OBJECTIVETo investigate the mechanism, clinical features and treatment of odontoid fracture combined with lower cervical spinal injury.

METHODSFrom January 1999 to December 2004, 57 cases of type II or shallow type III odontoid fractures were studied retrospectively. Six cases were found combined with lower cervical injury, the mean age was 54 years, and 4 of the 6 cases were complicated with cervical spondylarthrosis or ankylosing spondylitis. For the lower cervical injury, fracture-dislocation was found in 2 cases, the disruption of disc and ligament was found in 4 cases among which 2 cases were suffered from incomplete spinal cord injury; Both were caused by lower cervical spinal injury. All of the 6 cases were performed with surgery in odontoid fracture and lower cervical spinal injury simultaneously; Lower cervical spinal injuries were stabilized firstly in 2 cases, which responsible for neurological involvement; For the other 4 cases without neurological involvement, stabilization was performed in odontoid fracture firstly in 2 cases, due to inability to achieve reduction of odontoid fracture preoperatively, however, for the another 2 cases with anatomic reduction of the odontoid fracture preoperatively, lower cervical injuries were stabilized firstly.

RESULTSAfter an average follow-up of 10 months, all cases were obtained solid fusion both in odontoid fracture and lower cervical spinal injury, and without the complications associated with operation and prolonged bed rest. Two cases with neurological defect improved 1 scale in Frankel score.

CONCLUSIONSThe incidence of odontoid fracture combined with lower cervical spinal injury is about 10.5% of the odontoid fracture, and it is vulnerable in the elderly patient with cervical spondylarthrosis. MRI should be used routinely for accurate diagnosis. Surgical stabilization is the choice of treatment due to facilitating early rehabilitation and reducing the complications. The surgical schedule is planned according to the fact of neurological involvement and the extent of stability between the odontoid fracture and lower cervical spinal injury.