STUDY DESIGN

Retrospective radiological study.

OBJECTIVE

We aimed to determine whether the sagittal profiles of patients with lumbar spinal canal stenosis (LCS) change after decompressive laminectomy.

SUMMARY OF BACKGROUND DATA

Decompressive laminectomy is the standard technique in the surgical treatment for LCS. Numerous studies have reported favorable clinical outcomes. However, few studies have quantitatively evaluated the radiological outcome of the procedure, including the global balance of the spine and associated pelvic posture.

METHODS

This study involved 40 consecutive patients with LCS treated with decompressive laminectomy and a control cohort of 40 age- and sex-matched patients with LCS who were treated conservatively. The radiological parameters of the 2 groups including (1) global sagittal balance (C7 plumb line [C7PL], C7/sacrofemoral distance ratio, and spinosacral angle), (2) spinopelvic morphology (pelvic incidence, sacral slope, and pelvic tilt), and (3) spinal parameters (lumbar lordosis and thoracic kyphosis) were measured and compared at baseline, 1-year, and 2-year follow-ups.

RESULTS

The demographics and baseline radiological parameters were similar between the 2 groups. The mean C7PL of the laminectomy group was 3.9 ± 2.5 cm at baseline, which decreased significantly to 2.0 ± 1.9 cm at the 1-year follow-up (P = 0.006) and was maintained at this level at the 2-year follow-up (2.3 ± 2.1 cm) (P = 0.013). The mean lumbar lordosis of the laminectomy group was 31.4°± 15.1° at baseline, which increased significantly to 35.6°± 11.7° at the 1-year follow-up (P = 0.021) and was maintained at this level at the 2-year follow-up (35.1°± 14.8°) (P = 0.044).

CONCLUSION

In this study, decompressive laminectomy caused posterior migration of the C7PL and increased the lumbar lordosis.

LEVEL OF EVIDENCE