KTP Versus CO2 Laser Fiber Stapedotomy for Primary Otosclerosis

Abstract

To compare the 3-month postoperative hearing results after laser stapedotomy using a flexible potassium titanyl phosphate (KTP) or CO2 laser fiber in patients with primary otosclerosis. Prospective nonrandomized clinical study. Tertiary referral center, 862 stapedotomies were performed in 818 study patients between November 2006 and July 2011. Otosclerotic stapes fixation was treated with flexible KTP laser fiber in 410 patients (431 stapedotomies) and with flexible CO2 laser fiber in 408 patients (431 stapedotomies). Their preoperative and postoperative audiometric results were compared.Logistic regression analyses were performed to evaluate the main effect of laser fiber type and the effect after adjustment for independent predictors of a postoperative air-bone gap (ABG) 10 dB or lower. In the KTP laser group, the mean postoperative ABG was 4.3 dB compared with 3.1 dB in the CO2 group (difference, 1.1; 95% confidence interval, 0.4-1.9). In 90.4% of the patients in the KTP group, the postoperative ABG was 10 dB or lower, as compared with 96.5% in the CO2 group. The mean postoperative ABG at 4 KHz was 5.4 dB with KTP and 2.2 dB with CO2 (difference, 3.2; 95% confidence interval, 2.2-4.2). Sensorineural hearing loss was reported by 1 patient with KTP laser (0.3%) and by none with CO2 laser. "Type of laser" and "sex" were independent predictors of ABG 10 dB or lower. The chance to achieve a postoperative ABG 10 dB or lower for male subjects is 95%, when treated with CO2 laser and 85% when treated with KTP laser. For female subjects, these chances are 97% and 94%, respectively. The use of the CO2 laser fiber may be associated with better hearing results than the KTP laser fiber, regarding the ABG closure within 10 dB.