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

Ain Shams University

Status: Completed

Conditions: Ureteral Stents; Urolithiasis; Shock Wave Lithotripsy

Treatments: Device: Extracorporeal shock wave lithotripter

Study type: Interventional

Funder types: Other

Identifiers

NCT07337954

FMASU MS872024

Details and patient eligibility

About

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..

Full 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.

Enrollment: 56 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: No 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

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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56 participants in 1 patient group

ESWL without Initial JJ Stent

Experimental group

Description:

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)

Treatment:

Device: Extracorporeal shock wave lithotripter