Objective To evaluate the cl inical appl ication value and short-term results of Vertex rod-screw system in cervical expansive open-door laminoplasty. Methods Between February 2008 and January 2010, 28 patients underwent Vertex rod-screw system fixation in cervical expansive open-door laminoplasty, including 15 cases of cervical spondylotic myelopathy, 5 cases of ossification of posterior longitudinal l igament，and 8 cases of cervical spondylosis with spinal stenosis. There were 16 males and 12 females, aged 42-77 years (mean, 61.3 years). The disease duration was 2 months to 11 years. The decompression range of cervical spine was from C3 to C7. The operation time, blood loss, Japanese Orthopedic Association (JOA) scores, and incidence of axial symptom were recorded. Pre- and postoperative curvature angles were demonstrated by the cross angle between posterior vertebral body margins of C2 and C7 on cervical X-ray films. The angle of the opened laminae was measured on CT scan at last follow-up. Results The operation time was (142.5 ± 22.8) minutes, and the blood loss was (288.2 ± 55.1) mL. All incisions healed by first intention. All patients were followed up 14-25 months (mean, 22 months). CT showed that no reclosed open-laminae or loosening and breakage of rod-screw system occurred at 1 week and 1 year after operation. The axial bony fusion rate was 89.3% (25/28). The improvement rate of JOA scores at 1 week after operation (29.5% ± 15.0%) was significantly smaller than that at 1 year after operation (64.9% ± 28.1%) (t=0.810, P=0.000). No case presented with C5 nerve root palsy. The cervical curvature angle was (24.29 ± 5.04)° before operation, was (23.89 ± 3.57)° at 1 week, and was (23.41 ± 3.35)° at 1 year after operation, showing no significant difference between pre- and postoperative angles (P gt;0.05). The angle of the opened laminae was (27.90 ± 4.74)° at 1 week after operation, and was (28.07 ± 4.21)° at 1 year after operation, showing no significant difference (P gt; 0.05). Conclusion Vertex rod-screw system in cervical expansive opendoor laminoplasty is effective in preventing reclosed open-laminae, which can reduce the loss of cervical curvature angle.
Objective To develop a high-accuracy, better-safety and low-cost cervical pedicle locator system for guiding cervical pedicle screw placement. Methods Cervical pedicle screw locator system was made of stainless steel. Ten cervical specimens from voluntary donation were divided into two groups according to compatibil ity design: control group inwhich 60 screws were planted into C2-7 by free hand; and experimental group in which 60 screws were planted into C2-7 under the guidance of three-dimensional locator system. The condition of screw insertion was observed and the accuracy was evaluated by the integrity of pedicle walls. Results In the control group, 32 screws (53.33%) were placed inside the pedicles and 28 (46.67%) were outside; 9 screws (15.00%) led to nerve root injury, 5 screws (8.33%) caused vertebral artery injury and no spinal cord injury occurred; and the qual ification ratio of screw insertion was 76.67% (excellent 32, fair 14, poor 14). While in the experimental group, 54 screws (90.00%) were placed inside the pedicles and 6 (10.00%) were outside; 1 screw (1.67%) caused vertebral artery injury and no nerve root injury and spinal cord injury occurred; and the qual ification ratio of screw insertion was 98.33% (excellent 54, fair 5, poor 1). There was significant difference between the two groups (P lt; 0.05). Conclusion Cervical pedicle screw locator system has the advantages of easy manipulation, high accuracy of screw placement and low cost. With further study, it can be appl ied to the cl inical.