Does mandibular canal morphology affect the degree of nerve manipulation during bsso?

Does mandibular canal morphology affect the degree of nerve manipulation during bsso? Objectives The aim of this study was to determine the effect of inferior alveolar nerve canal morphology on the degree of inferior alveolar nerve manipulation during sagittal split ramus osteotomy. Materals and Methods This retrospective cohort study was conducted on patients who underwent sagittal split ramus osteotomy between 2019 and 2023. Age, gender, nerve manipulation data were recorded from patient records. The predictor variable was measurements of the mandibular canal. The horizontal distances of the mandibular canal to the buccal and lingual cortical bone (cortical and trabecular distance) and the diameter of mandibular canal were measures from three different points on preoperative Computer Tomography (CT): Point A (mesial to the second molar), Point B (1 cm distal to the second molar) and Point C (just anterior to the mandibular lingula). The main study outcome was the degree of nerve manipulation. The degree of nerve manipulation was evaluated as follows: Nerve not encountered, embedded in distal segment, embedded in proximal segment, dissected from proximal segment, nerve transected. Data were analyzed using Kruskall Wallis and Pearson Chi-square test with Turcosa Cloud (Turcosa Analytics Ltd Co, Turkey) statistical software. The significance level was accepted as P &lt; 0.05. Results In the study, 98 patients (196 osteotomy sites) were included, comprising 41 males and 57 females, with a mean age of 22.5 ± 5.37 years. No statistically significant relationship was found between age, gender, and the degree of nerve manipulation. At point A, a significant relationship was observed between the increase in trabecular bone thickness in the buccal part of the canal and the nerve not encountered (p=0.001). At point B, a statistically significant relationship was found between the increase in trabecular and cortical bone thickness in the buccal part of the canal and the nerve not encountered(p=0.004). At point C, a statistically significant relationship was identified between the increase in bucco-lingual canal diameter and the nerve embedded in the proximal segment (p=0.01). Conclusion The increase in the horizontal distance of the mandibular canal from the outer surface of the mandible and the increase in the diameter of the canal may affect the degree of nerve manipulation. The volume of cortical and trabecular bone around the mandibular canal should be considered before osteotomy. Keywords: BSSO,IAN Canal Morphology,IAN Manipulation<br>