Atlantoaxial Pedicle Screw Research Articles

Surgical treatment of different types of odontoid process fractures and clinical results

Objective To discuss surgical treatment methods for different types of odontoid process fractures and evaluate their therapeutic results. Methods Twenty-one patients with odontoid process fracture were classified into three types, ie, type Ⅰ,type Ⅱ and type Ⅲ fractures accoding to An-derson-D' Alonzo classifications. There were three patients with type Ⅰ fractures treated by traction of oc-cipital-jaw band and fixed with head-neck-chest plaster at 6 weeks and 13 with type Ⅱ fractures treated by cannulated screws following skull traction and reduction. As for five patients with type Ⅲ fractures, one was fixed with cannulated screws and the other four with atlantoaxial pedicle screw after the fracture got diaplasis by skull traction. Results All patients were followed up for 6-48 months (average 9 months), which showed bony union, with no complications in all patients. Conclusions Odontoid process fractures should be. treated according to different types. Conservative treatment for type Ⅰ fracture and cannulated screw fixation for type Ⅱ and low type Ⅲ fractures can attain satisfactory result. Aflanto-axial pedicle screw fixation can be an alternative for low type Ⅲ fractures that are not suitable for cannu-luted screw fixation. Key words: Spinal injuries; Cervical vertebrae; Odontoid process; Fracture fixation,in-ternal

Application of C1-C2 pedicle screw fixation in treatment of extension-type odontoid fracture combined with atlantoaxiai subluxation

Objective To explore the clinical outcome of atlantoaxial pedicle screw instrument in treatment of extension-type odontoid fracture combined with aflantoaxial subluxation. Methods From December 2002 to December 2006, seven patients with extension-type odontoid fracture combined with at-lantoaxial subluxation were reduced and fixed with atlantoaxial pedicle screw instrument of Vertex system under general anesthesia. There were five males and two females, at mean age of 39.2 years (range 21-59 years). All odontoid fractures were fresh type Aderson Ⅱ. JOA scores of spinal core function was 8.6-14.9 (average 10.7) preoperatively. The X-ray examination, CT scanning and skull traction were performed in all patients preoperatively. Results There found no severe complications such as injuries of vertebral artery, nerve root and spinal cord postoperatively. All patients obtained complete reduction and healing of the fracture and dislocation. The mean off-bed time was four days (3-6 days) after opera-tion. A follow-up for 12-36 months (average 22 months) in all patients showed that the clinical symptom was improved significantly six months postoperatively and that all screws were in proper position verified by X-ray and CT scanning. All patients obtained solid bony union on radiographs, with no loosing or breakage of instrument. The postoperative JOA scores was 13.5-16.9 (average 15.8). Conclusions Allantoaxial pedicle screw fixation has advantages of intraoperative reduction, reliable fixation and high fusion rate and can be used as an effective method for extension-type odontoid fracture combined with at-lantoaxial subluxation. Key words: Spinal fractures; Aflantoaxial subluxation; Fracture fixation, internal; Pedicle screw