Abstract
STUDY DESIGN: A prospective observational international study. OBJECTIVE: The aim of this study was to evaluate outcomes of decompressive surgery in patients with very severe degenerative cervical myelopathy (DCM). SUMMARY OF BACKGROUND DATA: Although decompressive surgery has been evidenced as a safe and effective approach for patients with myelopathic deficiencies, studies have suggested residual disability following treatment in patients with more severe disease presentation. METHODS: Postoperative outcomes of 60 patients with very severe DCM (modified Japanese Orthopaedic Association [mJOA] score ≤8) were compared to outcomes of 188 patients with severe DCM (mJOA 9-11). Postimputation follow-up rate was 93.1%. Unadjusted and adjusted analyses were performed using two-way repeated measures of covariance. RESULTS: The two cohorts were similar in demographics, length of duration of myelopathy symptoms, source of stenosis, and surgical approaches used to decompress the spine. The very severe and severe cohorts differed in preoperative Nurick grades (4.97 vs. 3.91, respectively, P < 0.0001) and Neck Disability Index scores (45.20 vs. 56.21, respectively, P = 0.0006). There were no differences in Short Form 36 (SF-36v2) physical (PCS) and mental (MCS) component summary scores. Both cohorts improved in mJOA, Nurick, Neck Disability Index, and SF-36v2 PCS and MCS scores. Despite the substantial postoperative improvements, patients in both cohorts had considerable residual symptoms. Two-thirds of the patients in the very severe cohort had severe (mJOA ≤11) or moderate (mJOA ≤ 14) myelopathy symptoms at 24 months follow-up. Longer duration of disease was associated with poorer treatment response. CONCLUSION: Decompressive surgery is effective in patients with very severe DCM; however, patients have significant residual symptoms and disability. The very severe subgroup (mJOA ≤8) of patients with DCM represents a distinct group of patients and their different clinical trajectory is important for clinicians and patients to recognize. Duration of symptoms negatively affects chances for recovery. Whenever possible, patients with DCM should be treated before developing very severe symptomatology. LEVEL OF EVIDENCE: 2.