A new simulator that lets neurosurgeons rehearse before operating–like pilots on a flight simulator–could revolutionize how doctors train for and handle brain surgery.
NeuroTouch, the prototype simulator developed by Canada’s National Research Council (NRC) and several other research groups, gives surgeons a dry run in virtual reality before entering the operating room, potentially reducing mistakes.
First, patient data from functional magnetic resonance imaging (fMRI) is rendered into a 3-D, high-resolution model of an individual’s brain. After the model is loaded into the system, doctors can touch and manipulate tumors and other virtual objects on screens in real time using a physical instrument resembling a scalpel. The instrument has six degrees of freedom and re-creates the force-feedback of the real tool and the varying resistance of tissue in brain regions with differing toughness. Meanwhile, photo-realistic on-screen imagery shows the simulated surgery, including bleeding and pulsing gray matter.
“This is the first simulator to fully integrate medical image processing, material models, finite element modeling, graphics, and haptics technologies to create a patient-specific simulation,” says Ryan D’Arcy, an NRC neuroscientist who helped develop NeuroTouch. “One other notable feature is the incorporation of functional brain mapping data from fMRI.” This allows critical brain regions, such as speech areas, to be imaged more accurately, D’Arcy says.
The $9.1 million, three-year project to develop a neurosurgery simulator began in April 2008 and involves some 50 clinicians and engineers from across Canada. The project marked a milestone last month when surgeons in Halifax, Nova Scotia, used it to rehearse before operating on a 48-year-old woman with a benign tumor near the speech center of her brain. The five-hour operation was successful, and the woman was discharged the following day. Though the procedure was relatively simple, it was the first time a simulator had been used to run through such an operation.
Lead surgeon David Clarke of Halifax’s Queen Elizabeth II Health Sciences Center praised the prototype for being very realistic. “The surgery team went in there with a knowledge and confidence that we could not otherwise have,” Clarke said after the surgery. “I think that that is not only good in terms of discussions with patients beforehand, but is good for their overall surgical outcome.”
As brain operations become less invasive but more complex, younger surgeons may be better trained using a simulator, says Rolando Del Maestro of the Montreal Neurological Institute and Hospital, who was involved with the project. “We neurosurgeons are going to be like simulator pilots, so we can find out if our skills are at a certain level,” says Del Maestro, who adds that the simulator might help accelerate training.
Abhijit Guha, a neurosurgeon at Toronto’s Hospital for Sick Children, who is unaffiliated with NeuroTouch, says that virtual surgery will never replace the real thing. “One weakness of the system is that it is based on archival MRI scans, which may not be valid as surgery proceeds due to brain and cerebrospinal fluid shifts,” Guha says. “Also, there is the judgment factor, especially when something goes wrong.”
A technical limitation of the prototype is that it can only represent tumors close to the surface of the brain, and surgeons can only use one hand. Development will continue through April 2011, however, and the final device will allow doctors to work on deep brain tumors with multiple surgical tools and both hands.
NRC plans to send prototypes to neurosurgery centers across Canada, and then transfer the technology to a commercial partner within two years. A commercial version could sell for $10,000 to $500,000, depending on its functions. “The package will include a PC-based planner for optimal surgical corridor selection as well as a trainer for surgical tasks and typical surgical procedures,” says NRC’s Robert DiRaddo, who led development. “The two will be integrated into a rehearsal system for patient-specific use.”
“The objective from the outset has been to commercialize the neurosurgical simulator,” D’Arcy says. “The goal is to put the simulator in clinics, hospitals, and teaching centers around the world, but there is a lot of work yet to be done.”