Additive manufacturing of patient-specific ear canal wall implants: a preclinical workability study

Abstract

Reconstruction of the posterior ear canal wall remains surgically demanding because implants must combine shape fidelity, intraoperative adjustability, mechanical integrity, and reliable handling in a confined anatomical space. Additive manufacturing offers patient-specific solutions with high geometric accuracy and design freedom, which are particularly relevant for ear canal wall implants, where fit and surgical workability strongly influence outcome. This study evaluated the preclinical workability of patient-specific 3D-printed hydroxyapatite ear canal wall implants from an ENT-surgeon’s perspective, with emphasis on handling, fit, drillability, and preservation of integrity after adjustment. Workability was assessed through in vitro cadaveric testing, ENT-surgeon observation, and a Likert-scale questionnaire addressing placement, precision, and adaptability. The implants could be positioned and manipulated well, and precise intraoperative adjustment was feasible using a fine diamond burr. Good overall fit was achieved after limited drilling-based modification. However, the material showed sensitivity to brittle failure under unfavorable drilling conditions, indicating that handling technique and drilling parameters are critical. These preliminary findings suggest that 3D-printed hydroxyapatite ear canal wall implants are promising for patient-specific reconstruction because they combine geometric customization with practical intraoperative adjustability. At the same time, their workability remains technique-sensitive and requires further validation.