- Email: [email protected]
Late Followup of Dynamic Evaluation of Upper Urinary Tract Obstruction
0022-534 7/82/1282/0346$02.00/0 Vol. 128, August Printed in U.S.A.
THE JOURNAL OF UROLOGY
Copyright© 1982 by The Williams & Wilkins Co.
LATE FOLLOWUP OF DYNAMIC EVALUATION OF UPPER URINARY TRACT OBSTRUCTION FREDERICK N. WOLK
AND
ROBERT H. WHITAKER
From the Department of Urology, Addenbrooke's Hospital, Cambridge, England
ABSTRACT
Of 33 perfusion studies reviewed for 30 patients at a minimum of 5 years 16 showed obstruction. In retrospect, this finding seems to have been correct in all cases and has confirmed our confidence in perfusion studies for investigating equivocal obstruction. Since the introduction in 1973 of clinical pressure flow studies to assess obstruction we have done >220 such studies in > 160 patients. 1 Although we were confident at the time of the procedure that we were obtaining an accurate assessment it clearly is important to review the results some years later to see whether, in retrospect, our confidence was well founded. During the last few years several reports on the beneficial use of these dynamic evaluations of suspected upper urinary tract obstruction have been published2- 4 and, hopefully, late followup in these series will be available in time. PATIENTS STUDIED
Between 1973 and May 1976, 33 kidneys or ureters were perfused in 30 patients. Patients studied before 1973 were reported in a separate series. 5 Closure of the series in May 1976 allowed for a minimum of 5 years of followup. Patients ranged from 7 months to 63 years old, with a mean of 25 years. The studies were done on the left side in 19 cases and on the right side in 14. Diseases accounting for the equivocal obstruction were primary and secondary megaureter, pelvioureteral junction problems in new cases or in patients who had had a previous pyeloplasty and megacalices (table 1). METHODS
Details of the perfusion technique have been described fully, 1• 6 and this technique has been used in all of the patients. Access to the system for perfusion was via an antegrade puncture in 20 studies and by direct puncture at the time of operation in 13. If there was any question of whether the bladder had affect on the upper tract dilation it was allowed to fill during the study and the pressure within it was noted carefully. A minimum of 5 years has elapsed since the last study in this group of patients and the progress has been assessed since then by any means available. Any change in the urographic appearances or renal function has been noted, together with symptomatic improvement or otherwise. Usually, improvement, no change or deterioration has been obvious but it was difficult to be certain occasionally. Although isotope methods have been used lately often no baseline studies had been done earlier. Because of the progress during the years after the study the renal units have been categorized as follows: 1) obstruction demonstrated, operation performed and followup showing urographic improvement in drainage and relief of symptoms, 2) no obstruction demonstrated, no operation performed and no deterioration in appearances, function or symptoms, 3) no obstruction demonstrated but operation performed irrespective of the dynamic findings and subsequent deterioration, and 4) no obstruction demonstrated but operation performed and followup showed no change from the previous appearances or symptoms. Obstruction was defined as a differential pressure between the kidney and bladder of > 15 cm. water at 10 ml. per minute. Absence of obstruction was shown by less pressure.
RESULTS
Table 1 shows whether obstruction was present in the 5 disease groups and table 2 shows the distribution of studies within the 4 categories. The distribution of pressures in the 33 studies is shown in the figure. Of the 16 studies in group 1 showing obstruction 11 were in patients with pelvioureteral obstruction and 1 was in a patient who previously had had pyeloplasty. Three patients in this group had bilateral hydronephrosis but only 1 had obstruction on both sides. The other 2 had nonobstructed hydronephrosis in the contralateral kidney and these studies were among the 8 in the nonobstructed hydronephrotic group. Many of the patients in the obstructed hydronephrosis group had postoperative studies showing the pressure returning to normal. 7 In all 11 obstructed hydronephrosis cases there was improvement on an excretory urogram (IVP) and in 9 of the 11 patients the symptoms disappeared, while the other 2 never had symptoms. The patient who had had pyeloplasty subsequently had the kidney removed. Similarly, the 4 patients with an obstructed megaureter showed considerable evidence on IVP of improvement postoperatively. Thus, the 16 studies in group 1 correctly revealed an obstruction, indicating that an operation was necessary, and we have had no reason to regret the surgical action we took on long-term followup. The 3 lowest pressures in this group of patients with obstruction were 20, 24 and 25 cm. water, with no results between 15 and 20 cm. water, a range of pressures at which we still are not sure that an operation is necessary to decrease the pressure. There were unobstructed pressures in all 5 disease entities. Eight were in patients presenting with hydronephrosis and there were 2 patients among these 8 with obstructed hydronephrosis on the opposite side. Two patients in this group had small stones in the pelviocaliceal system and we were not certain whether pyeloplasty should be done at the same time as removal of the stones. Two elderly women in this group had large renal pelves that were unobstructed but they also had TABLE
1. Distribution of studies on obstruction or nonobstruction in 5 disease groups.
Primary megaureter Secondary megaureter Primary hydronephrosis Hydronephrosis after pyeloplasty Megacalices
TABLE 2.
