Reflux

REFLUX, reverse flow, backflow of liquid (urine or contrast substance) in an unnatural direction; In urology, the term R. is used 1) with respect to the backflow of urine from the bladder into the ureter and renal pelvis—vesicoureteral R., 2) from the renal pelvis into the venous system of the kidney—pyelovenous R., and 3) from the renal pelvis into the lymphatic system of the kidney—pyelolymphatic R. Vesicoureteral R. should be distinguished from retroperistaltic movements of the ureter. In the latter phenomenon, there occurs a perverted peristaltic wave from the side of the ureter, and part of the contents of the bladder is actively transferred by the movements of the ureter into the ureter and renal pelvis. In vesicoureteral R., the ureter is temporarily or permanently hypotonic or atonic, and urine is thrown by active contractions of the muscular apparatus of the bladder from its cavity into the ureter and renal pelvis. The ureter thus remains passive. A prerequisite for vesicoureteral R. is a violation of the function of the closing apparatus of the ureteral orifice of the bladder, because physiologically the ureteral sphincter prevents urine from entering the ureter from the bladder. Heidenreich was the first to draw attention to the existence of vesicoureteral R., pointing out that with a significant expansion of the ureteral lumen, when the oblique passage of the ureter through the bladder wall is replaced by a straight line, the action of the valves observed at the vesical orifice is eliminated, making direct communication between the bladder and the ureters possible. Sampson (1903) confirmed the existence of vesicoureteral R. by experiments on cadavers, and later clinical observations also demonstrated its existence (Pozzi, Modlinsky, Alksne). After nephrectomy with ligation of the ureter, urine is sometimes excreted not from the urethra, but from the surgical wound. In these cases, the patient urinates through the stump of the ureter, with which the ligature either came off or was cut through. Since there is no leakage through the wound outside the act of urination, in such cases we are dealing not with retroperistalsis of the ureter, but with vesicoureteral R. Observations of R. have been significantly enriched after the application of cystography. During radiography of the bladder with liquid contrast substances, an image is sometimes obtained not only of the bladder but also of the upper urinary tract—ureter and renal pelvis—filled with contrast solution as a result of vesicoureteral reflux. The cause of vesicoureteral R. is either a functional disorder of the ureteral orifice (in diseases of the central nervous system, in cystitis, after anesthesia)—then it is often temporary—or an anatomical change in the orifice, which is revealed cystoscopically as a gaping of the latter. Such a condition of the orifice may be congenital (congenital atony of the urinary system) or acquired (acquired atony of the urinary system). Sometimes vesicoureteral R. is a result of surgical treatment of ureterocele. Clinically, vesicoureteral R. is sometimes revealed by pains appearing in the area of the kidney during the urge to urinate or during the act of urination. The pains are the result of stretching of the ureter and renal pelvis by urine flowing back into them from the bladder, since the patient partially 'urinates into his own kidney.' This phenomenon leads to progressive expansion of the upper urinary tract and complete loss of function of the corresponding kidney due to its atrophy. Pyelovenous R. was first described by Americans Hinman and Lee-Brown (1924), who found on pyelograms (see Pyelography) the entry of contrast substance into areas of renal parenchyma. Subsequently, the question of pyelovenous R. was studied experimentally on animals and freshly removed kidneys of animals and humans (Fuchs, Jacobi and others). The renal pelvis was filled either with contrast substances and subjected to radiological examination or with dye solutions in gelatin and studied microscopically. To obtain pyelovenous R. experimentally, intrapelvic pressure exceeding normal is required. Thus, Jacobi, experimenting on human kidneys, did not obtain pyelovenous R. at pressures up to 40 mm of mercury. Gradually increasing the pressure, he observed how the renal pelvis and calyces were excessively stretched, and at a pressure of 60-70 mm at the point of attachment of the mucous membrane of the calyces to the pyramid (fornix calicum), the usual place of least resistance, a rupture of the mucous membrane occurred and the contrast substance entered the interlobular veins located there and from there into the general venous system of the kidney, which is widely anastomosing. The arteries remain undamaged. Pyelovenous R. is revealed on a pyelogram in the form of arcuate or irregularly shaped small shadows located in the renal parenchyma at some distance from the calyces. However, the contrast substance can also enter the straight tubules of the kidney, forming a triangle corresponding to the location of the tubules, with its apex directed toward the calyx (Buschelbildung). To avoid pyelovenous R., certain conditions must be observed during ascending pyelography (see Pyelography). Clinically, pyelovenous R. plays a significant role in increasing intrapelvic pressure due to insufficient outflow of urine from the renal pelvis in pyelitis (see), in obstruction of the renal pelvis by a stone or in kinking of the ureter in nephroptosis. Pyelolymphatic R. was described in 1929 by the American Wood. On the pyelograms published by Wood and Fillis, large lymphatic vessels of the kidney filled with contrast substance and running parallel to each other, accompanying the a. and v. renalis, are visible. A similar picture was obtained in cases of lymphuria when there was communication between the lymphatic vessels of the kidney and its excretory system. The question of pyelolymphatic R. has not yet been studied experimentally, but it can be assumed that clinically this phenomenon plays a significant role, just like pyelovenous R.