To evaluate how stone location and size influence surgical approach selection in submandibular sialolithiasis, and to identify computed tomography (CT)-based imaging predictors to aid preoperative planning.

We retrospectively reviewed 428 consecutive surgeries (March 2020–December 2024). Preoperative non-contrast CT classified stones as distal duct, mid-duct, hilum, or intraglandular. Surgical approaches were transoral ductal incision, sialendoscopy-assisted removal, and external submandibular gland excision. Group comparisons used standard parametric/non-parametric tests. Receiver operating characteristic (ROC) analysis assessed size thresholds associated with selection of an invasive approach.

Distal duct stones were most often treated by transoral incision (83.7 %), mid-duct stones by sialendoscopy-assisted removal (58.1 %), and intraglandular stones by external excision (71.0 %). Stones in the hilum/intraglandular regions were significantly larger than those in distal or mid-duct locations (p < 0.001). ROC analysis identified 5.5 mm as the optimal cutoff for predicting selection of an invasive approach (AUC = 0.83; sensitivity 74.2 %; specificity 78.9 %). Overall surgical success was 97.8 %. Complication rates varied by approach, lowest after sialendoscopy-assisted removal (4.4 %) and highest after external excision (15.2 %).

A simple CT-based framework incorporating stone location and size was associated with approach selection and outcomes in submandibular sialolithiasis. Using a 5.5 mm size threshold alongside anatomic zoning may help guide minimally invasive, gland-preserving strategies and reduce morbidity. Prospective validation is warranted.