Patient-specific 3D-printed mold system for superior semicircular canal third-window repair: design, fabrication, and first-in-human feasibility.

Abstract

Superior semicircular canal (SSC) dehiscence is a pathological defect in the bony labyrinth of the inner ear that produces auditory and vestibular symptoms due to abnormal third-window mechanics. Conventional surgical methods, including canal plugging and resurfacing, may improve symptoms but can be associated with vestibular or auditory risks. This study reports the design, fabrication, technical verification, and first-in-human feasibility of a patient-specific, 3D-printed mold system for anatomical repair of the SSC. Using high-resolution computed tomography, three-dimensional reconstruction, and computer-aided design, a patient-specific mold conforming to the external SSC roof was fabricated. The mold enables extracorporeal shaping of polymethyl methacrylate (PMMA) bone cement outside the patient to create a patient-specific implant for closure of the pathological third-window defect with precise anatomical alignment. Technical verification using a 3D-printed temporal bone model demonstrated anatomical fit and defect coverage before clinical use. The system was applied in a first-in-human clinical feasibility case, with early postoperative symptom improvement/resolution and no clinically evident new vestibular or auditory deterioration during early assessment. Preoperative and postoperative audiometric and vestibular test results, including general VEMP and vHIT data, are reported to support transparent interpretation of the early clinical outcome. This first-in-human feasibility report suggests that patient-specific additive manufacturing may support precision otologic reconstruction, while further clinical studies are required to establish broader safety, durability, reproducibility, and clinical effectiveness.