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

## TL;DR

This study establishes a standardized method for biportal endoscopic spinal surgery in dogs, showing it is technically feasible and minimally invasive.

## Contribution

The study introduces a reproducible methodology for biportal endoscopic spinal surgery in canine thoracic disc disease models.

## Key findings

- Artificial disc material was successfully removed in all canine cadavers with clear visualization of spinal structures.
- Portal insertion angles and distances were measured, showing consistent anatomical feasibility.
- Surgical time decreased with increased surgeon experience, indicating learnability of the technique.

## Abstract

Thoracic intervertebral disc disease commonly affects small to medium-sized dogs, particularly the T12–13 disc space. Traditional spinal surgery requires wide incisions and extensive osteotomy, which can cause greater soft tissue damage and require longer recovery. In human medicine, a less invasive method, known as biportal endoscopic spinal surgery, is commonly used. However, despite the growing interest in its veterinary application, standardized methodology and anatomical guidelines have not yet been established. This study aimed to establish a reproducible and standardized experimental methodology for performing biportal endoscopic spinal surgery in dogs, using a thoracic intervertebral disc disease model. Fluorescently dyed artificial disc material was injected into the thoracic spine to simulate disc disease, and a computed-tomography-based measurement method was used to determine precise portal locations. The material was successfully removed from all the dogs, and the spinal cord and nerve roots were clearly visualized. These findings provide a foundation for the methodological standardization of biportal endoscopic spinal surgery in veterinary medicine. They may also facilitate its future clinical application as a minimally invasive spinal surgery technique.

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.