Fixed Neck Position in Multilevel Cervical Posterior Decompression and Fusion to Reduce Postoperative Disturbances of Cervical Spine Function

Laminectomy and fusion in multilevel degenerative cervical myelopathy - Correlation between objective and subjective postoperative restriction of cervical spine mobility

For patients with multilevel degenerative cervical myelopathy (DCM), laminectomy and fusion is an established technique. A concomitant effect of multilevel fusion is a restriction of cervical spine mobility. This retrospective study on DCM-patients with at least 4 laminectomy and fusion levels, compares data between objective and subjective restriction of the postoperative cervical spine mobility. The patient-reported restriction of cervical spine mobility was acquired by a five-step score. Measurements of cervical range of motion were performed using the CROM device and were correlated with the subjective scores. Fusion was performed over 6 levels in most of the 36 patients. For the subjective cervical spine mobility, 52.8% reported none to medium, 38.9% severe and 8.3% complete restriction. Mean objective cervical range of motion was 45.0° for flexion-extension, 26.3° for total lateral flexion and 51.4° for total rotation and therefore evidently reduced compared to non-operated patient cohorts in literature. There was a significant medium, negative correlation between the objective measurements and the patient-reported general restriction of cervical spine mobility, and with the physical component summary of SF-8. The significant objective reduction of cervical range of motion after laminectomy and multilevel fusion correlates with the patient-reported assessment for general restriction.

Does the postoperative cervical lordosis angle affect the cervical rotational range of motion after cervicothoracic multilevel fusion?

BACKGROUND

Laminectomy and multilevel fusion in patients with degenerative cervical myelopathy lead to severe restriction in cervical spine mobility. Since fusions from C₂ to the thoracic spine result in a permanently stiff subaxial cervical spine, it seems obvious to restore physiological cervical lordosis, especially with regard to sagittal balance. However, there are reports that a fusion in a more lordotic position leads to a reduction of rotational cervical range of motion in the still mobile segments C₀-C₂. This study investigates the relationship between postoperative cervical lordosis and the objective rotational range of motion and subjective restriction.

METHODS

In this single-center, retrospective cohort study, patients with degenerative cervical myelopathy operated via laminectomy and fusion from C₂ to the thoracic spine were included. X-ray imaging was evaluated for common lordosis parameters. The patient-reported rotational restriction of cervical spine mobility was acquired by a five-step score. Objective rotational range of motion was measured. The radiological parameters for cervical lordosis (C₂-C₇ lordotic angle, C₂-C₇ Cobb angle) were correlated with the measurements and the patient-reported subjective scores.

FINDINGS

We found a significant, medium negative correlation between the measurements for rotation and the C₂-C₇ lordotic angle and a significant, large negative correlation to the C₂-C₇ Cobb angle. For subjective restriction, no or only small correlation was observed.

INTERPRETATION

We found significant negative correlations between radiological cervical lordosis and objective measurements for rotation. These results indicate that for this particular patient population, a stronger postoperative cervical lordosis does not seem favorable under the aspect of rotational range of motion.