Atlantoaxial transarticular screw fixation with morselized autograft and without additional internal fixation: technical description and report of 57 cases.

STUDY DESIGN

Retrospective clinical and radiologic evaluation of posterior C1-C2 fusion by transarticular screw (TAS) with morselized autograft and without additional internal fixation.

OBJECTIVE

Description and assessment of a modified Magerl technique.

SUMMARY OF BACKGROUND DATA

The majority of spine surgeons prefer to supplement the posterior TAS with a posterior cable-secured strut graft and a postoperative rigid cervical orthosis. Our hypotheses are that the 2 posterior TASs alone are enough for stabilization and that morselized cancellous grafts have similar clinical result as the structural graft.

METHODS

Fifty-seven consecutive patients, including atlantoaxial instability in 52 and atlantoaxial dislocation in 5, were treated by bilateral TAS fixation alone with morselized grafts by the same surgeon. The postoperative external immobilization was abandoned.

RESULTS

A total of 114 transarticular screws were placed. Radiographs demonstrated all the screws were placed satisfactorily except two. One screw penetrated into the occipito-atlantal joint, and the other one slightly breached the vertebral artery groove but did not injure vertebral artery. None of these 2 screws was associated with clinical sequelae. There were 2 patients who had postoperative iatrogenic C2-C3 instability on dynamic radiograph, which did not need treatment. These cases had an average follow-up of 47 months (range, 24-76 months). All patients attained solid fusion without screw failure.

CONCLUSIONS

Bilateral transarticular screws alone and morselized grafts have high fusion rate in atlantoaxial arthrodesis without instrument failure. TAS fixation could provide stability that is clinically equivalent to the standard screws plus tension band construct as described by Magerl. With anatomic reduction and ideal screw position, additional internal fixation and postoperative collar are not necessary.