Sialendoscopy for the management of sialolithiasis in Japan.

Sialolithiasis, the formation of calculi in the major salivary glands, is the leading cause of obstructive salivary disease and occurs predominantly in the submandibular gland. Traditional management of hilar or parenchymal stones has often required submandibular gland excision, which carries the risk of visible scarring and potential facial nerve injury. Sialendoscopy has emerged as a minimally invasive alternative for both diagnosis and treatment. Since its introduction in the 1990s and subsequent refinement, it has become standard therapy in Europe and North America, but in Japan, despite national insurance coverage since 2014, adoption remains limited because of technical complexity, high cost of consumables, and limited endoscope durability. A review of the literature and our own 144-case experience demonstrated a 40 % success rate for stone removal using sialendoscopy alone in Japan. Stone mobility was the most important predictor of success, while size greater than about 7.5 mm and parenchymal location markedly reduced success rates. Complications were generally mild and self-limiting: transient glandular swelling and lingual nerve paresis resolved within months, though occasional ranula formation or recurrence required secondary procedures. Similar factors predict outcomes in parotid stones, with reported endoscopic success of about 30-50 %. Fourier transform infrared spectrophotometry of 133 stones showed calcium phosphate and protein as the main components, and a higher calcium phosphate fraction correlated with stronger ductal adhesion and lower success rates. Sialendoscopy is therefore a safe, effective, and cosmetically advantageous alternative to gland excision, and we hope that this review will help lay the groundwork for its broader adoption and continued advancement in Japan.