Single-level Cervical Fusion Research Articles

Motion Compensation Associated With Single-Level Cervical Fusion: Where Does the Lost Motion Go?

Seven adult human cadaveric cervical spines (C2-T1) were biomechanically tested in a programmable testing device. Compare the effects of incremental single-level fusion at different levels of the cervical spine. Clinical studies have reported degenerative symptomatic disc disease at disc levels adjacent to fusion. No known study has attempted to delineate the effects of single-level fusion at different levels of the cervical spine. The spines were tested in flexion, extension, right and left lateral bending, and right and left axial rotation for 7 different conditions: harvested and 6 independent single-level fused conditions (i.e., C2-C3, C3-C4, C4-C5, C5-C6, C6-C7, and C7-T1). Segmental motion and global stiffness data were normalized to the harvested condition and compared using a 1-way analysis of variance followed by a SNK test (P < 0.01). Motion compensation was distributed among the unfused segments with significant compensation at the segments adjacent to fusion. Significant increases occurred at the level above C3-C4 and C4-C5 fusions, and below for C5-C6 and C6-C7 fusions in both flexion and extension. Increase motion compensation occurred at segments immediately adjacent to a single-level fusion. Significant differences occurred at the level above the fusion site for the C3-C4 and C4-C5 fusion in both flexion and extension. When the lower levels (C5-C6, C6-C7) were fused, a significant amount of increased motion was observed at the levels immediately above and below the fusion. However, greater compensation occurred at the inferior segments than the superior segments for the lower level fusions (C5-C6, C6-C7).

Hollow cylindrical polymethylmethacrylate strut for spinal reconstruction after single-level cervical corpectomy

This prospective study was conducted to assess the safety of using a cylindrical polymethylmethacrylate (PMMA) strut for fusion and reconstruction of the cervical spine after single-level cervical corpectomy. The authors describe the clinical results obtained in patients after surgery. Fifty-four patients underwent single-level cervical corpectomy, fusion, and spinal reconstruction that involved the placement of hollow cylindrical PMMA struts. In each patient, the spine was reinforced with anterior cervical plates. The PMMA struts were filled with autologous bone obtained from the resected vertebral body. Follow-up radiographic evaluation involved plain lateral dynamic radiographs and computed tomography (CT) scans. Neurological status was assessed pre- and postoperatively using the Nurick Scale. A total of 46 patients (85.1%) attended follow-up visits for a minimum of 2 years. Spinal stability was documented in all patients on 12-month plain dynamic lateral radiographs; in 37 patients (80.4%), complete osseous fusion was demonstrated on the 12-month CT reconstructions. In the remaining nine patients, complete fusion had been achieved by 24 months. The overall mean preoperative Nurick grade was 2.94 +/- 0.97, and this improved significantly to 1.71 +/- 0.77 (p < 0.05) by 24 months. There were no complications related to the hollow cylindrical PMMA strut. The findings of this preliminary study indicate that hollow cylindrical PMMA struts can be safely used in cervical fusion after single-level corpectomy and that the clinical results are satisfactory. The hollow cylindrical PMMA strut is a good substitute for spinal reconstruction and fusion when combined with plate fixation in patients who have undergone anterior cervical single-level corpectomy.

8. Effects of single-level cervical fusion on adjacent-segment motion compensation

8. Effects of single-level cervical fusion on adjacent-segment motion compensation

The Effect of Cervical Plating on Single-Level Anterior Cervical Discectomy and Fusion

The use of anterior plates for single-level cervical fusions is controversial. Previous studies that evaluated single and multiple-level fusions have shown increased and decreased fusion rates when cervical plates are used. The purpose of this study was to compare the clinical and radiographic success of single-level discectomy performed with and without anterior cervical plate fixation. During a 6-year period, 80 patients were surgically treated with a single-level anterior cervical discectomy. Forty-four patients had cervical plates, whereas 36 had fusions without plates (average follow-up, 2.3 years). The pseudarthrosis rates were 4.5% (2 of 44) for patients with plating and 8.3% (3 of 36) without plating. This difference was not significant (p = 0.653). There was no correlation of pseudarthrosis with sex, age, level of surgery, history of tobacco use, or the presence of previous anterior surgery. The amount of graft collapse for patients with plating was 0.75 mm compared with 1.5 mm for those without a plate (p = 0.026). The amount of kyphotic deformity of the fused segment was 1.2 degrees with plating compared with 1.9 degrees for patients without plating (p = 0.079). Ninety-one percent of the patients with plating had good or excellent results compared with 88% in the group without cervical plates, based on Odom's criteria. The addition of plate fixation for single-level anterior cervical discectomy and fusion is safe and not associated with a significant increase in complication rates. The pseudarthrosis rates are not significantly different when a cervical plate is used.