RESPONSE TO LETTER TO THE EDITOR: “OUTCOMES OF STAPEDOTOMY IN PATIENTS WITH CONCOMITANT OTOSCLEROSIS AND SUPERIOR SEMICIRCULAR CANAL DEHISCENCE: SHOULD A RADIOGRAPHIC THIRD-WINDOW BE A CONTRAINDICATION TO STAPES SURGERY?” (2022)

In Reply: We thank the authors for reading our article with interest and for their valuable comments (1). These important points are worth considering when interpreting the results of our study, and we would like to further highlight these critical factors. It is certainly worth restating again that superior semicircular canal dehiscence (SCD), as principally addressed in our study, and superior semicircular dehiscence syndrome (SCDS) are separate entities each comprising a wide array of patient presentations. Although SCDS cannot exist without SCD, the presence of a radiographic dehiscence may simply be apparent because of inadequate slice thickness or visualization in the proper planes to give a false impression of a dehiscence when in fact a thin plate of bone remains intact. Even some patients with a true bony dehiscence may remain asymptomatic (2). Furthermore, SCDS, the physiologically active clinical syndrome caused by the bony dehiscence, can present anywhere from a mild nuisance to debilitating symptoms. Patients included in our study were found to have a SCD based on thin-slice computed tomography viewed in the plane of, and orthogonal to, the superior canal without clinical symptoms of a third window; that is to say, there were no preoperative vestibular symptoms. As such, the results of this study may not be applicable to patients with active SCDS. In such patients—those with active SCDS and otosclerosis—our clinical practice would typically not involve stapes surgery. When the question of an active dehiscence arises, we agree that vestibular-evoked myogenic potential (VEMP) testing may be useful; however, results can be difficult to interpret because of unpredictable stimulation of the third window due to the effect of otosclerosis (2). As expected, air conduction VEMPs may be absent in more than 75% of cases because of inefficient transmission of acoustic energy to the inner ear, whereas even bone conduction VEMPs may be absent in nearly a quarter of patients with otosclerosis, more so for those with a greater degree of hearing loss (3). We agree that additional details would allow for better interpretation of our study results. To clarify, in our 20 study patients, no radiographic abnormalities were noted other than SCD and evidence of otosclerosis, such as inner ear malformations or enlarged vestibular aqueducts. In the 13 primary stapedotomies, we did not experience any cases of perilymphatic gusher or other intraoperative complications. Stapes fixation was confirmed in all 13 cases by palpation of the ossicular chain. As for the seven revision cases, although we cannot comment specifically with regard to the initial surgery, there were no intraoperative complications during the revision cases that we performed. A slipped prosthesis was noted in three of these revisions, whereas the remaining four had no overt cause of stapedotomy failure, as the prosthesis appeared well seated in all. We will end in complete agreement with the authors that the conclusions of our study should be interpreted judiciously and are generalizable to patients with concomitant otosclerosis and radiographic superior SCD—specifically those with conductive hearing loss in the absence of other signs or symptoms of a third window. In such patients, stapedotomy offers excellent hearing outcomes in a majority of patients with a low risk of unmasking third-window symptoms. Pedrom C. Sioshansi, M.D. Department of Otolaryngology—Head and Neck Surgery Wake Forest University School of Medicine Winston-Salem, North Carolina [email protected]Nathan C. Tu, M.D. Department of Otolaryngology—Head and Neck Surgery Albany Medical Center Albany, New YorkSeilesh C. Babu, M.D.Christopher A. Schutt, MD. Department of Neurotology Michigan Ear Institute St. John Providence Hospital and Medical Centers, Farmington Hills, Michigan