For a patient experiencing a brain aneurysm, every second in the operating room counts in quickly and successfully clipping the aneurysm to stop blood flow and prevent permanent damage. Today, thanks to a new patented 3D surgical rehearsal platform created by Surgical Theater LLC, neurosurgeons can plan, safely rehearse, and perform complex surgeries utilizing a patient’s own CT and MRI images/scans (DICOM) before entering the operating room.

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Fig. 1 – Dr. Selman demonstrates how connection of multiple SRPs allowing remote participants to discuss and practice the same case with real-time feedback to collaborate on planning a specific surgery.
Using standard scanned images from any patient, the Selman Surgical Rehearsal Platform™ (SRP), generates 3D patient specific and accurate models of interactions between life-like tissue and surgical instruments. The tissue responds “realistically” to actions taken by the surgeon, thus allowing accurate pre-surgery planning and rehearsal. The unique software utilizes flight simulator technology to permit remote connection of multiple SRPs allowing participants anywhere in the world to simultaneously work together and practice the same case with real-time feedback and to collaborate on planning a specific surgery case. (See Figure 1)

“As a surgeon at an academic medical center, being able to collaborate with peers and guide younger surgeons through a complex neurosurgical procedure— on a model with life-like response—in advance of taking the patient to the operating room is ideal. It’s something that just wasn’t possible until now,” said Dr. Warren Selman, Surgical Theater’s Medical Director and Neurosurgeon-in-Chief at University Hospitals (UH) Case Medical Center in Cleveland, OH. Selman is also a Harvey Huntington Brown Jr. Professor and Chairman, Department of Neurological Surgery at Case Western Reserve University School of Medicine, also in Cleveland. The SRP is named after Selman, who is co-creator of the platform.

Not long ago, a random conversation at a coffee shop between Dr. Selman and the now-CEO and President of Surgical Theater, Moty Avisar, spurred the beginning of this innovative technology. Avisar, an ex-Israeli Air Force R&D officer who spent 20 years developing flight simulators, was talking to a friend about how flight simulators are used prior to military missions when Selman half-jokingly said wouldn’t it be great to be able to do something similar to be able to practice a medical procedure. Now two years later, that idea became a reality when the SRP publicly launched in October 2012.

Developing the Technology

Taking the flight simulator experience and an understanding of the need for highly realistic visual representations, wheth er a simulator is being utilized for military or medical practice, work initially began on creating algorithms and appropriate haptic feedback for accurate 3D modeling, according to Avisar.

“In military situations, we were creating algorithms that allowed a pilot to experience the difference visually be tween approaching a building or tank, for example. But in a medical setting, we had to figure out how to allow a surgeon to experience the differences between bone, tissue, and skin,” Avisar said.

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Fig. 2 – The controller simulates the grip of the surgical instrument.
Determining how best to allow for that led to the SRP using a volume rendering technique for the anatomical structure models based on CT/MRI scans. In addition, the SRP’s collision detection algorithm supports collision between surgical instruments (polygon models) and other polygon models and does not support collision between surgical instrument and tissue (volume models). Interaction between instrument and tissue is done by force simulation.

Along with visual feedback, how to provide haptic or “sensory” feedback was another key component of developing the SRP that required experimentation and testing before getting it right. In neurosurgery, because the cerebral tissue, in particular the damaged tissue in an aneurysm, is extremely delicate, the surgeon must apply the appropriate amount of force. Both too much and too little force could result in negative outcomes. As a result, providing realistic haptic feedback was vital to creating a product beneficial for surgeons.

“The SRP’s ability to provide this needed haptic feedback is in the controller that comes with the unit,” said Avisar. “The controller was modified to include the grip of the surgical instrument so the surgeon can hold what he is familiar with and what he will hold in the OR.” (See Figure 2)

Another key issue in development was ensuring that regardless of the scanner being utilized to create the CT/MRI images, the SRP would still create an accurate 3D image. To do this, a series of validation studies and tests were done with images from various scanners during development.

“The comparability of the SRP to various CT/MRI scanners was important to ensuring a neurosurgeon can trust the accuracy of the 3D practice and that the experience they are having with the SRP will provide them with an accurate clinical insight that will enhance the clinical outcome,” said Avisar. (See Figure 3)

The result of Surgical Theater’s development efforts was a new patented platform that includes a 3D/stereoscopic visual, controllers, desktop computer and portable/laptop system with the backbone of the platform being a unique algorithm that converts still/static images into a dynamic and interactive model. And, while the current model allows surgeons only to plan and rehearse microsurgical techniques for clipping intracranial aneurysms and extracting brain tumors, the SRP has an “open platform” design allowing further development and creation of case studies. Microvascular decompression and acoustic neuroma modules are the next to be released.

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Fig. 3 – 3D imagery allows surgeons to rehearse microsurgical techniques.
Realizing the value and role of collaboration in medicine, developers enabled the SRP to allow for tele-mentoring. Surgeons on opposite sides of the country with SRPs and an Internet connection can practice procedures with each other, medical students can be mentored by experienced neurosurgeons around the globe, and, ultimately, patients will benefit from having medical experts collaborating to provide them with the best possible care.

Looking to the future, Surgical Theater’s next generation product, the OR Hands-Free Viewer being developed in collaboration with Dr. Neil Martin, Chair of Neurosurgery at Ronald Reagan UCLA Medical Center, will allow surgeons to utilize the SRP’s imaging capabilities while in the operating room. By utilizing cameras and remote technology, actions such as scrolling through images and viewing 3D images will be possible using hand gestures. This will allow the surgeon to prepare at the surgery table, eliminating the need to touch anything but sterilized images.

Approval and Useage

In February, Surgical Theater LLC, received FDA approval of the Selman Surgical Rehearsal Platform, making it the first and only patented and FDA approved platform for cerebral and spine pre-surgery rehearsal in the marketplace.

“Receiving FDA approval is confirmation of the innovative technology that our company has worked so hard to create over the last several years and the beginning of what we believe will be improved patient outcomes for cerebral and spine surgery patients,” said Avisar.

Early this year, the company completed the first sale of its groundbreaking technology to UH Case Medical Center. Physicians at the medical center have been instrumental in the development of Surgical Theater.

“It is widely accepted that ‘purposeful practice makes perfect’ and having a tool like the SRP provides that opportunity and as such will help ensure improved patient safety and outcomes,” said Dr. Selman.

The Neurological Surgery Depart ment at UH Case Medical Center has been using the SRP for more than two years, and provided clinical insight to the company during its development. The hospital has been using the platform for clinical studies to document the value of pre-surgical rehearsal, and for resident and fellow education. Now with FDA approval, the platform will be additionally used for patient care. Several hospitals across the country are also considering purchases.

It’s anticipated that as the SRP is integrated into hospitals, use will result in higher degrees of surgical precision and safety, and ultimately, improved patient outcomes with reduced hospital costs and liabilities.

To hear Dr. Selman discuss the SRP, and to see it in action, visit http://www.techbriefs.com/tv/SRP.

This article was written by Alon Geri, Surgical Theater co-founder and VP of Engineering, in Cleveland, OH. For more information, visit http://info.hotims.com/45602-160.