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Investigating Wide Ureters with Ureteral Pressure Flow Studies
Vol. 116, July Printed in U.S.A.
THE JOURNAL OF UROLOGY
Copyright © 1976 by The Williams & Wilkins Co.
INVESTIGATING WIDE URETERS WITH URETERAL PRESSURE FLOW STUDIES ROBERT H. WHITAKER* From the Department of Urology, Addenbrooke's Hospital, Cambridge, England
ABSTRACT
A perfusion study is described and its usefulness in the diagnosis of ureterovesical obstruction is discussed. The study includes 31 children with either primary or secondary non-refluxing wide ureters or ureters that had been reimplanted previously. There are few, if any, more difficult problems in pediatric urology than the interpretation and management of an abnormally wide ureter. The problems of reimplanting a ureter, particularly into a thick-walled trabeculated bladder, are well known so that an investigation that will clearly indicate whether an operation is necessary is a valuable asset.
Rising
METHOD
The technique of a perfusion study to diagnose or refute obstruction at the ureterovesical junction has been described previously.'· 2 Since obstruction can only be meaningfully expressed in terms of pressures and flows it is essential to find a dynamic study for its diagnosis. A cannula is passed percutaneously and under radiographic control into the renal pelvis above the abnormal ureter. Alternatively, if the ureter is exposed operatively it can be punctured directly. A nephrostomy tube provides a further means of access. A perfusion of 5 or 10 ml. per minute is run into the system via a constant infusion pump and the pressure within the upper tract is measured continuously and recorded. The bladder pressure is measured via a urethral catheter and if this pressure is subtracted from the pressure within the upper tract a relative pressure is obtained that reflects the pressure drop across the ureterovesical junction at that particular flow rate. The pressure tracing gives the degree of obstruction, if any, and generally will fit into 1 of the categories listed in figure 1. A pressure drop of more than 12 cm. water across the ureterovesical orifice at 10 ml. per minute indicates the presence of obstruction.
High
Low
PATIENTS STUDIED
More than 115 such studies have now been performed in a variety of conditions when obstruction was suspected. 2·• This report will be limited to children with wide ureters of 3 types: 1) the primary non-refluxing wide ureter unassociated with a bladder abnormality (often referred to as the primary megaureter), 2) the dilated ureter seen secondary to bladder outflow obstruction or neurogenic bladder and 3) the ureter that remains wide after reimplantation. The perfusion study was used to determine whether an obstruction was present at the ureterovesical junction. Patients in whom it was clear from radiographic studies that there was unequivocal obstruction are not included in this report. The number of patients and their ages are shown in the table.
FIG. 1. Three broad categories of pressure results. Rising curvemarked obstruction, high curve-moderate obstruction and low curve -absence of obstruction.
Patients studied Mean Age/Range Primary wide ureters Secondary wide ureters Ureters after reimplantation
3 yrs./9 mos. to 11 yrs. 5 yrs./1 mo. to 10 yrs. 5 yrs./1 to 10 yrs.
No. Pts./No. Ureters 14/16 9/9 8/8
RESULTS
The results are summarized in figure 2. In those children with primary non-refluxing wide ureters (primary megaureAccepted for publication October 10, 1975. * Requests for reprints: Department of Urology, Addenbrooke's Hospital, Cambridge, England. 81
ters) there were 13 ureters that were clearly obstructed at the ureterovesical junction as shown by the perfusion test and 3 that showed no obstruction despite suggestive radiographic appearances (fig. 2, A). Of these 3 unobstructed ureters 1 was not reimplanted and has remained unaltered and asympto-
82
WHITAKER
PRIMARY WIDE URETER
A
SECONDARY WIDE URETER
B
POST REIMPLANTED URETER
C
FIG. 2. A, results in 16 primary wide ureters: 3 non-obstructed, 8 moderately obstructed, 5 badly obstructed. B, results in 9 secondary wide ureters: 5 non-obstructed, 3 moderately obstructed, 1 badly obstructed. C, results in 8 ureters after reimplantation: 4 non-obstructed, 3 moderately obstructed, 1 badly obstructed. Non-obstructed is defined as relative pressure of less than 12 cm. water, moderate obstruction as between 12 to 30 cm. water and marked obstruction as more than 30 cm. water.
