Implantation of cervical pedicle screw for treatment of cervical spine fracture-dislocation Manipulation technique, complications and biocompatibility / 中国组织工程研究

ABSTRACT

BACKGROUND: The characteristics of cervical anatomy and pedicle screw, operational specification, and individual screw implantation are the key factors of a successful implantation treatment.OBJECTIVE: This study was designed to investigate the cervical pedicle screw and host response as well as the recovery of spinal nerve functions during the surgery and follow-up period of cervical spine fracture-dislocation.DESIGN: A case analysis.SETTING: Department of Orthopaedics, General Hospital of Shenyang Military Area Command of Chinese PLA, Shenyang, Lianning Province, China.PARTICIPANTS: A total of 41 patients with cervical spine fracture-dislocation, who have complete follow-up data, were admitted to the Department of Orthopaedics, General Hospital of Shenyang Military Area Command of Chinese PLA between February 2002 and February 2006. Of the included patients, 18 were complicated by spinal cord injury (according to Frankel classification system, 6 were graded as A, 1 as B, 4 as C, and 7 as D.METHODS: Forty-one patients with cervical spine fracture-dislocation were treated by implanting a screw through the cervical pedicle and fixing it. Prior to surgery, all patients were subjected to X-ray, CT and MRI examinations. According to measurements, each cervical pedicle screw was individually implanted. The entire surgery was accomplished by Xiang Liang-bi, chief physician, whose qualification corresponds to the responsibilities.MAIN OUTCOME MEASURES: Material and host response during and after screw implantation as well as in the follow-up period. Recovery of spinal nerve function after screw implantation.RESULTS: All patients were followed up for 6-12 months and all incisions were healed primarily. Material and host response during the process of screw implantation A total of 218 screws were implanted. After initial implantation, 12 screws were loosened, and such a phenomenon disappeared in 11 screws by adjusting inserting point and inserting direction or/and increasing screw diameter or length. The remaining 1 screw was stabilized by increasing the fixed segments. After drilling, poles of 10 screws bled much and treated by hemostasis. C1-2 venous plexus hemorrhage was caused in 3 patients and stopped by compression, and Apofix internal fixation was used in 1 of 3 patients due to unclear surgical visual field. Material and host response after surgery and during the follow-up A total of 218 screws were inserted. Of the 218 screws, 196 were in correct position, and 22 were deviated to different degrees. Deviation of 1 screw caused injury to nerve root and that of another screw led to injury to blood vessel. Thirty-eight patients acquired satisfactory reduction and bone union. Three patients presented with symptoms of nerve root irritation due to incomplete reduction in the old fracture-dislocation. Among the 3 patients, 1 was subjected to anterior approach due to screw removed, and neither injury to vertebral artery, spinal cord, and nerve root nor internal fixation destroy was found in any other patients. Recovery of spinal nerve function after implantation Among the 18 patients complicated with spinal cord injury, 6 patients, who were assessed as grade A spinal cord injury, did not exhibit improvement in spinal cord function, while the remaining 12 presented with 1 or 2 grades of improvement.CONCLUSION: There is a lower probability for biocompatibility reaction, and spinal nerve function recovers better after implantation of cervical pedicle screw. So implantation of a cervical pedicle screw system is an effective and relatively safe method for treatment of cervical spine fracture-dislocation.