Pathology and Surgical Management of Urinary Retention Manifesting After Anorectal Malformation Surgery.

Introduction: Associated congenital anomalies, operative structural injury, and postoperative neurovesical dysfunction combine to cause urinary retention in children with a history of surgery for anorectal malformation (ARM). Aim: To study the presentation and management of urinary retention in patients with a history of ARM surgery. Methodology: Retrospective study. Results and Discussion: Twenty-five children presented with urinary retention with a history of ARM surgery performed elsewhere. There were 17 males (high - 14, intermediate - 2, and low - 1) and 8 females (cloaca). Sixteen children had an abnormal spine. Eight children had urethral injury (total transection - 3) and three had a large residual rectal stump. 41/48 renal units were dilated and 27 refluxing. Seventeen children had abnormal estimated glomerular filtration rate and five had undergone urinary diversion. Management: Definitive surgical management was individualized, the most pertinent consideration being whether normal voiding would be feasible or whether a continent low pressure urinary reservoir with clean intermittent catheterization (CIC) would be a safer option. Operative management included excision of the rectal stump (3), urethral reconstruction (2), bladder augmentation (17), Mitrofanoff port (22), bladder neck closure (2), and antireflux surgery (13). Follow-up estimated glomerular filtration rate had improved/normalized in all but two patients. HUN resolved/improved in all and 25/27 refluxing units ceased refluxing. All are socially continent with ten voiding normally and the rest on CIC.
Conclusion: Urinary retention after ARM surgery is multifactorial and requires prompt recognition and possibly urinary diversion. Final reconstruction aims at achieving continence with safe upper tracts. Urethral voiding is possible in the selected cases. Copyright:

INTRODUCTION

Urinary retention presenting immediately or recognized later after anorectal malformation (ARM) surgery is a complication which can lead to life-threatening consequences unless recognized and managed appropriately. Herein, we analyze our experience with 25 such children who had been operated for ARM elsewhere and presented to us with urinary retention. Some children had been diverted but others went unrecognized for many years and presented with consequent renal deterioration.

Aim

To analyze the etiology, effects, management, and outcome of patients who presented with urinary retention and history of undergoing pull-through operation for ARM.

METHODOLOGY

A retrospective study was conducted in a tertiary care hospital. Data (type of anorectal anomaly, previous surgery, symptomatology, presence of urinary tract infections [UTI], ultrasound, micturating cystourethrogram [MCUG], evaluation of spine by X-ray/magnetic resonance imaging, renal function test, and follow-up) were collected from the case sheets.

RESULTS AND ANALYSIS

Urinary retention had been recognized after ARM surgery in 25 patients (M:F = 17:8) with a mean age of 7.7 years (range, 2–18 years). All the eight girls had a cloacal anomaly. 14/17 of the boys had a high anomaly, while two had intermediate and one a low anomaly.

The children presented to us after varying time intervals following pull-through for ARM. Twelve children had been recognized in the immediate postoperative period, six within 2 years, and the remaining after 5 years. Five children (vesicostomy = 4 and ureterostomy = 1) had been diverted in the postoperative period. Three vesicostomies had stenosed. Clinical symptoms included dribbling of urine with retention and UTI in all patients except for two who had a well-functioning vesicostomy. One child had a persistent rectourethral fistula and another had a vesical stone.

Of the 48 renal units (unilateral agenesis – 1 and nephrectomy – 1), 41 had HUN and one kidney was shrunken. 27/48 units had dilating VUR and one unit had vesicoureteric junction obstruction after reimplantation done elsewhere [Table 1].

