2020 Volume 11 Issue 10 Pages 1202-1206
Introduction: In diffuse idiopathic skeletal hyperostosis (DISH), fracture of the continuous ankylosing vertebral body might cause severe stress on the damaged vertebral body. In addition, screws placed in traditional trajectories might become loose or back out to severe vertebral bone fragility caused by stress shielding. Therefore, introduction of a penetrating endplate screw (PES), which improves the insertion torque by penetrating the cranial vertebral endplate of the screw-inserted vertebra, is increasingly being performed instead of the traditional trajectory screw (TTS) for spinal injury in DISH. The aim of this study was to evaluate surgical outcomes using the PES method for thoracolumbar injury in DISH.
Method: From April 2014 to March 2018, we treated patients with DISH thoracolumbar injury with either percutaneous pedicle screw insertion using the PES method (PES method group, including PES alone or PES combined with TTS) or the TTS alone method (TTS group). We investigated the characteristics of patients, cases of reoperation due to implant failure and screw loosening in both groups. The results were expressed as mean±standard deviation and were statistically analyzed using Wilcoxon's rank sum test, chi-square test and Fisher's exact test.
Results: The study included 21 patients, 9 in the PES group (1 male and 8 females) and 12 in the TTS group (3 males and 9 females). Mean patient age in the two groups was 80±7 years and 79±7 years (p = 0.72), respectively, and mean body weight was 51±10 kg and 63±19 kg (p = 0.19), respectively. YAM values in the PES and TTS groups were 72±11% and 71±14% (p = 0.97), respectively. The number of ankylosing vertebral bodies extending cranially and caudally from the fractured vertebrae was 11±3 vertebral bodies and 11±2 vertebral bodies (p = 0.97), respectively. One patient in the TTS group underwent reoperation due to implant failure, with no such cases in the PES group (p = 0.57). Loosening of screws occurred in 22% (2/9 cases) of patients in the PES group, and 50% (6/12 cases) of patients in the TTS group (p = 0.20). The number of loosened screws was 5/85 (6%) in the PES group, 2/13 (15%) of the TTS in PES group patients who also received TTS, and 20/140 (14%) in the TTS group (p = 0.12).
Conclusion: Compared to the TTS method, the PES method showed less tendency for screw loosening and no reoperations due to implant failure. The PES method with penetration of cortical bone might be useful in the management of thoracolumbar spine injury in elderly DISH patients with severe bone fragility.
