is a freelance medical writer in Mamaroneck, NY.
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Loosely defined, robotics involves the use of machines to perform tasks. Robotic devices can carry out repetitive movements that would be tiring, boring, or otherwise difficult for humans, and can do so more precisely and consistently. Robotic tasks can be basic (for example, an arm repetitively pipetting of a single reagent into a series of microplate wells) or more complex, like a bank of robotics taking a specimen through an elaborate series of preparatory and analytic steps to yield a diagnosis. Increasingly, robotics is being used in medical settings to improve task performance and achieve therapeutic goals that would otherwise not be possible.
Image 1.
On target
James R. Doty, Clinical Professor of Neurosurgery at Stanford University in Palo Alto, CA, and a former CEo of Accuray, Incorporated, uses the CyberKnife robotic radiosurgery system (Accuray Incorporated, Sunnyvale, CA, USA) to destroy tumors in the brain and spine. Called a linear accelerator, this device delivers precise beams of radiation to localized areas in the nervous system. Doty notes that the advent of increased computing power, advances in real-time image guidance systems for anatomic localization, and the development of lightweight linear accelerators have all contributed to the development of stereotactic radiosurgery, which was first conceptualized in the 1950s by Lars Leksell in Sweden. Treatments in the 1960s, however—a period also lacking sophisticated brain imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT)—required immobilizing patients’ skulls by attaching them to rigid frames,. Additionally, radiotherapy treatment exposed a large field of tissue to high doses of radiation. Doty explains that the therapeutic Holy Grail was to have a system delivering killing doses of radiation to the lesion at different angles, with high accuracy to preserve normal tissue. However, it has challenged doctors to redefine their trade. “For surgeons, it has been difficult to embrace this technology because we go into surgery to do surgery, but technology decreases the number of patients requiring surgery. We like to say that doing stereotactic radiosurgery is doing surgery without a knife.”
“It's an exciting time,” says Doty, “because we can precisely deliver radiation to the brain and central nervous system and elsewhere in the body.” Doty notes that the linear accelerator is an industrial miniature, not a typical medical device, and positioned on a robotic arm similar to that used in the automobile industry for welding. “It's a robust device, and has the ability to make movements with sub-millimeter accuracy,” he says “Robotics has gone from the concept of mechanical accuracy to clinical accuracy.” He thinks this technology may also one day be adapted for neuromodulation, which uses an inflammatory rather than lethal dose of radiation to alter cellular membranes and treat drug-resistant seizure disorders, depression, and obsessive-compulsive disorder.
“Physicians are always interested in the latest and greatest gizmo,” Doty observes. “But we need to show clinical value and cost effectiveness. Otherwise, you can get caught up where those two paths don't meet.” Other applications of linear acceleration technology include targeting lung, prostate, breast, and liver tumors, with the object to increase efficacy and reduce complications. He notes that although early data show encouragingresults for new applications, follow-up data are needed. He believes that diagnosing lung cancer earlier may allow earlier, minimally invasive treatment. “I believe the early data are supported,” though noting that he was booed at a thoracic conference in the 1990s for suggesting the possibility of curing small lung lesions with one treatment while inducing few or no complications. The use of this technology to treat lung lesions will require further refinement, he says, because the movement caused by breathing changes the trajectory of the tumor. A vest with trackable, light-emitting diodes, providing a “4-D” (three spatial dimensions plus time) CT, may be used to track respirations.
Image 2.
From improving to enabling
Andrew D. Pearle at the Hospital for Special Surgery in New York, NY, is an orthopedic surgeon specializing in sports medicine, and a founding member of the hospital's Computer Assisted Surgery (CAS) program, one of the first in the United States. The program focuses on developing and validating surgical navigation and medical robotics in orthopedic surgery. Pearle uses a surgical system developed by MAKO Surgical Corporation (Ft. Lauderdale, FL, USA), which generates a 3-D model of a patient's knee from preoperative CT scans. This model is used by surgeons in partial knee replacement surgery, to plan what part and how much of a damaged joint should be removed and replaced with an implant. The system uses haptic feedback to create virtual walls to guide the surgeon's burr saw during bone removal: If the surgeon tries to remove bone beyond the predetermined boundaries, the robotic arm will resist and warn the surgeon with an alarm. If the surgeon persists, the saw will turn off.
