Anatomical Variations of the Canalis Sinuosus in the Anterior Maxilla: A Cone-Beam Computed Tomography Study

Abstract

Background: The canalis sinuosus (CS) is an intraosseous canal transmitting the anterior superior alveolar neurovascular bundle. Despite its clinical significance, it is often overlooked. Objectives: This study aimed to evaluate the diameter, location, and distances of the CS relative to adjacent structures using cone-beam computed tomography (CBCT). Patients and Methods: This retrospective cross-sectional study analyzed 580 CBCT scans. Multiplanar reconstructions were used to measure canal diameter (CS-D), distance to the anterior nasal spine-posterior nasal spine axis (CS-ANS/PNS), buccal cortical plate (CS-BCP), alveolar crest (CS-AC), and adjacent tooth apices (CS-ATA). CBCT records were evaluated using OnDemand 3D software version 10.0.1. Statistical analyses included chi-square tests, independent t-tests, and generalized estimating equations (GEE). Analyses were adjusted for key confounders. Results: CSs were observed in 219 patients (37.8%), totaling 337 canals. The lateral incisor region was the most common location (44.6%), and the first premolar region the least common (3.6%). Mean CS-D was 0.89 ± 0.38 mm, mean CS-ANS/PNS 14.92 ± 3.35 mm, mean CS-BCP 7.44 ± 1.16 mm, mean CS-AC 8.24 ± 2.34 mm, and mean CS-ATA 3.83 ± 1.38 mm. Canal position significantly influenced all measured distances (P < 0.001). In contrast, laterality (right vs. left) showed a statistically significant difference only for CS-BCP (P = 0.005), with slightly greater values on the right. Conclusion: The CS showed significant anatomical variability. Preoperative CBCT evaluation is essential to minimize injury and ensure predictable surgical outcomes. Radiologists must identify and localize CS and locate it meticulously in presurgical radiological reports of the anterior maxilla.