Category: Robotic Surgery: New Techniques - Malignant

VS8-2 - Development and Validation of Patient Specific Hydrogel Kidney Phantoms for Surgical Rehearsal prior to Complex Renal Cancer Surgery

Sat, Sep 22
10:00 AM - 12:00 PM

Introduction & Objective :

As surgical technology increases the opportunity to integrate novel surgical preparation into our daily practice to better outcomes and enhance patient safety. 3D printing technology has recently been utilized for creating replicas of organ structures for the surgeon to visualize important structures of the organ. However, these printed models are often made of hard plastic materials and lack patent interior cavity structures found in the target organ 

Methods :

We present our technique combining 3D printing and hydrogel injection molding to develop patient-specific kidney phantoms suitable for use as a simulation platform for a preoperative rehearsal of renal cancer surgery cases. To prove the authenticity of this process the models are validated for mechanical properties, anatomical accuracy as a patient-specific simulation platform for improving patient outcomes. Material properties of human kidneys were established by comparing the results of compression testing between multiple compositions of PVA and porcine kidneys. To prove anatomical accuracy, the model is CT scanned to create an identical CAD model that can be compared to the patient’s original imaging. A surgical rehearsal was completed in a simulated setting. Surgical metrics were gathered and results correlated with the rehearsal and real operation. 

Results :

The PVA condition that was found to best recreate the material properties of porcine kidneys was found to be 7% PVA after completing 2 processing cycles (RMSE=.0003). Patient’s anatomical geometry was analyzed, and the average mean discrepancy between the phantom and patient anatomy were -0.26 mm, -0.2 mm, 3.10 mm, 0.61 mm and 3.33 mm for kidney parenchyma, tumor, artery, vein, and calyx respectively. 98% of the phantom parenchyma and tumor in the model was within 3.5 mm of the patient’s imaging. 78% of the artery, 84% of the vein and 71% of the calyx of the phantom was within 4.5 mm range of the patients imaging. 8 patients were consented to create a kidney phantom for rehearsal prior to the live surgery. A single complex case in this video was demonstrated showing the correlation between the simulated and live case was shown, confirming the effectiveness of this model as a rehearsal tool. 

Conclusions :

Software that incorporates patient imaging into 3D printing applications, together with hydrogel molding techniques is capable of creating human kidney phantoms with authentic anatomical, physical, and functional properties. Application of this versatile, inexpensive and reproducible method for creating kidney phantoms has demonstrated a reduction in renal injury, by preserving renal volume and minimizing renal ischemia time. 

Ahmed Ghazi

Assistant professor of Urology , Director of Simulation Innovation Laboratory (SIL) , Co-Director-Fellowship In Endourology and Robotic Surgery
University of Rochester
Rochester, New York

Ahmed Ghazi MD, MSc, FEBU
Assistant professor of Urology
Director of Simulation Innovation Laboratory (SIL)
Co-Director-Fellowship In Endourology and Robotic Surgery
University of Rochester Medical Center

Rachel Melnyk

Engineer of Simulation Technology
University of Rochester
Rochester, New York

Shamroz Farooq

Biomedical Engineer
University of Rochester
Rochester, New York

Jean Joseph

W.W. Scott Professor and Chairman Departement of Urology Professor of Oncology
University of Rochester
Rochester, New York