Effect of an Adjustable Hinged Operating Table on Lumbar Lordosis during Lumbar Surgery

Study Design. Prospective observational study. Objectives. Quantify the amount of lumbar lordosis achieved on a hinged operative table in neutral, flexion, and extension. Summary of Background Data. Hinged operative tables may allow surgeons to adjust lumbar spine positioning intraoperatively. The amount of lumbar lordosis in neutral, flexion, and extension positions has not been quantified prospectively using a hinged table. Methods. Thirty patients undergoing elective lumbar surgery were enrolled. Standing x-rays taken in neutral, maximal flexion, and maximal extension were obtained. After prone positioning on a hinged operative table, x-rays in neutral, maximal flexion, and maximal extension were taken. Total lumbar lordosis was calculated for all six images by two physicians. Disc degeneration was graded using Pfirrmann grades. Results. Lumbar lordosis on the operative table was 56.5 ° ±2.1 °, 43.6 ° ±2.2 °, 63.2 ° ±2.0 ° compared with 46.9 ° ±3.1 °, 33.2 ° ±2.8 °, 52.3 ° ±3.3 ° on the standing films in neutral, flexion, and extension, respectively. Average flexion (12.9 ° ±1.1 °) and extension (6.7 ° ±1.2 °) were significantly different from neutral on the table (P<0.001). Lumbar lordosis was significantly higher on the operative table (P<0.001). Total range of motion was 19.6 ° ±1.9 ° on the table and 19.1 ° ±2.0 ° with standing (P=0.42). Average Pfirrmann disc grade was 2.77±0.10 that did not correlate with range of motion (P=0.40). Conclusion. In this cohort, the hinged operative table allowed for a physiologic arc of motion of nearly 20 ° from flexion to extension. A considerable amount of lumbar sagittal motion can be obtained on hinged operative tables without decreasing overall lumbar lordosis below physiologic levels.