Rollback Imaging as a Useful Tool in the Preoperative Evaluation of Osteoporotic Vertebral Fractures.

INTRODUCTION: When surgery is performed for osteoporotic vertebral fractures, the extent to which kyphosis can be corrected by the intraoperative position of the body is often determined by preoperative radiography in the extension position. However, patients have difficulty adopting an adequate extension position due to the pain associated with their vertebral fracture. We place a pillow beneath the fractured vertebral body before surgery and take radiographs in the supine position to evaluate the extent to which the kyphosis can be corrected. This study aimed to examine the usefulness of this imaging method by comparing postoperative radiographs with preoperative radiographs taken with a pillow placed beneath the fractured vertebral body. METHODS: Lateral preoperative radiographs were taken of the patients in seated flexion and extension positions and the supine position. Lateral radiographs (rollback) were also taken 5 min after placing a firm pillow 20 cm in diameter beneath the fractured vertebral body. The kyphotic angle was compared between preoperative lateral radiographs of patients in the flexion, extension, and supine positions, rollback, and postoperative lateral radiographs in the supine position. RESULTS: The mean kyphotic angle was 33.3° in the flexion position, 28.3° in the extension position, 14.8° in the supine position, and 5.6° in rollback preoperatively and 6.4° postoperatively. The preoperative kyphotic angle differed from the postoperative kyphotic angle by ≥11° in 91% and 83% of participants in the flexion and extension positions, respectively; the difference was ≤ 5° in 30% and 61% of participants in the supine position and rollback, respectively. Differences in the postoperative angle were small in the order of rollback, supine position, extension position, and flexion position. CONCLUSIONS: Compared with radiographs taken in the flexion, extension, and supine positions, rollback showed little difference from postoperative radiographs, which showed almost the same angle as the intraoperative kyphotic angle.