346
Nonobstruction
4
4
11
8 3
1
Distribution of studies in the 4 categories
Category
No. Studies
1 2 3
16 13
4
Accepted for publication September 18, 1981.
Obstruction
1 3
EVALUATION OF UFF'ER URINARY TRACT OBSTRUCTION
changed little. The third patient in group 4 was a 28-year-old diabetic man with a large megaureter and pressure of 7 cm . water at 10 ml. per minute. The loin pain continued despite a nephroureterectomy. We do not believe that we were misled in this group. The patient in group 3 was a 40-year-old man with bilateral megaureters, poor looking kidneys and progressive renal failure. The perfusion of 1 ureter at the time of its reimplantation showed pressures <11 cm. water. Despite a seemingly successful unilateral reimplant renal function continued to deteriorate and the patient was placed on dialysis. The bladder was normal and we believe that the patient had an intrinsic renal disease.
.
100
JO 80
70
60
~
;a:
.
50
;
E
u
40
.. .. • . • e
30
• •
20 10
•
••
• 10
.
DISCUSSION
. e
•
• • 20
347
30
40
Number of studies
Differential pressures in 33 studies. There are no results between 15 and 20 cm. water.
enough spinal osteoarthritis to account for the symptoms. Three patients had had pyeloplasty previously and subsequently presented with occasional loin discomfort. All 3 patients had low pressures. Four patients had a nonobstructed primary megaureter and 1 boy, who had had posterior urethral valves, had nonobstructed secondary megaureters. One patient in this group had nonobstructed hydronephrosis owing to megacalices. Of the 17 cases in group 2 no action was taken in 13. Followup in these 13 cases failed to reveal any deterioration by conventional means. This is an important group since a falsely negative pressure study could lull the clinician into a false sense of security. We do not believe that this has occurred in this group. Nevertheless, 4 patients with no obstruction were operated upon (groups 3 and 4). One child in group 4 with urinary tract infection and hydronephrosis that drained well on an IVP has not had a urinary tract infection since pyeloplasty. The last IVP showed a smaller pelvis but there was no change in the calices or in the ability of the kidney to drain. An older boy with a pressure of 14 cm. water underwent pyeloplasty and the pressure decreased to 12 cm. water postoperatively. The IVP
In this series of 33 studies we believe that we have sufficient evidence to suggest that the perfusion study provides an indication of obstruction or nonobstruction in each of the 30 patients. One of the most vexed questions that remains unanswered is the exact pressure level at which obstruction or absence of it can be diagnosed confidently. It is conceivable that a normal kidney is able to withstand pressures of 15 to 20 cm. water, while a poorly functioning kidney perhaps can tolerate only 10 to 12 cm. water. Only long-term reviews of large series will answer this question but, for the present, we believe that the somewhat arbitrary upper level of normal pressure of 15 cm. water that we chose 8 years ago remains a satisfactory cutoff point. It always has been surprising how in so few studies the result has been between 15 and 20 cm. water, which is odd when the very nature of these cases is equivocal. REFERENCES
R. H.: Methods of assessing obstruction in dilated ureters. Brit. J. Urol., 45: 15, 1973. Aaronson, I. A.: Application of perfusion pressure measurement to problems of upper urinary tract dilatation in children. S. Afr. Med. J., 56: 641, 1979. Jaffe, R. B. and Middleton, A. W., Jr.: Whitaker test: differentiation of obstructive from nonobstructive uropathy. Amer. J. Roentgen., 134: 9, 1980. Newhouse, J. H., Pfister, R. C., Hendren, W. H. and Yoder, I. C.: Whitaker test after pyeloplasty: establishment of normal ureteral perfusion pressures. Amer. J. Roentgen., 137: 223, 1981. Witherow, R. O'N. and Whitaker, R. H.: The predictive accuracy of antegrade pressure flow studies in equivocal upper tract obstruction. Brit. J. Urol., 53: 496, 1981. Whitaker, R. H.: The Whitaker test. Urol. Clin. N. Amer., 6: 529, 1979. Odiase, V. and Whitaker, R. H.: Dynamic evaluation of the results of pyeloplasty using pressure-flow studies. Eur. Urol., 7: 324, 1981.
