3D-Guided Temporal Bone Puncture Study

Objective Leveraging the fixed anatomical features of the skull, this study investigates the application of 3D guide plates in temporal bone puncture, offering a novel method for minimally invasive treatment of the cochlear scala tympani and localized drug intervention via temporal bone puncture. Methods A Philips 64-slice spiral CT was employed to conduct 0.67 mm thin-layer scans of goat skulls. Dicom data were imported into Mimics Research 21.0 software to reconstruct 3D models of the cochlear scala tympani and temporal bone. Reverse engineering was utilized to design a postauricular surface puncture path, avoiding critical neurovascular structures and targeting the cochlear scala tympani directly. The puncture path starts from the postauricular surface, sequentially passing through the skin (approximately 1–2 mm thick), subcutaneous tissue (approximately 1–3 mm thick), muscular layer (approximately 2–4 mm thick, including postauricular muscles and superficial temporalis fibers), periosteum (approximately 0.1–0.5 mm thick), cortical temporal bone (approximately 2–5 mm thick), mastoid air cells or cancellous bone (approximately 5–10 mm thick), and petrous portion of the temporal bone (approximately 2–4 mm thick), finally reaching the cochlear scala tympani (depth 1–2 mm). A guide plate fixed to the temporal bone surface was developed, featuring a reverse fixation guide tube (outer diameter 3.35 mm, inner diameter 3.5 mm) and a forward puncture guide tube (inner diameter 0.95–1.20 mm). Precise puncture was executed using a 1 mm drill bit through the guide tube, with postoperative CT confirming the puncture position and depth. Results Of 12 puncture samples, 11 successfully reached the cochlear scala tympani, yielding a success rate of 91.7%, with a puncture depth of 2 mm and deviation less than 0.1 mm. Guide tubes with an inner diameter of 1.10–1.20 mm facilitated smooth guidance without damaging critical structures. No complications such as total deafness, vertigo, facial paralysis, or cerebrospinal fluid leakage were observed. Discussion The 3D guide plate offers technical support for precise inner ear puncture. Metal guide plates exhibit superior stability compared to resin ones but are prone to clogging due to current printing precision limitations, necessitating design improvements. This study presents a feasible approach for establishing an intracranial drug reservoir and localized drug intervention in the cochlea and vestibule, with future integration of navigation technology enhancing clinical applicability. Conclusion The 3D guide plate-guided temporal bone puncture technique demonstrates high precision and safety, providing a new avenue for minimally invasive inner ear treatment. However, further optimization of guide plate materials and design is required to address individual variations in human temporal bones.