A comparative study on the effect of age on Neck Disability Index improvement at 24 months after surgical intervention for cervical spondylotic myelopathy: a Quality Outcomes Database study.

Objective: Cervical spondylotic myelopathy (CSM) is often accompanied by neck pain, which, along with more recognized neurological deficits like motor and sensory changes, significantly impacts patients' quality of life. The authors examined whether age influences improvements in neck disability and related quality-of-life measures after surgery for CSM. Using the Neck Disability Index (NDI) as the primary outcome, they compared long-term outcomes at 24 months among patients aged ≥ 65, ≥75, and < 65 years, exploring the effects of surgical intervention on both pain-related disability and functional recovery in older adults.

Methods: Using the Quality Outcomes Database, the authors conducted a detailed propensity score-matched analysis on cohorts aged ≥ 65 and ≥ 75 years compared with a < 65-year-old cohort while controlling for baseline NDI scores, other demographic variables, health status, underlying pathology, number of levels, indication for surgery, surgical approach, and type of surgery. Differences in NDI total and subdomain scores at 24 months postoperatively were the primary measures of improvement. Age-related variability in NDI differential was assessed. EQ-5D and calculated SF-6D were secondary measures.

Results: Of the 1141 patients in the cohort (January 2016 to December 2018), 687 patients were < 65 years, 325 were 65 to < 75 years, and 129 were ≥ 75 years of age. After propensity score matching, 197 patients each were well matched in the ≥ 65-year (mean 71.4 years) and < 65-year (mean 55.3 years) cohorts; similarly, 57 patients each were matched in the ≥ 75-year (mean 78.3 years) and < 65-year (mean 55.8 years) cohorts. Improvements in NDI scores and subdomain scores, EQ-5D, and calculated SF-6D were consistent at 3, 12, and 24 months postoperatively across all cohorts. At 24 months, patients ≥ 65 years showed NDI score improvements (-14.7 ± 22.3) similar to those < 65 years (-13.0 ± 21.3, p = 0.454), and patients ≥ 75 years demonstrated NDI improvements (-15.0 ± 19.7) comparable to those < 65 years (-17.6 ± 20.4, p = 0.499). A sensitivity analysis for linear relationship found that NDI improvement was statistically greater in older patients (7.5 points every 30 years, p < 0.0001), but this difference was below the minimal clinically important difference. Other clinical outcomes were similar between cohorts.

Conclusions: Surgical intervention for CSM yields substantial and similar improvements in NDI scores and other metrics among various age groups, including those aged at least 65 and 75 years. These results highlight the effectiveness of surgery across a broad patient demographic, underscoring its value in treating CSM irrespective of age.