Prevalence and Demographic Distribution of C1 Ponticulus Posticus in Southern India: A Prospective Observational Study

Objectives: To determine the prevalence and demographic distribution of C1 ponticulus posticus (arcuate foramen). Methods: This was a hospital based prospective observational study conducted in the Department of Radiology and Department of Neurosurgery, Government Stanley Medical College, Chennai between April 2019 and December 2019 among patients presenting to the department for CT neck and upper cervical spine in the course of evaluation for diseases including thyroid and parathyroid diseases, diseases of the cervical spine, oropharyngeal diseases, nasopharyngeal and laryngeal diseases. Results: The present study included a total of 120 patients. The overall prevalence of C1 ponticulus posticus was 5.8%; 3.3% presented with unilateral, and 2.5% with bilateral C1 ponticulus posticus; in the right and left sides, 95.8% had no C1 ponticulus posticus, 3.3% had complete and 0.9% had partial C1 ponticulus posticus. Of the 120 cases enrolled in the present study, 84 cases (70.0%) were less than 60 years of age; and 66.7% (80 cases) were males. Of the 7 cases with ponticulus posticus, majority (6 cases, 85.7%) were more than or equal to 60 years of age; whereas, of the 113 cases without ponticulus posticus, 26.5% were more than or equal to 60 years of age. This difference was found to be statistically significant (p<0.05). However, no statistically significant association was found between gender and the presence of C1 ponticulus posticus. Conclusion: Awareness of the prevalence and demographic distribution of C1 ponticulus posticus can help guide preoperative planning and intraoperative decision-making, potentially reducing the risk of iatrogenic injuries and improving surgical outcomes.