First of all, I would see a doctor to determine if there is a medical reason for your stones. The stone is most likely not a result of your pregnancy, but rather became symptomatic during your pregnancy It would be important for you to do everything you could to prevent other stones from occurring or the one you have getting larger. This could best be accomplished by drinking plenty of fluids, water.
Your doctor has decided to treat your symptoms rather than the stone, at least until after you deliver. Any type of manipulation in your bladder, pelvis, ureter or kidney could result in premature labor which is why you have the nephrostomy tube(simple urinary diversion). It is unfortunate that the tube has had to be replaced, but it is still the safest option in regards to your pregnancy. The tube should reduce the pressure on your kidney and relieve your symptoms,
There are some specific changes that occur during pregnancy that affect the urinary tract that might increase your chances of having problems with your stone or symptoms. The ureters can be dilated in pregnancy and may not eliminate urine as efficiently if dilation occurs, this is called hydronephrosis. The ureters increase in size approx. 1 cm due to increased renal vascular and interstitial volume during pregnancy. The collecting system and ureters during this time also decrease there ability to peristals(contract), resulting in dilation and sometimes pain. The big concern of dilation is stasis or stagnant urine. If the urine is not fully eliminated, stone or infection can occur. These changes usually occur in the second trimester and subside after delivery. The nephrostomy tube should prevent these problems and symptoms from occurring,
It regards to the use of an epidural for the placement or replacement of the nephrostomy tube, I think this would be entirely up to the individual in charge of your anesthesia and the protocols of the hospital.
A indwelling stent tube placed between the kidney and bladder cystoscopically under anesthesia is also an option.
This information is provided for general medical educational purposes only. Please consult your physician for diagnostic and treatment options pertaining to your specific medical condition. More individualized care is available at the Henry Ford Hospital and its satellites (1 800 653-6568).
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