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Nonobstructive Dilatation of the Upper Urinary Tract
THE JOURNAL OF UROLOGY
Vol. 71, No. 4, April 1954 Printed in U.S.A.
NONOBSTRUCTIVE DILATATION OF THE UPPER URINARY TRACT JOHN A. HUTCH
In this essay an effort is made to explain that type of hydro-ureter and hydronephrosis which seems to begin at the ureterovesical junction and is not associated with any lesion which actually occludes the lumen of the ureter. The term nonobstructive dilatation of the upper urinary tract was chosen as a title but this term is not accurate as there must be an obstruction at the ureterovesical junction in spite of the fact that large ureteral catheters pass the obstructed area without difficulty. It is emphasized that any disease or injury which produced trabeculation and sacculization of the bladder (injury or lesion of the spinal cord: obstruction at or below the bladder neck) may be complicated by nonobstructive dilatation of the upper urinary tract. It is postulated that these changes in the bladder wall (trabeculation and sacculation) are the actiwl etiologic agent of this dilatation of the upper 'urinary tract. It is suggested that our therapeutic efforts should be directed against those factors which cause the bladder trabeculation. ANATOMY OF URETEROVESICAL JUNCTION
A study of the anatomy of the intravesical ureter is important for an understanding of its part in dilatation of the upper urinary tract. Figure 1 is a schematic drawing of this structure. Note that on the mucosal side of the bladder the ureter is securely anchored to the trigone. On the adventitial side the ureter is fixed to the bladder wall by vV aldeyer's ureteral sheath which fuses the adventitia of the ureter to the detrusor fibers of the bladder wall. Also note the firm support given the intravesical ureter by the detrusor fibers which lie under it. These three anatomical features assure the oblique passage of the ureter through the bladder wall and serve as a strong support to the intravesical ureter. From a histological point of view the extravesical ureter consists of three layers, two longitudinal and one circular. In contrast, the intravesical ureter has no circular layer and consists of only longitudinal muscle fibers. Its activity is thus limited to shortening and lengthening. This point assumes importance in the physiology of the ureter. PHYSIOLOGY
Recently the activity of the intravesical ureter was studied cystoscopically in patients with normal bladders. In all cases indigo carmine had been injected intravenously. During the resting stage the ureteral orifice appeared as a longitudinal slit at the junction of the lateral border of the trigone and the intravesical ureter. During that period in which indigo carmine ·was spurting from the ureteral orifice no evidence of muscular activity could be observed in either the bladder Read at annual meeting, American Urological Association, St. Louis, Mo. May 14, 1953. 412
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UPPER URINARY TRACT DILATATION
wall or the intravesical ureter. However, at the very conclusion of thcJ spurt of blue dye the intravesical ureter and the lateral border of the trigom would rise sharply, carrying the ureteral orifice upward with it. At the heighth of this upward excursion the spurt of blue would suddenly stop as though a door had been slapped shut in its path. The intravesical ureter and lateral border of the trigone would slowly sink to its resting position to await the next spurt of urine. These observations suggest two conclusions regarding the physiology of the intravesical ureter. 1) The intravesical ureter plays no active part in the propulsion of urine from the ureter into the bladder. Its role in this function is a passive one like the nozzle of a hose.
Fm. 1
Fm. 2
Fm. 1. Schematic representation of Waldeyer's ureteral sheath. According to Cunningham in his Textbook of Anatomy, this sheath consists of longitudinal muscle fibers embedded in fibrocollagenous tissue. These muscle fibers are closely applied to adventitia of ureter. Proximally they arise from adventitia of ureter about centimeter or so above point at which ureter enters bladder. Distally they fuse with bladder musculature. Diagram illustrates how carefully anatomy of ureterovesical junction has been planned. Ureteral orifice is fixed in mucosa! side of bladder by insertion of ureter into trigone. Point at which ureter enters bladder is equally fixed by fusion of ureteral adventitia to bladder musculature by media of Waldeyer's sheath. Notice also firm support given intravesical ureter by detrusor muscle fibers. Oblique passage of ureter through bladder wall is thus assured. Fm. 2. Illustration of normal ureterovesical junction, and ureterovesical junction involved in a saccule. Point Xis point at which ureter enters bladder under normal conditions. In abnormal ureterovesical junction illustrated in B, X has assumed position well outside bladder.