Table 1

Morbidity contributing to urinary retention in 25 children after anorectal malformation surgery and management

Chief morbidity	Co-morbidity				Surgical management
	Urethra	Spine	HUN in units	VUR in units
Rectal stump (n=3 males)	Nil	2	4	Nil	All restored to normal voiding by excision of rectal stump=3 And urethral reconstruction=2 Additional Mitrofanoff=4/5 for nighttime drainage No augmentation No anti-reflux surgery
Complete urethral transection (n=2 males)	2	2	4	4
Complete urethral transection (n=1 female)	1	1	2	2	On CIC - Urethral=2/20 Mitrofanoff port=18/20 Bladder augmentation=17 Antireflux surgery - Ureteric reimplant=13 units TUU=9 units
Neurogenic bladder (n=12 males)	Partial urethral injury-5 Urethral diverticulum-1 Proximal hypospadias-2	8	19	17+1 VUJO
Neurogenic bladder (n=7 females)	Long common channel-6	3	12	4

HUN: Hydroureteronephrosis, VUR: Vesicoureteric reflux, VUJO: Vesicoureteric junction obstruction, CIC: Clean intermittent catheterization, TUU: Transureteroureterostomy

Serum creatinine ranged between 0.33 mg/dl and 1.78 mg/dl with a mean of 0.76 mg/dl.

Estimated glomerular filtration rate (eGFR) was >90 ml/min in eight patients, <89 and >60 ml/min in eight, <59 and >30 ml/min in seven patients, and <29 and >15 ml/min in two patients.

The bladder showed evidence of trabeculation/poor compliance on MCU/UDS/scopy in 18 patients.

Three patients had accidental complete (1 near complete) urethral transection and there was partial urethral injury in five patients [Figure 1]. One patient had localized megalourethra in the posterior urethra and two had proximal hypospadias repair. Four patients had a history of recurrent epididymo-orchitis.

Figure 1

(a) Near complete urethral injury in a male managed by initial Mitrofanoff clean intermittent catheterization prior to urethral reconstruction. (b) Complete urethral transection in a female with retention and vesicoureteric reflux. (c) Complete urethral transection in a male with vesicoureteric reflux

A large residual rectal stump causing bladder outflow obstruction was diagnosed in three patients, two of whom had undergone pull-through and another a Hartman's procedure [Figure 2a].

Figure 2

(a) Retained rectal stump compressing the bladder neck. (b) Neurogenic bladder with bilateral vesicoureteric reflux

Partial sacral agenesis was present in 16 patients.

Surgical management

Urgent relief of urinary obstruction was the primary concern and initial supravesical diversions had been done elsewhere (vesicostomy – 4 and ureterostomy – 1) or by us (Mitrofanoff ports – 2) prior to definite reconstruction. Definitive surgical management was individualized, the most pertinent consideration being whether normal voiding would be feasible or desirable or whether a continent low pressure urinary reservoir emptied by clean intermittent catheterization (CIC) would be a safer option.

Five boys with a predominantly structural outflow problem (complete/near complete urethral transection in two and retained rectal stump in three) underwent surgical correction of the structural abnormality with restoration of voiding per urethra. The rectal stumps were removed by posterior sagittal approach in one and abdominoperineal route in two boys.[1] One boy with urethral transection underwent replacement of the posterior urethra with isolated tubularised small bowel via a transpubic route.[2] The other boy had a prepucial island flap repair of the stenosed urethra via the perineal route.[3] A Mitrofanoff port (appendicular – 3 and Monti – 1) for nighttime drainage and additional safety was provided/retained in 4/5 boys. Bladder augmentation was not performed in this group and VUR was managed expectantly.

Twelve boys with a predominantly neurogenic retention and all eight girls (1 with urethral transection and the rest neurogenic) were managed with CIC via the urethra in two (one boy and one girl) and via a Mitrofanoff port in the others (15 appendicular, 3 ureteric). In 15/18 children who underwent a Mitrofanoff port for CIC, urethral CIC was precluded by complete urethral transection (1 girl), partial urethral injury (5 boys), megalourethra (1boy), proximal hypospadias repair (2 boys), and a hidden urethral orifice in six girls with high cloaca. Bladder augmentation was undertaken in 17/20 children in this group (ileocystoplasty – 15, colocystoplasty – 1, and ureterocystoplasty – 1). Surgical correction of VUR with bladder augmentation was done in 18 units (reimplant – 10 and TUU – 8). In two patients who had dilating VUR with large postvoid residue, antireflux surgery (re-implant -1) [Figure 2b] was done without augmentation.

