved in all patients.

5.12 Itching, dry nose, dry skin, taste alterations, a depressed gag reflex and sensation in the infratemporal fossa (no details were provided) were each reported as occurring on single occasions in different patients, between 30 days and 1 year after the procedure in the randomised sham‑controlled crossover trial of 32 patients.

5.13 In addition to safety outcomes reported in the literature, specialist advisers are asked about anecdotal adverse events (events which they have heard about) and about theoretical adverse events (events which they think might possibly occur, even if they have never done so). For this procedure, specialist advisers did not highlight any anecdotal adverse events. They considered that damage to adjacent structures (such as the sinuses) was a theoretical adverse event.