2) The intravesical ureter does play an active part in the prevention of reflux. At the conclusion of the spurt of urine the longitudinal muscles of the ureter contract actively and occlude the lumen of the ureter so that no bladder urine may enter. PATHOLOGY OF URETEROVESICAL JUNCTION
Actual pathologic changes at the ureterovesical junction with the exception of obstructive lesions like tumor, calculi, infection or ureterocele, confine themselves to varying degrees of weakness of the detrusor muscle which normally lies underneath the intravesical ureter. All gradations from the normal (fig. 2, A) to the mature saccule about the intravesical ureter (fig. 2, B) can be observed in patients who have bladder trabeculation. Let us go back to figure 2, A and mark an X at the point at which the ureter enters the outside of the bladder. Now assume that the muscle behind the ureter becomes weakened and forms a saccule, and that the ureter itself is carried into
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Fm. 3. A, cystogram of paraplegic who died of progressive renal failure. At autopsy urinary tract removed intact and cystogram made. X-ray reproduced was fortunate shot which outlines saccule above ureteral orifice and intravesical ureter beautifully. Intravesical ureter can be seen passing along floor of saccule. It is suggested in text that undilated portion of ureter is normal intravesical ureter which has assumed an extravesical position. It is also suggested that point at which ureter begins to dilate is junction of intraand extravesical ureter. B, 60-minute delayed cystogram of child with myelomeningocele. In complete x-ray peristaltic wave is apparently passing down ureter forcing Skiodan into lower ureter. Note how undilated intravesical ureter is buckled as fluid is forced into it from above. Had flow of fluid been reversed (i.e. passing from bladder into ureter) at time x-ray was taken, intravesical ureter might have been straight. C, cystogram in case of cord injury showing extreme bladder trabeculation, bilateral outpocketing of bladder in region of ureterovesical junction and bilateral reflux. Intravesical ureter on left is clearly visible lying in extravesical position. Complete x-ray is reproduced in figure 6. D, cystogram in case of cord injury illustrating intravesical ureter in extravesical position.
the depth of this diverticulum, so that its course now runs along the floor of this saccule (fig. 2, B). The point corresponding to X would now lie outside the outer wall of the bladder. We have, therefore, grounds of a theoretical nature upon which to postulate that under certain conditions in which the intravesical ureter is engulfed in a saccule, the intravesical ureter may assume an extravesical position! In an earlier paper attention was called to a phenomenon which was observed in 60 per cent of the cystograms of 94 cord injury patients with vesico-ureteral
UPPER URINARY TRACT DILATATION
415
reflux. It has been called the "notch sign" or "ureteral gap" and is characterized by a short segment of ureter just before it enters the bladder which does not fill ,vith contrast medium. Subsequently, I have been able to secure four cystograms in which this ureteral gap has been filled (fig. 3). They confirm the theoretical conclusion that the intravesical ureter may assume an extravesical position. They also suggest that the dilatation of the ureter begins at the junction of the intra- and extravesical ureter and therefore does not involve the intravesical ureter or the ureteral orifice. This material suggests two things: 1) that the intravesical ureter may assume an extravesical position, and 2) that the dilatation of these ureters begins at the junction of the intravesical and extravesical ureter. DISCUSSION OF THE MANNER IN WHICH THESE CHANGES AT THE URETEROVESICAL JUNCTION AFFECT THE UPPER URINARY TRACT
Under normal conditions the ureterovesical junction prevents reflux and augments, or at least does not hinder, the passage of urine from the ureter to the bladder. vVhen damaged it may lose one or both of these functions. An intravesical ureter which has lost the support of the detrusor fibers which normally lie underneath it will be unable to prevent reflux because there is no longer any firm bladder muscle for it to be compressed against. As the intravesical pressure increases bladder urine will leak back up such a ureter and stimulate contraction of the muscles of the ureter. Over a period of time such a ureter will dilate from muscular fatigue. This chain of events undoubtedly plays a role in the dilatation of the upper urinary tract in those cases where reflux exists. There are, however, many cases of hydro-ureter and hydronephrosis in which there is no demonstrable reflux. Also, many cord injury patients develop dilated upper urinary tracts despite the fact that they have open bladder drainage (suprapubic or urethral) from the day of their injury. Certainly reflux could not be a major factor in the dilatation of the upper urinary tract in a patient whose bladder is never allowed to fill. Reflux alone does not satisfactorily explain all of these cases. Other factors must be sought. For many years urologists have believed that these ureters were obstructed at or near their junction with the bladder. Operations have been devised to enlarge this area of the ureter in an effort to enlarge this obstructing segment. Others have explored these ureters surgically in an effort to find obstructing valves and bands. Still others have divided the ureter above the area of stricture and re-implanted the ureter into a new site in the bladder. The ureterograms of these patients are characteristic for obstruction or partial obstruction. The delayed emptying pyelo-ureterograms are convincing evidence for the presence of obstruction at the ureterovesical junction (fig. 4). In spite of this apparent obstruction, large ureteral catheters will pass the strictured area without difficulty. This obstruction must be one of function and not an actual occlusion of the ureteral lumen! The exact mechanism by which the changes described at the ureterovesical junction produce an obstruction to the flow of urine from the ureter to the blad-
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Fm. 4. A, pyelo-ureterogram in case of cord injury in which blood urea nitrogen was 80. B, 30-minute upright film on same patient. Urethral catheter left indwelling in bladder to afford outlet from bladder. In spite of this, upper urinary tract emptied very little.