Bladder neck closure was done for two children in this group for nonneurological pathology: one girl with complete urethral transection had developed a persistent vesicocutaneous fistula from the damaged bladder neck to the vulval outlet and one boy had a large posterior megalourtethra which collected urine and mucus.

Other surgeries included repair of a persistent rectourethral fistula (n = 1), vasectomy for ectopic vas (n = 1), appendicular Malone in nine, removal of vesical stone in one, and ileal vaginoplasty in two patients.

Follow-up

Follow-up is from 4 months to 15 years with a mean period of follow-up of 5 years. Eighteen patients had a follow-up of more than 2 years. All patients are socially continent. Ten patients are voiding normally but seven of them use nighttime drainage via Mitrofanoff. Fifteen are on CIC.

Upper tracts are stable with resolution of HUN in 18 units, improved in all the others. Of 27 refluxing units, follow-up MCUG was available in all but one child (n = 2 units) and there is complete resolution of VUR (5 units without antireflux surgery).

One patient with augmentation presented with multiple vesical stones after 15 years which were removed.

Serum creatinine ranged from 0.33 mg/dl to 1.86 mg/dl and the mean was 0.76 mg/dl.

Current eGFR in the 25 patients was >90 ml/min in 14, <89 and >60 ml/min in 9, and <59 ml/min and > than 30 ml/min in 2 patients. Considering only the patients with an abnormal eGFR either preoperatively or postoperatively, the eGFR has improved in 14 patients, unchanged in one and slightly worsened in two patients [Figure 3]. Even these two patients have resolution of HUN and the progression of chronic kidney disease (CKD) is probably due to reflux nephropathy.

Figure 3

Preoperative and follow-up estimated glomerular filtration rate values of children with abnormal estimated glomerular filtration rate (calculated by Schwartz formula in patient less than 16 years and chronic kidney disease-EPI formula in older children)

DISCUSSION

Many comorbidities, both congenital and acquired, either separately or in combination, contribute to urinary retention in ARM. Children born with ARM have a 30%–50% incidence of genitourinary and spinal abnormalities, more so in high ARM and cloaca.[4] Renal agenesis, VUR, and spinal defects with attendant neurogenic bladder are important congenital associations which should be meticulously sought prior to the pull-through operation. In addition, neurogenic retention with secondary VUR can be acquired after ARM surgery. This could be due to spinal defects not evaluated preoperatively or operative damage to the pelvic nerves.[5678]

Surgical mishaps such as partial or total urethral transection during surgery and retained rectal stump are best avoided, and early recognition is mandatory when they occur. Other urethral pathology such as megalourethra, posthypospadias repair, persistent rectourethral communication, and the “hidden” urethral meatus in high cloaca complicate the management by making urethral CIC difficult.

Although incontinence was a common presenting feature, the underlying urinary retention resulted in unhealthy bladders, HUN, VUR, UTI, and CKD. The eGFR was abnormal in 17 of the 25 children. The worst affected children were those with complete urethral transection who managed to survive by partial recanalization of the transected urethra and one girl with neglected neurogenic bladder. The least affected were among those with extrinsic compression of the urethra by a large retained rectal stump and those with prompt effective diversion or early CIC. In three girls, undiversion had been attempted elsewhere without resolution of the obstructive pathology resulting in further renal deterioration.

Neurogenic retention (n = 19) (with spinal anomaly in 11) forms the largest group among the 25 reported herein. Only one child was managed with urethral CIC alone till repeated UTI with increasing renal scars secondary to VUR necessitated bilateral ureteric reimplantation. A Mitrofanoff port for CIC was provided in 17 children as many of them had had comorbidities precluding urethral CIC (urethral stricture – 5, megalourethra – 1, repaired hypospadias – 2, and high cloaca – 6). Bladder augmentation was done for 16 patients as they showed evidence of high-pressure bladder on UDS/Scopy/MCUG or had been diverted for the same. The issue of antireflux surgery along with augmentation is controversial, as marked reduction of bladder pressures can eliminate VUR (as in 2 of our augmented but unoperated ureters), but there could be an element of true vesicoureteric incompetence in ARM which should be tackled. Thus, antireflux surgery was undertaken in 20 ureters, either by ureteric reimplantation alone (n = 12) or refluxing to nonrefluxing/reimplnated ureter (TUU, n = 8). This management of VUR was highly successful with complete resolution of VUR.

