Middle Ear Myoclonus Cured by Selective Tenotomy of the Tensor Tympani

Abstract

To describe a case of middle ear myoclonus that was successfully cured by selective transection of the tensor tympani (TT) without sectioning the stapedius tendon (ST) and to review previously reported cases, elucidating precipitating factors for interventions targeting middle ear muscles. One case we encountered and a recent systematic review published in 2012. In addition to our case, 23 cases identified by the previous systematic review regarding middle ear myoclonus in which surgical interventions were conducted. Outcomes for selective tenotomy of TT or ST were analyzed focusing on the following 6 preoperative factors: 1) history of facial palsy, 2) provoking factors for tinnitus, 3) auscultation of the ear, 4) movement of the ear drum, 5) complication with palatal myoclonus, and 6) confirmation of myoclonus during surgery. Among these, the first 2 factors represented significant factors for selective tenotomy of ST (p < 0.05 and p < 0.01, respectively). Furthermore, no auscultation of the ear was significant for selective tenotomy (p < 0.01), specifically for ST. Confirmation of muscle contraction during surgery contributed significantly (p < 0.01) to targeted intervention, but selective tenotomy of TT was successfully performed in 3 cases without such confirmation by confirming variations in compliance with tympanometry Assessment of the history of facial palsy, provoking factor of tinnitus, auscultation of the ear, and confirmation of myoclonus during surgery appear helpful in predicting which middle ear muscle is undergoing myoclonus. Furthermore, long-time-based tympanometry offers objective information for planning targeted intervention for middle ear muscles and clarifying clinical outcomes.