An approach to EVAR simulation using patient specific modeling.

Background: The Simbionix Angiomentor Procedure Rehearsal Studio (PRS) offers accurate virtual anatomy for measurement, stent graft selection, and deployment of endovascular aneurysm repair (EVAR) devices.

Methods: Selected Gore Excluder EVAR cases from our EVAR database were reviewed and DICOM data loaded into the Simbionix Angiomentor simulator using PRS software. Using centerline measurements created on PRS, neck diameter (D1), length from lowest renal artery to each iliac bifurcation (Ll and Lr), and common iliac artery diameter (Dl and Dr) were recorded. All measurements for device selection were made based on data recorded on the simulator. Simulated EVAR was then performed using PRS on a dual limb endovascular simulator. Changes in device selection based on intraoperative measurements and use of three-dimensional (3D) anatomic overlay made by the attending vascular surgeon performing the case were recorded. The devices actually used for successful repair were considered gold standard for comparison. At the completion of each virtual case, simulations were rated by an experienced vascular surgeon for realism, imaging quality, and final product on a 5-point scale.

Results: Ten cases with complete operative data and available computed tomography scans were chosen at random. Fifty percent of the cases (5/10) had changes in device length when using the "in vivo" 3D volume filled model and angiographic measurements. Analysis of variance revealed no significant differences between the groups in any measurement-main body diameter P = 0.960; main body length P = 0.643; and contralateral limb length P = 0.333. Review of simulation scoring showed ratings of diminished realism (average 2.3/5) due to unrealistic ease of wire passage and gate cannulation; however, simulation imaging and final product were scored favorably (3.7 and 3.4, respectively).

Conclusions: The use of centerlines, angiographic measurements, and 3D modeling within the PRS software approaches real-life device selection and represents an opportunity for high fidelity patient-specific preoperative EVAR case rehearsal.