Different Horizons of C1–C2 Instability and Its Surgical Outcome after Posterior C1–C2 Fixation: An Early Institutional Experience at a Tertiary Heath Care Center in Eastern India

Background: Over the decades, many techniques had been described to treat the C1–C2 instability including the occipito-cervical fixation, Magerl’s transarticular screw fixation, and Goel C1–C2 screw–plate techniques. Recently, anterior methods of C1–C2 fixation has also been described. Here, we present our own experience of various complex cases of C1–C2 instability treated by posterior approach.

Materials and Methods: We have performed and reviewed 23 various complex C1–C2 instability cases from April 2023 to June 2024 at AIIMS, Kalyani, a newly established tertiary care center in Eastern India. All cases were thoroughly evaluated by CT craniovertebral junction (CVJ) (flexion/extension) with vertebral angiography preoperatively. Then postoperative follow-up radiology was performed with CT CVJ and MRI (on case basis) at immediate post-op, 3 months, 6 months, and 12 months.

Results: We have performed C1–C2 fixation in 23 cases (male = 11, female = 12, mean age = 36 years). Congenital atlantoaxial dislocation (CAAD) with Chiari 1 malformation (n = 9), failed foramen magnum decompression (FMD) (n = 2), CAAD without Chiari (n = 3), AAD with rheumatoid arthritis (n = 2), CAAD with Os odontonium (n = 2), hangman fracture with C1–C2 instability (n = 2), AAD with osteoarthritis of joint (n = 2), mortality (n = 1). Intraoperatively, one patient had vertebral artery injury due to its anomalous course; however, patient was neurologically intact due to co-dominant vertebral artery (VA). In our cases of anomalous VA or high riding VA, C2 screw was placed safely either by mobilizing the VA or by safeguarding it with Penfield at foramen transversarium. We have preferred different entry points for the C1 and C2 screws in cases of anomalous VA. Postoperative imaging showed no screw malpositioning, and no screw loosening, fracture, or bone absorption around the screws. All patients had improved in immediate postoperative and subsequent follow up periods. One patient had mortality who was case of failed foramen magnum decompression due to Chiari 1 malformation with syringomyelia.

Conclusion: Posterior C1–C2 fixation is a safe and definitive methods to address C1–C2 instability. Irrespective of VA abnormality C1–C2 fixation is feasible with safeguarding of the VA. C1-C2 fixation is also the treatment for Chiari malformation with C1–C2 instability. In failed FMD, C1–C2 fixation is a viable option in cases of Chiari malformation with syrinx. Occipito-cervical fixation is not required.

Publication History

Article published online:
07 February 2025