Background: Transarticular screw fixation is seen as the "gold standard" in instrumented fusion of C1 and C2. However, drawbacks are the necessity of a reduction before instrumentation and a risk of vertebral artery injury. Therefore, C1 lateral mass and C2 isthmic screws are an alternative. The present study assessed the feasibility of C1-2 stabilization with C1 lateral mass and C2 isthmic screws and evaluated quality of life.
Method: All data of 35 consecutive patients treated from May 2006 to September 2009 were collected. Patients had C1 lateral mass and C2 isthmic screws.
Results: Twenty patients were operated on for traumatic instabilities, six for neoplastic instabilities, five for infectious instabilities and two each for degenerative and congenital instabilities. Sixty-six of 70 C1 screws had an ideal position, while four were placed suboptimal without the need for revision. Twelve of 68 C2 screws were not ideal but acceptable; one screw needed a surgical revision. There was one non-surgery related case of neurological deterioration after multilevel instrumentation. No vascular injuries occurred. Realignment was correct in all patients. After a median follow-up of 12 months, patients showed a reduction of pain, disability and improvements in EQ-5D items. SF36 data compared with a normative population and a historical cohort showed lower levels of function in all domains.
Conclusion: C1-C2 instrumented fusion with lateral mass and isthmic screws is a safe procedure. Sufficient screw position and alignment was possible in all cases. Therefore, at our institution transarticular screws were abandoned in favor of C1 lateral mass and C2 isthmic screws.