Does snake-eye appearance affect the clinical outcome of ACDF in treating cervical myelopathy

Purpose: To explore the impact of the snake-eye appearance (SEA) on the efficacy of anterior cervical discectomy and fusion (ACDF) in treating Degenerative Cervical Myelopathy (DCM).

Methods: A total of 316 Patients were divided into three groups, those with SEA were in the SEA group, and those with the absence of SEA were in the non-SEA group. Meanwhile, in the non-SEA group, patients with grade 1 or 2 increased signal intensity (ISI) on T2-weighted MRI were in the ISI group, and the remaining patients without ISI were in the non-ISI group. The modified Japanese Orthopaedic Association scale (mJOA) and the neurologic functional improvement rate (IR) were measured. The number of patients who achieved upper-limb motor weakness improvement was recorded and compared. Propensity score matching (PSM) was used among the three groups.

Results: The postoperative JOA and IR were similar in the SEA and non-SEA group; however, they were significantly lower than in the non-ISI group after PSM(P < 0.05). Besides, only 32.1% of patients in the SEA obtained an improvement of upper-limb motor weakness, which was the lowest in three groups after PSM (60.7% in the non-SEA group and 78.6% in the non-ISI group, P < 0.05).

Conclusions: We suggested that patients with SEA tend to achieve an inadequate neurological recovery after ACDF. Besides, a SEA may be an unfavorable prognostic factor for upper extremity motor function recovery.