der is not known. When one studies the methods by which reflux is prevented he is impressed with the importance of the collapsibility of the intravesical ureter. We know that this segment of ureter consists of a single layer of longitudinal muscle fibers, whereas the extravesical ureter has two longitudinal and one circular layer. At operation it is found to be a thin walled structure indeed. We are all aware of the ease with which it is perforated by a ureteral catheter. To compensate for this collapsibility the intravesical ureter is normally firmly supported by W aldeyer's ureteral sheath and by the bladder muscles through which it passes. If the intravesical ureter should lose the support upon which it normally depends, it is conceivable that it could buckle under the force of the advancing bolus of urine propelled by the peristaltic wave of the extravesical ureter, and thus act as a partial obstruction to the flow of urine from the ureter into the bladder. Figure 3, B supports this hypothesis. Throughout the course of this paper it has been inferred that bladder trabeculation is the basic etiologic factor in many cases of nonobstructive dilatation of the upper urinary tract. One would expect to find a high incidence of association between dilatation of the upper urinary tract and those diseases which produce bladder trabeculation. Bladder trabeculation is caused by obstruction at or below the bladder neck, and by injury or disease of the spinal cord. In both of these great groups of diseases, hydro-ureter and hydronephrosis are common findings. The upper urinary tract of a child with congenital bladder neck contraction may be indistinguishable from the upper urinary tract of a child with meningomyelocele. The basic pathology of the two conditions is very different. The feature they share in common is bladder trabeculation. The pyelograms of a patient with prostatic hypertrophy may reveal hydro-ureter and hydronephrosis very much like that seen in patients with injury of their spinal cord. As different as these conditions are, they share one thing in common-bladder trabeculation.
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We have been taught that the hydro-ureter and hydronephrosis in cases of obstruction at or below the bladder neck are due to back pressure, the increased intravesical pressure being transmitted to the upper urinary tract in some manner. More specifically, it may be that the bladder trabeculation damages the ureterovesical junction to such an extent that it either allows reflux to occur or creates an obstruction in the ureter in the manner described on the preceding pages. Bladder trabeculation in patients with injuries to the spinal cord is due to the powerful and erratic impulses which reach the bladder from the damaged distal stump of the spinal cord. Bladder spasms powerful enough to force voiding around a large catheter are common in these patients. Boyce has measured the electromotive force of these spasms by means of bladder electromyography. He found that in patients with hyperactive neurogenic bladders, during a typical bladder spasm "the phases were of enormous electromotive force," as much as 25 times greater than in the normal bladder. When a spastic trabeculated neurogenic bladder is freed from its connection with the central nervous system by means of rhizotomy or spinal anesthesia it will assume a normal contour and capacity (fig. 6). These points and others indicate quite clearly that the neurogenic bladder becomes trabeculated because of impulses reaching it from the damaged spinal cord. DILATATION OF THE UPPER URINARY TRACT IN CHILDREN
The problem of nonobstructive dilatation of the upper urinary tract in children is a difficult one indeed. No single explanation will cover all of these cases. The child with congenital bladder neck obstruction develops bladder trabeculation and dilatation of the upper urinary tract in the same manner as an adult with prostatic hypertrophy. Likewise the child with meningomyelocele develops bladder trabeculation and dilatation of the urinary tract essentially like the patient with a spinal cord injury. There is, however, a third group of patients who have dilatation of their ureters and renal pelves in spite of the fact that they have no bladder trabeculation, and that the ureteral orifice appears normal cystoscopically. Seven patients who would fall into this third group were studied recently at the University of Iowa, and in four of these cases there were associated congenital anomalies of the ureter such as double ureter or septal defects in the bladder wall involving the intravesical ureter. '\iVhen one considers the careful anatomy of the intravesical ureter it seems natural that developmental defects in its structure would be observed occasionally. This defect may involve Waldeyer's sheath or the detrusor muscles underneath the intravesical ureter. It seems likely that in the paper-thin bladder of megalobladder the detrusor fibers are too thin to support the intravesical ureter in its oblique course through the bladder wall. As our knowledge of the acquired lesions which produce dilatation of the upper urmary tract increases we will be better able to understand the congenital defects.
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JOHN A. HUTCH PATHOGENESIS
Figure 5 portrays the ideas expressed in this paper regarding the pathogenesis of nonobstructive dilatation of the upper urinary tract more concisely than any word picture. It has been pointed out that any pathological condition which produces bladder trabeculation may cause hydro-ureter, hydronephrosis and calyectasis. It has also been shown that impulses from the damaged distal stump of cord injury patients and obstruction to the flow of urine at or below the bladder neck may cause this bladder trabeculation. Fm. 5. Pathogenesis of nonobstructive dilatation of upper urinary tract Impulses from damaged stump of spinal cord
Hydro-ureter Hydronephrosis Calyectasis Obstruction at/or Bladder Damaged ureteral Delayed emptybelow bladder neck -+ Trabeculation -+ vesical junction ing )" ',. Loss of renal Functional obstruction function Congenital anomalies of ureter to flow of urine from and/or bladder wall at UV junction ureter to bladder Reflux
)"
/
Bladder trabeculation and sacculization may cause a weakness in the bladder muscle which normally lies under the intravesical ureter. This damages the ureterovesical junction and may even cause it to assume an extravesical position. On a congenital basis some children are born with anomalies which damage the ureterovesical junction. Such an anomaly may involve the ureter as it enters the bladder or it may involve the bladder wall in such a manner that it cannot give the intravesical ureter the support it needs to function effectively. The ureterovesical junction has two functions: one is to prevent reflux; the second is to aid the ureter in propelling urine from the ureter into the bladder. It follows that damage to such a structure would result in a failure of one or both of these functions and result in either reflux or a functional obstruction to the downward flow of urine or both. It is suggested that as a result of such an obstruction the upper urinary tract begins to dilate at the point of junction of the intravesical and extravesical ureter and progresses to involve the entire upper urinary tract. Reflux per se can cause dilatation of the ureter and renal pelvis by increasing the work load of these structures as they try to expel the regurgitating urine. In many cases these two factors (reflux and functional obstruction) work together to damage the upper urinary tract. TREATMENT OF NONOBSTRUCTIVE DILATATION OF THE UPPER URINARY TRACT
Therapy must be directed against the bladder trabeculation in those conditions in which bladder trabeculation is the basic etiological factor. In cases of prostatic hypertrophy or bladder neck contraction or urethral stricture, the standard treatment has been the removal of the obstruction and this has relieved the bladder trabeculation with resulting improvement in the upper urinary tract.
