[Endoscopy-assisted transoral removal of deep hilar and intraparenchymal stones in the Wharton's duct].

Objective To investigate the different surgical approaches and long-term outcomes of endoscopy-assisted transoral removal of deep hilar and intraparenchymal stones in the Wharton′s duct. Methods From January 2008 to March 2018, 481 consecutive patients with deep hilar and intraparenchymal calculi in the Wharton′s duct underwent endoscopy-assisted transoral removal at Deparment of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology. There were 250 males and 231 females. Their ages ranged from 9-86 years. We operated 476 patients under local anesthesia on an outpatient basis, and the remaining 5 were operated under general anesthesia. On the basis of ultrasonography, spiral CT, sialography and endoscopy, the calculi were classified into 4 types: hilum stones (located at the hilum or proximally with a distance <5 mm from the hilum), infra-hilum stones (intra-glandular stones with a distance of 5-10 mm from the hilum), intraparenchymal stones (with a distance ≥10 mm from the hilum), and multiple stones (concomitant hilum and intra-glandular stones). The treatment approaches included: hilum duct slitting, intraparenchymal duct slitting, submandibulotomy and intraductal retrieval. The success rate, immediate safety and effectiveness of different types of stones were evaluated. After surgery, the patients were followed up, and gland function was analyzed on the basis of clinical symptoms and signs. Results The calculi sizes varied from 3 to 25 mm, with a mean of 7.8 mm. The calculi were located in the right submandibular gland in 259 patients, in the left submandibular gland in 219 patients and in bilateral glands in 3 patients. The calculi were successfully removed in 446 glands, with a success rate of 92.1% (446/484). The success rate varied according to the stone sites: 97.8% (363/371) for hilum stones, 64.4% (29/45) for infra-hilum stones, 4/16 for intraparenchymal stones and 96.2% (50/52) for multiple stones. The main treatment methods applied included hilum duct slitting in 347 glands, intraparenchymal duct slitting in 13, submandibulotomy in 4, intraductal retrieval in 73, and hilum duct slitting accompanied by intraductal retrieval in 9. Ductal breakage occurred in 2 glands. All patients complained of mild to moderate pain with a duration of 3-7 days. Nine had temporal lingual nerve injury. During 3-120 months′ follow-up (mean 36 months) of the total 484 glands, 1.6% (7/446) developed ranula, 1.3% (6/446) experienced obturation of the main duct and 2.0% (9/446) had recurrent stones. The remaining 95.1% (424/446) glands were symptom-free with good function. Conclusions Endoscopy-assisted transoral removal of deep hilar and intraparenchymal submandibular calculi is a safe and effective gland-preserving procedure. According to the depth, size and number of the calculi, variant surgical approaches should be attempted to maximize the success rate and to minimize the side effects. Key words: Submandibular gland; Salivary gland calculi; Salivary duct calculi; Sialendoscopy