Tag Archives: neuroradiologists

Hollywood and neurosurgery

Usually a story about Hollywood and science (in this case, neurosurgery) is focused on how scientifically accurate the portrayal is. This time the situation has been reversed and science has borrowed from Hollywood. From an April 25, 2017 Johns Hopkins University School of Medicine news release (also on EurekAlert), Note: A link has been removed,

A team of computer engineers and neurosurgeons, with an assist from Hollywood special effects experts, reports successful early tests of a novel, lifelike 3D simulator designed to teach surgeons to perform a delicate, minimally invasive brain operation.

A report on the simulator that guides trainees through an endoscopic third ventriculostomy (ETV) was published in the Journal of Neurosurgery: Pediatrics on April 25 [2017]. The procedure uses endoscopes, which are small, computer-guided tubes and instruments, to treat certain forms of hydrocephalus, a condition marked by an excessive accumulation of cerebrospinal fluid and pressure on the brain. ETV is a minimally invasive procedure that short-circuits the fluid back into normal channels in the brain, eliminating the need for implantation of a shunt, a lifelong device with the associated complications of a foreign body.

“For surgeons, the ability to practice a procedure is essential for accurate and safe performance of the procedure. Surgical simulation is akin to a golfer taking a practice swing,” says Alan R. Cohen, M.D., professor of neurosurgery at the Johns Hopkins University School of Medicine and a senior author of the report. “With surgical simulation, we can practice the operation before performing it live.”

While cadavers are the traditional choice for such surgical training, Cohen says they are scarce, expensive, nonreusable, and most importantly, unable to precisely simulate the experience of operating on the problem at hand, which Cohen says requires a special type of hand-eye coordination he dubs “Nintendo Neurosurgery.”

In an effort to create a more reliable, realistic and cost-effective way for surgeons to practice ETV, the research team worked with 3D printing and special effects professionals to create a lifelike, anatomically correct, full-size head and brain with the touch and feel of human skull and brain tissue.

The fusion of 3D printing and special effects resulted in a full-scale reproduction of a 14-year-old child’s head, modeled after a real patient with hydrocephalus, one of the most common problems seen in the field of pediatric neurosurgery. Special features include an electronic pump to reproduce flowing cerebrospinal fluid and brain pulsations. One version of the simulator is so realistic that it has facial features, hair, eyelashes and eyebrows.

To test the model, Cohen and his team randomly paired four neurosurgery fellows and 13 medical residents to perform ETV on either the ultra-realistic simulator or a lower-resolution simulator, which had no hair, lashes or brows.

After completing the simulation, fellows and residents each rated the simulator using a five-point scale. On average, both the surgical fellows and the residents rated the simulator more highly (4.88 out of 5) on its effectiveness for ETV training than on its aesthetic features (4.69). The procedures performed by the trainees were also recorded and later watched and graded by two fully trained neurosurgeons in a way that they could not identify who the trainees were or at what stage they were in their training.

The neurosurgeons assessed the trainees’ performance using criteria such as “flow of operation,” “instrument handling” and “time and motion.”

Neurosurgeons consistently rated the fellows higher than residents on all criteria measured, which accurately reflected their advanced training and knowledge, and demonstrated the simulator’s ability to distinguish between novice and expert surgeons.

Cohen says that further tests are needed to determine whether the simulator will actually improve performance in the operating room. “With this unique assortment of investigators, we were able to develop a high-fidelity simulator for minimally invasive neurosurgery that is realistic, reliable, reusable and cost-effective. The models can be designed to be patient-specific, enabling the surgeon to practice the operation before going into the operating room,” says Cohen.

Other authors on this paper include Roberta Rehder from the Johns Hopkins School of Medicine, and Peter Weinstock, Sanjay P. Parbhu, Peter W. Forbes and Christopher Roussin from Boston Children’s Hospital.

Funding for the study was provided by a grant from the Boston Investment Conference. The research team acknowledges the contribution of FracturedFX, an Emmy Award-winning special effects group from Hollywood, California, in the development of the surgical models.