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On the other hand, our treatment of dilatation of the upper urinary tract in patients with spinal cord disease or injury has been far from satisfactory. Since the bladder trabeculation in these cases is due to impulses from the spinal cord, the treatment must be directed toward the de-innervation of the bladder. Rhizotomy to include the sacral cord at least must be considered. Rhizotomies have been performed on cord injury patients for other purposes with marked improve-
Fm. 6. A, 15-minute excretory urogra~ (pre-rhizotomy) revealing no excretion of Sl~iodan in 15 minutes. B, cystogram (pre-rh1zotomy) revealmg severe bladder "1:rabeculatrnn and bilateral reflux. C 15-minute excretory urogram (post-rh1zotomy) revealmg much 11:1proved function. D, cystogram (post-rhizotomy). Consider changes that have occurred m bladder musculature to explain change in bladder contour.
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JOHN A. HUTCH
ment noted in the upper urinary tract as a coincidental finding. Last year Dr. A. L. Dean and his associates presented a paper before the American Urological Association in which anterior and posterior rhizotomy from D12 to S5 was done on twelve cord injury patients in an effort to achieve better balanced nuerogenic bladders. Seven of their twelve cases had reflux preoperatively. In four of these seven cases the reflux disappeared postoperatively, and in a fifth case the reflux changed sides. Four of their twelve cases had severely damaged upper urinary tracts preoperatively. After rhizotomy, one of these patients improved markedly; two improved slightly, and one case of longstanding renal damage showed no change (fig. 6). Dr. Ernest Bors recently reported seven cord injury cases treated with posterior rhizotomy from D9, DlO or Dll through S5. These were done in an effort to stop the headache and hypertension which occur in cervical and high thoracic lesions when the bladder fills. Dr. Bors mentions one patient whose reflux disappeared after rhizotomy. It is probable that the posterior rhizotomy altered the trabecular pattern in the bladder to such a degree that the ureterovesical junction became competent. It stands to reason that in cases of longstanding damage to the ureterovesical junction, elimination of the bladder spasm alone may not be enough to correct this damage. Here one must consider a plastic procedure at the ureterovesical junction. The one described by Hutch is the most physiological, and has given excellent results in the correction of reflux and encouraging results in the reduction of hydronephrosis and hydro-ureter, and in improving the emptying time of partially obstructed ureters. Applied in conjunction with bladder de-innervation it should yield even better results. There are some of these cases due to neurogenic causes in which rhizotomy is undesirable as it would cause loss of peripheral function. Here a ureterovesical plastic procedure should be considered initially. In those cases in which there is no bladder trabeculation, a ureterovesical plasty may be indicated initially. There remains that group of cases in which nephrectomy or nephrostomy is the only feasible procedure. 1399 S. Main St., Walnut Creek, Calif. REFERENCES BoRS, E.: A.M.A. Arch. Surg., 61: 803, 1952. BOYCE, W. H.: J. Urol., 67: 650, 1952. CAMPBELL, M. F.: J. Urol., 68: 584, 1952. DEAN, A. L.: Personal communication. HuTCH, J. A.: J. Urol., 68: 457, 1952. HuTcH, J. A. AND BuNTs, R. C.: J. Urol., 66: 218, 1951. MEIROWSKY, A. M., SCHEIBERT, C. D. AND HINCHEY, T. R.: J. Neurosurg., 7: 33-43, 1950. SAMPso;,,r, J. A.: Bull. Johns Hopkins Hosp., 14: 194, 1903. SATANI, Y. Am. J. Physiol., 49: 474, 1919. SCARFF, J.E. AND PooLE, J. L.: J. Neurosurg., 3: 285--293, 1946. SWENSON, 0.: Surgery, 28: 371, 1950. WALL, B. AND WACHTER, H. E.: J. Urol., 68: 684, 1952. WISLOCKI, G. B. AND O'CoNoR, V. J.: Bull. Johns Hopkins Hosp., 31: 197, 1920.
