Aim: To study the outcome of a cohort of patients with atlantoaxial instability (AAI) treated with a combination of C1-C2 transarticular screws and C1 lateral mass fixation.
Background: Several surgical techniques have been described for stabilization of the atlantoaxial complex. Each technique differs in its biomechanical properties, advantages, and disadvantages. In this series, we describe our experience with a combined four-point fixation technique that combines C1-C2 transarticular screws with C1 lateral mass fixation for AAI. Materials and methods: We present a single-center retrospective case series of 30 patients who were surgically treated for AAI over one decade. All patients presented with symptoms and signs of AAI and consequently underwent extensive clinical and radiological evaluation prior to surgery.
The median follow-up of our cohort was 8.3 months (3.143) with three patients lost to follow-up. Pre and postoperative symptoms were compared, including the visual analog scale (VAS) scores for neck and C2 radicular pain. All patientsf preand postoperative lateral dynamic cervical radiographs were evaluated and the posterior atlantodental interval (PADI) was measured. Ranawat functional disability score was used for pre and postoperative evaluation.
Results: Of the 30 patients, 8 were male and 22 female. The mean age was 60.4 years (18-78 years). The median hospital stay following surgery was 5 days (2.25 days). The mean preoperative VAS score for neck pain was 6.3 vs 4.3 at the first postoperative review (p ≤ 0.001) on paired comparison. Ranawat scores were available for 26 out of 30 patients. The scores improved following surgery in 8/26 (30.7%) patients, did not change in 17 (65.4%) patients, and deteriorated in only one patient (3.8%). Like the VAS score, improvement in Ranawat score following surgery was significant (p = 0.02).
Complications in this series included two unilateral intraoperative vertebral artery injuries associated with placement of C1-C2 transarticular screws, another patient had worsening C2 pain following surgery, and three patients had numbness in the C2 distribution following the procedure. Radiologically, two patients had suboptimal unilateral C2 screw placement despite satisfactory intraoperative fluoroscopic imaging. There were no infections and no implant failure.
Conclusion: The addition of C1 lateral mass screws to C1-C2 transarticular screw fixation for the treatment of AAI is an effective and safe procedure worthy of note. Our results and experience prove that this method is extremely beneficial where decompression of the posterior elements of C1 is required and may obviate the need of additional posterior wiring traditionally described. Further studies are necessary to look at the longterm fusion rates and compare them with other procedures.
Keywords: Atlantoaxial fixation, Atlantoaxial instability, Atlantoaxial joint, Neck pain.
How to cite this article: Sikander M, Martin S, Dabbous B, Griffiths S, Karia S, Pereira E, Cadoux-Hudson T. Combined C1-C2 Transarticular with C1 Lateral Mass Screw Fixation for the Treatment of Atlantoaxial Instability: A Single Center Experience. J Spinal Surg 2016;3(4):133-139.
Source of support: Nil
Conflict of Interest: None