Bots at the Operating Table

Medibot attacking a virus

The Star Wars 2-1B series medical droid is the fictional soft-spoken medical droid that provides Luke Skywalker with a prosthetic hand in the Star Wars saga. Somewhat human-like in appearance, the fictional 2-1B model’s arms feature exceptional joint articulation with precision crafted servo grip pincers at the end of each limb. These pincers can be removed and replaced with multiple arm attachments for various medical tools – including software packages for diagnosis and treatment including hypodermic injectors and cutting saws.

Most medical robots or “medibots” today require human assistance. They are tools that human doctors can use for remote surgery and minimally invasive surgery, offering greater precision, miniaturization, smaller incisions, decreased blood loss, less pain, and quicker healing time. Not limited by human joints, their articulation extends beyond normal manipulation and they can be used for 3D magnification.

The da Vinci System – provides surgeons with an alternative to both traditional open surgery and conventional laparoscopy, putting a surgeon’s hands at the controls of a state-of-the-art robotic platform. Surgeons can perform even the most complex and delicate procedures through very small incisions with unmatched precision. Here’s a video of human-controlled da Vinci pincers peeling a grape:

The HeartLander – is a miniature mobile robot that delivers minimally invasive therapy to the surface of a beating heart. Using keyhole incisions and the 20-millimeter-long HeartLander bot, a surgeon guides the caterpillar-like device using a joystick. When this bot becomes commercially available, a surgeon will create a small incision on the patient’s chest and use a pair of forceps to place the robot directly on a beating heart. Using the joystick, she then guides the bot to deliver medicine directly to affected areas. The bot can also be used to attach pacemaker electrodes or assist with specialized techniques for curing arrhythmia. This worm-like robot moves using an ingenious mechanism driven by miniature ultrasonic piezoelectric motors. Here’s a video of a HeartLander bot crawling around a living pig’s heart:

Developed by The Robotics Institute at Carnegie Mellon University, this bot is still a proof-of-concept. The research team is resolving a number of issues that include the development of the bot’s wireless remote control mechanism so that it doesn’t rely on a stiff tether that causes problems with locomotion. The tether currently supplies energy to the HeartLander, although the researchers expect the production version to use an on-board battery.

ViRob – is a tiny “millibot” (a scale of 10-3 meters), 1 millimeter in diameter and 5 millimeters long. A magnetic field makes its legs move inside a human body where it can deliver drugs to hard-to-reach spots and take small tissue samples for testing. Ultimately, the ViRob may be used inside blood vessels, but so far, it is unable to handle the turbulence of coursing blood.

In addition to taking tissue samples, ViRob’s developers at the Technion-Israel Institute of Technology in Haifa are investigating several other applications. These include delivering cancer drugs and getting a camera to hard-to-reach areas — for example, deep within the lungs. Miniature cameras are currently about 1.5 millimeters in diameter — slightly too large — but “cameras are getting smaller every year,” says project engineer Moshe Shoham. Here’s a video of a ViRob crawling along a small piece of tubing:

Another possible application is the insertion of cochlear implants – small electrodes placed within the ear’s spiral-shaped cochlea to stimulate the auditory nerve.

Ophthalmic Robot – is another millibot, slightly smaller than ViRob – 0.9 by 0.3 millimeters. Like ViRob, it is pulled around by electromagnets outside the body and does not have on-board propulsion and steering mechanisms. It is being developed for delicate surgery on blood vessels so small they’re difficult to impossible to see without magnification. According to New Scientist, one application for the ophthalmic robot is to measure oxygen levels at the surface of the retina –- an indication of its blood supply. Its shell is coated with a photoluminescent chemical, the brightness of which depends on oxygen concentration.

The machine had a database of 10,000 similar operations and – in the words of its designers – was "more than qualified to operate on any patient."

The ophthalmic robot can be used to treat retinal vein occlusion, which occurs when a blood clot blocks the major vein at the back of the eye. The current surgical procedure involves inserting a needle into a hollow cylinder known as a trocar on the surface of the eye and injecting a drug into a vein, a difficult feat at best because of hair-thin blood vessels.

Nanobots – are likely to be the next generation of medibots (see the h+ article “Nanobots in the Bloodstream” in Resources). At a scale of 10-9 meters, advanced nanobots “will be able to sense and adapt to environmental stimuli such as heat, light, sounds, surface textures, and chemicals; perform complex calculations; move, communicate, and work together; conduct molecular assembly; and, to some extent, repair or even replicate themselves.” Propulsion and guidance problems have yet to be resolved. Here’s an animated video showing how a nanobot might go about replacing neurons:

Today’s surgical bots have come a long ways since George Lucas first visualized the medical droids of Star Wars. In May 2006, the first “AI doctor” conducted unassisted surgery on a 34-year old-male to correct heart arrhythmia and the results were rated as better than an above average human surgeon. The machine had a database of 10,000 similar operations and – in the words of its designers – was "more than qualified to operate on any patient."

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