Percutaneous instrumentation with cement augmentation for traumatic hyperextension thoracic and lumbar fractures in ankylosing spondylitis: a single-institution experience

Abstract

OBJECTIVE The typical traumatic thoracolumbar (TL) fracture in patients with ankylosing spondylitis (AS) is a hyperextension injury involving all three spinal columns, which is associated with unfavorable outcomes. Although a consensus on the management of these highly unstable injuries is missing, minimally invasive surgery (MIS) has been progressively accepted as a treatment option, since it is related to lower morbidity and mortality rates. This study aimed to evaluate clinical and radiological outcomes after percutaneous instrumentation with cement augmentation for hyperextension TL fractures in patients with AS at a single institution. METHODS This cohort study was completed retrospectively. Back pain was assessed at preoperative, postoperative, and final follow-up visits using the visual analog scale (VAS). Patient-reported outcomes via the Oswestry Disability Index (ODI) and the new mobility score (NMS) were obtained to assess disability and mobility during follow-up. Radiological outcomes included the Cobb angle, sagittal index (SI), union rate, and implant failure. Intra- and postoperative complications were recorded. RESULTS A total of 22 patients met inclusion criteria. The mean patient age was 74.2 ± 7.3 years with a mean follow-up of 39.2 ± 17.4 months. The VAS score for back pain significantly improved over the follow-up period (from 8.4 ± 1.1 to 2.8 ± 0.8, p < 0.001). At the last follow-up, all patients had minor disability (mean ODI score 24.4 ± 6.1, p = 0.003) and self-sufficiency of mobility (mean NMS 7.5 ± 1.6, p = 0.02). The Cobb angle (5.2° ± 2.9° preoperatively to 4.4° ± 3.3° at follow-up) and SI (7.9° ± 4.2° to 8.8° ± 5.1°) were maintained at follow-up, showing no loss of segmental kyphosis. Bone union was observed in all patients. The overall complication rate was 9.1%, while the reoperation rate for implant failure was 4.5%. CONCLUSIONS Percutaneous instrumentation with cement augmentation for traumatic hyperextension TL fractures in AS demonstrated good clinical and radiological outcomes, along with a high bone union level and low reoperation rate. Accordingly, MIS reduced the complication rate in the management of these injuries of the ankylosed spine.