Anatomical Validation and Technical Feasibility of Biportal Endoscopic Spinal Surgery Including Technical Notes in a Cadaveric Canine Thoracic Intervertebral Disc Disease Model

Biportal endoscopic spinal surgery (BESS) is a minimally invasive technique that is widely used in human spinal procedures; however, its standardized methodology and anatomical adaptation for veterinary applications have not yet been established. This study aimed to develop a reproducible experimental framework for performing BESS in dogs and evaluate its technical feasibility. A thoracic intervertebral disc disease model was created by injecting a fluorescently dyed artificial disc material containing methylene blue into the T12-13 intervertebral space of 13 medium-sized canine cadavers. Portal locations were determined using a computed tomography-based measurement method, and instruments specifically designed for BESS were used to perform mini-hemilaminectomies of the accessory process. The artificial disc material was successfully removed in all cases with clear visualization of the spinal cord and nerve roots. The mean portal insertion angle and distance were 31.00 ± 2.79° and 32.95 ± 3.05 mm, respectively, and the average residual material volume was 6.89% ± 1.66% of the initially inserted volume. Surgical time significantly decreased as the surgeon's experience increased. These results demonstrate the successful methodological standardization of BESS tailored to canine thoracic anatomy and provide foundational data supporting its potential as a minimally invasive spinal surgery technique for future clinical veterinary applications.