Volume 44, Issue 2 p. 238-240
Case Report
Free Access

Cystoscopic placement of transurethral stent in a fetus with urethral stenosis

R. Ruano

Corresponding Author

R. Ruano

Department of Obstetrics and Gynecology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil

Correspondence to: Dr R. Ruano, Universidade de São Paulo, Faculdade de Medicina, Obstetrics Department, Av. Dr. Enéias de Carvalho Aguiar, 255, 10° andar, São Paulo, Brazil, CEP 05403-900 (e-mail: [email protected])Search for more papers by this author
C. T. Yoshizaki

C. T. Yoshizaki

Department of Obstetrics and Gynecology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil

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A. M. Giron

A. M. Giron

Department of Urology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil

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M. Srougi

M. Srougi

Department of Urology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil

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M. Zugaib

M. Zugaib

Department of Obstetrics and Gynecology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil

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First published: 26 December 2013
Citations: 20

ABSTRACT

We report the case of a fetus with severe megabladder, displaying the ‘keyhole’ sign on ultrasound imaging, that underwent cystoscopy at 22 weeks' gestation. There was a familial history of mild urethral atresia. Fetal cystoscopy revealed congenital urethral atresia. A guide wire was advanced through the fetal urethra and a transurethral vesicoamniotic stent was placed successfully. The fetus was delivered at 36 weeks' gestation and postnatal cystoscopy confirmed the absence of posterior urethral valves or urethral atresia. The infant was 5 years old with normal renal function at the time of writing. We conclude that fetal cystoscopic placement of a transurethral stent for congenital urethral stenosis is feasible. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd

CASE REPORT

A 26-year-old woman, gravida 2 para 1, was referred to our Fetal Center at 18 weeks' gestation because of the diagnosis of fetal megabladder at 16 weeks' gestation. Ultrasound examination confirmed a severe megabladder, displaying the ‘keyhole’ sign and increased wall thickness (Figure 1), associated with mild bilateral hydronephrosis (Grignon Grade II1) and mildly hyperechoic kidneys. No other associated anomaly was seen, but the amniotic fluid volume was reduced (amniotic fluid index (AFI) = 5.1 cm). Fetal echocardiographic findings were normal. Interestingly, family history revealed that the father, brother and uncle of the fetus were diagnosed with urethral stenosis during childhood (without perinatal manifestation). Amniocentesis for fetal karyotyping was performed, with the karyotype confirmed as 46,XY. Fetal ultrasound examination and vesicocentesis were performed weekly. Urinary biochemistry did not indicate an unfavorable prognosis (Na, 90–93 mmol/L; Cl 78–80 mmol/L; osmolarity, 185–191 mOsm/L).

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Fetal ultrasound image at 18 weeks' gestation, confirming a very large bladder with ‘keyhole’ sign.

At 22 weeks' gestation, bilateral hydronephrosis and echogenicity of the kidneys worsened (Grignon Grade III1). In addition, a further reduced volume of amniotic fluid was noted (AFI = 4.0 cm). After extensive counseling by pediatric and urologic specialists, the parents elected to proceed with percutaneous fetal antegrade cystoscopy and possible laser fulguration of the posterior urethral valves. Fetal cystoscopy was performed under maternal epidural anesthesia according to our previously reported protocol2-4. Ultrasound-guided fetal anesthesia was conducted by injecting fentanyl (15 µg/kg) and pancuronium (1.0 mg/kg) into the fetal leg using a 22-gauge needle. A 2.2-curved sheath was introduced percutaneously into the upper part of the fetal bladder. Using a 1.0-mm fetoscope (11 510 A, Karl Storz, Tuttlingen, Germany) we visualized a moderately dilated posterior urethra. The fetoscope was then advanced towards the urethra. Interestingly, no clear obstruction, such as posterior urethral valves or urethral atresia, was seen (Figure 2). Warm normal saline was flushed, but no flow was seen through the penile urethra. Indeed, ultrasound imaging revealed the flow coming back to the bladder. A guide wire was advanced through the urethra and a 0.9-mm stent was placed in the penile urethra. The position of the stent was confirmed by ultrasound (Figure 3) and power Doppler imaging confirmed passage of fluid through the transurethral stent into the amniotic cavity (Figure 4).

