Hearing outcomes in subtotal facial nerve decompression with preserving ossicular chain intact.

Background: Facial paralysis patients with normal hearing often require ossicular chain dislocation throughout the entire process of facial nerve decompression surgery, and their hearing tends to be slightly impaired after surgery. There is not detailed explanation of hearing changes after facial nerve decompression with preserving intact ossicular chain.

Purpose: This study aimed to determine the efficacy and hearing outcomes of facial nerve decompression with preserving ossicular chain intact transmastoid supralabyrinthine recess pathway in Bell's palsy.

Methods: A retrospective study comparing the pre- and post-operative facial nerve HB functional grades and hearing results of 12 patients with Bell's palsy who underwent facial nerve decompression.

Results: Preoperative and postoperative mean House-Brackmann (HB) scores respectively were 4.41 ± 0.67 and 1.58 ± 0.79 grades; The recovery rate to HB grade I, II was 100% or to grade III or lower was 83.3% (10/12). The pre- and post-operative mean PTAs (0.125, 0.25, 0.5, 1, 2, 4, 8KHz) were 19.1 ± 1.9 dB and 36.8 ± 4.1 dB; The pre- and postoperative low frequencies (0.125, 0.25KHz) were 18.5 ± 2.3 dB and 26 ± 3.8 dB; The pre- and postoperative speech frequencies (0.5, 1, 2KHz) mean PTAs were 18.5 ± 1.9 dB and 21.5 ± 2.9 dB; Comparison of pre- and post-operative hearing outcomes at all frequencies, low frequencies, and speech frequencies showed no statistically significant differences (p < 0.05); The pre- and postoperative high frequencies (4, 8KHz) were 20.6 ± 4.7 dB and 70.4 ± 11.6 dB and the hearing outcomes were statistically significant (p >0.05).

Conclusion: Subtotal facial nerve decompression with preserving ossicular chain intact transmastoid supralabyrinthine recess pathway does not cause the verbal frequency hearing loss of Bell's palsy, but it has high frequency sensorineural hearing loss, which tend to be unavoidable and independent of the skill of the surgical operator.