Atlantoaxial pedicle screw system for odontoid fracture-caused atlantoaxial instability in 21 cases / 中国组织工程研究

ABSTRACT

BACKGROUND: Posterior transarticular screw fixation (Magerl’s) is recommended for atlantoaxial instability. However,some patients do not suit for Magerl’s fixation. OBJECTIVE: To evaluate the clinical outcomes of atlantoaxial pedicle screw system in the treatment of atlantoaxial instability from odontoid fracture. DESIGN,TIME AND SETTING: The retrospective case analysis was performed at the Department of Orthopedics,Sichuan People’s Hospital between July 2004 and June 2007. PARTICIPANTS: Twenty-one cases of atlantoaxial instability from odontoid fracture were selected. According to Anderson and D’Alonzo classification,9 of them belonged to type II odontoid fracture with atlantoaxial instability and 12 to type Ⅲ with severe atlantoaxial dislocation. All cases suffered pain at occipitocervical part and limited activities of cervical spine. According to Frankel classification in function of spinal cord,16 cases of them belonged to Grade E and 5 cases to D. METHODS: All cases were fixed with C1 and C2 pedicle screws system following skull traction and reduction. MAIN OUTCOME MEASURES: Biocompatibility between materials and host; bone graft fusion and functional improvement. RESULTS: No vertebral artery injury or spinal injury was found during operation,neither incision infection was. All cases were followed up for at least 8 months. Postoperative radiograph and CT detection revealed good positions of all screws with no loosening or breakage. All fractures healed within 5 months,and activities of cervical vertebra were not obviously limited except slightly limited rotation function. As for nerve function,5 cases of Grade D recovered up to Grade E. CONCLUSION: Posterior pedicle screw fixation system exhibits no specific biocompatibility responses. It greatly improves atlantoaxial stability and promotes functional recovery of spinal cord but has little influence on cervical function.