Auditory and Vestibular Symptom Improvement With Surgery for Superior Canal Dehiscence Syndrome

Abstract

Objective(1) To measure the change in auditory and vestibular symptoms following superior canal dehiscence (SCD) surgery, and (2) to determine differences in clinical features and surgical outcomes between superior canal dehiscence syndrome (SCDS) patients with primarily auditory or vestibular complaints.Study DesignRetrospective cohort study.SettingSingle surgeon series at the tertiary academic medical center from 2002 to 2021.MethodsRetrospective review of SCDS patients who underwent surgical repair. (1) Patients were administered a standardized symptom questionnaire at preoperative and follow‐up visits, and results were compared with paired statistical testing. (2) Patients were divided into 2 cohorts based on either auditory or vestibular chief complaint and differences in demographic, clinical, and outcome variables were examined.ResultsOur study included 113 patients with 118 operated ears. Twenty‐seven patients (24%) had radiographic bilateral dehiscence. 10/11 auditory symptoms (91%) and 5/8 vestibular symptoms (63%) solicited on the questionnaire improved significantly with surgery, except for nonpulsatile tinnitus, sense of imbalance, positional dizziness, and oscillopsia. Analyses stratified by chief complaint (auditory vs vestibular) revealed overall similar characteristics and surgical outcomes. Patients with chief vestibular complaints underwent surgery at an earlier age (45.5 vs 53.9 years, p < 0.05).ConclusionSCD surgery alleviates a wide range of auditory and vestibular symptoms. Overall, we did not find significant differences between patients with chief auditory versus vestibular complaints, and both groups benefited from surgery. Symptoms are not directly linked to third‐window physiology and certain vestibular symptoms may be more likely to persist. Bilateral dehiscence may play an important role in persistent symptoms as well.

Narrowing of Low‐Frequency Air‐Bone Gap and Its Association with Symptom Resolution Following Superior Canal Dehiscence Repair

“…Auditory symptoms such as autophony, amplification, and hyperacusis are more attributable to third-window physiology than vestibular symptoms. 22 As such, our…”

“…Prior studies have found the resolution rates for auditory symptoms such as autophony, amplification, and hyperacusis to be remarkably higher than that of vestibular symptoms such as imbalance and dizziness following SCD surgeries. 18,[22][23][24] Suresh et al 22 summarized 2 major hypotheses for this phenomenon. First, SCD plugging may impair the function of semicircular canals or induce benign paroxysmal positional vertigo, thereby resulting in persistent vestibular symptoms following surgery.…”

“…Bold = 95% CI does not overlap with the reference point. Abbreviations: aβ, adjusted beta coefficient; aOR, adjusted odds ratio.findings may suggest that elimination of the third window mainly narrows ABG at ≤500 Hz, and ABG narrowing beyond 500 Hz is driven by a separate process.Considering the 2 hypotheses proposed by Suresh et al,22 patients without ABG narrowing at 1000 Hz may be those with iatrogenic impairment of the vestibular apparatus or…”

Predictors of non-primary auditory and vestibular symptom persistence following surgical repair of superior canal dehiscence syndrome

“…Although many studies show clinical improvement in most surgical patients, a formal analysis on persistent symptoms following operative repair is limited ( 16 – 19 ). Some research has suggested that mechanically induced symptoms (i.e., low-frequency conductive hearing loss, autophony, pulsatile tinnitus, and sound- and pressure-induced vertigo) tend to resolve more readily compared to headaches, chronic disequilibrium, and brain fog.…”

“…Theories to explain residual symptoms include “unmasking” of the contralateral ear in patients with bilateral dehiscence, iatrogenic alteration of the vestibular system or comorbid pathologies, and limitations of modern surgical repair techniques. Several studies have shown worse outcomes in patients with bilateral disease compared to those with unilateral disease, and it has come into question whether patients with bilateral defects receive bilateral repair or only unilateral repair ( 19 , 21 , 23 – 26 ). In addition, our group identified that in female patients, three factors were associated with prolonged recovery: (1) a history of migraines, bilateral SCD, and a larger dehiscence.…”