Prediction of postural imbalance improvement after surgery for degenerative cervical myelopathy

OBJECTIVE The objective of this study was to quantify the perioperative postural imbalance of subjects with degenerative cervical myelopathy (DCM) and to identify associated factors. METHODS This prospective study included consecutive subjects with DCM (n = 70) and cervical radiculopathy (i.e., controls) (n = 20) who were managed surgically according to standard of care guidelines. The DCM and control subjects had similar demographic characteristics. Eligible patients with DCM were 18 years or older with a modified Japanese Orthopaedic Association (mJOA) score ≤ 16. Control patients had mJOA score ≥ 17 without signs of myelopathy. All included subjects had a minimum 6-month postoperative follow-up. Postural balance was measured using force plate assessments during quiet upright standing. Specific measures were used to assess the trajectory of the center of pressure (CoP), including the 95% confidence ellipse area (EA), root mean squared CoP excursion (RMSml), and mean CoP velocity (MVEL). Multivariate analyses were performed to identify factors associated with changes in postural balance after surgery. RESULTS Postoperative assessments revealed significant improvements in EA (p < 0.001), RMSml (p < 0.001), MVEL (p < 0.001), numerical rating scale (NRS) scores for neck pain (p < 0.001), and mJOA scores at both 6 and 12 months (p < 0.001). Multivariate regression showed that baseline balance measures were strong predictors of the degree of postoperative stability improvement (p < 0.001). Baseline NRS scores for neck pain independently influenced postural balance recovery at 6 months (p < 0.05) but not at 12 months. CONCLUSIONS The authors’ study identified significant improvement in postural balance at 6 and 12 months after decompressive surgery for DCM, particularly in patients with more profound initial imbalance. Baseline postural balance and neck pain both significantly predicted the degree of functional lower extremity recovery, indicating their potential relevance as prognosticating measures.