Posterior Urethral Valves (PUVs) – are one of the rare abnormalities of the urinary tract of the fetus, which is detected in the womb. Once again, in such a case, intrauterine treatment can increase the chances of babies’ life. The frequency of development of PUVs is one case per 5-10 thousand births. Due to the obstruction that occurs when urine exits the baby’s bladder in the womb, urination problems happen. That leads to a decrease in the amount of amniotic fluid. Lack of amniotic fluid negatively affects the development of fetal lungs to the extent that almost 75 percent of babies with this disease die either in the womb or in the postpartum period. Ensuring the proper urination of the fetus helps the development of lungs, prevents a shortage of amniotic fluid, and thus increases chances of life.
One of the ways to restore fetal urination is vesicoamniotic shunting, which allows the flow of urine from the bladder to enter the amniotic cavity. Studies have shown that the use of catheters increases the chances of fetal life by about half. Despite this, it is not entirely clear that the use of vesicoamniotic shunting catheters protects the kidneys of new-borns and prevents the development of kidney failure in their later life.
Posterior urethral valve (before the installation of a vesicoamniotic shunting catheter), accompanied by bladder and ureters expansion, as well as a lack of amniotic fluid. A case that was observed in our clinic.
After five weeks after the installation of the vesicoamniotic shunting catheter, the amount of amniotic fluid increased, as well as the size of the kidneys and bladder decreased.
New technologies and minimally invasive endoscopy methods allow treatments by inserting a camera into the fetal bladder (fetal cystoscopy). This, first of all, allows to find out the exact cause of the obstruction at the exit of the bladder (posterior urethral valves, urethral atresia, stenosis, etc.), after which, if possible, the obstruction can be eliminated. Therefore, ensuring the proper flow of fetal urine in the womb prevents the shortage of amniotic fluid and thus increases the baby’s chances of life by promoting the normal development of the lungs.
Laser ablation of posterior urethral valves that obstruct the urinary tract (fetoscopic laser ablation of the urethral valve) thanks to fetal cystoscopy has recently become a widespread medical practice and a promising treatment method. According to recent data, this practice contributes to the survival of infants and supports their kidney function. In our clinic, we also apply cystoscopic laser ablation of the urethral valve to remove posterior urethral valves (PUVs) of fetuses suitable for in-utero treatments. Before deciding on intrauterine surgery to treat fetal lower urinary tract obstruction, it is important to know if the fetus has additional structural or chromosomal problems.
You can find an article published in the journal “Perinatoloji” about the cases of fetoscopic laser surgeries by clicking on the link below.
PUV (posterior urethral valve) is an anomaly in which a membrane (valve), which is not supposed to be there, forms in the back of the urethra (the organ that removes urine from the bladder). This formation prevents urine from leaving the bladder and thus causes stagnation of urine in the urethra.
In-utero treatment of PUVs is performed by installing vesicoamniotic shunting catheters or using a fetoscopic laser. In vesicoamniotic shunting surgeries, the catheter may be displaced or clogged; in fetoscopic laser operations, problems such as the failure of the procedure itself, miscarriage, premature birth, loss of water, or fistula in the child due to the use of the laser may occur.
The duration of fetal surgeries varies depending on the type of operation. Some procedures last less than an hour, while others can last for several hours.
In cases that require the installation of a vesicoamniotic shunt, prepared shunt catheters are placed so that one of their ends remains inside the baby's bladder, while the other one remains in the amniotic sac that contains amniotic fluid. When the treatment involves fetoscopic laser procedures, the mother is given anesthesia, and the fetus, in turn, is also given anesthesia through the umbilical cord, and muscle relaxants (drugs that reduce muscle tone and decrease motor activity), and a fetoscopy device is inserted into the fetal bladder. The posterior urethral valve is then removed by laser ablation.
Yes, PUV removal surgeries are successfully performed in our country.