Imaging-identified round window niche veil and intratympanic therapy efficacy in sudden sensorineural hearing loss

Intratympanic (IT) therapy is a common procedure to deliver drugs into the cochlear for the treatment of inner ear diseases. Round window niche veil (RWNV) is an extra anatomical barrier potentially impending drug delivery. However, RWNV's identification is neglected, and its effect on IT efficacy awaits investigation.

Patients with unilateral sudden sensorineural hearing loss (SSNHL), undergoing temporal bone HRCT examination and initiating IT therapy were enrolled and followed up for 30 days. Participants were independently assessed and identified into RWNV⁺ and RWNV^- by an imaging-based workflow. Primary outcome was response (clinically important hearing improvement ≥10 dB) to IT therapy, whilst secondary outcomes included pure-tone average threshold (PTA) and word recognition score (WRS) gains from baseline. Frequency-specific hearing threshold, WRS at varying levels, and haring levels by severity were also reported. Logistic or linear regression models were employed to investigate the IT therapy outcomes in RWNV⁺ versus RWNV^-.

A total of 169 patients (44.4 ± 12.6 yr; 52.1% females) were included and stratified into RWNV⁺ (56.2%) and RWNV^- (43.8%), with good inter-reader agreement (Kappa, 0.798-0.892). Clinical response to IT administration was achieved in 34.7% of RWNV⁺ versus 50.0% of RWNV^- cases. RWNV⁺ associated with inferior response probability (OR = 0.441; 95% CI, 0.216-0.902), independent of clinical prevalent variables. RWNV⁺ potentially synergized with established risk factors (prolonged course, vertigo) and further diminished efficacy. RWNV⁺ also correlated with poorer PTA_0.5-4 kHz gains (β = -5.16; 95% CI, -9.86 to -0.47) and worser WRS at 70-90 dB SPL (p < 0.05).

RWNV identified by a HRCT-based workflow is independently associates with inferior IT therapy efficacy in SSNHL. Pre-treatment imaging assessment may help to predict potential benefits from IT therapy.