ObjectiveTo evaluate the effectiveness of the single segmental cervical disc replacement with ProDisc-C, and to explore the location change of the flexion/extension center of rotation (COR) of the target level as well as its clinical significance. MethodsBetween June 2010 and February 2012, 23 patients underwent single segmental cervical disc replacement with ProDisc-C, and the clinical data were retrospectively analyzed. Of 23 patients, 9 were male, and 14 were female with the age range from 27 to 65 years (mean, 45 years), and the disease duration ranged from 10 to 84 months (mean, 25 months). There were 15 patients with radiculopathy, 5 patients with myelopathy, and 3 patients with mixed cervical spondylosis. The involved segments were C4,5 in 5 cases, C5,6 in 14 cases, and C6,7 in 4 cases. Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) were adopted to evaluate the effectiveness. Preoperative and Postoperative radiographic parameters, such as cervical overall range of motion (ROM), target segmental ROM, the adjacent segmental ROM, and intervertebral height were compared. Besides, the location changes of the COR of the target level were further analyzed by the alteration of its coordinates (COR-X,COR-Y), and the relationships between the location changes of the COR and the effectiveness or the radiographic results were analyzed. ResultsAll the operations were completed successfully; 1 case had hoarseness after operation, which disappeared at 3 months after operation. All cases were followed up 18.3 months on average (range, 6-36 months). There was no device migration, loosening, subsidence, or fracture at last follow-up. The JOA score increased significantly and the NDI score decreased significantly at last follow-up when compared with preoperative scores (P<0.05). No difference was found in the cervical overall ROM, target segmental ROM, the adjacent segmental ROM, and the COR-Y of the target level between pre-operation and last follow-up (P>0.05); while the intervertebral height and the COR-X increased significantly (P<0.05). The change of the COR-X had no obvious correlation with the postoperative JOA, NDI, and target segmental ROM (P>0.05). According to whether the difference of the COR-X between pre- and post-operation was less than the average value 1.86 mm or not, the patients were divided into 2 groups; significant difference was shown in the postoperative target segmental ROM between 2 groups (P<0.05), but no significant difference was found in the postoperative JOA、NDI, cervical overall ROM, adjacent segmental ROM, and the intervertebral height between 2 groups (P>0.05). ConclusionSingle segmental cervical disc replacement with ProDisc-C can obtain satisfactory outcomes. The cervical overall ROM, target segmental ROM, and adjacent segmental ROM can be effectively maintained, and the intervertebral height is increased. The location of the flexion/extension COR of the target segment shifts forward after insertion of the ProDisc-C prosthesis, and the postoperative target segmental ROM becomes smaller as the distance of the displacement of the COR becomes greater.
ObjectiveTo explore early clinical effects of Centerpiece-based unilateral open-door cervical expansive laminoplasty plus centerpiece titanium minitype plate fixation, to research the data of the best slotting in the CT-based open-door cervical operation and to provide the reference for accurate operation. MethodsA retrospective analysis of the patients who had received Centerpiece-based unilateral open-door cervical expansive laminoplasty plus centerpiece titanium plate fixation from West China Hospital of Sichuan University from February 2013 to November 2013 were performed. The neurological function assessment results (JOA score), cervical curvature indexhave, Pavlov value, spinal canal cross-sectional area and different position, angle and depth of C7 lamina slotting data of all patients before and after the operation were all analyzed and compared. ResultsA total of 58 patients were included. The postoperative JOA score was significantly higher than that of the preoperative (9.4±2.9 vs. 14.7±2.6, t=11.417, P=0.000). The sagittal diameter of vertebral canal (21.3±2.1 mm vs. 9.7±2.1 mm, t=27.737, P=0.000), Pavlov value (0.92±0.13 vs. 0.44±0.12, t=30.621, P=0.000), and spinal canal cross-sectional area (276±37 mm2 vs. 129±25 mm2, t=32.104, P=0.000) at the end of the last follow-up were significantly greater than those of preoperative. When comparing the last follow-up with preoperative, cervical curvature index showed significant difference (11.2±11.5 vs. 9.3±11.7, t=-1.713, P=0.000). Significant differences were found in the comparison of the ideal position and angle of the open door of the C7 lamina and the angle and position of the operation (all P values >0.05); when comparing the position and angle of the ideal position and angle of the C7 lamina hinge with that of the actual operation, no significant differences were found (all P values >0.05); but when comparing the ideal depth with the actual depth of the operation, a significant difference was found (P<0.05). ConclusionCenterpiece micro plate used in posterior cervical expansive open-door laminoplasty forming operation of laminectomy fixed screw loosening and plate breakage, can effectively maintain the lamina in the open state, and prevent it to be closed. The patients have good recovery of nerve function after operation and the clinical efficacy is good.