In this study, we conducted a single-center, retrospective analysis of 47 consecutive patients who underwent either two-adjacent-level ACDF with PEEK cages (n = 22) or one-level ACCF with TMC (n = 25) for cervical spondylosis. The patients were enrolled between May 2014 and December 2015. The involved vertebral levels were C3-C4-C5, C4-C5-C6, or C5-C6-C7. Patients with recent infection, neoplasm, trauma, rheumatoid arthritis, autoimmune disease, kyphotic deformity, or an ossified posterior longitudinal ligament were excluded from the study. All patients were symptomatic after appropriate conservative management. All operations were performed by the same surgical group. Patients with significant compression from the vertebral level were treated with ACCF, while those with compression from the disc level without compression from the vertebral level were treated with ACDF. When mild to moderate compression existed at the vertebral level and significant compression existed at the disc level, patients received either an ACDF or ACCF approach after a detailed discussion of potential benefits and risks between the patient and the surgeon. The study was performed in accordance with the provisions of the Declaration of Helsinki. Ethical issues concerning patients' rights and interests, safety and health were discussed by the medical ethics committee of The Affiliated Hospital of Xuzhou Medical University and agreed in line with the principles of medical ethics. The permit number is xyfylw2014015. For the retrospective study the patient consent was not necessary.
The patients were categorized into two groups according to the type of surgery received: the ACDF group included patients who received two-adjacent-level ACDF, and the ACCF group included patients who received one-level ACCF. Cages were packed with anterior cortical bone of the adjacent vertebra in the ACDF group or autograft from the resected vertebra in the ACCF group. All surgeries were stabilized with a fixed Atlantis anterior fixation plate (Weiman, Tianjin, China). Screws were used in the cranial and caudal vertebra in all patients. Two additional screws were placed in the middle vertebrae in the two-adjacent-level ACDF group. PEEK cages (Weiman) were used as interbody grafts during the ACDF procedure, and TMCs (Weiman) were used as structural grafts during the ACCF procedure. The TMC is open and parallel ends design and the cage is parallel ends design.
The operation time, blood loss, and hospital stay of the included patients were recorded. Follow-ups were conducted at 2 weeks and at 3, 6, and 12 months after the surgery. Visual analogue scale (VAS) was used to evaluate clinical outcome. The Japanese Orthopaedic Association (JOA) score was used to assess functional recovery.
Plain radiography and flexion/extension lateral radiography were performed at preoperative, 2 weeks, and 3, 6, and 12 months after surgery to assess radiological parameters, including the overall cervical sagittal angle (CSA), segmental angle (SA) and the height of the treated level, and fusion status. The CSA and SA were measured by Cobb’s method. The CSA was defined as the angle formed by the lines drawn parallel to the lower endplates of C2 and C7 on a neutral lateral radiograph. The SA was defined as the angle formed between the superior margin of the upper vertebral body and the inferior margin of the lower vertebral body of the treated level on a neutral lateral radiograph. Subsidence of more than 3 mm was considered to be statistically significant . Fusion was defined as the presence of continuous bridging trabeculae between the cage and adjacent endplates and the absence of motion of more than 2 mm between spinous processes on flexion/extension at the treated level . Two independent observers recorded the outcomes.
Statistical analysis was performed using SPSS version 12.0 (SPSS, Chicago, IL, USA). Quantitative data are presented as the mean ± standard deviation. Chi-square tests were used to analyze differences in preoperative demographic characteristics and in clinical and functional outcomes between the two groups. Fisher’s exact test was used to analyze differences in complications between the groups. P-values of <0.05 were considered statistically significant.