| Part I : Biomechanical analysis of the intergrated anterior cervical plate cage benezech implantobjective: To investigate the effect of intergrated anterior cervical plate cage benezech implant on the cervical spine stability and biomechanical character, in order to provide biomechanical basis for clinical application.Methods: Five types were made in 6 almost fresh adult cadaveric cervical spines (C2-T1): intact condition, simulated vertebral disc removal, PCB fixation, CBK fusion cage fixation, CBK fusion cage and Secuplate titanium plate conjoined fixation. Their stability was tested by experimental stress analysis at C5~ 6.Results: 1. The cervical spine became unstable and the range of motion increased significantly after the removal of vertebral disc. There was significant difference between intact condition group and simulated vertebral disc removal one (P<0.05) . 2. After instrumentation of cervical PCB fixation, the strength increased 24%, the flexibility decreased 31%, the stiffness increased 14.3%, and the migration decreased 15%, which were compared with simulated vertebral disc removal group. And there was significant difference between PCB fixation group and simulated vertebral disc removal one (P<0.05) . And the range of motion of cervical spine after the insertion of correct size of PCB was similar to that of intact condition. 3. The CBK fusion cage group was unsatisfied under extension and torsion tests, but there was significant difference between CBK fusion cage fixation group and simulated vertebral disc removal one (P<0.05). 4. After instrumentation of cervical CBK fusion cage and Secuplate titanium plate conjoined fixation, the strength increased 27%, the flexibility decreased 38%, the stiffness increased 17%, and the migration decreased 17%, which were compared with simulated vertebral disc removal group. And there was significant difference between CBK fusion cage and Secuplate titanium plate conjoined fixation group and simulated vertebral disc removal one (P<0.05) . But the motion of the segment following insertion of CBK fusion cage and Secuplate titanium plate conjoined fixation almost lost and the range of motion of the adjacent segment increased.Conclusions: Both secuplate titanium plate fixation and CBK fusion cage fixation have biomechanical weak points., but some complementation existed between them. And the PCB has occupied their advantages. The PCB implant might have little effect on the biomechanical property of the spine and could match the biomechanical environment.Part II: Clinical application of the intergrated anterior cervical plate cage benezech implantObjective: To evaluate the effect of integrated anterior cervical plate cage benezech (PCB) implant on Clinical application.Methods: After a standard anterior cervical disectomy and preparation of the disc space, the correct size of PCB implant was inserted . Self-tapping screws were inserted without any intensifier. Variant and autogenous bone chips were used . Forty-three cases underwent fixation by one segment, twenty-two by two segments and three by three segments. This implant was used in 68 cases that were followed up for 4-36 months (average 17 months), of which there were 18 with cervical trauma complicated by acute intervertebral disc protrusion and 40 with cervical spondylitic myelopathy, and 10 patients who suffered from traumatic instability of cervical spine.Results: No non-fusion case of cervical vertebrae interbody was found through x-ray or CT. The preoperative score was 5-12 points (average 9.97) according to the Japanese Orthopaedic Association (JOA) in cervical spondylitic group and the postoperative score was 12-17 points (average 15.95), with mean recovery rate of 85.9%.The changes of middle disc height and overall cervical curvature was obviously difference between preoperative datas and postoperative ones (P<0.01). 28 cases were differently made recovery according to Frankle classes,with cervical trauma complicated by acute intervertebral disc protrusion or with being suffered from traumatic instability of cervical spine, of which there one case was made recovery from A to B, one form A to C, two from B to C, two form B to D, six from C to D ,five from C to E , ten from D to E , and one case in class A had no change. At the same time, by the Barthel index, five cases were full marks (100 scores), ten cases were light defilade (>60scores), seven cases were midrange defilade (40" 60scores), six cases were pond defilade (≤40 scores). No intraoperative complications occurred except for one screw loosing and backed out. In the meantime, no complications were found in the donor site.Conclusions: The PCB implant can prevent from complications, provide immediately biomechanical stability, and restore intervertebral height and lordosis. So it is a safe and reliable system on Clinical application. |
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