Endoscopic Salivary Stone Fragmentation with Pneumatic Lithotripsy in a Simulation Model

Abstract

Objective: To evaluate the endoscopic fragmentation and removal of human salivary stones by employing intracorporeal pneumatic lithotripsy in a clinical simulation model of the submandibular gland.

Study design: Simulation model evaluating endoscopic management of human salivary stones.

Setting: Laboratory.

Subjects and methods: A flexible nitinol contact probe adapted to a CO2-driven handheld salivary pneumatic lithotripter was deployed through a sialendoscope to disrupt parotid (n = 1) and submandibular (n = 8) stones embedded in separate 3-dimensionally printed plastic models of the mouth and submandibular glands. Simulation included endoscopic removal of small stone fragments by standard basket retrieval supplement by irrigation and suction through a salivary duct introducer system. Correlations were made between stone volume and density with the duration of the procedures and number of pneumatic pulses required to disrupt and remove stone fragments.

Results: Among the 8 stones fragmented sufficiently to permit either full endoscopic removal (n = 7) or removal of the central portion leaving an adherent rind to the duct (n = 1), the average procedure time (32 minutes) and the average number of pneumatic pulses (98) correlated with stone density (range, 0.4-1.5 g/mL) and stone volume (range, 0.05-0.4 mL). One stone was sufficiently resistant to fragmentation as to prevent successful removal.

Conclusions: Modification to the evolving technology of intracorporeal pneumatic management of nephrolithiasis was successfully applied in an ex vivo model to simulate management of sialolithiasis.

Keywords: endoscopic; lithotripsy; minimal access surgery; pneumatic lithotripsy; salivary gland; salivary stone; sialadenitis; sialendoscopy; sialolithiasis.