Abstract
BACKGROUND: Accurate assessment of thoracolumbar kyphosis (TLK) flexibility is paramount in preoperative planning for patients with symptomatic old osteoporotic thoracolumbar fractures (so-OTLF) exhibiting kyphotic deformity. While conventional standing hyperextension lateral radiographs (SHLR) are utilized, comparative analyses with prone computed tomography (CT) scout views in the sagittal plane remain limited. This study aims to evaluate and compare the efficacy of SHLR and full-length spine CT (FLS-CT) scout views in the prone position for assessing TLK flexibility in so-OTLF patients. METHODS: A retrospective analysis was conducted on patients with so-OTLF and kyphotic deformity who underwent posterior corrective fusion surgery. Sagittal parameters were measured independently by two spine surgeons using standing radiographs, SHLR, and prone FLS-CT scout views. TLK flexibility was quantified as the difference between standing and either SHLR or FLS-CT measurements. Paired t-tests were employed to compare sagittal Cobb angles and TLK flexibility between hyperextension and prone positions. Intra- and interobserver reliability were assessed using the intraclass correlation coefficient (ICC). RESULTS: Thirty-four patients (mean age 66.1 ± 7.2 years, 30 females) were included. The mean TLK on standing radiographs was 50.9° ± 13.8°. SHLR demonstrated a mean TLK reduction of 7.8° (95 % CI: 6.6°-9.1°) to 43.1° ± 12.6° (P < 0.05). FLS-CT revealed a mean TLK of 31.8° ± 12.4°, a reduction of 19.1° (95 % CI: 17.4°-20.9°) compared to standing radiographs (P < 0.05). TLK flexibility in the prone position was significantly higher than in the hyperextension position (mean difference: 11.3°, P < 0.001). Both SHLR and FLS-CT demonstrated high intra- and interobserver reliability (ICC >0.82), with FLS-CT exhibiting superior reliability (intraobserver ICC: 0.97, interobserver ICC: 0.94) compared to SHLR (intraobserver ICC: 0.90, interobserver ICC: 0.82). CONCLUSIONS: Prone FLS-CT scout views provide a more accurate assessment of TLK flexibility in patients with so-OTLF and kyphotic deformity compared to conventional SHLR. This enhanced accuracy may facilitate improved preoperative evaluation and surgical planning.