Change of VOR gain and pure-tone threshold after single low-dose intratympanic gentamicin injection in Meniere’s disease

Abstract

Background: Intratympanic gentamicin injection (ITG) is a well-accepted means to treat intractable Meniere’s disease (MD).

Aims/Objectives: To investigate change of vestibule-ocular reflex (VOR) gain and pure-tone threshold after low-dose ITG for MD.

Methods: Sixteen patients with definite MD who were treated by low-dose ITG were retrospectively reviewed. We defined VOR gain difference as an amount of decreased gain in video head impulse test one month after ITG. Patients were classified into two groups: single injection vs. multiple injections. Multiple injections group was composed of patients with poor vertigo control after initial ITG who required second or third ITG later in follow up period.

Results: VOR gain differences of both horizontal and posterior canal plane were higher than those of anterior canal plane. Between two groups, mean VOR gain difference of horizontal canal plane in multiple injections group was lower than that in single injection group. Only two patients showed increased pure-tone threshold more than 10 dB.

Conclusion and significance: Our results suggest that ITG appears to cause a differential loss of function across three semicircular canals. Furthermore, if VOR gain difference of horizontal canal is relatively low after initial ITG, patient might have poor vertigo control and be required another ITG.

Chinese abstract

背景：鼓室内注射庆大霉素（ITG）是治疗难治性梅尼埃病（MD）的普遍接受的方法。

目的：探讨低剂量ITG治疗MD后前庭-眼反射（VOR）增益和纯音阈值的变化。

方法：回顾性分析16例经小剂量ITG治疗的经确诊患有MD的患者的临床资料。我们将VOR增益差定义为ITG后一个月视频头部脉冲试验中增益降低的量。将患者分为两组：单次注射组和多次注射组。多次注射组由初次ITG治疗后眩晕控制差的患者组成, 他们在随访期后期需要第二次或第三次ITG。

结果：水平管平面和后管平面的VOR增益差异均高于前管平面。在这两组间, 多次注射组水平管平面的平均VOR增益差均低于单次注射组。只有两名患者的纯音阈值的增加大于10 dB。

结论与意义：我们的研究结果表明, ITG似乎会引起三个半规管功能的不同丧失。此外, 如果在初次ITG治疗后水平管VOR增益差相对较低, 患者的眩晕控制则可能会差, 需要再次接受ITG。

Keywords:

• Meniere’s disease
• gentamicin
• video head impulse test

Disclosure statement

No potential conflict of interest was reported by the authors.