Hypoglossal nerve stimulation for moderate to severe obstructive sleep apnoea

5.1 Transient ipsilateral hemi-tongue paresis was reported in 15% (2/13) of patients in a prospective case series of 13 patients from a systematic review and meta-analysis of 200 patients.

5.2 Tongue abrasion was reported in 26% (33/126) of patients in a follow-up study of 95 patients from a prospective case series of 126 patients within 4 years of the procedure.

5.3 Bleeding was reported in 1 patient within 30 days of implantation in a prospective case series of 46 patients. This was caused by a hypertensive crisis and surgical intervention was needed; hypertension was treated with medication. In the same study, haematoma was reported in 7% (3/46) of patients. One of the 2 cases classified as non-serious occurred within 30 days of implantation and the other occurred more than 30 days after implantation. The third case was classified as a serious event and occurred within 30 days of implantation.

5.4 Rupture of a vein was reported in 6% (2/31) of patients during cervical tunnelling in a prospective case series of 31 patients; 1 of the patients needed 1 further cervical incision.

5.5 Seroma at an incision site was reported in 10% (2/20) of patients after the procedure in a retrospective case series of 20 patients. One seroma occurred at the sensing‑lead incision 1 week after surgery and the other occurred at the implantable pulse‑generator incision 4 weeks after surgery. Both resolved uneventfully with percutaneous needle drainage.

5.6 Headache was reported in 6% (8/126) of patients in the prospective case series of 126 patients within 1 year of the procedure.

5.7 Infection was reported in 1 patient in a prospective case series of 22 patients from the systematic review and meta-analysis of 200 patients; the device was removed.

5.8 Dry mouth was reported in 13% (16/126) of patients in the prospective case series of 126 patients within 3 years of the procedure.

5.9 Discomfort due to electrical stimulation was reported in 58% (73/126) of patients in the prospective case series of 126 patients within 4 years of the procedure. In the same study, discomfort related to incisions was reported in 29% (37/126) of patients and discomfort not related to incisions was reported in 27% (34/126) of patients within 4 years of the procedure.

5.10 Paraesthesia was reported in 13% (6/46) of patients (within 30 days of implantation in 5 patients, and more than 30 days after implantation in 1 patient) in the prospective case series of 46 patients.

5.11 Device migration more than 30 days after implantation was reported in 1 patient in the prospective case series of 46 patients. Cuff dislodgement was reported in 2 patients in a prospective case series of 31 patients, and in 1 patient in a prospective case series of 21 patients, from the systematic review and meta-analysis of 200 patients; all 3 patients needed a new procedure to replace it.

5.12 Device removal was reported in 4 patients in the prospective case series of 31 patients, and in 2 patients in the prospective case series of 21 patients, from the systematic review and meta-analysis of 200 patients. Device removal was also reported in 3 patients, 1 to 4 years after the procedure, in the prospective case series of 126 patients. The reasons for removal were insomnia, septic sternoclavicular joint adjacent to the device and non-response to therapy. Device removal for cosmetic reasons was reported in 1 patient in a case series of 60 patients.

5.13 Leads breaking was reported in 15% (2/13) of patients in the prospective case series of 13 patients from the systematic review and meta-analysis of 200 patients.

5.14 Defective implanted pulse‑generator connector was reported in 1 patient in the prospective case series of 13 patients from the systematic review and meta-analysis of 200 patients.

5.15 Other complications reported in the systematic review and meta-analysis of 200 patients included postoperative pain and stiffness, sore throat, stitch abscess, local swelling, fever and lack of tongue response to stimulation.

5.16 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, the specialist advisers did not list any anecdotal adverse events. They considered that the following were theoretical adverse events: fatigue of the upper airway dilator muscles leading to worsening sleep apnoea, and hypoglossal nerve damage.