Details are in the caption following the image
Cystoscopic view of the posterior fetal urethra.
Details are in the caption following the image
Ultrasound confirmation of fetal transurethral stent placement (arrows).
Details are in the caption following the image
Power Doppler ultrasound image demonstrating passage of fluid through the transurethral stent into the amniotic cavity (arrow).

The next day, the fetal bladder was reduced in size, although wall thickness remained increased, and amniotic fluid volume was normal. Weekly ultrasound examinations confirmed the position of the transurethral stent, normal bladder size and bilateral hydronephrosis (Grade II) with normal echogenicity of the kidneys, as well as normal amniotic fluid volume (AFI > 13.0 cm). However, at 36 weeks' gestation fetal ultrasound examination revealed that the transurethral shunt had migrated completely into the fetal bladder, resulting in recurrence of megabladder and severe oligohydramnios. A 2840-g male infant was delivered by Cesarean section, with 1-min and 5-min Apgar scores of 9 and 10, respectively. Postnatal cystoscopy confirmed the absence of posterior urethral valves or urethral atresia. The stent was then removed from the bladder. In addition to urethral impairment, the newborn had an imperforate anus, requiring colostomy, which was repaired at the age of 5 months. The child was 5 years old and had normal renal function, without urinary infection for 2 years, at the time of writing.

DISCUSSION

This case represents a rare situation in which fetal urethral stenosis was suspected because of familial history, and was confirmed by fetal cystoscopy. It is rare that there is a family history of the condition in fetuses with lower urinary tract obstruction (LUTO), although Siebert et al.5 reported a case of familial recurrence of urethral stenosis/atresia. In our case familial history led us to anticipate a potential situation of fetal urethral stenosis and to plan for the possibility of placing a transurethral stent.

The present case demonstrates that fetal transurethral catheterization with placement of a stent is feasible. To the best of our knowledge, the successful fetal cystoscopic placement of a transurethral stent has been reported only once6. This technique seems to be particularly useful for fetal urethral stenosis, when a complete urethral obstruction is not present. However, fetal transurethral stent placement could be considered after fetal cystoscopic laser fulguration of the posterior urethral valves in order to avoid thermal stenosis after laser therapy, particularly when this procedure is performed at an earlier gestational age (e.g. at 16 weeks), in order to prevent the need for repeat fetal cystoscopy.

Another feature of the present case was the diagnosis of urethral stenosis, but not of urethral atresia. These two conditions have been considered to be similar in the literature but they may have a different prognosis, based on severity of the obstruction7-9. Urethral atresia is a more severe form of LUTO in which there is complete obstruction of the bladder outlet. Urethral stenosis, i.e. a narrowing of the urethra, can obstruct the bladder outlet partially or even completely, depending on the degree and severity of the disease. Interestingly, all classical findings of severe LUTO, including the ‘keyhole’ sign which cannot be used to classify severity of the obstruction7, 10, were present in our case. This case also confirms that fetal cystoscopy may play a role in prenatal elucidation of the etiology of fetal LUTO, allowing direct therapy targeted at the basic cause of the disease2-4, 11.

The present report demonstrates a proof of principle that fetal cystoscopy may be beneficial for fetuses with severe LUTO. A systematic review showed that fetal cystoscopic laser ablation improved outcome when compared to cases without fetal intervention (odds ratio, 20.51 (95% CI, 3.87–108.69)), but had similar results when compared to cases with vesicoamniotic shunting (odds ratio, 1.49 (95% CI, 0.13–16.97))12. Therefore, a randomized controlled trial is still necessary to demonstrate the benefit, and absence of harm, of fetal cystoscopy as compared to vesicoamniotic shunting with long-term follow-up (a planned trial is registered with ClinicalTrials.gov, identifier: NCT01552824).

In conclusion, fetal cystoscopic placement of a transurethral stent for congenital urethral stenosis is feasible. Further studies are necessary to evaluate the placement of a transurethral stent after fetal cystoscopic laser fulguration of posterior urethral valves.