Early and Late Hearing Outcomes after CO2 Laser Stapedotomy
Ronayooth Boonchoo MD*, Pichai Puapermpoonsiri MD*
Affiliation : * Department of Otolaryngology, Bangkok Metropolitan Administration Medical College and Vajira Hospital
Background : Carbon dioxide (CO2) laser stapedotomy is now one of the standard surgical treatments for
otosclerosis. However, there are little normative data of the course of postoperative hearing acuity and the
course of postsurgical depression of cochlear function of this technique.
Objective : To compare the hearing outcomes between early(between 1 to 3 months) and late (more than 1
year) postoperative periods in otosclerotic patients who underwent CO2 laser stapedotomy.
Materials and Methods : The charts of 73 primary CO2 laser stapedotomy procedures performed at Bangkok
Metropolitan Administration Medical College and Vajira Hospital between 1997 and 2005 were reviewed.
Only patients with early postoperative audiometric data between 1 to 3 months and with long-term postopera-
tive audiometric data more than 1 year were selected for inclusion in the present study. Any patients who
underwent CO2 laser stapedotomy for diseases other than otosclerosis and those who had revision surgery
were excluded from the present study. The early and the late postoperative hearing outcomes were compared
using postoperative closure of air-bone gaps and postoperative sensorineural hearing loss at pure-tone
average and different frequencies.
Results : A group of 26 patients who underwent 30 CO2 laser stapedotomies met the criteria for analysis. The
hearing outcomes were followed at the early and the late postoperative periods for an average of 1.8 and 36.2
months, respectively. The present study indicated that closure of air-bone gaps at pure-tone average and
individual frequencies began in the early postoperative period and continued to improve through the late
postoperative period. Bone conduction hearing thresholds were stable even in the early postoperative follow-
up and the improvement in bone conduction hearing thresholds at 1 and 2 kHz and worsening at 4 kHz were
seen.
Conclusion : After CO2 laser stapedotomy, the stability of cochlear function begins in the early postoperative
period and remains stable through the late postoperative period. The conductive component of hearing
thresholds continues to improve through the late postoperative period. Thus, the early postoperative hearing
outcomes reflect a side effect of postsurgical sensorineural hearing loss and the long-term postoperative
hearing outcomes determine the efficacy of this procedure.
Keywords : Laser, Stapedotomy, Hearing, Otosclerosis
