Impact of Renal Anatomy on Shock Wave Lithotripsy Outcomes for Lower Pole Kidney Stones

Impact of Renal Anatomy on Shock Wave Lithotripsy Outcomes for Lower Pole Kidney Stones: Results From a Prospective Multifactorial Analysis

Kidney stone disease affects almost 10% of overall population, often requiring a surgical intervention. Currently, shock wave lithotripsy is considered a first-line treatment option for patients suffering from symptomatic kidney stones smaller than 2.0 cm, providing reasonable stone-free rate. Actually, the outcomes from SWL vary largely due to several factors including stone burden, stone density, stone-skin distance (SSD), and patient's body habitus. Furthermore, the imaging exam modality (i.e. ultrasound versus computed tomography scan) performed to assess the presence of residual fragments also impacts on SWL outcome analysis.

We aim to perform a well-controlled prospective evaluation of all variables that may impact on fragmentation and clearance of lower pole calculi after SWL. These variables are assessed exclusively by a noncontrast computed tomography scan (NCCT), eliminating the necessity of an intravenous urography to study renal collecting system anatomy; an imaging exam that is not routinely performed anymore for kidney stone patients.

Study Overview

• Status: Completed
• Conditions: Kidney Calculi; Urolithiasis; Urinary Lithiasis
• Intervention / Treatment: Device: SWL - Compact Delta Dornier Med Tech

Detailed Description

Variables in study:

• Age, gender, body mass index (BMI), and waist abdominal circumference
• Noncontrast computed tomography scan (NCCT): stone density (average of 3 measurements), stone size, stone area, skin to stone distance (average of 3 measurements: zero, 45o and 90o), and collecting system anatomy: infundibular length, width, and height, and infundibulopelvic angle

Study design:

All patients will be submitted to a noncontrast computed tomography scan before to SWL. A radiologist with expertise in urolithiasis will evaluate all exams.

Patients will be submitted to SWL under the following conditions: outpatient, general anesthesia, 3000 impulses, rate of 90/min, discharged from hospital in the same day with alpha-blocker (doxazosin) during 30 days.

Patients will be followed up as follow:

• One week after SWL: medical visit To evaluate complications such as pain, dysuria, hematuria, steinstrasse, visit to the emergency department.
• 12 weeks after SWL: new NCCT scan To evaluate kidney stones fragmentation and clearance.

Univariate (Student's T test) and multivariate analysis (multiple logistic regression) will be done to assess the impact of patient's corporal habitus (BMI and abdominal waist circumference), stone characteristics (size, area, density and SSD), and renal collecting system anatomy (infundibular length, width and height, and infundibulopelvic angle) on SWL outcomes (fragmentation and stone-free rates).

• Study Type: Interventional
• Enrollment (Actual): 104
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Brazil
  • SP
    • Sao Paulo, SP, Brazil
      • University of Sao Paulo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

> 17 year-old. Symptomatic single stone of 5 to 20mm located in the lower pole of the kidney. Informed consent signed.

Exclusion Criteria:

Patients with congenital kidney abnormalities (i.e. horseshoes kidney, pelvic kidney, ectopic kidney), patients with ureteral stent (i.e. Double J stent) in the ipsilateral kidney of the stone in study, patients with chronic kidney disease (glomerular filtration rate <60 mL/minute/1.73m2 measured by the equation "Modification of Diet in Renal Disease"), and patients with absolute contraindication to SWL (i.e. coagulopathy, pregnancy, urinary tract infection, or abdominal aneurysm >4.0cm).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Shockwave lithotripsy (SWL); All patients will be submitted to a noncontrast computed tomography before to shockwave lithotripsy (SWL). Patients will be submitted to SWL under the following conditions: outpatient, general anesthesia, 3000 impulses, rate of 90/min, discharged from hospital in the same day with alpha-blocker (doxazosin) during 30 days.

Device: SWL - Compact Delta Dornier Med Tech; All patients will be submitted to a noncontrast computed tomography before to SWL. Patients will be submitted to SWL under the following conditions: outpatient, general anesthesia, 3000 impulses, rate of 90/min, discharged from hospital in the same day with alpha-blocker (doxazosin) during 30 days.; Other Names: Extracorporeal shockwave lithotripsy; Compact Delta Dornier Med Tech; Nephrolithotripsy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Stone Clearance	After 12 weeks, all patients will be submitted to a new NCCT scan to evaluate stone fragmentation and stone clearance.	12 weeks after SWL

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
SWL Complications	Secondary endpoint will be SWL complications (i.e. pain, hematuria, urinary tract infection, Steinstrasse)	12 weeks after SWL

Collaborators and Investigators

• Sponsor: University of Sao Paulo
• Investigators: Principal Investigator: Fabio CM Torricelli, MD, University of Sao Paulo

Study record dates

Study Major Dates

• Study Start: April 1, 2012
• Primary Completion (Actual): August 1, 2014
• Study Completion (Actual): December 1, 2014

Study Registration Dates

• First Submitted: April 29, 2012
• First Submitted That Met QC Criteria: May 1, 2012
• First Posted (Estimate): May 2, 2012

Study Record Updates

• Last Update Posted (Estimate): January 7, 2015
• Last Update Submitted That Met QC Criteria: December 17, 2014
• Last Verified: December 1, 2014

More Information

Terms related to this study

• Keywords: Tomography; Kidney Calculi; Urinary Lithiasis
• Additional Relevant MeSH Terms: Pathologic Processes; Kidney Diseases; Urologic Diseases; Pathological Conditions, Anatomical; Urinary Calculi; Urolithiasis; Calculi; Kidney Calculi; Nephrolithiasis; Lithiasis
• Other Study ID Numbers: 00795812.8.0000.0068