Anterior cervical corpectomy for the treatment of spondylotic myelopathy: results of a prospective double-armed study with a three-year follow-up.

Abstract

Since the first description in the 1950s, cervical spondylotic myelopathy (CSM) has posed many challenges to neurosurgeons and spine surgeons. Direct comparison among different operative approaches has failed to produce valuable results due to either an insufficient number of enrolled patients or a lack of standardization of baseline conditions. This prospective double-armed non-randomized study with a 3-year follow-up involved 80 patients with degenerative cervical myelopathy surgically and conservatively treated. The primary aim was to determine the efficacy of corpectomy in mild-moderate and severe CSM and to compare the outcomes of conservative and surgical treatment. Eighty patients were stratified into two arms, on the basis of the mJOA score: mild-moderate (mJOA ≥12) and severe myelopathy (mJOA score <12). Each arm was subdivided into two treatment groups (operative or conservative): A1, mild-moderate myelopathy treated with corpectomy; A2, mild-moderate myelopathy treated conservatively; B1, severe myelopathy treated with corpectomy; B2, severe cervical myelopathy treated conservatively. The clinical outcome was evaluated with the modified JOA score, timed 10-meter walk, Mehalic grade, motor evoked potentials, the SF-12, and further assessed by external observers blinded to the type of treatment. No significant differences in the recovery rates were found between the A1 and A2 groups at 6 months, although better results were recorded in the surgical groups (A1 and B1) at 12 months and at the final follow-up, as suggested by the significantly higher recovery rates. Multivariate analysis showed an inverse correlation between the duration of symptoms and the recovery rate (P<0.0001). Moreover, the preoperative timed 10-meter walk (P<0.004), the preoperative hypointensity on T1-weighted MR images (P<0.001), a higher Mehalic grade (P<0.02), the pre-treatment MEP (P<0.002), and the preoperative spinal canal diameter (P<0.004) significantly influenced the recovery rate. This prospective double-armed non-randomized study demonstrates that corpectomy is an effective and safe treatment, especially for severe forms of myelopathy. In mild-moderate conditions, a discrepancy between neurological improvement and expressed level of satisfaction was found. The present results also show that a multiparametric evaluation is crucial for proper patient selection for corpectomy.