Introduction
Sialolithiasis is the most common cause of salivary gland disease, involving the submandibular gland in 80-90% of cases.1 Most submandibular stones have a discrete size of 5-10 mm and are located in the distal tract of Wharton duct, the hilum, and the hilo-parenchymal area.2,3 The differing size of the stones, as well as their location is surgically significant. Proximal duct and hiloparenchymal submandibular stones are traditionally treated with transcervical sialadenectomy. Main risks are injury to the facial, lingual or hypoglossal nerves, facial artery bleeding, infection and unaesthetic scars. On the other hand, salivary glands can restore their function after stone removal. Therefore, conservative techniques, such as sialendoscopy and sialendoscopy-assisted transoral procedures, have been developed in the last years.4-6 However, only mobile and small submandibular duct stones (≤4 mm) can be treated by means of interventional sialendoscopy alone.6Indeed, a combined sialendoscopy-assisted transoral approach is necessary in most cases.6 Then, sialendoscopy-assisted transoral surgery for large sizes (>7 mm) and deep hilo-parenchymal stones emerged as a valid alternative to transcervical submandibular sialadenectomy.4-6
The spread of robotic technology in the head and neck field especially for oropharyngeal disorders has favored its application also for the management of anterior oral floor diseases.2 In the last years, transoral robot-assisted removal of submandibular gland stones has been described using the Da Vinci Si HD (Intuitive Surgical, Sunnyvale, CA).2 Flex Robotic system (Medrobotics Inc., Raynham, MA, USA) represents another minimally invasive and validated approach for head and neck cancer surgery.7Here, we describe a minimally invasive technique for transoral removal of deep parenchymal submandibular stones by Flex Robotic System. We provide a step-by-step description of the transoral robotic approach to the Wharton’s duct and the parenchyma of the submandibular gland through the oral floor.