Posterior urethral valves

POSTERIOR

URETHRAL

VALVES

Role of Temporary and Permanent Urinary Diversion DAVID T. MININBERG,

M.D.

HAROLD

M.D.

p. GENVERT,

From the Department of Surgery, Division of Urology, The New York Hospital-Cornell Medical Center, The James Buchanan Brady Foundation, NeMr York, New York

ABSTRACT-Between 1960 and 1983, 67 boys were treated for posterior uretiwai’ ualzrjv. Deqitc adequate valve ablation, axotemia eventually developed in 19, and they unc!erwent prjrmancnt urinary diversion. Normal renalfunction was not achieved in any of these childrcx. LIi2el:sion days not appear to have changed the natural course of their renal insufficiency, u>/liclhis most 1;k&j to irlrp;lsecondary to damage incurred prior to their initial presentation. Prognostic factors ,~m,f~tl tiy this select population are examined.

In 1919 Hllgh Hampton Young reported on valvular congenital obstruction of the posterior urethra.’ Posterior urethral valves are now a well-recognized clinical entity. Advances in radiologic and urologic equipment and techniques show posterior urethral valves to occur more commonly than first thought. A multicenter review in the British Isles between 1970 and 1980 estimated the incidence to be approximately one in 25,000 births.” In spite of adequate surgical management a significant percentage of cases progress to endstage renal disease or death. The prognosis in infants presenting under the age of one month is clearl!. Lvorse, and some series report mortalit\in this group to be as high as 50 percent.” This probably relates to the severity of the damage done to the kidneys prior to diagnosis, and perhaps txven prior to birth. In the past, a large number of children who presented with progressi\,e azotemia despite adequate valve ablation underwent urinary diversion for presumpti\re persistence of inadequate drainage. Recently. it has been shown that one quarter of ureterostomy-diverted children died of azotemia despite free urinary drainage.4 Other impestigators ha\-r> described the relationship be-

tween valves, unilateral reflux, and ,a d;;splastic kidney” which suggests that the 1~; of renal function occurs long before birth. A retrozpective analysis of our experience with poster.or urethral valves was undertaker to examine tnis issue. The question remains m.hether or not permanent urinary diversion is helpful in children with deteriorating renal function despite SIu-gical correction of their valves. An evaluation of several prognost-ic factors was performed in an attempt to identify. at the time of initial presentation, those children who are at risk to progress to azotemia. Material

and Methods

Between 1960 and 1983, 67 boys \verI? treated for posterior urethral valves: 32 were treated with transurethral fulguration of then valves (TUFV) alone, while 35 underwent a diversionary procedure during their course of therapy. Of this latter group. 16 of 35 (46% ) underwent preliminary diversion via nephrostomy as a temporary means of obtaining proximal drainage before definitive management of the obstructive valves was undertaken. The! were e\-entually undiverted. Nineteen of 35 (54 % ) underwent permanent diversion via

TABLE I. Age at presentation *

Group Preliminary diversion Permanent diversion TUFV only “Figures

TABLE III. RefZux*

Less Than One Year

Greater Than One Year

Mean Age

12116 (75)

4/16 (25)

0.2

11/19 (58) 8132 (25)

8119 (42) 24132 (75)

in parentheses

indicate

Preliminary diversion Permanent diversion TUFV only

:

*Figures

percent.

TABLE II. Uremia/azotemia

-Blood Normal

Group Preliminary diversion Permanent diversion TUFV only *Figures tMg/dL.

Urea NitrogenUremic Meant

Moderate

None

16116 (100)

, ,

*.

19/19 (100) 15132 (47)

7132 (22)

10/32’(31)

in parentheses

indicate

percent.

at presentation *

Normal

CreatininAzotemic Mean f

7/16 (44)

9/16 (56)

25

218 (25)

618 (75)

1.2

3/15 (20) 18/26 (69)

12115 (80) 8126 (31)

44 14

218 (25) 11119 (58)

6/8 (75) 8119 (42)

1.6 0.8

in parentheses

indicate

percent.

cutaneous ureterostomy or ileal conduit when renal function either did not improve or continued to deteriorate. Results Twelve of the 16 children (75%) who had preliminary diversion presented before the age of one year, and 11 of 19 (58 %) of the children with permanent diversion were less than one at the time of initial therapy. Of the children who had TUFV only, 75 percent were older than one year when first seen (Table I). The mean levels of blood urea nitrogen (BUN) and creatinine at time of initial presentation in children who underwent preliminary diversion were 25 and 1.2 mg/dL, respectively, while in those permanently diverted it was 44 and 1.6 mg/dL. The percentage of each group that was uremic and azotemic at the time of initial presentation is presented in Table II. All 35 of the children who had diversions were noted to have severe unilateral or bilateral reflux and hydronephrosis on radiologic studies. Of the nondiverted group 47 percent had a similar degree of reflux, 22 percent had moderate reflux, and 31 percent had no reflux (Table III). The final outcome of these children was broken down into four categories: Cured included boys who returned to normal parameters of reconsisted nal function; compromised function of those whose renal function stabilized or deteriorated but remained at levels capable of sustaining life; and the two final groups consisted of children whose renal function deteriorated to