matic, 1 was reimplanted but remained wide and, subsequently, was found to be unobstructed on a further study and 1 has remained satisfactory after reimplantation. All of the obstructed ureters have been reimplanted successfully. An example in this group is a I-year-old boy with a solitary left kidney who was seen after 2 attacks of urinary tract infection. The urogram showed a wide left ureter (fig. 3) and it was thought mandatory to be certain whether an obstruction was present before reimplanting. A perfusion study showed a slightly raised pressure of 14 cm. water and, subsequently, the ureter was tapered and reimplanted. Postoperatively, the perfusion pressure was reduced to 7 cm. water and the patient has made good progress. The group of secondary non-refluxing wide ureters was comprised of 9 boys with posterior urethral valves (fig. 2, B). Of these boys 1 had a marked degree of obstruction at the ureterovesical junction, 3 had moderate obstruction and 5 could tolerate a flow of 10 ml. per minute through the junction at a relative pressure of less than 12 cm. water, indicating the absence of obstruction. The final group consisted of 8 children who had had a ureter reimplanted but the success of the operation was questionable (fig. 2, C). The perfusion pressures were markedly high in 1 child who had required a nephrostomy postoperatively. Three ureters in boys with posterior urethral valves and thick-walled bladders showed higher than normal pressures and in 4 other ureters the pressures were normal, indicating a successful reimplantation. DISCUSSION
In those children with primary wide ureters it is noteworthy that some of the ureters, despite the abnormal radiographic appearances, were not obstructed. The perfusion test allows one to choose for operation only those ureters with definite obstruction. In the boys with secondary ureters from bladder outflow obstruction, which is seen in posterior urethral valves, it is often difficult to assess which ureters need reimplanting and which would improve spontaneously during the years. We have found this perfusion test to be of great practical value in this situation. In general, it is surprising to find how often no obstruction was present at the ureterovesical junction and this
FIG. 3. Urogram of 1-year-old boy with solitary left kidney and equivocal obstruction at ureterovesical junction. Pressure study showed that there was significant degree of obstruction.
has biased our management in favor of a conservative approach in these children. After reimplanting a wide ureter it is sometimes disappointing to find that the width of the ureter fails to resolve and the question arises as to whether the operation has been entirely successful. This problem was most often encountered after reimplantation into a thick-walled bladder. A low perfusion pressure is reassuring and prevents the need for repeated x-ray studies. The perfusion study is recommended for the difficult case when the correct decision is vital for the effective management of an abnormal ureter. Mr. D. Innes Williams allowed me to include the results of some of his patients. REFERENCES
1. Whitaker, R. H.: Methods of assessing obstruction in dilated ureters. Brit. J. Urol., 45: 15, 1973.
2. Whitaker, R. H.: Diagnosis of obstruction in dilated ureters. Ann. Roy. Coll. Surg., 53: 153, 1973. 3. Whitaker, R. H.: The ureter in posterior urethral valves. Brit. J. Urol., 45: 395, 1973. 4. Whitaker, R.H.: Urodynamic assessment ofureteral obstruction in retroperitoneal fibrosis. J. Urol., 113: 26, 1975. 5. Marshall, V. and Whitaker, R.H.: Ureteral pressure flow studies in difficult diagnostic problems. J. Urol., 114: 204, 1975. 6. Whitaker, R. H.: Equivocal pelvi-ureteric obstruction. Brit. J. Urol., 47: 771, 1976.
THE JOURNAL OF UROLOGY
Copyright © 1976 by The Williams & Wilkins Co.
INVESTIGATING WIDE URETERS WITH URETERAL PRESSURE FLOW STUDIES ROBERT H. WHITAKER* From the Department of Urology, Addenbrooke's Hospital, Cambridge, England
ABSTRACT
A perfusion study is described and its usefulness in the diagnosis of ureterovesical obstruction is discussed. The study includes 31 children with either primary or secondary non-refluxing wide ureters or ureters that had been reimplanted previously. There are few, if any, more difficult problems in pediatric urology than the interpretation and management of an abnormally wide ureter. The problems of reimplanting a ureter, particularly into a thick-walled trabeculated bladder, are well known so that an investigation that will clearly indicate whether an operation is necessary is a valuable asset.
Rising
METHOD
The technique of a perfusion study to diagnose or refute obstruction at the ureterovesical junction has been described previously.'· 2 Since obstruction can only be meaningfully expressed in terms of pressures and flows it is essential to find a dynamic study for its diagnosis. A cannula is passed percutaneously and under radiographic control into the renal pelvis above the abnormal ureter. Alternatively, if the ureter is exposed operatively it can be punctured directly. A nephrostomy tube provides a further means of access. A perfusion of 5 or 10 ml. per minute is run into the system via a constant infusion pump and the pressure within the upper tract is measured continuously and recorded. The bladder pressure is measured via a urethral catheter and if this pressure is subtracted from the pressure within the upper tract a relative pressure is obtained that reflects the pressure drop across the ureterovesical junction at that particular flow rate. The pressure tracing gives the degree of obstruction, if any, and generally will fit into 1 of the categories listed in figure 1. A pressure drop of more than 12 cm. water across the ureterovesical orifice at 10 ml. per minute indicates the presence of obstruction.
High
Low
PATIENTS STUDIED
More than 115 such studies have now been performed in a variety of conditions when obstruction was suspected. 2·• This report will be limited to children with wide ureters of 3 types: 1) the primary non-refluxing wide ureter unassociated with a bladder abnormality (often referred to as the primary megaureter), 2) the dilated ureter seen secondary to bladder outflow obstruction or neurogenic bladder and 3) the ureter that remains wide after reimplantation. The perfusion study was used to determine whether an obstruction was present at the ureterovesical junction. Patients in whom it was clear from radiographic studies that there was unequivocal obstruction are not included in this report. The number of patients and their ages are shown in the table.