1. Whitaker,
2. 3.
4.
5. 6. 7.
THE JOURNAL OF UROLOGY
Copyright© 1982 by The Williams & Wilkins Co.
LATE FOLLOWUP OF DYNAMIC EVALUATION OF UPPER URINARY TRACT OBSTRUCTION FREDERICK N. WOLK
AND
ROBERT H. WHITAKER
From the Department of Urology, Addenbrooke's Hospital, Cambridge, England
ABSTRACT
Of 33 perfusion studies reviewed for 30 patients at a minimum of 5 years 16 showed obstruction. In retrospect, this finding seems to have been correct in all cases and has confirmed our confidence in perfusion studies for investigating equivocal obstruction. Since the introduction in 1973 of clinical pressure flow studies to assess obstruction we have done >220 such studies in > 160 patients. 1 Although we were confident at the time of the procedure that we were obtaining an accurate assessment it clearly is important to review the results some years later to see whether, in retrospect, our confidence was well founded. During the last few years several reports on the beneficial use of these dynamic evaluations of suspected upper urinary tract obstruction have been published2- 4 and, hopefully, late followup in these series will be available in time. PATIENTS STUDIED
Between 1973 and May 1976, 33 kidneys or ureters were perfused in 30 patients. Patients studied before 1973 were reported in a separate series. 5 Closure of the series in May 1976 allowed for a minimum of 5 years of followup. Patients ranged from 7 months to 63 years old, with a mean of 25 years. The studies were done on the left side in 19 cases and on the right side in 14. Diseases accounting for the equivocal obstruction were primary and secondary megaureter, pelvioureteral junction problems in new cases or in patients who had had a previous pyeloplasty and megacalices (table 1). METHODS
Details of the perfusion technique have been described fully, 1• 6 and this technique has been used in all of the patients. Access to the system for perfusion was via an antegrade puncture in 20 studies and by direct puncture at the time of operation in 13. If there was any question of whether the bladder had affect on the upper tract dilation it was allowed to fill during the study and the pressure within it was noted carefully. A minimum of 5 years has elapsed since the last study in this group of patients and the progress has been assessed since then by any means available. Any change in the urographic appearances or renal function has been noted, together with symptomatic improvement or otherwise. Usually, improvement, no change or deterioration has been obvious but it was difficult to be certain occasionally. Although isotope methods have been used lately often no baseline studies had been done earlier. Because of the progress during the years after the study the renal units have been categorized as follows: 1) obstruction demonstrated, operation performed and followup showing urographic improvement in drainage and relief of symptoms, 2) no obstruction demonstrated, no operation performed and no deterioration in appearances, function or symptoms, 3) no obstruction demonstrated but operation performed irrespective of the dynamic findings and subsequent deterioration, and 4) no obstruction demonstrated but operation performed and followup showed no change from the previous appearances or symptoms. Obstruction was defined as a differential pressure between the kidney and bladder of > 15 cm. water at 10 ml. per minute. Absence of obstruction was shown by less pressure.
RESULTS
Table 1 shows whether obstruction was present in the 5 disease groups and table 2 shows the distribution of studies within the 4 categories. The distribution of pressures in the 33 studies is shown in the figure. Of the 16 studies in group 1 showing obstruction 11 were in patients with pelvioureteral obstruction and 1 was in a patient who previously had had pyeloplasty. Three patients in this group had bilateral hydronephrosis but only 1 had obstruction on both sides. The other 2 had nonobstructed hydronephrosis in the contralateral kidney and these studies were among the 8 in the nonobstructed hydronephrotic group. Many of the patients in the obstructed hydronephrosis group had postoperative studies showing the pressure returning to normal. 7 In all 11 obstructed hydronephrosis cases there was improvement on an excretory urogram (IVP) and in 9 of the 11 patients the symptoms disappeared, while the other 2 never had symptoms. The patient who had had pyeloplasty subsequently had the kidney removed. Similarly, the 4 patients with an obstructed megaureter showed considerable evidence on IVP of improvement postoperatively. Thus, the 16 studies in group 1 correctly revealed an obstruction, indicating that an operation was necessary, and we have had no reason to regret the surgical action we took on long-term followup. The 3 lowest pressures in this group of patients with obstruction were 20, 24 and 25 cm. water, with no results between 15 and 20 cm. water, a range of pressures at which we still are not sure that an operation is necessary to decrease the pressure. There were unobstructed pressures in all 5 disease entities. Eight were in patients presenting with hydronephrosis and there were 2 patients among these 8 with obstructed hydronephrosis on the opposite side. Two patients in this group had small stones in the pelviocaliceal system and we were not certain whether pyeloplasty should be done at the same time as removal of the stones. Two elderly women in this group had large renal pelves that were unobstructed but they also had TABLE
1. Distribution of studies on obstruction or nonobstruction in 5 disease groups.
Primary megaureter Secondary megaureter Primary hydronephrosis Hydronephrosis after pyeloplasty Megacalices
TABLE 2.
