Delayed Yet Durable Functional Recovery Following Posterior Cervical Decompression and Fusion for Mild Degenerative Cervical Myelopathy

STUDY DESIGN: Retrospective cohort. OBJECTIVE: This study was designed to: (1) compare functional recovery after PCDF across baseline severity groups, (2) determine the rate of achieving a severity-adjusted minimum clinically important difference (MCID) in modified Japanese Orthopaedic Association (mJOA) scores, and (3) assess how these outcomes evolve over two years. BACKGROUND: Degenerative cervical myelopathy (DCM) is the leading cause of spinal cord dysfunction in older adults. Posterior cervical decompression and fusion (PCDF) is a well-accepted option for moderate and severe disease, yet its role in mild DCM remains uncertain. METHODS: We retrospectively reviewed adults undergoing elective PCDF for DCM at a single tertiary care center from 2010 to 2022. Patients were stratified by preoperative mJOA score as mild (15-17), moderate (12-14), or severe (<12). Severity-adjusted MCID thresholds were defined as mJOA increases of +1, +2, and +3 points, respectively. Patient-reported outcomes were collected preoperatively and at 6, 12, and 24 months postoperatively. Multivariate logistic regression identified predictors of MCID achievement at 1 year. RESULTS: One hundred thirty-seven patients were included (62 mild, 48 moderate, and 27 severe) with similar baseline demographics across groups. At 12 months, moderate (OR: 2.92, 95% CI: 1.25-7.02) and severe (OR: 3.40, 95% CI: 1.26-9.48) patients were significantly more likely to achieve MCID than mild cases ( P < 0.02). By 24 months, MCID achievement rates converged (41.9% mild, 42.9% moderate, and 46.7% severe; P = 0.95). CONCLUSIONS: Greater preoperative myelopathy severity predicts larger early functional gains and higher MCID achievement after PCDF. However, by two years, patients with mild disease achieve MCID at similar rates to more severe cases, suggesting a delayed but meaningful benefit. These findings may guide surgical decision-making and patient counseling, particularly in the mild DCM population. LEVEL OF EVIDENCE: Level III.