CBCT-Based Morphological Study of the Accessory Foramina of the Canalis Sinuosus: Prevalence, Morphological Variants, and Significance for Implant Surgery

Objective: The canalis sinuosus in the premaxillary region often has accessory canals palatal to the central and lateral incisors. These small anatomical structures are of increasing interest due to numerous case reports of postoperative complications following surgery in the upper anterior region. Methods: This study examined the number, position, and extent of the accessory foramina of the canalis sinuosus in 210 patients. Furthermore, this study examined the distances to neighboring teeth and to the buccal cortical bone in edentulous patients. Three-dimensional tomographic (CBCT) images were created with a resolution of 0.2 voxels and were evaluated using the Osirix MD 11.0 program. Results: The results showed a prevalence of 97% for accessory foramina, confirming them as a clear anatomical structure. Males had significantly more terminal openings of the canalis sinuosus than females, with clustering in the fourth to sixth decades of life. The foramina had a mean extension of 0.9 mm and a mean distance of 4.6 mm to adjacent teeth. Conclusions: This narrow position is particularly relevant for surgical procedures. Greater attention should be focused on larger foramina in implant planning, as postoperative complications are increasingly being described. Foramina and accessory canals should be detected in three-dimensional, navigated implant planning in order to minimize the risk of injury during oral surgery.