Sixteen studies were included in the review (n=346 patients, range 9 to 56). Three studies were randomised and 13 were non-randomised; no further details of study design were reported. The mean follow-up ranged from six weeks to 28 months.
Short-term follow-up (less than 12 months): There was an overall reduction in Epworth Sleepiness Scale of 31% (OR 0.69, 95% CI 0.63 to 0.75; 14 studies) associated with radio frequency ablation, with no evidence of statistical heterogeneity. Similarly, there was an overall reduction in Respiratory Disturbance Index of 31% (OR 0.69, 95% CI 0.61 to 0.77; 12 studies), with no evidence of statistical heterogeneity. Nine studies, reporting the lowest oxygen saturation, showed no improvement after radio frequency ablation.
Long-term follow-up (over 24 months): Two studies reported data for two year follow-up. The Epworth Sleepiness Scale showed a 32% overall reduction (OR 0.68, 95% CI 0.43 to 0.73). The Respiratory Disturbance Index showed a 45% overall reduction (OR 0.55, 95% CI 0.45 to 0.72).
Complications of radio frequency ablation: Thirteen studies reported complications rates. Two tongue abcesses progressed to airway obstruction requiring tracheotomy. All soft palate ulcers and fistula healed without incident. Tongue base radio frequency ablation may carry a higher risk of serious complications.