Efficacy and Safety of Intratympanic Botulinum Toxin Injection on Middle Ear Myoclonic Tinnitus.

[OBJECTIVES] Investigating the efficacy and safety of intratympanic Botulinum toxin (IT-BTX) injection as a novel treatment for middle ear myoclonic tinnitus (MEMT).

[METHODS] Medical records and tinnitus questionnaires of the patients with MEMT who underwent IT-BTX were retrospectively reviewed. The efficacy of IT-BTX on MEMT as well as its safety were evaluated by audiology tests and tinnitus questionnaires.

[RESULTS] A total of 57 patients who completed the questionnaires at pre- and post-IT-BTX were enrolled. Tinnitus handicap inventory (THI) scores decreased significantly from pre-IT-BTX (44.31 ± 26.8) to 31.42 ± 23.6 (p < 0.001), 32.92 ± 24.9 (p = 0.004), and 25.71 ± 22.9 (p < 0.001) at 1-, 3-, and 6-months post-IT-BTX, respectively. Additionally, visual analog scales (VAS) of loudness (LD), awareness (AW), annoyance (AN), and effect on life (EF) significantly decreased post-IT-BTX (p < 0.05): LD from 4.19 ± 2.4 to 2.47 ± 2.0, 2.89 ± 2.2, and 2.38 ± 1.9 at 1-, 3-, and 6-months; AW from 41.75 ± 29.5 to 24.38 ± 23.3, 26.94 ± 23.3, and 22.10 ± 21.7; AN from 5.00 ± 2.8 to 2.82 ± 2.1, 3.47 ± 2.4, and 2.78 ± 2.2; EF from 4.82 ± 2.8 to 2.89 ± 2.2, 3.28 ± 2.4, and 2.73 ± 2.2 at 1-, 3-, and 6-months post-IT-BTX. Notably, 40.3% of the IT-BTX patients experienced a complete cure of their MEMT symptoms, while 50.8% demonstrated partial resolution after IT-BTX. There were no side effects or complications after IT-BTX during their follow-up period. Comparing delta values between the single injection group and multiple injection group revealed significant differences in VAS LD at the post-1-month time point and between the 1-month and 6-month intervals.

[CONCLUSION] IT-BTX is an effective, safe treatment for MEMT, significantly improving symptoms without complications, and offers a promising alternative before middle ear tendon resection.