Cervical decompression and fusion using lateral mass plates (Axis Fixation System) were performed in ten patients with cervical myelopathy. Three patients had cervical spondylotic myelopathy (CSM); three, rheumatoid arthritis (RA); two, OPLL; one, spinal cord tumor and one, traumatic facet locking. At first, laminoplasty was performed in nine patients and facet locking was surgically reduced in one. Secondly, the plates were placed on the bilateral lateral masses and cancellous bone screws (3.5mm in diameter) were inserted outward in the axial plane and parallel to the facet joints in the sagittal plane. Finally, bone chips were packed in the facet joints for all patients and en-bloc iliac bones were placed intersegmentally between the opened lamina for five patients. Neither neurological nor vascular complications were seen. At one-year follow-up on average, neck pain and myelopathy were improved and bone union was completed in all patients. Vertebral body translation in seven patients was 4.2mm before the surgery, 0.7mm after the surgery, and 1.1mm at the follow-up period. The correction of translation was lost in two cases of one-level fusion and osteoporosis. The sagittal alignments of fusion area were preserved in all except for a patient with one-level fusion. CAT analysis of 50 screws showed that screws inserted 15 to 25 degrees outward provided secure anchorage of the bone without artery injuries.
