3D-CT vs Ellipsoid for JJ Stent Prediction Before ESWL

Estimation of Critical Stone Burden Requiring JJ Stent Before Extracorporeal Shockwave Lithotripsy Using 3D-CT

This prospective single-center study compares 3D-CT volumetry versus traditional ellipsoid formula to determine critical stone burden predicting JJ stent necessity before ESWL for 1-2 cm renal stones. Fifty-six patients with single radio-opaque renal stones will receive up to two ESWL sessions using Dornier lithotripter without initial stenting. Stone characteristics will be assessed via NCCT: linear dimensions (ellipsoid formula), 3D volume (voxel-based segmentation), Hounsfield units, and skin-to-stone distance. Patients will be stratified by ESWL outcomes to compare volume measurements between clearance success and stent-requiring groups..

Study Overview

• Status: Completed
• Conditions: Urolithiasis; Shock Wave Lithotripsy; Ureteral Stents
• Intervention / Treatment: Device: Extracorporeal shock wave lithotripter

Detailed Description

This prospective single-center study at Ain Shams University evaluates 3D-CT volumetry versus traditional ellipsoid formula for predicting critical stone burden requiring preoperative JJ stent placement in patients undergoing ESWL for 1-2 cm renal stones. Eligible patients (target n=56) with single radio-opaque renal stones will receive two ESWL sessions using Dornier lithotripter without initial stenting. Stone characteristics will be assessed via non-contrast CT (NCCT): linear dimensions (ellipsoid formula: length×width×height×0.52), 3D volume (automated voxel-based segmentation), Hounsfield units, and skin-to-stone distance.

Patients will be stratified by ESWL outcomes: stone clearance without stenting versus those requiring JJ stent due to complications (infection, incomplete fragmentation, obstruction/Stein Strasse). Volume measurements will be compared between groups using appropriate statistical tests (t-test, ROC analysis). The study aims to establish a 3D-CT volume threshold for stent prediction and validate its superiority over ellipsoid formula, particularly for irregular stone morphology.

• Study Type: Interventional
• Enrollment (Actual): 56
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo Governorate
    • Cairo, Cairo Governorate, Egypt, 1151
      • Faculty of Medicine, Ain Shams University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18-65 years
• BMI 18-30 kg/m²
• Single radio-opaque renal stone 1-2 cm
• Suitable for ESWL per clinical assessment

Exclusion Criteria:

• Multiple renal stones
• Solitary kidney
• Impaired renal function
• Congenital renal anomalies
• Ureteric obstruction
• Systemic comorbidities
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• 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: ESWL without Initial JJ Stent; All 56 patients received standardized ESWL treatment using third-generation Dornier lithotripter (maximum 2 sessions, 2500 shock waves/session). No preoperative JJ stent placement. Stone volume assessed via dual methods: 3D-CT volumetry (voxel-based segmentation) and ellipsoid formula (greatest dimensions on NCCT). Follow-up at 2 weeks with KUB/ultrasound; JJ stent placed for complications (incomplete fragmentation, obstruction, Stein Strasse, infection)

Device: Extracorporeal shock wave lithotripter; ESWL delivered at 70-80 shocks/min, max 2500 shocks/session, voltage ramped to 90 kV. Stone localization via fluoroscopy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Stone Volume by 3D-CT Volumetry	Comparison of stone volume measured by 3D-CT volumetry (voxel-based segmentation, cm³) versus traditional ellipsoid formula (greatest dimensions method) to determine critical stone burden predicting JJ stent necessity after ESWL. ROC analysis identified optimal cutoff (>1.88 cm³) for stent requirement	Pre-ESWL baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
JJ Stent Necessity	Rate of JJ stent placement due to ESWL complications (incomplete fragmentation, obstruction, Stein Strasse, infection)	2 weeks post-ESWL
ESWL Success Rate	Stone-free rate (complete clearance or asymptomatic fragments <4mm on KUB/ultrasound)	2 weeks after maximum 2 ESWL sessions

Collaborators and Investigators

• Sponsor: Ain Shams University

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2024
• Primary Completion (Actual): June 30, 2024
• Study Completion (Actual): June 30, 2024

Study Registration Dates

• First Submitted: December 26, 2025
• First Submitted That Met QC Criteria: January 7, 2026
• First Posted (Actual): January 13, 2026

Study Record Updates

• Last Update Posted (Actual): January 13, 2026
• Last Update Submitted That Met QC Criteria: January 7, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: stone burden; stone volume; 3D-CT, volumetry; stent necessity
• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urolithiasis
• Other Study ID Numbers: FMASU MS872024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No individual participant data (IPD) will be shared. Summary results are available in the publication and ClinicalTrials.gov results database.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No