An Imaging‐Guided, Patient‐Specific Guiding Aid (RWNGuide) for Safe and Reproducible Inner Ear Drug Delivery

ABSTRACT

Local drug delivery to the inner ear offers a promising approach for sensorineural hearing loss but remains challenging. Current techniques, direct round window injections, remain invasive, whereas trans‐tympanic injection is imprecisions and surgeon‐dependent, often failing to localize therapeutics within the round window niche (RWN). A patient‐specific external ear guiding aid, RWNGuide, is developed as a precision guide for standardized, reproducible delivery to the RWN. Cone‐beam computed tomography datasets from 23 patients are reconstructed to characterize the external ear channel (EEC) and RWN morphology. Computational modeling and trajectory optimization guide RWNGuide design, conforming to the EEC while maintaining coaxial alignment with the RWN. Devices are fabricated using Polyjet 3D printing and evaluated in human cadaveric temporal bones. Inserting fit, channel alignment, handling, and delivery accuracy are assessed and compared against conventional injection methods. RWNGuide demonstrates secure positioning, accurate channel orientation toward the RWN, and reproducible delivery without injury to adjacent middle ear structures. Quantitative surface analysis confirms sub‐millimeter fit accuracy. Compared with trans‐tympanic and direct RWN injections, RWNGuide improves delivery accuracy and safety, with longer procedural time due to intraoperative verification. This image‐based, patient‐specific device reduces procedural variability and enhances precision, supporting a scalable strategy for image‐guided inner ear delivery.