Can the 6-minute Walking Test Assess Ambulatory Function Impairment in Patients With Cervical Spondylotic Myelopathy?

Study design: Prospective cohort study.

Objective: Investigating the ability of a 6-minute walking test (6MWT) to assess functional status in patients with cervical spondylotic myelopathy (CSM).

Summary of background data: The 6MWT provides an objective assessment of a patient's ability to walk. There is the potential for its application to the assessment of functional status in patients with CSM.

Materials and methods: One hundred thirty-five patients from our institution were prospectively enrolled from July 2022 to August 2023. A control group of age-matched and sex-matched healthy individuals was established. The 6MWT was conducted in strict accordance with established guidelines. The Nurick score, the Prolo score, the Cooper-myelopathy-scale score (CMS), the Japanese Orthopedic Association score (JOA) and the European-myelopathy-scale score (EMS) were assessed preoperatively. Visual Analog Scale (VAS) for pain or numbness and Oswestry Neck Disability Index (NDI) were also collected. Radiographic parameters were measured and recorded. Continuous variables between patients and controls were compared by applying the t test. The χ 2 test was used to compare gender ratios between groups. Pearson correlation analysis was used to analyze the association between continuous variables and ordinal variables. Subgroups of CSM patients were analyzed according to global spinal alignment types based on whether the SVA was ≥50 mm. Clinical scores and imaging parameters were compared by t test.

Results: The preoperative 6-minute walking distance (6MWD) of CSM patients was 309.34 ± 116.71 m, which was significantly lower than that of the controls (464.30 ± 52.59 m, P <0.01). The 6MWD was significantly correlated with scores on all clinical scales except the VAS. CMS Lower extremity score had the strongest correlation with preoperative 6MWD in CSM patients (r=-0.794, P <0.01). Of the sagittal alignment parameters, only C7 sagittal vertical axis (SVA) and T1 slope were significantly correlated with 6MWD(r=-0.510, -0.360, respectively). CSM patients with SVA >50 mm had significantly lower 6MWD than CSM patients with SVA ≤50 mm (168.00 ± 137.26 vs. 346.24 ± 84.27 m, P <.01).

Conclusions: The 6MWD of CSM patients was significantly lower than that of the healthy population and correlated well with commonly used clinical scales. The 6MWD can potentially assist in the assessment of functional status in patients with CSM.