Comparison of a zero-profile anchored spacer (ROI-C) and the polyetheretherketone (PEEK) cages with an anterior plate in anterior cervical discectomy and fusion for multilevel cervical spondylotic myelopathy.

Purpose: We aimed to analyze the clinical and radiographic efficacy of a new zero-profile anchored spacer called the ROI-C in anterior discectomy and fusion (ACDF) for multilevel cervical spondylotic myelopathy (MCSM).

Method: We retrospectively reviewed the clinical, radiological outcomes and complications of multilevel ACDF with the ROI-C or with the polyetheretherketone (PEEK) cages with an anterior plate. From April 2011 to April 2014, 60 patients with MCSM were operated on using ACDF, with the ROI-C in 28 patients and PEEK cages with an anterior plate in 32 patients. The operative time, intraoperative blood loss, and clinical and radiological results were compared between the ROI-C group and the cage-plate group.

Results: The mean follow-up time was 23.8 ± 6.6 months, ranging from 12 to 36 months. At the first month and the last follow-up, the neck disability index (NDI) scores were decreased, and the Japanese Orthopedic Association (JOA) scores were significantly increased, compared with the presurgical measurements in both groups. There were no significant differences in NDI scores or JOA scores between the two groups (P > 0.05), but there were significant differences in the operation time, blood loss and the presence of dysphagia (P < 0.05). In addition, the cervical Cobb angle and disk height showed significant corrections, compared to those measured before the operation. There was no adjacent disc degeneration observed in the ROI-C group, and one patient with skip levels showed disc degeneration of the normal level between the skip levels in the cage-plate group. The degeneration rate of the cage-plate group was 3.1 %.

Conclusions: The primary clinical and radiographic efficacies of both ROI-C and cages with plates in ACDF for MCSM were satisfactory; both approaches could improve and maintain cervical lordosis and disk height. However, the ROI-C was associated with a simpler operation, a shorter operation time, less blood loss, and a lower risk of postoperative dysphagia compared to the PEEK cage with an anterior plate.