FIG. 1. Three broad categories of pressure results. Rising curvemarked obstruction, high curve-moderate obstruction and low curve -absence of obstruction.
Patients studied Mean Age/Range Primary wide ureters Secondary wide ureters Ureters after reimplantation
3 yrs./9 mos. to 11 yrs. 5 yrs./1 mo. to 10 yrs. 5 yrs./1 to 10 yrs.
No. Pts./No. Ureters 14/16 9/9 8/8
RESULTS
The results are summarized in figure 2. In those children with primary non-refluxing wide ureters (primary megaureAccepted for publication October 10, 1975. * Requests for reprints: Department of Urology, Addenbrooke's Hospital, Cambridge, England. 81
ters) there were 13 ureters that were clearly obstructed at the ureterovesical junction as shown by the perfusion test and 3 that showed no obstruction despite suggestive radiographic appearances (fig. 2, A). Of these 3 unobstructed ureters 1 was not reimplanted and has remained unaltered and asympto-
82
WHITAKER
PRIMARY WIDE URETER
A
SECONDARY WIDE URETER
B
POST REIMPLANTED URETER
C
FIG. 2. A, results in 16 primary wide ureters: 3 non-obstructed, 8 moderately obstructed, 5 badly obstructed. B, results in 9 secondary wide ureters: 5 non-obstructed, 3 moderately obstructed, 1 badly obstructed. C, results in 8 ureters after reimplantation: 4 non-obstructed, 3 moderately obstructed, 1 badly obstructed. Non-obstructed is defined as relative pressure of less than 12 cm. water, moderate obstruction as between 12 to 30 cm. water and marked obstruction as more than 30 cm. water.
matic, 1 was reimplanted but remained wide and, subsequently, was found to be unobstructed on a further study and 1 has remained satisfactory after reimplantation. All of the obstructed ureters have been reimplanted successfully. An example in this group is a I-year-old boy with a solitary left kidney who was seen after 2 attacks of urinary tract infection. The urogram showed a wide left ureter (fig. 3) and it was thought mandatory to be certain whether an obstruction was present before reimplanting. A perfusion study showed a slightly raised pressure of 14 cm. water and, subsequently, the ureter was tapered and reimplanted. Postoperatively, the perfusion pressure was reduced to 7 cm. water and the patient has made good progress. The group of secondary non-refluxing wide ureters was comprised of 9 boys with posterior urethral valves (fig. 2, B). Of these boys 1 had a marked degree of obstruction at the ureterovesical junction, 3 had moderate obstruction and 5 could tolerate a flow of 10 ml. per minute through the junction at a relative pressure of less than 12 cm. water, indicating the absence of obstruction. The final group consisted of 8 children who had had a ureter reimplanted but the success of the operation was questionable (fig. 2, C). The perfusion pressures were markedly high in 1 child who had required a nephrostomy postoperatively. Three ureters in boys with posterior urethral valves and thick-walled bladders showed higher than normal pressures and in 4 other ureters the pressures were normal, indicating a successful reimplantation. DISCUSSION
In those children with primary wide ureters it is noteworthy that some of the ureters, despite the abnormal radiographic appearances, were not obstructed. The perfusion test allows one to choose for operation only those ureters with definite obstruction. In the boys with secondary ureters from bladder outflow obstruction, which is seen in posterior urethral valves, it is often difficult to assess which ureters need reimplanting and which would improve spontaneously during the years. We have found this perfusion test to be of great practical value in this situation. In general, it is surprising to find how often no obstruction was present at the ureterovesical junction and this
FIG. 3. Urogram of 1-year-old boy with solitary left kidney and equivocal obstruction at ureterovesical junction. Pressure study showed that there was significant degree of obstruction.
has biased our management in favor of a conservative approach in these children. After reimplanting a wide ureter it is sometimes disappointing to find that the width of the ureter fails to resolve and the question arises as to whether the operation has been entirely successful. This problem was most often encountered after reimplantation into a thick-walled bladder. A low perfusion pressure is reassuring and prevents the need for repeated x-ray studies. The perfusion study is recommended for the difficult case when the correct decision is vital for the effective management of an abnormal ureter. Mr. D. Innes Williams allowed me to include the results of some of his patients. REFERENCES
1. Whitaker, R. H.: Methods of assessing obstruction in dilated ureters. Brit. J. Urol., 45: 15, 1973.
2. Whitaker, R. H.: Diagnosis of obstruction in dilated ureters. Ann. Roy. Coll. Surg., 53: 153, 1973. 3. Whitaker, R. H.: The ureter in posterior urethral valves. Brit. J. Urol., 45: 395, 1973. 4. Whitaker, R.H.: Urodynamic assessment ofureteral obstruction in retroperitoneal fibrosis. J. Urol., 113: 26, 1975. 5. Marshall, V. and Whitaker, R.H.: Ureteral pressure flow studies in difficult diagnostic problems. J. Urol., 114: 204, 1975. 6. Whitaker, R. H.: Equivocal pelvi-ureteric obstruction. Brit. J. Urol., 47: 771, 1976.