Somnus Medical Technologies

W. Hohenhorst, P. Van De Heyning, and European Somnoplasty Study Group

Introduction: RF therapy was introduced as minimally invasive procedure for the treatment of sleep related breathing disorders by Powell, Riley, and Guilleminault in 1996. Tissue is heated in a controlled fashion using low levels of radiofrequency energy applied through a needle electrode. Tissue temperature can be adjusted between 60 and 90o C. The controlled hyperthermia at the needle tip coagulates surrounding tissue while the proximal needle is insulated to prevent mucosal damage. In that way the applied energy, in contrast to laser and electrocautery, can be used for creating precisely defined tissue lesions. We are presenting the results of a multi-center European clinical study which was carried out to determine the efficacy of RF.

Methods: A prospective, non-randomized, multi-clear European clinical study was carried out to determine the efficacy of RF. In the study protocol, the number of RF procedures per patient was limited to 3 and a maximum energy of 700 Joules was applied to create one midline lesion in the soft palate. Outpatient RF-treatment under local anesthesia was carried out midline, approximately 1 cm below the hard palate in the soft palate. Polysomnography (PSG) was performed at baseline and 8 weeks after the last RF-treatment. Snoring data from PSG and subjective, semiquantitative scales were used to assess the change in snoring frequency and loudness after RF. 52 patients completed treatment according to the study protocol. The mean number of treatments per patient was 2.7 ± 0.5, the mean energy applied per treatment was 598 ± 89 Joules, and the mean total energy per patient was 1703 ± 608 Joules.

Results: A significant reduction in snoring symptoms was obtained using RF. The snoring index (visual analog snoring scale 0-10) was improved in 86.7% of the patients after RF treatment and the mean snoring index was reduced from 7.8 ± 2.0 to 4.1 ± 2.9 (p=?). The mean Epworth Sleepiness Score was reduced from 8.1 ± 4.5 to 6.2 ± 4.1 (p=?). Since all patients were non-apneic snorers with a mean Respiratory Disturbance Index (RDI) of 4.9, no significant changes (abnormal respiratory events or measures of oxygenation) were observed during PSG at follow-up. No severe adverse events like bleeding or infections were observed.

Perspective: RF is a safe and almost painless procedure to treat snoring in an outpatient. The efficacy of the method could be increased using patient-anatomy-specific sites of application and by increasing the number of lesions and total applied energy per treatment.