206

Severe

Group

the point of renal dialysis and transplantation and those children who died. Forty-four percent of the preliminary diversion group were cured, 50 percent remained with compromised function, and 6 percent died. Fifty-eight percent of the permanently diverted group had compromised function, 32 percent required dialysis/transplantation, and 10 percent died. No children from that group returned to normal levels of renal function. Of the boys who had fulguration of the valves alone, 78 percent were cured, 19 percent remained with compromised function, and 3 percent underwent transplantation (Table IV). Once the final outcome had been determined, a retrospective analysis of the cases was performed to identify those factors that might indicate a poorer prognosis. Age at presentation appeared to have little impact on final outcome. Although the mean age of the group that was cured was older than the remaining three groups, this was not significant (Table V). The initial BUN in each of the groups appeared to have some significance. Thirty-three percent of the boys who were eventually cured were uremic initially as opposed to 57 percent of those in whom compromised function persisted. One hundred percent of the group that progressed to transplantation or death presented with uremia. Serum creatinine evaluation showed similar findings (Table VI). Severe reflux was seen least commonly in the cured group (44 % ), as opposed to high percentage in the other groups (Table VII).

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VOLUMEXXXIII.NUMBER3

-Permanent Cutaneous Ureterostom>.

Preliminary Diversion

Categor? Cured Compromised function Dial>xis/transplant Dead TO.I.AI.S

7116 (44) 8116 (SO)

DiversionIleal Conduit

8; lb 5110 2119 15

111s (6) 16

Cured Compromised function Dialysis/ transplant Dead * l:iclll-c*h

Greater Than One Year

Mean

Categor!

12132 (38)

20132 (62)

2.5

13125 (q52)

12125 (48)

1.0

Cured Compromised function Dialysis/ transplant Dead

in parvntlrc5c~5

(67) (FjO) intlicak

216 214

.12

T/~BI,E:VII.

Less Than One Year

316 213

25132 (78) 6/32 (19) 1132 (3)

($58) 3; ;9 (32) l/l9 (10) (19) 4

‘lY21~I.l~: V. Age prcsen tation comparisons Catcgor!

(33) (50)

1.0 1.4

TUFV On11

Reflw

comparisons Percent------Moderate

None

44

9

47

x4

12

4

Severe

100 100

. .

p~~rc’cnt.

TABLE VI.

Signijicance of uremia/axotemia -Blood Normal

Categoq Cured

6i C,b

Compromised function Dialysis/transplant Dead

43 % . .

Urea NitrogenUremic Mean*

33%’ 57 9% 100% 100 %’

Analysis of growth and development revealed that boys in the cured or compromised function group had similar height and weight percentiles. Those who progressed to end-stage renal failure or death presented in very low percentiles for height and weight development (Table VIII).

14 22 135 127

at przsentation

pCreatinine-----Normal Azotemic

558o/( 31 “/(

42 % 69 %m

Mean*

0.8 1.o

. .

100 ‘r(’

3

.

100 “i(’

.1

T:\I~I.I,: VIII.

Growth und decr~lopmcnf at pre,Yentation

Group

-Average Height

Cured Compromised function Dialysis/transplant Dead

x3 3; -1 3

Percentib Weight 46 30 6 3

Comment Posterior urethral valves presents with a broad spectrum of abnormalities ranging from minimal voiding dysfunction to completely obstructive valves. Although it has been commonl!. recognized that two types of valves exist (T~rpe I and Type III of Young’s original classification), the embryologic etiology is still controversial. Some investigators consider valves to be a residual portion of the endodermal urogenital membrane” Lvhile others see them as n~aldevelopment of the mesonephric ductal sys-

Despite appropriate surgical intervention in children with posterior urethral valves. a certain number will progress to end-stage renal failure and occasionally death. This has been the challenging group to follow and manage, since it is difficult for the urologist to observe a child becoming progressivelv more azotemic without intervening with some form of urinaq diversion. Radiologic evaluation of these boys often reveals that despite good valve ablation. the upper tracts often remain tortuous and dilated, suggesting persistent obstruction. It has

