Complications related to an Interlaminar Fixation Device supplemented to Transarticular Screw Fixation of Atlantoaxial Joint

In atlantoaxial transarticular screw fixation, two screws are usually used to fix both sides of the joint, but not in all cases. We have experienced two cases in which one of the two screws was not able to be applied, because of the high-riding of a vertebral artery and a severe deformity of C2/3 facet. In order to increase the stability, we used the Trois-X system (3XS), which is a rod and clamp system having a transverse bar, for posterior interlaminar fixation. Contrary to our expectation, we had a complication with this device. In the atlantoaxial transarticular screw fixation, C1/2 joints were fixed in neutral position in contrast to the posterior interlaminar fixation that fixes C1/2 in an extended position. So less room is available between the occiput and C1 posterior arch for the screw fixation. Since some parts of 3XS extend over the C1 posterior arch, the room between the C1 and the occiput was reduced and the device came in contact with the occipital bone in extension. The contact induced osteolysis of the C1 lateral mass that required a second operation. In atlantoaxial transarticular screw fixation, this bulky device should be used carefully for interlaminar fixation, especially for the patients having a short distance between the occiput and C1 posterior arch.