돌발성난청에서 성상신경절 차단 직후 순음청력치는 즉각적으로 변화되는가?

Immediate Changes of Pure Tone Audiogram Results Following Stellate Ganglion Block in Sensory Neural Hearing Loss

Background: Vascular occlusive event is one of the etiologies of sudden sensorineural hearing loss (SNHL). Stellate ganglion block (SGB) induces dramatic and intense vasodilatation in head and neck. Based on this principle, SGB has used as one of the treatment modalities in SNHL. This study was performed to evaluate immediate response of SGB on pure tone audiogram (PTA) in SNHL. Methods: Forty patients were studied. Each patient received daily ipsilateral SGB in paratracheal approach using 0.2% bupivacaine for 2 weeks. On first, third, and fifth day of treatment, we checked their PTA twice 1 hour before (Pre-PTA) and after (Post-PTA) SGB. Pre- and Post-PTA were compared. Several factors were analyzed as a prognostic factor of therapeutic results. Results: Eleven of 40 patients revealed decreased PTA after SGB. Degree of decreased PTA were insignificant ($2.5{\pm}1.6$ dB). Initial and final PTA results was $76.2{\pm}22.5$ and $49.8{\pm}28.3$ dB, respectively. Thirty-one of 40 patients were improved their PTA over 10 dB. The recovery was mainly influenced by the severity of initial hearing loss (P<0.001) and slightly by age (P<0.05). However, the change of PTA after SGB, time interval to receive SGB, sex, site, and number of SGB were not correlated to therapeutic outcome. Conclusions: These results suggest that vasodilatation by SGB has no immediate improvement in SNHL. Therefore, we question whether SGB is beneficial to all patients with SNHL as a therapeutic modality.