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Updated: Aug 15, 2026

Assessing Urinary Tract Junction Obstruction Defects by Methylene Blue Dye Injection
Published on: October 12, 2017
Percutaneous upper urinary tract dynamics in equivocal obstruction
Abstract:
Percutaneous pressure flow studies in the upper urinary tract remain the definitive method of distinguishing stasis from obstruction. They are not technically difficult and the results of 2 large series show minimal, minor complication rates. The results in over 200 studies show that a clear-cut answer as to whether or not an obstruction is present is obtained in over 95% of patients, the remainder showing pressures in an equivocal range.
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