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been suggested that these findings may be due to decompensations of the ureteral musculature itself, rather than obstruction8 This has been supported by direct ureteral pressure measurements made by Whitaker9 Normal bladder emptying is also a significant factor. This would suggest that the degree of renal function that many of these children will end up with is as much if not more a function of the intrauterine effects of the valvular obstruction rather than the subsequent surgical manipulation. BecklO has shown that ureteral obstruction during the first half of gestation in sheep will result in a hydronephrotic dysplastic kidney. Bellinger et al.” reported a case of a dilated bladder secondary to posterior urethral valves which was detected in a fifteen-week-old fetus during routine prenatal sonography. On subsequent abortion and autopsy, Type I valves were present. The kidneys were small, hydronephrotic, dysplastic, and contained numerous cysts. Other autopsy series from children with congenital urethral obstruction have shown the kidneys to be primarily dysplastic with numerous cysts. l2 Therefore, in the child who has persistent, progressive azotemia despite appropriate valve ablation secondary to inadequate function, renal dysplasia and maldevelopment rather than obstruction may be the causation. Warshaw et al. l3 reported on a group of 54 patients with initial obstructive uropathy who progressed to end-stage renal disease. All had undergone prior corrective surgery or diversion, but nevertheless progressed to requiring dialysis. Our data support this latter observation. None of the children who underwent a permanent diversion for progressive azotemia achieved normal renal functon despite adequate urinary drainage. Only 4 percent of the children who had TUFV alone, or temporary diversion with subsequent TUFV and undiversion, went on to dialysis or death. Forty-two percent of the permanently diverted group either required dialysis or died. Ideally, one would like to be able to identify at the time of initial diagnosis which children will suffer this poor outcome. Because of the wide variety of clinical presentation, it is difficult to identify absolute prognostic factors. Most investigators have noted that the younger the child at the time of diagnosis, the poorer the prognosis. I4 Our data reveal other factors that also suggest a dismal outcome. One hundred percent of the children who progressed to dialy-

208

sis or death initially presented with markedly elevated BUN and creatinine. Failure of these two parameters to rapidly fall toward normal levels is an unfavorable prognostic sign. All had severe reflux and hydronephrosis on radiologic evaluation as well. Significant reflux at the time of initial presentation also was clearly a negative factor. It is not clear if this is a manifestation of dysplasia-abnormal parenchyma induced by an ectopically placed ureter, or a primary causal factor. Most of the valve children initially presented in lower percentiles for growth and development. However, those who had the worse outcome often presented with severely retarded height and weight. Obviously, the management of the patient with posterior urethral valves must still be individualized. Nevertheless, recent reviews would suggest that urinary diversion, whether temporary or permanent, is often not necessary, and the majority of patients can be managed safely with TUFV alone.15 Our data support this, as well as suggest that in most cases where permanent diversion was instituted, the ultimate outcome was not affected. New York, New York 10021 (DR. MININBERG) References 1. Young HH, Frontz WA, and Baldwin JC: Congenital obstruction of the posterior urethra, J Ural 3: 289 (1919). 2. Atwell JD: Posterior urethral valves in the British Isles. A Multicenter B.A.P.S. review, J Pediatr Surg 18: 70 (1983). 3. Johnston JH, and Kulatilake AE: The sequelae of posterior urethral valves, Br J Urol 43: 743 (1971). 4. Rabinowitz R, et al: Upper tract management when posterior urethral valves ablation is insufficient, J Urol 122: 370 (1979). 5. Hoover DL, and Duckett JW: Posterior urethral valves unilateral reflux and renal dysplasia: a syndrome, J Urol 128: 994 (1982). 6. Froheiberg DH, Thuroff JW, and Riedmiller H: Posterior urethral valves: theoretical considerations on embryological development, Eur Urol 8: 325 (1982). 7.. Livne PM, Delaure J, and Gonzales ET: Genetic etiology of uosterior urethral valves. I Urol 130: 781 (1983). 8. Duckett JW: Current management‘of posterior urethral valves, Ural Clin North Am 1: 471 (1974). 9. Whitaker RH: The ureter in posterior urethral valves, Br J Urol 45: 395 (1973). 10. Beck AD: The effect of intra-uterine urinary obstruction upon the development of the fetal kidney, J Urol 105: 784 (1971). 11. Bellinger MF, Cornstock CH, Gross0 D, and Zaino R: Fetal posterior urethral valves and renal dysplasia at 15 weeks gestational age, J Urol 129: 1238 (1983). 12. Cussen LJ: Cystic kidneys in children with congenital urethral obstruction, 1 Urol 106: 939 (1971). 13. Warshaw BL, *et al: Progression to’end stage disease in children with obstructive uropathy, J Pediatr 100: 183 (1982). 14. Williams DI, and E&stein HB: Obstructive valves in the posterior urethra, J Urol 93: 236 (1965). 15. Kurth KH, Alleman ERJ, and Schroder FH: Major and minor complications of posterior urethral valves, J Urol 126: 517 (1981).

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1989

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NUMBER

3