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Neurotechnology devices such as implanted deep-brain stimulation (DBS) systems and spinal cord stimulation systems have delivered a wealth of new therapeutic advances to clinicians in neurological and neurosurgical specialties. In recent years, manufacturers of neurosurgical equipment have returned the favor, developing devices that improve the process of implanting neurostimulation systems. The interaction between manufacturers of neurostimulation devices and vendors of neurosurgical equipment promises to enhance the viability of both markets.
Brain surgery has always been a complicated endeavor, in large part owing to the need for craniotomy, which involves the opening of the skull for surgical access. It routinely requires the surgeon to drill multiple holes in the skull, followed by sawing between those holes in order to remove part of the skull.
One of the primary tools at the disposal of neurosurgeons is stereotaxic surgery, which involves computer display of CT or MRI scans of the operation site. Stereotaxy systems allow neurosurgeons to navigate around the brain in three dimensions with the help of the computer imaging system. DBS systems are generally implanted with the aid of a stereotaxic surgery system.
In the past, stereotaxy systems have incorporated a head frame that is screwed directly to the patient's skull prior to surgery. The frame helps define a trajectory to the intended site of the DBS electrodes. Unfortunately, the frame also adds to the trauma that the patient experiences during the implantation procedure, which many DBS users cite as the biggest negative factor relating to their device.
A Melbourne, FL company called Image-Guided Neurologics has recently developed a new frameless stereotaxy system, which alleviates much of the turmoil associated with the procedure. The company's Navigus Trajectory Guide is used in conjunction with an image-guided workstation. The company is also developing a new product called Navigus DBA, that is targeted specifically at DBS implantation. The new device will be able to be used either in the operating room, or in an MRI environment. When used in the MR environment, it is adapted with a fluid filled alignment stem visible in the MR environment. Once aligned, Navigus DBA functions as a stable skull-mounted guide for the introduction of a surgical instruments or stimulation lead.
Another manufacturer of neurosurgical equipment is BrainLAB AG of Munich, Germany. The company's BrainSuite stereotaxy system integrates image-guided surgery, intra-operative MRI, microscopy and visualization, and data management technology. The system incorporates Siemens' Magnetom MRI system and a Zeiss OPI microscope. The first BrainSuite system was recently installed at Staten Island University Hospital in New York.
One of the most innovative firms in the neurosurgical equipment market is Stereotaxis, Inc., in St. Louis, MO. The company targets its stereotaxy systems for clinical applications in two neurosurgical domains. The first is interventional neuroradiology (INR), which refers to catheter based treatment of neurovascular disease such as aneurysms and blood clots. The other area is minimally invasive neurosurgery. Both domains address expanding, unmet critical needs, and each has significant limitations due to current instrumentation and manual techniques.
In January, Stereotaxis received FDA approval for its new Niobe Magnetic Navigation System, which uses computer-controlled magnets, positioned external to the body, to steer catheters and guidewires throughout the cardiovascular system. The system works with Siemens' Axiom Artis dFC digital fluoroscopy system, which is used to visualize the devices as they are navigated. Stereotaxis says the catheter delivery system may eventually be used to steer DBS electrodes to a precise location in the brain.
Stereotaxis' catheter delivery system is being designed as a minimally-invasive, general-purpose, flexible instrument that can be navigated along complex paths. Once arrived at its destination, the device can then be used (conjointly with appropriate devices) for procedures such as biopsy, neurostimulation, ablation, delivery of drugs, or delivery of stents or coils.
Stereotaxis hopes that its efforts will expand the number of physicians that can carry out interventional procedures. There are currently only about 300 physicians in the U.S. fully trained as interventional neuroradiologists. There are about 5,200 neurosurgeons in the U.S., many of whom would be willing to expand their use of minimally-invasive techniques if this did not require, for example, an additional two years of fellowship training.
Recent technology advances at the company include the development of smaller, lower-cost magnet arrays. Early Stereotaxis magnetic devices involved large, expensive, liquid-helium superconducting magnets. The device has already been reduced in weight by more than half, using permanent rather than superconducting magnets. Mike Kaminski, Stereotaxis COO, says, "The Niobe system defines a new era in interventional medicine, one where computers help the physician navigate medical devices more rapidly and more precisely than they can be navigated manually, freeing the physician to focus on the patient and the outcome."
The Stereotaxis system's ability to control and navigate devices along the course of brain vessels and along the borders of brain tissue has been demonstrated in early-stage, FDA-approved human studies. The number of patients, 30, is moderate, but the results have been encouraging.
Until now, there has been little or no integrated instrument-image control, which should be a reasonable, expected application of computer-integrated surgical automation. The Stereotaxis workstation platform is being designed and developed to pioneer instrument-image integration, with the aim of becoming the surgical-instrumentation equivalent of a CAD/CAM station: an information-intensive, versatile, easily manipulated device that allows for accurate, precise control of surgical instruments simultaneously with highly-detailed mapping of the operational domain.
Ease of use is a principal objective. One of the systems under development uses joystick control similar to that used in many video games. Chief Executive Bevil Hogg reported at a recent meeting that "a 10-year-old [using the equipment] beat our doctor to the target site" of a medical simulation.
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