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

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT07337954

Enrollment

Registered

2026-01-13

Start date

2024-01-01

Completion date

2024-06-30

Last updated

2026-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Shock Wave Lithotripsy, Ureteral Stents, Urolithiasis

Keywords

stone volume, 3D-CT, volumetry, stent necessity, stone burden

Brief summary

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..

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.

Interventions

DEVICEExtracorporeal shock wave lithotripter

ESWL delivered at 70-80 shocks/min, max 2500 shocks/session, voltage ramped to 90 kV. Stone localization via fluoroscopy.

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

DIAGNOSTIC

Masking

NONE

Masking description

No masking was employed. This open-label study involved standardized ESWL treatment for all patients without initial JJ stent placement. Investigators, patients, and outcome assessors were fully aware of treatment protocol and imaging assessments (3D-CT volumetry vs ellipsoid formula). Post-hoc stratification by ESWL outcomes (success vs complications requiring stent) was performed without blinding

Intervention model description

All 56 patients underwent standardized ESWL protocol (Dornier lithotripter, 2 sessions max, no initial JJ stent) with dual stone volume assessment: 3D-CT volumetry (voxel-based segmentation) vs ellipsoid formula (greatest dimensions). Patients stratified post-hoc by outcomes: success without stenting (n=14) vs complications requiring stent (n=42). No randomization; single treatment arm with diagnostic comparison

Eligibility

Sex/Gender

ALL

Age

18 Years to 65 Years

Healthy volunteers

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

Design outcomes

Primary

Measure	Time frame	Description
Stone Volume by 3D-CT Volumetry	Pre-ESWL baseline	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

Secondary

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

Countries

Egypt

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026