Dura Vibration Difference Between PTP Bone Resection and Upper Facet Joints En Bolc Resection in Posterior Thoracic Decompression.

Abstract

Objective: In thoracic posterior decompression surgery, the traditional pedicle-to-pedicle (PTP) approach may have limitations in achieving complete decompression and may also pose potential risks of injury to the spinal cord. Through comparative analysis with the PTP method, the study explored the safety of posterior thoracic decompression via the pedicle-ossification tunnel (POT), aiming to provide a more scientific and safer clinical surgical pathway selection.

Methods: Combined with preoperative image data and intraoperative operation images, the POT decompression method was deeply analyzed. In this study, the thoracic vertebrae of sheep were taken as experimental specimens. The water sac was placed close to the joint level of the articular process to simulate the spinal cord, and the experiment was carried out by the surgical methods of PTP and POT respectively with a high-speed bur. The laser displacement sensor (LDS) was used to monitor the vibration displacement of the water sac, and the collected vibration data was divided into 0.1 s/frame (500 vibration signal data points), which were used to calculate the curvature change of the vibration displacement curve. The Wilcoxon rank sum test was used for statistical analysis. Milling parameters for the high-speed bur were set to: milling depth 0.5 mm, milling speed 0.5 mm/s, milling angle 45^°, and spherical bit size 4 mm.

Results: Combining the detailed preoperative image data and intraoperative images of key operations, the study first provides a detailed description of the surgical steps for safe posterior thoracic decompression via the POT. Then, based on Euler-Bernoulli beam theory, the vibration of the "spinal cord" under different surgery pathways (POT and PTP) in posterior thoracic decompression was further studied. The statistical analysis showed that the vibration amplitude and curvature value of the vibration curve of POT and PTP were significantly different (p < 0.05). As the milling position approached POT, the amplitude and curvature values also decreased gradually.

Conclusion: Through theoretical analysis and experimental verification, the safety and effectiveness of posterior thoracic decompression via POT was thoroughly investigated. The milling pathway via POT could not only achieve the surgical purpose of complete decompression, but also avoid the contact area between OLF and dura as much as possible, thus reducing the irritation to the spinal cord.