Comparative analysis of clinical outcomes of surgically stabilised atlanto-axial instability with various surgical methods

Objectives: The atlanto-axial segment consists of the atlas and axis forming a complex transitional structure bridging the occiput and cervical spine. The functional result of the joint is to provide support for the occiput and greatest range of motion and flexibility possible while maintaining stability. The main objective of the study is to assess clinical changes post surgery of atlanto-axial instability fixation comparing impact of various surgical methods.

Materials and Methods: Single centred prospective study with sample size of 50. Demographic data, detailed history of symptoms and other co-morbidities were recorded. The anatomic characteristics of cervicovertebral junction, presence of compression and atlantoaxial instability evaluated. Operative details, types of approach, method of fixation chosen-transarticular screws, screw and rod fixation (SRF), occipitocervical plating and combination of transarticular screws on one side and SRF other side noted. Comparison was done based on demographic data, clinical features and neurological status pre and post operatively.

Results: Mean age was 30.22 years, ranging from 7 to 71 years with majority belonged to 11-20 years age-group (17/50, 34%). Majority of the patients had a congenital cause for instability (22/50, 44%), 17 of the 50 patients (34%) had co-morbidities with Down’s syndrome being most common. Most common symptom being quadriparesis followed by neck pain. Most common procedure done was C1-C2 Screw plus rod fixation followed by trans-articular screw. Mean Nuricks grading was 3.32±1.09 pre-operatively with significant change was noted at 3 months post-op follow-up 2.84±1.21 (p<0.05).

Conclusion: There is significant co-relation between pre-operative neurological status and functional post-operatively. No significant difference was seen in rate of fusion with respect to method of fixation and functional outcome in relation to method of fixation. Rate of fusion is directly associated with the quality of bone at the articular surfaces of C1-C2 facet joints.