Circumcision and its complications, levels of urinary tract obstruction, hypospadias and epispadias

Overview

Paediatric urology in the syllabus covers three areas:

1. Circumcision: when it is needed, how it is done, and what can go wrong.
2. Urinary tract obstruction at its three levels, many of which are now found on antenatal ultrasound as hydronephrosis.
3. Hypospadias and epispadias, the main congenital anomalies of the urethral opening.

The normal foreskin

• At birth the foreskin is stuck to the glans; the adhesions separate gradually.
• A non-retractile foreskin is normal in young boys: about 50% at 1 year, about 10% at 4 years and about 1% at 16 years still cannot retract.
• Ballooning of the foreskin on passing urine and white smegma collections ("smegma pearls") are normal; reassure, no operation.
• Never forcibly retract the foreskin: it causes tears, scarring and true phimosis.

Circumcision

Indications

Other options for mild true phimosis: topical steroid cream; preputioplasty (keeps the foreskin).

Contraindications

• Hypospadias (and other penile anomalies: epispadias, chordee without hypospadias, buried / webbed penis, micropenis): the foreskin may be needed for reconstruction.
• Bleeding disorders (e.g. haemophilia) until corrected; a boy who bleeds badly after circumcision should be tested for a clotting disorder.
• Unwell or very premature baby; local infection.
• Ambiguous genitalia (until assessed).

Techniques (outline)

• Medical circumcision: under general anaesthesia with a long-acting local block (dorsal penile nerve block or caudal) for pain relief. Mark the corona, excise the foreskin, secure vessels with bipolar diathermy or ligatures, close with absorbable sutures.
• Plastibell device in infants: a plastic ring is tied under the foreskin; the ring and dead tissue drop off in about 5–8 days.
• Dangerous techniques: blind clamp-and-cut (risk of glans amputation) and monopolar diathermy on the penis (current concentrates at the base and can coagulate the whole penis). Use bipolar only.

Complications

Three levels of urinary tract obstruction

Obstruction in children is grouped by level, because the level determines which kidneys are affected and how urgent it is.

General investigations

Timing: postnatal ultrasound is usually delayed a few days after birth (newborns are relatively dehydrated, which can hide dilatation), except when posterior urethral valves are suspected (bilateral hydronephrosis in a boy), which need early imaging.

Upper level: PUJ obstruction

• Commonest cause of significant congenital hydronephrosis; can be bilateral.
• Presents: antenatal hydronephrosis, abdominal mass in an infant, intermittent loin or abdominal pain after drinking a lot (Dietl crisis), UTI, haematuria after minor trauma.
• Many mild cases resolve spontaneously: follow with serial ultrasound.
• Pyeloplasty (Anderson–Hynes dismembered pyeloplasty: excise the narrow segment and rejoin the pelvis to the ureter, moving any crossing vessel) for symptoms, worsening dilatation, falling split function or infection.
• A kidney contributing more than about 20% of total function is worth saving; nephrectomy is considered when function is very poor (under about 10%).

Middle level: VUJ obstruction

• Primary obstructive megaureter: an aperistaltic segment of the lower ureter; dilated ureter and pelvis. Many improve; surgery is ureteric reimplantation (with tapering) if function falls or infections recur. Temporary stent or ureterostomy in infants.
• Ureterocele: cystic swelling of the end of the ureter inside the bladder, often draining the upper pole of a duplex kidney, commoner in girls; can block the bladder neck. Treated by endoscopic puncture/incision, or excision and reimplantation.
• Vesicoureteric reflux (not an obstruction but a common cause of dilatation): many resolve; antibiotic prophylaxis, endoscopic injection or reimplantation in a few.

