Surgical treatment of odontoid fracture with atlantoaxial instability

English Keywords:Odontoid fracture  Atlantoaxial instability  Anterior approach  Posterior approach  Odontoid screw fixation  C1-2 pedicle screw fixation

English Abstract:

  【Abstract】 Objectives: To explore the appropriate surgical strategy of odontoid fracture complicated with atlantoaxial instability. Methods: From April 2005 to February 2014, 48 cases with type Ⅱ and shallow type Ⅲ odontoid fracture were surgically treated in our hospital, including 33 males and 15 females with an average age of 44.3±29.0 years old (ranging from 21 to 74 years old). Among them, there were 43 fresh fractures and 5 old fractures. According to Grauer type classification, 12 cases were type Ⅱa, 13 cases were Ⅱb, 11 cases were Ⅱc and 12 cases were shallow type Ⅲ. They all had trauma history, suffering from cervical pain and limited neck movement. All cases had received skull traction. Anterior odontoid screw fixation, posterior cervical instrumented fusion and Halo-vest external fixation were used in our series. 22 cases underwent anterior odontoid screw fixation. 24 cases underwent posterior cervical instrumented fusion, and the other 2 patients underwent Halo-vest external fixation because of old age and bad general condition. Among the anterior odontoid screw fixation cases, 1 patient complicated with C6 fracture received C6 subtotal resection and plate internal fixation. Among the cervical instrumented fusion cases, 4 cases underwent C2 lamina screw because of vertebral artery straddle. The fusion of fracture and the movement of neck were evaluated. Results: All the patients underwent the operation successfully. Two patients who underwent anterior surgery showed unsatisfactory reduction, one of them received a revision surgery by replacing a thick screw with solid fusion in later CT examination, the other one was treated with posterior cervical instrumented fusion and showed solid fusion after 4 months. Two patients suffered from superior laryngeal nerve injury but the symptom improved in 1 month. One case suffered from vertebal artery injury after insertion of the screw but the blooding stopped without clinical symptom. In the other one case, the pedicle screw invaded into the spinal canal, but no clinical symptom was observed. No CSF leakage or spinal cord injury was noted. All 48 patients were followed up for an average of 25 months (ranging from 12 to 120 months). Bony fusion was achieved in all the patients. Cervical movement in the group of anterior cannulated odontoid screw fixation recovered to normal, while the group of posterior C1-C2 screw-rod fixation had some degree of limitation in rotation. Conclusions: For Grauer type Ⅱ and shallow type Ⅲ odontoid fracture, surgical strategy should be based on the fracture type, reduction of skull traction, age and the general condition. Good therapeutic results can be achieved by choosing individualized surgical plan.