Sialoendoscopy allows endoscopic intraluminal visualization of the duct system of major salivary glands and enables the surgeon to diagnose and treat inflammatory and obstructive disorders of the ducts.1 Although other pathologic conditions are regularly diagnosed and treated by sialoendoscopy, sialolithiasis accounts for about 50% of indications yet represents the most frequent cause of unilateral gland swelling. When a salivary stone (sialolith) is not amenable to endoscopic removal, various techniques, such as extracorporeal or intracorporeal fragmentation or a combined endoscopic-external approach, come into play.2,3 In the case of large submandibular sialoliths located far away from the ostium, some surgeons incise Wharton duct beyond the hilum of the gland into parenchymal areas, a procedure that carries risk of damage to the lingual nerve.3- 9 When sialoendoscopy includes additional interventional techniques, overall sialolith extraction rates between 70% and 95% have been reported.1,4,5,10,11 Excellent removal rates exceeding 90% must be interpreted carefully, as they most often represent late case series of experienced surgeons.12 Despite its apparent simplicity, sialoendoscopy is a technically challenging procedure with a notable learning curve; therefore, success rates are proportional to the experience and endoscopic skills of the surgeon.12,13 However, there is disagreement about what situations necessitate fragmentation and which technique should be used preferentially. It is unclear when external lithotripsy is superior to internal lithotripsy, when lasers should be used instead of a manual burr, or when a combined procedure or removal of the entire salivary gland should be performed in lieu of invasive fragmentation, such as duct incisions. Fragmentation techniques are not universally allowed because of early reported complications, as well as additional instrument cost and legal requirements.12 Limitations for endoscopic sialolith removal must first be clarified to evaluate indications for application of other complex, expensive, and possibly hazardous methods (eg, open surgery, combined endoscopic-external approach, extracorporeal or intracorporeal lithotripsy, and incisions of the main excretory salivary duct >1 cm). Because limitations and prognostic factors influence each other, we sought to investigate the latter to elucidate the probability of endoscopic sialolith. With knowledge of prognostic factors, further research can investigate ways to obtain information about the characteristics of sialolith s to allow evidence-based triage of patients with sialolithiasis.