Dilators

DILATORS (dilators) for expanding the urethra are instruments resembling bougies with spreading branches. The spreading of the branches occurs by means of a screw located in the handle of the dilator; the latter is equipped with a dial with a pointer showing the degree of expansion. The advantage of dilators over bougies is that they make it possible to expand the urethra significantly more than the normal size of its external opening. Unlike bougies, which affect the urethral mucosa by pressure, dilators act primarily by stretching. Oberlander and Kollmann theoretically and practically developed the question of the systematic treatment of chronic urethritis using dilators. The application of dilators is most indicated when there are foci of inflammation located in the anterior urethra, in the Littré glands and the Morgagni crypts, as well as infiltrates that are difficult to resolve under the influence of bougies. Oberlander dilators are double-bladed. They are little used because, by stretching the urethra only in one plane, they exert uneven pressure on its walls. To avoid pinching the mucosa upon withdrawal, Oberlander dilators are used with rubber covers. - Seeking expanding instruments that more closely resemble the action of ordinary metal probes, a number of authors have constructed dilators with a larger number of branches. The pressure and stretching produced by the instrument will be distributed more evenly the more branches the dilator has, located at equal distances from each other. Kollmann dilators are practically the most convenient (see illustration). They are four-bladed, with their planes intersecting at right angles, acting in two directions. These dilators are constructed in such a way that they can be used without a cover, without fear of pinching the mucosa when screwing. The handle with the screw thread inside it is removed from the expanding part of the dilator, which can be boiled. Heymann somewhat modified the Kollmann dilator by arranging the screw thread in the handle completely openly, which makes it possible to dry and oil it after use. This makes it possible to boil the entire instrument together with the handle without fear of damaging the latter from rust. There are various types of four-bladed Kollmann dilators: a straight dilator with an expanding plane about 12 cm long, used for expanding the entire anterior urethra without affecting the area of the external opening at the same time; a straight dilator with a short expanding plane about 5 cm long, for expanding isolated infiltrates of the anterior urethra; a dilator with Dittel or Beniqué-Guyon curvature for expanding the posterior urethra; a dilator with Dittel or Beniqué-Guyon curvature for simultaneous expansion of the anterior and posterior urethra. - When both the anterior and posterior parts of the urethra are affected, it is better to use dilators separately for each part. When using instruments that simultaneously expand the anterior and posterior parts of the canal, the membranous part and the external sphincter are strongly stretched and traumatized, as a result of which the tone of the latter may be impaired. Expansion of the posterior urethra with a dilator should be resorted to as rarely as possible despite the proposal of Oberlander and Kollman, because infiltrates in the posterior part of the canal are predominantly superficial and in general easily yield to treatment with bougies. Moreover, in the presence of significantly expressed inflammatory phenomena in the prostate gland and seminal vesicles, the use of a dilator can lead to exacerbations of the process in them. Finally, in case of unexpected damage to the instrument, it is much more difficult to extract it from the posterior urethra than from the anterior. In addition to those listed, there are special dilator-irrigators for combined treatment with expansion with simultaneous irrigation. To achieve the latter purpose, the central axis of an ordinary dilator is arranged in the form of a hollow tube with a larger or smaller number of holes, through which the irrigation fluid is passed. Four-bladed Kollmann dilator-irrigators are constructed on the same principle as ordinary dilators. For dilator-irrigators, it is important that when introduced into the canal, they do not cover the outlet ducts of the glands located along the median line of the upper wall in the anterior urethra, and in the posterior along the median line of the lower wall. When using straight dilators, this position is achieved by rotating the instrument in the urethra around its axis. For the corresponding arrangement of the branches in the posterior urethra, Dommer modified the curved Kollmann irrigator in such a way that its branches, located on the vertical and horizontal planes, are rotated around their axis by 45°. In addition to the Kollmann dilator-irrigators listed, there are also three-bladed dilator-irrigators by Kollmann-Wossidlo, Frank, Fischkin and a two-bladed dilator-irrigator by A. Levin. The dilator-irrigators listed have not become widespread and are used only when the four-bladed Kollmann dilator cannot pass through the external opening of the urethra without preliminary incision. The technique for introducing dilators is the same as for bougies. Expansion should be performed slowly and carefully, one must take into account the slightest painful sensations of the patient. With forcible rupture, uniform resolution of the infiltrate and its reverse development is never achieved. At each subsequent session, the degree of stretching is increased by 1-2 dial divisions, guided by the degree of irritation of the urethra and the strength of reactive phenomena after the previous expansion. The maximum expansion in each case depends on the caliber of the canal, the number of folds of the urethral mucosa and the size of the penis. The dilator is left in the canal for 5-10 minutes. The interval between individual sessions is on average five days, and it can be increased or decreased depending on the reaction that occurs after expansion. Wound dilators, rectal dilators - see Surgical Instruments. Uterine dilators - see Obstetrical Instruments. Eyelid dilators - see Ophthalmological Instruments.

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