Vol. 71, No. 4, April 1954 Printed in U.S.A.
NONOBSTRUCTIVE DILATATION OF THE UPPER URINARY TRACT JOHN A. HUTCH
In this essay an effort is made to explain that type of hydro-ureter and hydronephrosis which seems to begin at the ureterovesical junction and is not associated with any lesion which actually occludes the lumen of the ureter. The term nonobstructive dilatation of the upper urinary tract was chosen as a title but this term is not accurate as there must be an obstruction at the ureterovesical junction in spite of the fact that large ureteral catheters pass the obstructed area without difficulty. It is emphasized that any disease or injury which produced trabeculation and sacculization of the bladder (injury or lesion of the spinal cord: obstruction at or below the bladder neck) may be complicated by nonobstructive dilatation of the upper urinary tract. It is postulated that these changes in the bladder wall (trabeculation and sacculation) are the actiwl etiologic agent of this dilatation of the upper 'urinary tract. It is suggested that our therapeutic efforts should be directed against those factors which cause the bladder trabeculation. ANATOMY OF URETEROVESICAL JUNCTION
A study of the anatomy of the intravesical ureter is important for an understanding of its part in dilatation of the upper urinary tract. Figure 1 is a schematic drawing of this structure. Note that on the mucosal side of the bladder the ureter is securely anchored to the trigone. On the adventitial side the ureter is fixed to the bladder wall by vV aldeyer's ureteral sheath which fuses the adventitia of the ureter to the detrusor fibers of the bladder wall. Also note the firm support given the intravesical ureter by the detrusor fibers which lie under it. These three anatomical features assure the oblique passage of the ureter through the bladder wall and serve as a strong support to the intravesical ureter. From a histological point of view the extravesical ureter consists of three layers, two longitudinal and one circular. In contrast, the intravesical ureter has no circular layer and consists of only longitudinal muscle fibers. Its activity is thus limited to shortening and lengthening. This point assumes importance in the physiology of the ureter. PHYSIOLOGY
Recently the activity of the intravesical ureter was studied cystoscopically in patients with normal bladders. In all cases indigo carmine had been injected intravenously. During the resting stage the ureteral orifice appeared as a longitudinal slit at the junction of the lateral border of the trigone and the intravesical ureter. During that period in which indigo carmine ·was spurting from the ureteral orifice no evidence of muscular activity could be observed in either the bladder Read at annual meeting, American Urological Association, St. Louis, Mo. May 14, 1953. 412
413
UPPER URINARY TRACT DILATATION
wall or the intravesical ureter. However, at the very conclusion of thcJ spurt of blue dye the intravesical ureter and the lateral border of the trigom would rise sharply, carrying the ureteral orifice upward with it. At the heighth of this upward excursion the spurt of blue would suddenly stop as though a door had been slapped shut in its path. The intravesical ureter and lateral border of the trigone would slowly sink to its resting position to await the next spurt of urine. These observations suggest two conclusions regarding the physiology of the intravesical ureter. 1) The intravesical ureter plays no active part in the propulsion of urine from the ureter into the bladder. Its role in this function is a passive one like the nozzle of a hose.
Fm. 1
Fm. 2
Fm. 1. Schematic representation of Waldeyer's ureteral sheath. According to Cunningham in his Textbook of Anatomy, this sheath consists of longitudinal muscle fibers embedded in fibrocollagenous tissue. These muscle fibers are closely applied to adventitia of ureter. Proximally they arise from adventitia of ureter about centimeter or so above point at which ureter enters bladder. Distally they fuse with bladder musculature. Diagram illustrates how carefully anatomy of ureterovesical junction has been planned. Ureteral orifice is fixed in mucosa! side of bladder by insertion of ureter into trigone. Point at which ureter enters bladder is equally fixed by fusion of ureteral adventitia to bladder musculature by media of Waldeyer's sheath. Notice also firm support given intravesical ureter by detrusor muscle fibers. Oblique passage of ureter through bladder wall is thus assured. Fm. 2. Illustration of normal ureterovesical junction, and ureterovesical junction involved in a saccule. Point Xis point at which ureter enters bladder under normal conditions. In abnormal ureterovesical junction illustrated in B, X has assumed position well outside bladder.
