Objective: To characterize the clinical, radiologic, and electrophysiological features of spontaneous autoplugging in superior semicircular canal dehiscence (SSCD) and compare them to untreated and surgically treated cases. Methods: This retrospective observational study was conducted in a tertiary referral center in Paris, France. Fifty-nine SSCD ears were categorized into 3 groups: untreated (n=36), autoplugging (n=5), and surgically plugged (n=18). Autoplugging was defined as the absence of a fluid signal in the dehiscent canal on high-resolution 3D T2-weighted MRI in patients with no history of ear surgery. All patients underwent clinical assessment, audiometry, video head impulse test (vHIT), cervical vestibular-evoked myogenic potentials (cVEMP), and high-resolution imaging. Group comparisons used nonparametric tests with FDR correction and power analysis. Results: vHIT gain was significantly reduced in both the autoplugging (0.56 ± 0.09) and surgical groups (0.57 ± 0.13) compared with untreated SSCD (0.77 ± 0.19, P =0.0003). The reduction was confined to the superior canal, whereas lateral and posterior canal gains remained normal. Autophony persisted in the autoplugging group (80%) but was significantly reduced in the surgical group (22.2%, P <0.0001). cVEMP thresholds were abnormally low in untreated (62.0 ± 11.1 dB) and autoplugging ears (62.5 ± 9.6 dB), and significantly higher post-surgery (83.5 ± 12.3 dB, P <0.001). Conclusion: Autoplugging mimics surgical plugging in terms of canal dysfunction but fails to alleviate third-window symptoms. It may represent an incomplete, spontaneous adaptation in SSCD pathophysiology. Level of Evidence: Level 3.
Djian et al. (Tue,) studied this question.