Lower level: posterior urethral valves (PUV)

• Congenital membranous folds in the posterior (prostatic) urethra, just below the verumontanum, acting like flap valves: urine cannot flow out, but a catheter passes up easily.
• Only in boys; about 1 in 5000–8000 male births.
• Antenatal: bilateral hydronephrosis, distended thick-walled bladder, dilated posterior urethra ("keyhole" sign), oligohydramnios (which causes pulmonary hypoplasia and Potter features in severe cases).
• Postnatal: palpable bladder, poor or dribbling urinary stream, UTI and urosepsis, failure to thrive, renal failure; milder cases present later with wetting.
• Investigation of choice: MCUG, showing a dilated, elongated posterior urethra above the valves, a thick trabeculated bladder with diverticula, and often reflux.
• Management:

1. Urethral catheter (feeding tube) to drain the bladder immediately; correct fluids and electrolytes (post-obstructive diuresis), treat infection. 2. Endoscopic valve ablation (cystoscopic incision) once stable. If the urethra is too small: vesicostomy temporarily. 3. Lifelong follow-up: "valve bladder" dysfunction, reflux, infection, hypertension.

• Outlook: about a third develop chronic renal failure despite early treatment.

Hypospadias

Definition and embryology

• The urethral opening lies on the ventral (under) surface of the penis, scrotum or perineum, proximal to the normal site at the tip of the glans.
• Cause: incomplete fusion of the urethral folds (incomplete tubularisation of the urethra) in the fetus; partly androgen dependent. In females the urethral folds form the labia minora.
• Commonest congenital anomaly of the urethra: about 1 in 200–300 boys.

Features (the triad)

1. Ventral, proximal meatus
2. Hooded foreskin (dorsal hood, foreskin deficient ventrally)
3. Chordee: downward (ventral) bending of the penis, worse on erection, from fibrous tissue replacing the missing urethra and spongiosum

Classification by meatal position

Effects and management

• Abnormal urine stream (spraying, downward), cannot stand to void, curved erection and later sexual and fertility problems, cosmetic and psychological effects.
• Hypospadias does not cause obstruction or UTI by itself (unless there is meatal stenosis).
• Do not circumcise: the foreskin is used for the repair.
• Surgery by a paediatric urologist, usually before about 18 months to 2 years (before the child is aware of the genitals and before toilet training).
• Aims: straighten the penis (orthoplasty), build a urethra to bring the meatus to the tip of the glans (urethroplasty), reconstruct the glans and skin.
• Common operations: tubularised incised plate (TIP, Snodgrass) urethroplasty for distal types; foreskin flaps or staged repairs (grafts) for proximal types.
• Complications: urethrocutaneous fistula (commonest), meatal stenosis, urethral stricture, diverticulum, persistent chordee, wound breakdown.

Epispadias and bladder exstrophy

• Epispadias: the urethral opening is on the dorsal (upper) surface of the penis, with an upward curve (dorsal chordee). Much rarer than hypospadias.
• In girls: bifid clitoris and a short, wide urethra.
• If the defect involves the bladder neck, the child has urinary incontinence.
• Epispadias is part of the exstrophy–epispadias complex. In bladder exstrophy (ectopia vesicae), the bladder plate is open and exposed on the lower abdominal wall, with widely separated pubic bones (no symphysis) and epispadias. It results from abnormal development of the cloacal membrane (failure of mesoderm to migrate into the lower abdominal wall). It is rare (about 1 in 50 000) and more common in boys.
• In isolated epispadias the pubic bones are joined.
• Treatment: staged reconstruction (bladder closure in infancy, often with pelvic osteotomies; epispadias repair; later bladder neck reconstruction for continence; augmentation if the bladder stays small).

Quick revision

• Non-retractile foreskin is normal: about 50% at 1 year, 10% at 4.
• True phimosis = BXO; medical circumcision for BXO, recurrent balanoposthitis, recurrent UTI with abnormal tract.
• Contraindications: hypospadias, epispadias, buried penis, bleeding disorder.
• Complications: bleeding (commonest), infection, glans/urethral injury, meatal stenosis.
• Upper level PUJ (pyeloplasty); middle VUJ (megaureter, ureterocele; reimplant); lower outlet (PUV; catheter, ablation).
• PUV: boys, bilateral hydronephrosis, MCUG; about a third get renal failure.
• Hypospadias: ventral meatus, hooded foreskin, chordee; 1 in 300; repair before about 2 years; no circumcision.
• Epispadias: dorsal meatus, exstrophy, separated pubes, incontinence.

Written by The House Job from standard references (Bailey & Love; Basis of Paediatrics).

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