2) The intravesical ureter does play an active part in the prevention of reflux. At the conclusion of the spurt of urine the longitudinal muscles of the ureter contract actively and occlude the lumen of the ureter so that no bladder urine may enter. PATHOLOGY OF URETEROVESICAL JUNCTION
Actual pathologic changes at the ureterovesical junction with the exception of obstructive lesions like tumor, calculi, infection or ureterocele, confine themselves to varying degrees of weakness of the detrusor muscle which normally lies underneath the intravesical ureter. All gradations from the normal (fig. 2, A) to the mature saccule about the intravesical ureter (fig. 2, B) can be observed in patients who have bladder trabeculation. Let us go back to figure 2, A and mark an X at the point at which the ureter enters the outside of the bladder. Now assume that the muscle behind the ureter becomes weakened and forms a saccule, and that the ureter itself is carried into
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JOHN A. HUTCH
Fm. 3. A, cystogram of paraplegic who died of progressive renal failure. At autopsy urinary tract removed intact and cystogram made. X-ray reproduced was fortunate shot which outlines saccule above ureteral orifice and intravesical ureter beautifully. Intravesical ureter can be seen passing along floor of saccule. It is suggested in text that undilated portion of ureter is normal intravesical ureter which has assumed an extravesical position. It is also suggested that point at which ureter begins to dilate is junction of intraand extravesical ureter. B, 60-minute delayed cystogram of child with myelomeningocele. In complete x-ray peristaltic wave is apparently passing down ureter forcing Skiodan into lower ureter. Note how undilated intravesical ureter is buckled as fluid is forced into it from above. Had flow of fluid been reversed (i.e. passing from bladder into ureter) at time x-ray was taken, intravesical ureter might have been straight. C, cystogram in case of cord injury showing extreme bladder trabeculation, bilateral outpocketing of bladder in region of ureterovesical junction and bilateral reflux. Intravesical ureter on left is clearly visible lying in extravesical position. Complete x-ray is reproduced in figure 6. D, cystogram in case of cord injury illustrating intravesical ureter in extravesical position.
the depth of this diverticulum, so that its course now runs along the floor of this saccule (fig. 2, B). The point corresponding to X would now lie outside the outer wall of the bladder. We have, therefore, grounds of a theoretical nature upon which to postulate that under certain conditions in which the intravesical ureter is engulfed in a saccule, the intravesical ureter may assume an extravesical position! In an earlier paper attention was called to a phenomenon which was observed in 60 per cent of the cystograms of 94 cord injury patients with vesico-ureteral
UPPER URINARY TRACT DILATATION
415
reflux. It has been called the "notch sign" or "ureteral gap" and is characterized by a short segment of ureter just before it enters the bladder which does not fill ,vith contrast medium. Subsequently, I have been able to secure four cystograms in which this ureteral gap has been filled (fig. 3). They confirm the theoretical conclusion that the intravesical ureter may assume an extravesical position. They also suggest that the dilatation of the ureter begins at the junction of the intra- and extravesical ureter and therefore does not involve the intravesical ureter or the ureteral orifice. This material suggests two things: 1) that the intravesical ureter may assume an extravesical position, and 2) that the dilatation of these ureters begins at the junction of the intravesical and extravesical ureter. DISCUSSION OF THE MANNER IN WHICH THESE CHANGES AT THE URETEROVESICAL JUNCTION AFFECT THE UPPER URINARY TRACT
Under normal conditions the ureterovesical junction prevents reflux and augments, or at least does not hinder, the passage of urine from the ureter to the bladder. vVhen damaged it may lose one or both of these functions. An intravesical ureter which has lost the support of the detrusor fibers which normally lie underneath it will be unable to prevent reflux because there is no longer any firm bladder muscle for it to be compressed against. As the intravesical pressure increases bladder urine will leak back up such a ureter and stimulate contraction of the muscles of the ureter. Over a period of time such a ureter will dilate from muscular fatigue. This chain of events undoubtedly plays a role in the dilatation of the upper urinary tract in those cases where reflux exists. There are, however, many cases of hydro-ureter and hydronephrosis in which there is no demonstrable reflux. Also, many cord injury patients develop dilated upper urinary tracts despite the fact that they have open bladder drainage (suprapubic or urethral) from the day of their injury. Certainly reflux could not be a major factor in the dilatation of the upper urinary tract in a patient whose bladder is never allowed to fill. Reflux alone does not satisfactorily explain all of these cases. Other factors must be sought. For many years urologists have believed that these ureters were obstructed at or near their junction with the bladder. Operations have been devised to enlarge this area of the ureter in an effort to enlarge this obstructing segment. Others have explored these ureters surgically in an effort to find obstructing valves and bands. Still others have divided the ureter above the area of stricture and re-implanted the ureter into a new site in the bladder. The ureterograms of these patients are characteristic for obstruction or partial obstruction. The delayed emptying pyelo-ureterograms are convincing evidence for the presence of obstruction at the ureterovesical junction (fig. 4). In spite of this apparent obstruction, large ureteral catheters will pass the strictured area without difficulty. This obstruction must be one of function and not an actual occlusion of the ureteral lumen! The exact mechanism by which the changes described at the ureterovesical junction produce an obstruction to the flow of urine from the ureter to the blad-
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JOHN A. HUTCH
Fm. 4. A, pyelo-ureterogram in case of cord injury in which blood urea nitrogen was 80. B, 30-minute upright film on same patient. Urethral catheter left indwelling in bladder to afford outlet from bladder. In spite of this, upper urinary tract emptied very little.
