Surgery for Degenerative Cervical Myelopathy: What Really Counts?

Abstract

Study design: Retrospective study (data analysis).

Objective: The purpose of this study was to assess the role of different factors on postoperative outcome of patients with degenerative cervical myelopathy (DCM).

Summary of background data: Ongoing degenerative changes of DCM lead to progressive neurological deficits. The optimal timing of surgical treatment is still unclear, especially in patients with mild DCM.

Methods: Patients with DCM treated in our clinic between 2007 and 2016 were retrospectively analyzed. Pre- and postoperative neurological function was assessed by the modified Japanese Orthopaedic Association Score (mJOA Score) at different stages. The minimum clinically important difference (MCID) was used to evaluate the improvement after surgery. The comorbidities were recorded using the Charlson Comorbidity Index (CCI). Possible associations between age, sex, CCI, preoperative symptoms duration, high signal intensity (SI) on T2-weighted magnetic resonance imaging (MRI) with mJOA Score and MCID were analyzed using univariate analysis and multivariate regression models. Additionally, subgroup analysis was performed according to the severity of DCM (mild: mJOA Score ≥15 points; moderate: mJOA Score of 12-14 points; and severe: mJOA Score <12 points).

Results: The mean age of the final cohort (n = 411) was 62.6 years (range: 31-96 years), 36.0% were females. High SI on T2-weighted MRI was detected in 60.3% of the cases. In the multivariate analysis, patients' age (P = 0.005), higher CCI (P = 0.001), and presence of high SI on T2-weighted MRI (P = 0.0005) were associated independently with lower pre- and postoperative mJOA Score and postoperative MCID. Subgroup analysis revealed age and high SI on T2-weighted MRI as predictors of pre- and postoperative mJOA. However, symptom duration did not influence neurological outcome according to the severity of DCM.

Conclusion: Surgery for DCM leads to significant functional improvement. However, better outcome was observed in younger individuals with lower CCI and absence of radiographic myelopathy signs. Therefore, DCM surgery, particularly before occurrence of high SI on MRI, seems to be essential for postoperative functional improvement regardless the above-mentioned confounders.Level of Evidence: 3.