The investigators report no financial stake or interests in the success of the simulator.

Here’s what the model looks like,

Caption: A. Low-fidelity simulated surgical model for ETV. B. High-fidelity model with hair, eyelashes and eyebrows. Credit: Copyright AANS. Used with permission.

An April 25, 2017 Journal of Neurosurgery news release on EurekAlert details the refinements applied to this replica (Note: There is some repetitive material),

….

A neurosurgery residency training program generally lasts seven years–longer than any other medical specialty. Trainees log countless hours observing surgeries performed by experienced neurosurgeons and developing operative skills in practice labs before touching patients. It is challenging to create a realistic surgical experience outside an operating room. Cadaveric specimens and virtual reality programs have been used, but they are costly and do not provide as realistic an experience as desired.

The new training simulation model described in this paper is a full-scale reproduction of the head of an adolescent patient with hydrocephalus. The external appearance of the head is uncannily accurate, as is the internal neuroanatomy.

One failing of 3D models is the stiffness of most sculpting material. This problem was overcome by addition of special-effects materials that reproduce the textures of external skin and internal brain structures. In addition, the operative environment in this training model is amazingly alive, with pulsations of a simulated basilar artery and ventricles as well as movement of cerebrospinal fluid. These advances provide visual and tactile feedback to the trainee that closely resembles that of the surgical experience.

The procedure selected to test the new training model was endoscopic third ventriculostomy (ETV), a minimally invasive surgical procedure increasingly used to treat hydrocephalus. The goal of ETV is to create a hole in the floor of the third ventricle. This provides a new pathway by which excess cerebrospinal fluid can circulate.

During ETV, the surgeon drills a small hole in the skull of the patient and inserts an endoscope into the ventricular system. The endoscope accommodates a lighted miniature video camera to visualize the operative site and specialized surgical instruments suited to perform operative tasks through the endoscope. The video camera sends a direct feed to external monitors in the operating room so that surgeons can clearly see what they are doing.

To evaluate the usefulness of the training simulation model of ETV, the researchers solicited feedback from users (neurosurgical residents and fellows) and their teachers. Trainees were asked to respond to a 14-item questionnaire focused on the external and internal appearances of the model and its tactile feel during simulated surgery (face validity) as well as on how closely the simulated procedure reproduced an actual ETV (content validity). The usefulness of the model in assessing trainees’ performances was then evaluated by two attending neurosurgeons blinded to the identity and training status (post-graduate year of training) of the residents and fellows (construct validity).

The neurosurgical residents and fellows gave high scores to the training model for both face and content validity (mean scores of 4.69 and 4.88, respectively; 5 would be a perfect score). The performance scores given to individual trainees by the attending neurosurgeons clearly distinguished novice surgeons from more experienced surgeons, accurately reflecting the trainees’ post-graduate years of training.

The training model described in this paper is not limited to hydrocephalus or treatment with ETV. The simulated head accommodates replaceable plug-and-play components to provide a fresh operative field for each training session. A variety of diseased or injured brain scenarios could be tested using different plug-and-play components. In addition, the ability to pop in new components between practice sessions greatly reduces training costs compared to other models.

When asked about the paper, the senior author, Alan R. Cohen, MD, at Johns Hopkins Hospital, said, “This unique collaboration of interdisciplinary experts resulted in the creation of an ultra-realistic 3D surgical training model. Simulation has become increasingly important for training in minimally invasive neurosurgery. It also has the potential to revolutionize training for all surgical procedures.

Here’s a link to and a citation for the paper,

Creation of a novel simulator for minimally invasive neurosurgery: fusion of 3D printing and special effects by Peter Weinstock, Roberta Rehder, Sanjay P. Parbhu, Peter W. Forbes, Christopher J. Roussin, and Alan R. Cohen. Journal of Neurosurgery: Pediatrics, published online, ahead of print, April 25, 2017; DOI: 10.3171/2017.1.PEDS16568

This paper appears to be open access.