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.

LEVEL OF EVIDENCE: 3.