Urethral transection in boys during ARM surgery is a major disaster and should be avoided. A catheter is kept in the urethra as a rule during the pull-through operation, especially by the PSARP approach to aid dissection of the rectum from the urethra during and after the division of the rectourethral fistula.[9] No attempt should be made to encircle the fistula, which could inadvertently include the urethra as well. The level of urethral transection is, however, variable and depends on the level of dissection. In boys, injury to the bladder neck is generally spared during pull-through and hence reconstruction to restore normal voiding should be done. However, there is a place for preliminary vesical diversion as a vesicostomy or a Mitrofanoff port as often they are infants at the time of initial injury and the infant urethra is a delicate structure. Another advantage of delaying reconstruction is attempted urethral voids by the child dilate the urethra above the transection which allows an easier repair. The defect in the urethra was bridged successfully by the transpubic route with a Monti's tube of the ileum in one child and via the perineal route using a prepucial island skin tube in the other. Both are voiding well though one has been advised nighttime drainage via the Mitrofanoff port. VUR was managed expectantly in these two boys. Both patients had bilateral Grade V VUR which has completely resolved in one and the other child has not had a MCUG.

Retained rectal stump above the rectourethral fistula was the result of dividing the bowel too cephalad to the site of the fitula or as in one case, performing a Hartman's type of colostomy. This leaves a large diverticulum behind the urethra, which fills up with secretions/urine/stones/fecolith and not only obstructs the urine outflow but also the terminal bowel and occasionally fistulates into the gastrointestinal tract.[9] This is a pitfall when operating from the abdomen for an intermediate anomaly whether by open or laparoscopic approach. Surgical correction was performed by removing the residual rectal pouch via the PSARP or abdominal route. Although all are voiding well, two of these children also have a Mitrofanoff port for CIC, one boy had an additional spinal lesion and the other had very dilated upper tracts.

Boys with retentive urinary changes continue to be prone to epididymo-orchitis.[10] Vasal reflux of urine is a symptom of obstruction in the posterior urethra either by spasm of the external sphincter or urethral stenosis and this can continue even after CIC via Mitrofanoff is instituted. This problem is caused by attempted voids due to transient bladder activity which may force urine into the posterior urethra and vas. While this was so in three boys, one boy had an ectopic vas and underwent vasectomy.

The eight girls with cloaca are an important group of ARM children with urinary retention. Although neurogenic urinary retention was the major group in this report, other serious causes are urethral transection as a surgical mishap during PSARVUP (n = 1) and neonatal urocolpos. Urocolpos was, however, not seen in this series. Mitrofanoff CIC rather than urethral reconstruction has been our approach in cloaca to relieve urinary retention.[11] Vaginal pull-through with partial ileal substitution was performed by the abdominoperineal route in two girls (one with hematometra). Both are menstruating uneventfully. Others are asymptomatic though some are menstruating via cloacal channel.

The ureterorenal outcome in the 25 children shows recovery of renal function in all but two patients. UHN has improved with resolution in 10 and stabilization in the others. VUR has resolved in all cases (MCU not done in 1). All cases are socially continent. Ten cases are voiding normally but seven of them use nighttime drainage via Mitrofanoff. Fifteen cases are on CIC. No child remains incontinent though bladder neck surgery has been done in only two out of 25 children.

CONCLUSION

Urinary retention after ARM surgery is multifactorial with neurological and structural causes. A thorough examination and evaluation of the spine and the bladder is essential. This is especially true in children with cloaca and high ARM as it may be a combination of factors leading to obstruction, renal failure, and early deterioration of the kidney. Early recognition of overflow incontinence postoperatively and timely suprapubic diversion are beneficial.

Final reconstruction requires careful consideration of possibility of urethral reconstruction, need for Mitrofanoff, and need for antireflux surgery and augmentation. Our goal of renal preservation, social continence, and normal voiding in the selected cases has been achieved.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.