Finite Element Analysis Case Examples

Practical Applications in Vascular Surgery Decision-Making

Professor Atef Allam • Computational Surgery • Clinical Applications

Computational Precision in Clinical Practice

Finite Element Analysis transforms theoretical biomechanics into actionable clinical insights, providing patient-specific risk stratification beyond traditional diameter-based criteria.

Case 1: High-Risk AAA with Localized Stress Peak

Demonstrating limitations of global measurements in heterogeneous aneurysms

Patient Data

AAA Diameter: 5.2 cm
Blood Pressure: 150/90 mmHg
Imaging: CT angiogram with 3D reconstruction

Global Wall Tension

T = P × r = 150 × 2.6 = 39 N/m

Below 60 N/m threshold

FEA Findings

Thrombus-covered region: Stress concentration of 65 N/cm²

Asymmetric bulge: 20% higher stress on posterior wall

Decision: Open repair required
Global tension misleading - FEA revealed hidden rupture risk

Case 2: Descending TAA with Calcification

Material heterogeneity effects on intervention planning

Patient Data

TAA Diameter: 5.8 cm
Blood Pressure: 130/80 mmHg
Features: Extensive calcification maps

Global Wall Tension

T = 130 × 2.9 = 37.7 N/m

FEA Analysis

Calcified regions: Lower stress (protected by stiffness)

Non-calcified regions: Stress peaks at 55 N/cm²

Decision: TEVAR with precision planning
Material heterogeneity guided device positioning

Surgical Decision Algorithm

Imaging Assessment

CT/MRI + 3D reconstruction
Calculate global tension as screening

T = Systolic BP × Radius

FEA Analysis

Inputs: Geometry, BP, tissue properties
Outputs: Peak stress map, rupture risk

Risk Stratification

Tension/Stress	Action
T < 40 N/m	Surveillance
T = 40–60 N/m	Consider EVAR
T > 60 N/m or High FEA	Open repair

FEA vs. Laplace's Law

Parameter	Laplace's Law	FEA
Accuracy	Global tension estimate	Localized stress mapping
Clinical Use	Rapid screening	High-risk refinement
Limitations	Ignores heterogeneity	Requires expertise

Clinical Example

5.5 cm AAA: T = 45 N/m (Laplace) vs 80 N/cm² stress peaks (FEA) → Repair needed

Future Innovations

🤖 AI-Powered FEA

Automated stress predictions from routine CT scans using machine learning

⚡ Dynamic Modeling

Real-time BP fluctuation simulation during exercise and daily activities

🔄 Predictive Remodeling

Longitudinal models predicting aneurysm growth and intervention timing

"FEA personalizes aneurysm management by revealing hidden stress concentrations, but Laplace's Law remains invaluable as a rapid screening tool. The optimal approach combines both methodologies for comprehensive risk assessment."