Evaluation of coblator assisted tongue base resection surgery results with polysomnography and magnetic resonance imaging in patients with obstructive sleep apnea

Due to the low cost, low complication and morbidity, tongue base resection with coblator has been used frequently in the treatment of OSA in recent years. The aim of our study is investigate the relation of polysomnography (PSG) parameters with volumetric changes which is obtained by surgery. In our study, 24 patients in 18-65 age range are included. Patients which are diagnosed as moderate or severe OSA and tongue base grade 2-3-4 according to Cormack-Lehane classification and more than %50 obstruction in the tongue base with Müller maneuver are included. Magnetic resonance imaging (MRI) has done in all patients, in preoperative and postoperative 3-6.month period. Preoperative and postoperative tongue base and retroglossal airway volumes were measured using three-dimensional applications program on GE PACS study station. Preoperative mean apnea-hypopnea index (AHI) is 42.2±22.5, postoperative mean AHI is 29.9±17.7 and statistical significance is found between this values (p<0.001). We measured the preoperative mean tongue base volume 49.2±7.4 cm3, postoperative 37.5±8.3 cm3 (p<0.001); also we found mean retroglossal airway volume preoperative 11±3.3 cm3, postoperative 16.7±4.8 cm3 (p<0.001). No statistically significant correlation is detected between tongue base and retroglossal airway volumetric changes and evaluated PSG parameters as AHI, supine AHI, nonsupine AHI and oxygen desaturation index (ODI). Retroglossal airway volume has increased %96.5±97.9 in surgically successful group and %46.9±30.8 in unsuccessful group. Tongue base volume has decreased %33±11.2 in surgically successful group and %20.2±13.9 in unsuccessful group. Nevertheless statistically significant difference couldn't found between successful and unsuccessful patient groups. As a result coblator asisted tongue base surgery achieve an objective decrease in tongue base and also objective increase in retroglossal airway volume. However the findings show that, there is no statistically significant relationship between alterations in AHI and tongue base and retroglossal airway volume changes. This result is attributed to multifactorial pathophysiology of OSA. Key words: Obstructive sleep apnea, polysomnography, magnetic resonance imaging