der is not known. When one studies the methods by which reflux is prevented he is impressed with the importance of the collapsibility of the intravesical ureter. We know that this segment of ureter consists of a single layer of longitudinal muscle fibers, whereas the extravesical ureter has two longitudinal and one circular layer. At operation it is found to be a thin walled structure indeed. We are all aware of the ease with which it is perforated by a ureteral catheter. To compensate for this collapsibility the intravesical ureter is normally firmly supported by W aldeyer's ureteral sheath and by the bladder muscles through which it passes. If the intravesical ureter should lose the support upon which it normally depends, it is conceivable that it could buckle under the force of the advancing bolus of urine propelled by the peristaltic wave of the extravesical ureter, and thus act as a partial obstruction to the flow of urine from the ureter into the bladder. Figure 3, B supports this hypothesis. Throughout the course of this paper it has been inferred that bladder trabeculation is the basic etiologic factor in many cases of nonobstructive dilatation of the upper urinary tract. One would expect to find a high incidence of association between dilatation of the upper urinary tract and those diseases which produce bladder trabeculation. Bladder trabeculation is caused by obstruction at or below the bladder neck, and by injury or disease of the spinal cord. In both of these great groups of diseases, hydro-ureter and hydronephrosis are common findings. The upper urinary tract of a child with congenital bladder neck contraction may be indistinguishable from the upper urinary tract of a child with meningomyelocele. The basic pathology of the two conditions is very different. The feature they share in common is bladder trabeculation. The pyelograms of a patient with prostatic hypertrophy may reveal hydro-ureter and hydronephrosis very much like that seen in patients with injury of their spinal cord. As different as these conditions are, they share one thing in common-bladder trabeculation.
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We have been taught that the hydro-ureter and hydronephrosis in cases of obstruction at or below the bladder neck are due to back pressure, the increased intravesical pressure being transmitted to the upper urinary tract in some manner. More specifically, it may be that the bladder trabeculation damages the ureterovesical junction to such an extent that it either allows reflux to occur or creates an obstruction in the ureter in the manner described on the preceding pages. Bladder trabeculation in patients with injuries to the spinal cord is due to the powerful and erratic impulses which reach the bladder from the damaged distal stump of the spinal cord. Bladder spasms powerful enough to force voiding around a large catheter are common in these patients. Boyce has measured the electromotive force of these spasms by means of bladder electromyography. He found that in patients with hyperactive neurogenic bladders, during a typical bladder spasm "the phases were of enormous electromotive force," as much as 25 times greater than in the normal bladder. When a spastic trabeculated neurogenic bladder is freed from its connection with the central nervous system by means of rhizotomy or spinal anesthesia it will assume a normal contour and capacity (fig. 6). These points and others indicate quite clearly that the neurogenic bladder becomes trabeculated because of impulses reaching it from the damaged spinal cord. DILATATION OF THE UPPER URINARY TRACT IN CHILDREN
The problem of nonobstructive dilatation of the upper urinary tract in children is a difficult one indeed. No single explanation will cover all of these cases. The child with congenital bladder neck obstruction develops bladder trabeculation and dilatation of the upper urinary tract in the same manner as an adult with prostatic hypertrophy. Likewise the child with meningomyelocele develops bladder trabeculation and dilatation of the urinary tract essentially like the patient with a spinal cord injury. There is, however, a third group of patients who have dilatation of their ureters and renal pelves in spite of the fact that they have no bladder trabeculation, and that the ureteral orifice appears normal cystoscopically. Seven patients who would fall into this third group were studied recently at the University of Iowa, and in four of these cases there were associated congenital anomalies of the ureter such as double ureter or septal defects in the bladder wall involving the intravesical ureter. '\iVhen one considers the careful anatomy of the intravesical ureter it seems natural that developmental defects in its structure would be observed occasionally. This defect may involve Waldeyer's sheath or the detrusor muscles underneath the intravesical ureter. It seems likely that in the paper-thin bladder of megalobladder the detrusor fibers are too thin to support the intravesical ureter in its oblique course through the bladder wall. As our knowledge of the acquired lesions which produce dilatation of the upper urmary tract increases we will be better able to understand the congenital defects.
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JOHN A. HUTCH PATHOGENESIS
Figure 5 portrays the ideas expressed in this paper regarding the pathogenesis of nonobstructive dilatation of the upper urinary tract more concisely than any word picture. It has been pointed out that any pathological condition which produces bladder trabeculation may cause hydro-ureter, hydronephrosis and calyectasis. It has also been shown that impulses from the damaged distal stump of cord injury patients and obstruction to the flow of urine at or below the bladder neck may cause this bladder trabeculation. Fm. 5. Pathogenesis of nonobstructive dilatation of upper urinary tract Impulses from damaged stump of spinal cord
Hydro-ureter Hydronephrosis Calyectasis Obstruction at/or Bladder Damaged ureteral Delayed emptybelow bladder neck -+ Trabeculation -+ vesical junction ing )" ',. Loss of renal Functional obstruction function Congenital anomalies of ureter to flow of urine from and/or bladder wall at UV junction ureter to bladder Reflux
)"
/
Bladder trabeculation and sacculization may cause a weakness in the bladder muscle which normally lies under the intravesical ureter. This damages the ureterovesical junction and may even cause it to assume an extravesical position. On a congenital basis some children are born with anomalies which damage the ureterovesical junction. Such an anomaly may involve the ureter as it enters the bladder or it may involve the bladder wall in such a manner that it cannot give the intravesical ureter the support it needs to function effectively. The ureterovesical junction has two functions: one is to prevent reflux; the second is to aid the ureter in propelling urine from the ureter into the bladder. It follows that damage to such a structure would result in a failure of one or both of these functions and result in either reflux or a functional obstruction to the downward flow of urine or both. It is suggested that as a result of such an obstruction the upper urinary tract begins to dilate at the point of junction of the intravesical and extravesical ureter and progresses to involve the entire upper urinary tract. Reflux per se can cause dilatation of the ureter and renal pelvis by increasing the work load of these structures as they try to expel the regurgitating urine. In many cases these two factors (reflux and functional obstruction) work together to damage the upper urinary tract. TREATMENT OF NONOBSTRUCTIVE DILATATION OF THE UPPER URINARY TRACT
Therapy must be directed against the bladder trabeculation in those conditions in which bladder trabeculation is the basic etiological factor. In cases of prostatic hypertrophy or bladder neck contraction or urethral stricture, the standard treatment has been the removal of the obstruction and this has relieved the bladder trabeculation with resulting improvement in the upper urinary tract.
