The robot, developed by Dmitry Oleynikov and colleagues at the University of Nebraska Medical Center in Omaha, can move around inside the stomach or abdomen to give surgeons a new perspective on the area being operated on. It is also equipped with a retractable needle, allowing it to perform biopsies.
The device is made up of two rotating aluminium cylinders connected by a thick axle, which carries the camera. The spiral pattern on the surface of the cylinders allows them to grip the walls of the abdominal cavity and move around. "They have been designed not to slip or damage the tissue," Oleynikov says.
The robot is only 15 millimetres in diameter, allowing it to be inserted through the small incisions in the abdomen used for keyhole surgery (Surgical Endoscopy, vol 20, p 135). It is controlled from a console equipped with a joystick. When Oleynikov used the robotic tools to help remove the gall bladder from pigs, he only needed to make two incisions rather than the usual four. This is because the robots can be inserted into incisions already made for cutting and grasping tools, unlike endoscopic cameras, which need separate incisions. And by using several robots it should be possible to view the area from a variety of angles. "We have put up to three of these in at the same time through the same incision," he says.
Oleynikov has also used the robots to explore the abdominal cavity of a live pig, having got it there via the animal's mouth and an incision in through the stomach wall. This was to test a procedure known as natural orifice surgery, in which the surgeon removing a gall bladder or doing a liver biopsy, for example, inserts the instruments via the mouth and then through small incisions in the stomach lining, thus avoiding the need for an external incision. This is believed to result in less trauma to the abdominal wall, and means the patient is left without a scar. At the end of the operation, the surgeon backtracks, suturing the stomach lining before removing any excised tissue through the patient's mouth.
Endoscopic cameras are not very effective for natural orifice operations as their freedom of movement is limited. The team hopes its robots will do better. But some question the need for such procedures. "Logic defies why you have to take such a complicated route to get to the abdomen," says Ara Darzi, a pioneer of minimally invasive surgery at Imperial College London.
Oleynikov will present his findings at the Society of American Gastrointestinal and Endoscopic Surgeons' meeting later this year.
Author: Duncan Graham-Rowe
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