226. Postoperative SVA >4 cm has no impact on neck pain scores after C2-T2 fusion for myelopathy: results from a multicenter cohort study

BACKGROUND CONTEXT

Recent literature has examined the importance of cervical alignment with regards to health-related quality-of-life outcomes. Several cervical alignment parameters have been identified as potential goals for correction of cervical spinal deformities. Of these parameters, the C2-7 sagittal vertical axis (SVA) has been utilized as a measure of global cervical alignment, and previous work has suggested that achieving a postoperative SVA of 4 cm or less is ideal with regard to patient outcomes.

PURPOSE

The purpose of this study was to determine the impact of SVA on postoperative neck pain scores after posterior cervical laminectomy and fusion for myelopathy.

STUDY DESIGN/SETTING

We performed a retrospective review of a multicenter prospective cohort of patients undergoing posterior cervical laminectomy and fusion from C2-T2 for subaxial cervical stenosis and degenerative cervical myelopathy from 2011-2018.

PATIENT SAMPLE

A total of 173 patients were identified.

OUTCOME MEASURES

SVA and VAS neck pain scores were recorded.

METHODS

We collected demographic information and assessed cervical alignment on standing radiographs performed preoperatively as well as at 6 months or greater postoperatively. The cohort was divided into 2 groups based on a postoperative SVA of <4 cm or ≥4 based on established criteria. We then examined differences between the groups with regard to preoperative and postoperative alignment, demographics, and neck pain scores as measured by the visual analog scale. A univariate analysis was performed to assess for differences between the 2 groups. All statistical analyses were performed with JMP®Pro 14.1.0.

RESULTS

A total of 173 patients were identified for inclusion. In this cohort, 70 patients were identified as having a postoperative SVA <4 cm and 103 patients were identified as having an SVA ≥4cm. In both groups, the change in SVA showed a worsening of alignment. This was significantly higher in the SVA >4 cohort compared to the SVA <4 cohort (-11.6 vs -3.3, p<.001). There was also a significantly higher proportion of female patients in the SVA <4 cohort (54.3% vs 30.1%). Otherwise, there were no other significant differences in demographics between the 2 groups. Of the 173 patients, 108 patients (62.4%) had VAS neck pain scores recorded at greater than 6 months postoperatively. With regard to VAS neck pain scores, they improved in both groups with long-term follow-up. There was no significant difference between the cohorts with respect to neck pain scores at any time point. Using the established minimal clinically important difference for VAS neck pain following cervical surgery, we found that 61.9% of the SVA <4 cohort and 52.9% SVA >4 cohort achieved MCID with no significant difference between the groups (p = .432).

CONCLUSIONS

The primary goal for posterior cervical laminectomy and fusion in the treatment of degenerative myelopathy is to achieve adequate decompression of the spinal cord and a stable, fused spine. While previous work has established the importance of SVA alignment in treatment of cervical deformity, in this multicenter cohort of patients undergoing C2-T2 posterior cervical fusion for degenerative myelopathy, postoperative SVA >4 cm was not associated with a significant difference in long-term patient-reported outcomes with regard to neck pain.

FDA DEVICE/DRUG STATUS

This abstract does not discuss or include any applicable devices or drugs.