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On the other hand, our treatment of dilatation of the upper urinary tract in patients with spinal cord disease or injury has been far from satisfactory. Since the bladder trabeculation in these cases is due to impulses from the spinal cord, the treatment must be directed toward the de-innervation of the bladder. Rhizotomy to include the sacral cord at least must be considered. Rhizotomies have been performed on cord injury patients for other purposes with marked improve-
Fm. 6. A, 15-minute excretory urogra~ (pre-rhizotomy) revealing no excretion of Sl~iodan in 15 minutes. B, cystogram (pre-rh1zotomy) revealmg severe bladder "1:rabeculatrnn and bilateral reflux. C 15-minute excretory urogram (post-rh1zotomy) revealmg much 11:1proved function. D, cystogram (post-rhizotomy). Consider changes that have occurred m bladder musculature to explain change in bladder contour.
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ment noted in the upper urinary tract as a coincidental finding. Last year Dr. A. L. Dean and his associates presented a paper before the American Urological Association in which anterior and posterior rhizotomy from D12 to S5 was done on twelve cord injury patients in an effort to achieve better balanced nuerogenic bladders. Seven of their twelve cases had reflux preoperatively. In four of these seven cases the reflux disappeared postoperatively, and in a fifth case the reflux changed sides. Four of their twelve cases had severely damaged upper urinary tracts preoperatively. After rhizotomy, one of these patients improved markedly; two improved slightly, and one case of longstanding renal damage showed no change (fig. 6). Dr. Ernest Bors recently reported seven cord injury cases treated with posterior rhizotomy from D9, DlO or Dll through S5. These were done in an effort to stop the headache and hypertension which occur in cervical and high thoracic lesions when the bladder fills. Dr. Bors mentions one patient whose reflux disappeared after rhizotomy. It is probable that the posterior rhizotomy altered the trabecular pattern in the bladder to such a degree that the ureterovesical junction became competent. It stands to reason that in cases of longstanding damage to the ureterovesical junction, elimination of the bladder spasm alone may not be enough to correct this damage. Here one must consider a plastic procedure at the ureterovesical junction. The one described by Hutch is the most physiological, and has given excellent results in the correction of reflux and encouraging results in the reduction of hydronephrosis and hydro-ureter, and in improving the emptying time of partially obstructed ureters. Applied in conjunction with bladder de-innervation it should yield even better results. There are some of these cases due to neurogenic causes in which rhizotomy is undesirable as it would cause loss of peripheral function. Here a ureterovesical plastic procedure should be considered initially. In those cases in which there is no bladder trabeculation, a ureterovesical plasty may be indicated initially. There remains that group of cases in which nephrectomy or nephrostomy is the only feasible procedure. 1399 S. Main St., Walnut Creek, Calif. REFERENCES BoRS, E.: A.M.A. Arch. Surg., 61: 803, 1952. BOYCE, W. H.: J. Urol., 67: 650, 1952. CAMPBELL, M. F.: J. Urol., 68: 584, 1952. DEAN, A. L.: Personal communication. HuTCH, J. A.: J. Urol., 68: 457, 1952. HuTcH, J. A. AND BuNTs, R. C.: J. Urol., 66: 218, 1951. MEIROWSKY, A. M., SCHEIBERT, C. D. AND HINCHEY, T. R.: J. Neurosurg., 7: 33-43, 1950. SAMPso;,,r, J. A.: Bull. Johns Hopkins Hosp., 14: 194, 1903. SATANI, Y. Am. J. Physiol., 49: 474, 1919. SCARFF, J.E. AND PooLE, J. L.: J. Neurosurg., 3: 285--293, 1946. SWENSON, 0.: Surgery, 28: 371, 1950. WALL, B. AND WACHTER, H. E.: J. Urol., 68: 684, 1952. WISLOCKI, G. B. AND O'CoNoR, V. J.: Bull. Johns Hopkins Hosp., 31: 197, 1920.