New Software Instructs Neurosurgeons Where to Slice

Surgeons cut a hole into the skull as small as half the size of a penny and cannot necessarily see what is below. Sometimes they create an opening as large as 70 mm--the size of some camera lenses--forcing surgeons to cut through wide areas of bone and tissue.

Surgeons must then move through more than 400 miles of blood vessels and fragile lobes controlling speech, sight, smell, and memory every time they want to excise a tumor or relieve symptoms of Parkinson’s disease, depression, and other neurologic disorders. Determining the best trajectory to attack a tumor or fluid-filled cyst is as much science as it is art.

“Field of image or computer-assisted surgery is a very evolving project in medicine--especially in neurosurgery,” noted Dr. Yigal Shoshan, head of Hadassah Hospital’s (Jerusalem, Israel) neurosurgery department, who along with Dr. Leo Joskowicz, a Hebrew University computer science professor, is developing the software.

The software combines a wide range of data to create a three-dimensional (3D) brain map instead of the conventional two-dimensional magnetic resonance imaging (MRI). Functional MRI (fMRI) scans capture blood flow alterations that reflect areas of increased neural activity, rather than simply an image of the organ. Overlaying the functional MRI image is another data set from a magnetic resonance angiography (MRA), which focuses on the brain’s arteries and targets abnormalities, blockages, and aneurysms.

All these data are processed to generate green and red color codes representing where surgeons should and should not cut. The areas that the software analyzes as too hazardous or too close to vital parts of the brain are placed in the red zone. Not only does it pave the way for safer surgeries, it potentially allows for more effective treatment. “If we are inserting an electrode to the basal ganglia of the brain to treat Parkinson’s--we are talking about submillimetric accuracy,” he said.

In July 2012, a team of six scientists and computer engineers assessed their prototype at Hadassah Hospital. In one test case, they gave the physicians a basic MRI scan showing a lesion on it. They asked each of the 10 doctors to plan a surgery based on the MRI alone, and then compare their plan with the software’s suggestions. Altogether, their research analyzed more than 240 surgical paths.

Whereas the final results of the study have yet to be published and the software has yet to get US Food and Drug Administration (FDA) approval for additional testing, Dr. Shoshan noted that the findings would show how the software enables physicians to choose more accurate and safer trajectories. He reported that the software was particularly useful with junior residents. “The software helps young doctors to be better,” he said, noting how it closes the gap between senior- and junior-level doctors. He noticed less experienced doctors could easily correct or modify their initial surgical plans and also learn from their mistakes. It’s a very strong teaching tool and executing tool,” he says. “It’s like a game--if you choose a very good trajectory and you get a small risk ratio, you may win.”

Dr. Shoshan came up with the plan with Dr. Joskowicz, a former IBM computer scientist, who had worked on similar software that was built to organize all sorts of data--birth records, financial data, and surgeries.

In the 1990s, Joskowicz worked at IBM’s T.J. Watson Research Center in Yorktown Heights, NY, USA. Researchers there developed software to customize prostheses for hip replacement surgeries. The program used data from computed tomography (CT) scans to make individualized prosthetics based on a patient’s bone structure.

Joskowicz began working with Hadassah Hospital neurosurgeons 10 years ago, taking his previous experience and applying it to a new realm. “It takes a long time to develop these things. It takes perseverance. A good idea is far from being enough,” Joskowicz says.

For Hadassah physicians, where there is a large volume of patients, the speed and accuracy of decision-making is vital. The hospital has Jerusalem’s only neurosurgery department. Every year, the unit performs an estimated 1,500 surgical procedures, hospitalizes close to 2,000 patients, and cares for about 4,500 patients in its outpatient clinic, Shoshan says.

Hadassah’s doctors successfully operated without damaging other parts of the brain using the standard MRI-based planning method. But, if they had used the new 3D data-synthesizing software, it most likely would have decreased risk to the patient.

Fifteen percent of brain surgeries for benign tumors go awry from complications like internal bleeding or misplaced incisions that lead to permanent neurologic damage. The worst-case scenario is death. However, recent advances in surgical technology are changing the field. The surgeries of the future will be extremely accurate, in all probability enhanced by virtual and robotic technology. Drs. Joskowicz and Shoshan’s new software may be utilized to plan those future surgeries.

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