P87. A novel percutaneous pedicle screw technique for patients with diffuse idiopathic skeletal hyperostosis - the single or double endplates penetrating screw (SEPS/DEPS) technique – Clinical results and validation of fixation strength using finite element an

• Published in: North American Spine Society journal (NASSJ) 2024-07, Vol.18, p.100491, Article 100491
• Main Authors: Takeuchi, Takumi, Moroi, Takehiko, Konishi, Kazumasa, Takahashi, Masahito, Hosogane, Naobumi
• Format: Article
• Language: English
• ISSN: 2666-5484; 2666-5484
• DOI: 10.1016/j.xnsj.2024.100491

The patients with diffuse idiopathic skeletal hyperostosis (DISH) have fragile bone due to fused vertebral bodies and is difficult to obtain enough fixation. We have developed a novel percutaneous pedicle screw (PPS) insertion technique, in which the screw penetrates upper endplate of vertebral body and lower endplate of adjacent vertebral body to enhance the fixation, named the single or double endplates penetrating screw (SEPS/ DEPS) technique. This technique might be useful in patients associated with DISH, as DISH patients may have minimal influence from disc penetration with screws due to fused vertebral body. The purpose of this study is to introduce this novel technique and to compare the clinical effectiveness of this technique with the conventional pedicle screw (CPS) technique. Also, to investigate biomechanically, the finite element (FE) analysis was conducted to compare the fixation strength between CPS and SEPS/DEPS using the osteoporotic vertebral body models. N/A N/A N/A In SEPS/DEPS technique, screw is inserted upwards from the outer caudal side of the pedicle toward the inner cranial side. The screw has to penetrate the upper endplate of the inserted vertebra in the lateral view before across the inner edge of the pedicle in the A-P view. In the SEPS technique, the screw penetrates only upper endplate of the inserted vertebra, while the screw also penetrates the lower endplate of the adjacent vertebra on the cranial side in the DEPS technique. Firstly, the effectiveness of the SEPS/DEPS technique were clinically evaluated in OVF patients. The screws were inserted with SEPS/DEPS to DISH vertebrae, whereas with conventional PPS technique to non-fused vertebrae. Twelve OVF patients with DISH were included in this study; all the screws were inserted with SEPS/DEPS technique in 3 patients and hybrid of both the DEPS and the conventional PPS techniques was used in 9 patients, according to the vertebral continuity. As a control group, 12 OVF patients with DISH treated only by conventional method were included. The rates of implant failures were compared between the SEPS/DEPS group and the control group. The insertion torque was also measured in 3 hybrid patients. Secondly, the FE analysis was conducted to validate the effectiveness of SEPS/DEPS. Twenty vertebrae (T12 and L1) from 10 osteoporotic patients were obtained to create the 10 FE models. A single screw was placed at the left T12 pedicle with CPS and SEPS/DEPS and the fixation strength was