[The Diameter of the Stenon and Wharton Ducts. Significance for Diagnosis and Therapy]

In assessing new minimally invasive diagnostic techniques (duct endoscopy) and therapy (lithotripsy) of salivary gland disease, it is of importance to know the true dimensions of the secretory ducts. Twenty-five ducts of the parotid gland and 20 ducts of the sub-mandibular gland were examined histologically at different points of their anatomic course and their in vivo diameters were evaluated using a previously determined formalin-induced shrinking factor. The mean diameter of Stensen's duct at four different points along its length ranged between 0.5 mm and 1.4 mm, depending on the site. A narrowing at the middle of the duct was striking. In all preparations examined, the minimum width of the secretory duct was located at the ostium. In Wharton's duct the narrowest duct diameter was also identified at the ostium. The mean values for the duct diameters ranged between 0.5 mm and 1.5 mm. For diagnostic and therapeutic purposes, endoscopes, balloon catheters and stone-extraction baskets should conform as much as possible to physiological duct widths. A diameter of 1.2 mm should be considered the upper limit for duct instruments. Our findings also suggest that in the case of salivary stone lithotripsy the best results will be achieved when the maximum size of a stone fragment does not exceed 1.2 mm.