Successful outcome following prenatal intervention in a female fetus with bladder outlet obstruction

Fetoscopic laser surgery to decompress distal urethral obstruction caused by prolapsed ureterocele

We report on the successful use of fetoscopic surgery to treat a case of prolapsed ureterocele in a female fetus. At 21 weeks' gestation, a double renal system with an intravesical ureterocele obstructing the bladder outlet was diagnosed, causing severe megacystis, bilateral hydronephrosis and progressive oligohydramnios. Ultrasound evaluation following referral to our center confirmed severe bilateral hydronephrosis with pelvic and calyceal dilatation, but amniotic fluid volume was normal and the ureterocele was not visualized in the bladder. Instead, a cystic mass within the external genitalia was observed, suggestive of a prolapsed ureterocele, causing intermittently severe obstruction of the urethra. The parents were counseled about the uncertain prognosis and fetal surgery to decompress the urinary system was proposed. The procedure involved firing a contact diode laser until perforation of the ureterocele was achieved. Following laser surgery, resolution of megacystis, reduction of hydronephrosis and normalization of amniotic fluid volume were observed. Our report demonstrates that fetoscopic decompression of a distal urethral obstruction is feasible in the rare event of congenital prolapsed ureterocele.

Fetal surgery for severe lower urinary tract obstruction

Fetal interventions have been proposed for treatment of severe lower urinary tract obstruction (LUTO), as this condition is associated with high rates of perinatal mortality and postnatal renal impairment. The rationale for in utero treatment for those cases is based on the possibility of relieving the obstruction, improving the amniotic fluid volume, and preventing renal and bladder damage. Candidates for fetal intervention should be rigorously selected based on the confirmation of severe LUTO (dilated bladder and bilateral hydronephrosis), oligohydramnios or anyhydramnios and 'favorable' fetal urinalysis (dependent on gestational age). Nowadays there are two different therapeutic options with specific technical approaches. Vesico-amniotic shunting is an easier procedure, but with a higher frequency of related complications. Fetal cystoscopy can be used for diagnostic purpose and for treatment of posterior urethral valves, with suggestive advantage of allowing a more physiological release of the obstruction. According to the literature, estimated survival rates and postnatal normal renal function frequencies are approximately 40 and 50% after vesico-amniotic shunting and 75 and 65% after fetal cystoscopy, respectively.

Fetal cystoscopy for severe lower urinary tract obstruction--initial experience of a single center

OBJECTIVE

To report the experience with fetal cystoscopy and laser fulguration of posterior urethral values (PUV) for severe lower urinary tract obstruction (LUTO).

METHODS

Between July 2006 and December 2008, fetal cystoscopy was offered to 23 patients whose fetuses presented with severe LUTO, favorable urinary analysis and gestational age <26 weeks. Fetal urinary biochemistry was evaluated before and after cystoscopy. All infants were followed 6-12 months after birth. Abnormal renal function was defined when serum creatinine higher than 50 micromol/L (2 Standard Deviation) or the necessity of dialysis or renal transplantation. Autopsy was always performed whenever fetal or neonatal deaths occurred.

RESULTS

Eleven patients decided to undergo fetal therapy and 12 elected to continue with expectant observation. There was no difference between both groups in gestation age at diagnosis and referral examinations. Urethral atresia was diagnosed in 4/11 (36.4%) fetuses by fetal cystoscopy. At 26 weeks, fetuses that were managed expectantly presented with worse urinary biochemistry results (p < 0.05). Survival rates and percentage of infants with normal renal function were significantly higher in the cystoscopic group than in the expectant group (p < 0.05).

CONCLUSIONS

Percutaneous fetal cystoscopy is feasible using a thinner special cannula for prenatal diagnosis and therapy of LUTO. Prenatal laser ablation of the PUV under cystoscopy may prevent renal function deterioration improving postnatal outcome.