Smaller safe surgical margin for resecting mandibular ameloblastomas in digitally assisted surgery

The clinical adoption of digital surgical guides and the determination of safe surgical margins for precise mandibular ameloblastoma resection remain inadequately explored.This study aims to evaluate the precision of digital surgical guide technology in the resection of mandibular ameloblastoma and, based on the histological status of resection margins, to investigate the minimum acceptable safe bone margin distance that ensures radical tumor removal.

This study analyzed 23 patients with ameloblastoma who underwent digitally guided segmental mandibulectomy at the Department of Oral and Maxillofacial Surgery between May 2023 and September 2025. All cases underwent three-dimensional virtual surgical planning based on preoperative imaging boundaries to predefine the osteotomy margins. Data collected included gender, age, clinical and radiographic features, surgical approach, histopathological type, histopathological status of the bone margins, and the minimum vertical distance from the tumor border to the osteotomy margin.The patients were divided into two cohorts according to the predefined target resection margins established during virtual planning: Cohort 1 had a target margin of 5-10 mm, aimed to evaluate the geometric discrepancy between the preoperatively planned and postoperatively measured surgical margins, along with their corresponding histopathological status; Cohort 2 had a uniformly preset target margin of 6 mm, intended to assess the histological status of the actual resection margins achieved at this distance.

Cohort 1: The mean deviation between the planned and postoperatively measured surgical margin distances was 1.05 mm in 10 patients, with no statistically significant difference (P > 0.05). Histopathological examination confirmed negative margins in all cases. Cohort 2: A total of 26 bone margins were generated from 13 patients. After excluding one case where the posterior margin was unassessable due to condylar resection, 25 margins were ultimately assessed. Histopathological examination revealed one case of conventional ameloblastoma with a positive anterior margin, resulting in a positive margin rate of 4.0% (1/25).

Digital surgical guidance achieves millimeter-level precision in resecting mandibular ameloblastomas. Even with a planned 6-mm bone margin, a 4.0% positive margin risk remains; however, this distance can be considered a practical minimum benchmark for balancing oncological radicality and functional preservation.