346
Nonobstruction
4
4
11
8 3
1
Distribution of studies in the 4 categories
Category
No. Studies
1 2 3
16 13
4
Accepted for publication September 18, 1981.
Obstruction
1 3
EVALUATION OF UFF'ER URINARY TRACT OBSTRUCTION
changed little. The third patient in group 4 was a 28-year-old diabetic man with a large megaureter and pressure of 7 cm . water at 10 ml. per minute. The loin pain continued despite a nephroureterectomy. We do not believe that we were misled in this group. The patient in group 3 was a 40-year-old man with bilateral megaureters, poor looking kidneys and progressive renal failure. The perfusion of 1 ureter at the time of its reimplantation showed pressures <11 cm. water. Despite a seemingly successful unilateral reimplant renal function continued to deteriorate and the patient was placed on dialysis. The bladder was normal and we believe that the patient had an intrinsic renal disease.
.
100
JO 80
70
60
~
;a:
.
50
;
E
u
40
.. .. • . • e
30
• •
20 10
•
••
• 10
.
DISCUSSION
. e
•
• • 20
347
30
40
Number of studies
Differential pressures in 33 studies. There are no results between 15 and 20 cm. water.
enough spinal osteoarthritis to account for the symptoms. Three patients had had pyeloplasty previously and subsequently presented with occasional loin discomfort. All 3 patients had low pressures. Four patients had a nonobstructed primary megaureter and 1 boy, who had had posterior urethral valves, had nonobstructed secondary megaureters. One patient in this group had nonobstructed hydronephrosis owing to megacalices. Of the 17 cases in group 2 no action was taken in 13. Followup in these 13 cases failed to reveal any deterioration by conventional means. This is an important group since a falsely negative pressure study could lull the clinician into a false sense of security. We do not believe that this has occurred in this group. Nevertheless, 4 patients with no obstruction were operated upon (groups 3 and 4). One child in group 4 with urinary tract infection and hydronephrosis that drained well on an IVP has not had a urinary tract infection since pyeloplasty. The last IVP showed a smaller pelvis but there was no change in the calices or in the ability of the kidney to drain. An older boy with a pressure of 14 cm. water underwent pyeloplasty and the pressure decreased to 12 cm. water postoperatively. The IVP
In this series of 33 studies we believe that we have sufficient evidence to suggest that the perfusion study provides an indication of obstruction or nonobstruction in each of the 30 patients. One of the most vexed questions that remains unanswered is the exact pressure level at which obstruction or absence of it can be diagnosed confidently. It is conceivable that a normal kidney is able to withstand pressures of 15 to 20 cm. water, while a poorly functioning kidney perhaps can tolerate only 10 to 12 cm. water. Only long-term reviews of large series will answer this question but, for the present, we believe that the somewhat arbitrary upper level of normal pressure of 15 cm. water that we chose 8 years ago remains a satisfactory cutoff point. It always has been surprising how in so few studies the result has been between 15 and 20 cm. water, which is odd when the very nature of these cases is equivocal. REFERENCES
R. H.: Methods of assessing obstruction in dilated ureters. Brit. J. Urol., 45: 15, 1973. Aaronson, I. A.: Application of perfusion pressure measurement to problems of upper urinary tract dilatation in children. S. Afr. Med. J., 56: 641, 1979. Jaffe, R. B. and Middleton, A. W., Jr.: Whitaker test: differentiation of obstructive from nonobstructive uropathy. Amer. J. Roentgen., 134: 9, 1980. Newhouse, J. H., Pfister, R. C., Hendren, W. H. and Yoder, I. C.: Whitaker test after pyeloplasty: establishment of normal ureteral perfusion pressures. Amer. J. Roentgen., 137: 223, 1981. Witherow, R. O'N. and Whitaker, R. H.: The predictive accuracy of antegrade pressure flow studies in equivocal upper tract obstruction. Brit. J. Urol., 53: 496, 1981. Whitaker, R. H.: The Whitaker test. Urol. Clin. N. Amer., 6: 529, 1979. Odiase, V. and Whitaker, R. H.: Dynamic evaluation of the results of pyeloplasty using pressure-flow studies. Eur. Urol., 7: 324, 1981.
1. Whitaker,
2. 3.
4.
5. 6. 7.