Innovative Simulation Models Providing More Effective Care for High-Risk Vascular Patients

As a mechanical engineering major, Chander Sadasivan had no idea that his engineering skills would someday be used to help solve real-world medical problems. Now, as director of the Cerebrovascular Center for Research, Sadasivan’s innovative simulation models are helping doctors more safely treat high-risk vascular patients while serving as a valuable training tool.

Sadasivan’s path changed as an undergrad while flipping through an encyclopedia, where he came across an entry for a flagellum, a thin, tail-like structure that bacteria and other microorganisms use to swim.

“I was stunned to see the complexity of this mechanism that nature had built,” he said. “That was my ‘ah-ha’ moment.”

Though he couldn’t foresee one day solving biological or medical problems, he felt that biomedical engineering was a better fit. In 2010, after earning his master’s degree in mechanical engineering with a bioengineering focus at SUNY Buffalo and then his PhD in bioengineering at University of Miami, Sadasivan came to Stony Brook University, where his vision of future modeling concepts became clearer.

“3D printers were coming out more and more and a lot of researchers started realizing that we could use 3D printing for a lot of things,” said Sadasivan, an assistant professor in the Department of Neurosurgery in the Renaissance School of Medicine at Stony Brook University. “At the time I read one of the first papers saying that maybe this is one way we can take a patient’s imaging and create replicas of their anatomies using computer-aided design software to help treat them.”

Early 3D printing technology was slow and unreliable, but as the technology improved, so did Sadasivan’s expertise. Today, his focus is on minimally invasive interventional surgery, which involves catheter-based treatments for vascular diseases, and more specifically, diseases in blood vessels of the brain.

240430 3d printing in chandramouli sadasivan's lab in neurosurgery
A 3D vessel model of a specific patient’s aortic aneurysm.

By utilizing patients’ brain CAT scans or vascular angiograms, he extracts the geometry of the patient-specific vascular abnormality such as a brain aneurysm, arterio-venous malformation (AVM), aortic aneurysm and others, and then meticulously creates 3D-printed molds in his lab. He then casts the patient’s specific vasculature with polymers such as silicone to impart realistic properties to the vessel replica. Sadasivan also incorporates pumps to attach to the models to duplicate the flow of blood during the procedures.

He then takes these models to physicians like David Fiorella, MD, director of the Stony Brook Cerebrovascular Center and a pioneer in the field of neuro-interventional therapies, who can evaluate different medical devices and approaches to treat that patient’s vascular disease, especially when the cases are complex.

“After Dr. Fiorella has utilized the patient-specific model he then proceeds to treat the patient with a more detailed plan in these complex cases,” said Sadasivan. “By the time a patient is in the OR, the surgeon knows exactly what route to take because it’s already been tested in that patient’s vessel model.”

Sadasivan’s models are also utilized for teaching and training Stony Brook residents, fellows, and other novice practitioners, who learn on the silicone replicas rather than patients in surgery.

240430 3d printing in chandramouli sadasivan's lab in neurosurgery
A skull model, used for practicing on cerebral vessel aneurysms, helps students practice delicate techniques and procedures.

“The paradigm for a long time has been ‘See one, teach one, do one.’ The attending physician teaches the resident, and they learn with the attending physician in the care of the patients,” he said. “It is a gradual learning process. Medical simulation can now help this learning process especially with this specific type of 3D printing because of the realistic models and patient-specific scenarios to practice on. It offers possibilities we didn’t have 15 years ago. It gives them a chance to make errors.”

Sadasivan has worked to refine his process to deliver models with the lifelike properties of tissue and blood vessels.

“These models are complex, it’s not just a matter of pressing a button and creating one,” he said. “They’re so realistic that I’ve had some trainees worry when working on a model that they might damage it. But that’s exactly why the model is there. Go ahead and do whatever you need to do. That’s how you learn.”

Sadasivan noted that some patients have conditions that require opening the skull to drain excess fluid by placing a catheter, which requires a certain technique and procedure. “Physicians would have to create a small hole in the patient’s skull to drain fluid, for example, which is a very common procedure. But when a practitioner is new, one has to learn,” he said. “Are they making the hole at the right angle? Can they pass a catheter at the right angle and the right distance to get to the right location? They can practice on skull models, and that provides them a tremendous advantage.”

Marlene Baumeister, clinical research nurse coordinator in the Cerebrovascular Center, said that in addition to creating innovative models, Sadasivan is also an effective teacher.

Marlene baumeister, dawn madigan and priscilla munoz in sadasivan lab
Marlene Baumeister, Dawn Madigan and Priscilla Munoz in the Cerebrovascular Center for Research lab.

“Students from many departments work in this lab,” she said. “His work might fall in line with a bioengineering student, a medical student, a biology student, a material science student, or a computational math student, for example. They might be doing hands-on work setting up a model to simulate blood flow or figuring out the best polymer composition to use or trying to understand the math behind it. His work applies to many fields.”

Some of Sadasivan’s funded research projects include the NIH, industry-sponsored, Office of the Vice President for Research (OVPR) and Long Island Network for Clinical and Translational Science (LINCATS).

Beyond the Department of Neurosurgery, Sadasivan collaborates with many other departments across Stony Brook including Vascular Surgery, the School of Dental Medicine, Mechanical Engineering, Materials Science and Chemical Engineering, Applied Mathematics and Computer Science.

Sadasivan is also the primary operator of the equipment in the catheterization lab, dedicated to varied research projects and training sessions with multiple departments, as well as medical device companies. The 3D-printed vascular replicas with duplicated blood flow are utilized in this lab to provide a complete reconstruction of interventional radiology procedures in the “natural” environment that physicians work in every day. This further enhances the real-life effects to planning vascular disease treatments or physician training or researching the behavior of different medical devices.

Underneath his work, Sadasivan carries the memory of a personal loss, an aunt who suffered a ruptured brain aneurysm when he was in graduate school.

“This was devastating to my family and it’s always in the back of my mind throughout my work replicating blood vessel abnormalities such as aneurysms to help patients today,” he said. “And that’s one reason this work is very rewarding. For many researchers, years can go by before they see the fruits of their labor. My research is for immediate care, and it leads directly to better patient outcomes.”

— Robert Emproto

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