Is more lordosis associated with improved outcomes in cervical laminectomy and fusion when baseline alignment is lordotic?

Abstract

Background context: In cervical spondylotic myelopathy (CSM), cervical sagittal alignment (CSA) is associated with disease severity. Increased kyphosis and C2-C7 sagittal vertical axis (SVA) correlate with worse myelopathy and poor outcomes. However, when alignment is lordotic, it is unknown whether these associations persist.

Purpose: The study aimed to investigate the associations between CSA parameters and patient-reported outcomes (PROs) following posterior decompression and fusion for CSM when baseline lordosis is maintained.

Study design/setting: This is an analysis of a prospective surgical cohort at a single academic institution.

Patient sample: The sample includes adult patients undergoing primary cervical laminectomy and fusion for CSM over a 3-year period.

Outcome measures: The PROs included EuroQol-5D, Short-Form-12 (SF-12) physical composite (PCS) and mental composite scales (MCS), Neck Disability Index, and the modified Japanese Orthopaedic Association scores. Radiographic CSA parameters measured included C1-C2 Cobb, C2-C7 Cobb, C1-C7 Cobb, C2-C7 SVA, C1-C7 SVA, and T1 slope.

Methods: The PROs were recorded at baseline and at 3 and 12 months postoperatively. The CSA parameters were measured on standing radiographs in the neutral position at baseline and 3 months. Wilcoxon rank test was used to test for changes in PROs and CSA parameters, and Pearson correlation coefficients were calculated for CSA parameters and PROs preoperatively and at 12 months. No external sources of funding were used for this work.

Results: There were 45 patients included with an average age of 63 years who underwent posterior decompression and fusion of 3.7±1.3 levels. Significant improvements were found in all PROs except SF-12 MCS (p=.06). Small but statistically significant changes were found in C2-C7 Cobb (mean change: +3.6°; p=.03) and C2-C7 SVA (mean change: +3 mm; p=.01). At baseline, only C2-C7 SVA associated with worse SF-12 PCS scores (r=-0.34, p=.02). Postoperatively, there were no associations found between PROs and any CSA parameters. Similarly, no CSA parameters were associated with changes in PROs.

Conclusions: Although creating more lordosis and decreasing SVA are associated with improved myelopathy and outcomes in patients with kyphosis, our study did not find such associationsin patients with lordosis undergoing posterior laminectomy and fusion for CSM. This suggests that any amount of lordosis may be sufficient.

Keywords: Cervical lordosis; Cervical myelopathy; Cervical sagittal alignment; Cervical spondylosis; Patient-reported outcomes; Posterior cervical fusion; Posterior laminectomy and fusion.