Staying on course

The true innovation at the core of the PoleStar system is the concept of bringing the MRI to the OR as opposed to performing surgical procedures in an MRI suite.’What’s the big deal? It’s not brain surgery,’ the familiar saying …

The true innovation at the core of the PoleStar system is the concept of bringing the MRI to the OR as opposed to performing surgical procedures in an MRI suite.’What’s the big deal? It’s not brain surgery,’ the familiar saying goes.

But what if it really IS brain surgery?

The incredibly complex procedure to remove a tumor from the brain demands precise imaging and excellent navigation. A cut too much one way of the other could knock out a critical function, like the use of an arm or a leg.

In the past century, brain imaging has evolved from X rays to high-resolution computed tomography and magnetic resonance imaging (MRI). Functional MRIs help identify specific brain regions involved in particular activities. There are now 3D systems that match the instrument position to the 3D map and displays it on a computer screen, enabling the surgeon to see the critical area within a millimeter of accuracy.

But even such sophisticated systems are not enough.

The 3D maps are still created with historical images, taken hours before the operation. Due to the changing structure of the brain tissue when cells or a tumor is excised, the old images lose their value. It’s as if you are driving, referring to a map of the road drawn the night before – and today, someone is walking across the street right in front of you. Updating the preoperative imaging is the major challenge.

Israeli company Odin Medical Technologies is meeting that challenge with its PoleStar N20 – the first compact MRI that can be used DURING surgery to monitor progress, enabling midcourse corrections. Developed in conjunction with Denver-based Medtronic Surgical Navigation Technologies (SNT), the leading manufacturer of image-guided surgery systems, the PoleStar recently debuted at the annual meeting of the Congress of Neurosurgeons. The Polestar N20 system has received clearance by the U.S. Food and Drug Administration (FDA).

“The PoleStar N20 sets a new standard in intraoperative MRI. With its unique, compact design, the PoleStar allows neurosurgeons to take advantage of intraoperative imaging without the compromises inherent in other systems, such as extensive renovation of the operating room or restrictions upon the surgeons’ choice of instruments,” said Nadim Yared, vice president and general manager of Medtronic Surgical Navigation Technologies.

The debut of the PoleStar N20 is the culmination of years of research and development by Odin and Medtronics in conjunction with a number of leading institutions such as the Sheba Medical Center in Israel and Barrow Neurological Institute in the U.S.

David Gal, president and chief executive officer of Odin Medical Technologies said, “The true innovation at the core of the PoleStar system is the concept of bringing the MRI to the OR as opposed to performing surgical procedures in an MRI suite.”

The result is a compact, mobile MRI unit designed to seamlessly integrate with the operating room while not requiring the OR to be dedicated to its use.

At Oregon Health and Science University, the PoleStar also assists in the placement of deep brain stimulation devices, used to treat tremors associated with essential tremor and Parkinson’s disease. OHSU is the sixth hospital in the U.S. and the first hospital on the West Coast to install this state-of-the-art system.

The PoleStar N-10 system can provide images of the brain before, during and after surgery. This allows the surgeon to better plan their approach, evaluate their progress during surgery and verify results. Prior to the development of intraoperative MRI, neurosurgeons were only able use MRI scans pre- and postoperatively. Using the PoleStar N-10 system, the surgeon can take as many MRI images as needed. The entire process takes a few minutes.

“Intraoperative MRI not only allows the surgeon to be more precise and efficient, the system also helps them make adjustments due to brain shift, the natural movement or ‘settling’ of the brain, which can take place before and during surgery,” said Kim Burchiel, M.D., chairman of the neurological surgery in the OHSU School of Medicine. “Diseased brain tissue and normal tissue look the same to the naked eye. However, tumors are much easier to see using MRI images. By taking multiple MRI images throughout the procedure, we can track and adapt to brain shift. This repeated imaging also helps ensure that we remove all the diseased tissue, preventing the need for repeated surgeries.”

Before the first incision is made, a laser beam is used to position the system for surgery. Once correct positioning is determined, the initial MRI images are taken. The machine memorizes its location so additional images during surgery can be recorded from the exact same position. The MRI system is then lowered to its nonactive position under the surgery table to allow full access to the patient. When the surgeon wants to take additional images, the system automatically returns to its memorized imaging position.

Barrow Neurological Institute at St. Joseph’s Hospital and Medical Center, located in Phoenix, is among the first American institutions to acquire the PoleStar N20. Stephen Papadopoulos, M.D., of Barrow Neurological Institute (BNI) said, “The clinical and financial impact of dedicating one of a hospital’s operating theatres solely to the use of an intraoperative MRI can be disastrous, as many of these rooms sit idle when the iMR unit is not in use. With the PoleStar, we avoid these issues as the unit can be stored when not in use, allowing the room to be utilized for other types of surgery.”

Sheba Medical Center in Israel has already performed two surgeries with the new PoleStar N20. “The field of view encompasses the entire brain,” said Moshe Hadani, M.D. “The acquisition of images is faster than before due to the ease of the positioning of the patient. Most importantly, the image quality is very good, comparable to diagnostic images. In addition, navigation is very accurate throughout the procedure, with no need for registration. With no registration required, the application of the system is greatly simplified, and pre-operative set-up time is minimized.”