Modified posterior transarticular screw fixation for atlantoaxial instability / 中国矫形外科杂志

[Objective]To explore the techniques and effect of atlantoaxial instability with posterior transarticular screw fixation.[Method]A prospective clinical analysis was performed for the results of the modified posterior C1、2 transarticular screw fixation,in which the middle site of lower margin in the axial inferior articular process was used as the screw entry point in the procedure.Twenty cases of atlantoaxial instability underwent the modified C1、2 stabilization with morselized autograft from September 2001 to September 2006.There were 15 males and 5 females,averaged 32.2 years(range 17 to 49 years).Of them,4 cases suffered from fresh injuries,14 from old trauma,1 from congenital deformity,and 1 from intraspinal tumor.Postoperative indexes including the reduction extent of vertebral body,internal fixation,bone fusion,clinical symptoms and their complication were observed periodically.[Result]Bilateral screw fixation was used alone in 17 cases,with Gallie interspinous wiring for added stability in 3.Anatomical reduction of the atlantoaxial joints was achieved in19 cases,while rotational dislocation was restored to a great extent in 1.Fixation of all the internal devices was very well in the group.All cases were followed up from 16 to 64 months(21 months on average).C1、2 bony fusion was obtained in postoperative 2 to 3 months,clinical symptoms relieved and no complications occurred.[Conclusion]The modified posterior transarticular screw fixation using new screw entry site is recommended as an effective treatment for C1、2 instability due to its simple procedure and satisfying curative effect.

Atlantoaxial Instability due to Hypoplasia of the Odontoid Process

The authors present a case of a 39-year old man, admitted with neck pain and tingling sensation on his right upper extremity. On radiological investigation, atlantoaxial instability due to odontoid process hypoplasia and mild upper cervical cord compression by abnormal soft tissue were revealed. We performed posterior C1-2 transarticular screw fixation with posterior bone graft and could obtain good postoperative result.

Posterior C1-2 Transarticular Screw Fixation in Atlantoaxial Instability

Posterior transarticular screw fixation is known to be one of the best surgical method for the atlanto-axial instability. Between April 1995 and February 1997, this technique was used in the treatment of 21 patients(10 men, 11 women) suffering from this condition. The average age at the time of operation was 39 years(range, 17 to 63). and mean follow-up period was 14(mean 3 to 25) months. The indication for fusion were nine cases, type II-A odontoid process fracture; three cases, type II-P odontoid process fracture; three cases, os odontoideum; three cases transverse ligament laxity due to rheumatoid disease; and three cases, transverse ligament injury without bone fracture. Eleven operations involved cases were operated with posterior C1, 2 transarticular screw fixation using a 3.5 mm cortical screw augmented th interlaminar iliac graft and sublaminar wire fixation. The other ten patients underwent the same surgery without sublaminar wire fixation. In two cases d screw were misplaced; one was placed lateromedially and the other caused widening of the joint capsule space, but there were corrected by reoperation. Patients were ambulated with Philadelphia neck collar on the first post-operation day. At the end of three months follow-up, bone union was seen in all cases, and the following conclusions may be drawn: 1) Immediately after surgery, ambulation is possible; 2) The rate of occurrence of bone union is high; 3) A halo vest is not needed; 4) Sublaminar wiring is also unnecessary.