Clinical Outcomes of Transdiscal Screws for Thoracolumbar Spinal Fractures with Marked Anterior Distraction Gap Accompanied by Diffuse Idiopathic Skeletal Hyperostosis

Background and Objectives: Diffuse idiopathic skeletal hyperostosis (DISH)-related spinal fractures with marked anterior distraction are highly unstable and pose substantial surgical challenges. The transdiscal screw for diffuse idiopathic skeletal hyperostosis (TSD) technique has been proposed to enhance fixation strength by penetrating adjacent vertebral endplates; however, its clinical utility in large-displacement cases remained unclear. Materials and Methods: In this retrospective study, we reviewed 21 patients with thoracolumbar DISH-related fractures and an anterior fracture gap ≥ 15 mm, who underwent posterior fixation between 2010 and 2024. 11 patients underwent TSD fixation (TSD group), and 10 underwent conventional fixation without bilateral TSD (control group). Results: The mean number of fused segments did not differ significantly between the groups (5.0 ± 1.4 vs. 5.0 ± 1.3, p = 0.43). Operative time was comparable (164 ± 57 vs. 168 ± 60 min, p = 0.90). Blood loss tended to be lower in the TSD group (306 ± 334 vs. 528 ± 658 mL, p = 0.33). For fracture-gap reduction, the TSD group improved from 17.4 ± 2.3 mm preoperatively to 13.8 ± 4.4 mm postoperatively and 2.0 ± 3.6 mm at final follow-up, while the control group showed less reduction (16.8 ± 2.2, 15.4 ± 1.4, and 7.0 ± 9.1 mm, respectively). Screw loosening occurred in three TSD patients and six controls (p = 0.13). All patients in the TSD group achieved bone union without reoperation, whereas four controls experienced implant backout, three required reoperation, and two failed to achieve bone union (p = 0.035). Conclusions: Posterior fixation using TSD provided reliable stability, maintained reduction, and reduced the risk of implant failure compared with conventional fixation in highly unstable DISH-related fractures with anterior distraction. Although larger prospective studies are needed, TSD may represent a valuable surgical option for this challenging patient population.