Assessment of Flexible Ureteroscopy Residual Fragments

Flexible ureteroscopy (URF) is being widely used for the treatment of kidney stones up to 20 mm. The assessment of residual fragments must be done because they could cause pain and additional surgical interventions. However, nor the timing or modality of image study for this assessment is standardized yet.

Computed Tomography (CT) has become the standard for diagnosing urinary stones. Stone-former patients are submitted to many CT studies during life due to stone-related events. However, the cumulative exposure to the ionizing radiation of CT may induce tumors. Therefore, efforts to reduce radiation exposure are recommended such as better selection of the timing to submit the patient to CT, low radiation dose protocols and restriction of body region to be examined.

Up to 38% of the patients have residual fragments more than 2 mm assessed by CT after URF. The investigators goal is to predict witch patients should be submitted to CT for the assessment of residual fragments after URF and to evaluate the clinical significance of residual fragments and URF complications.

Method

115 consecutive symptomatic adult (>18 years-old) patients diagnosed by CT with kidney stone more than 5 mm and less than 20 mm or less than 15 mm in inferior calyx are going to be submitted to URF. Residual fragments are going to be assessed by CT, ultrasound and plain radiography during post-operative period. The study protocol is approved by our hospital's ethics committee, and written informed consent is going to be obtained from all patients according to the Declaration of Helsinki Ethical Principles for Medical Research Involving Human Subjects.