Friday, September 28, 2018 1:00 PM–2:30 PM abstracts: a new look at imaging: 204. Comparison of supine lateral x-ray, and CT images with standing lateral x-ray in predicting kyphosis flexibility with apex at T10-L2 in adult degenerative spinal deformity

Abstract

BACKGROUND CONTEXT On sagittal plane, standing lateral x-ray has been taken as the main method to evaluate kyphosis and sagittal balance, which inevitably increase kyphosis magnitude from body weight and gravity. However, surgical sagittal imbalance correction strategy, such as the Smith-Peterson osteotomy (SPO), Pedicle Subtraction Osteotomy (PSO), and posterior vertebral column resection (PVCR), etc, are critically dependent on kyphosis magnitude and kyphosis rigidity. Supine lateral x-ray and CT scan, regularly in supine position, are possibly better ways to evaluate the flexibility and true magnitude of kyphosis. PURPOSE Our goal was to study kyphosis with apex at T10-L2 (TLK) magnitude change among standing lateral x-ray, spine lateral x-ray and supine CT scan. Standing lateral spine radiographs and CT scan may be superior to the standing lateral x-ray to evaluate the true magnitude of kyphosis. STUDY DESIGN/SETTING A retrospective study was conducted using retrospectively collected data at a spine surgery center. PATIENT SAMPLE A total of 45 adult degenerative spinal deformity patients with TLK, with kyphosis apex at T10-L2, were retrospectively studied. OUTCOME MEASURES Data were statistically analyzed using the SPSS software 17.0 version (SPSS, Inc, USA). METHODS A total of 45 adult degenerative spinal deformity patients with TLK, with kyphosis apex at T10-L2, were retrospectively studied with standing lateral x-ray and lateral, full supine x-ray and CT image. All radiographs were analyzed by measuring the TLK angles, lumbar lordosis (LL, T12-S1) and thoracic kyphosis (TK, T5-T12), respectively. The TLK was divided into three groups based on angle magnitude measured on standing radiographs (20°–40°, 40°–60°, and more than 60°) RESULTS Significant differences were found between TLK angles measured on standing radiographs and supine radiograph (P CONCLUSIONS Supine lateral x-ray and supine CT could be taken as reliable alternatives to standing lateral radiographs in the assessment of true kyphosis magnitude in adult spinal deformity patients with thoracolumbar kyphosis.