No matter how steady you try to hold your hand, it will still tremble several times a second, moving a distance roughly the same as the thickness of a sheet of paper each time. While that might not matter much for the average person, it can be a very big deal to surgeons performing fine-scale surgery on things like eyes or nerve fibers. While there are experimental robotic devices to help smooth out the shakes, researchers from Johns Hopkins University have come up with something else – a surgical tool with a jiggling tip.
Known as SMART (Smart Micromanipulation Aided Robotic-surgical Tool), the hand-held device incorporates a near-infrared laser that shines out of its tip and onto a target area of the patient’s tissue. That laser serves as a distance sensor, using a single fiber optic cable to both receive pulses of light that it then emits, and to transmit the reflections of those pulses back to an attached computer. By analyzing that data, the computer can determine when and by how much the tool is wavering in relation to the tissue.
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The tip of the SMART tool also includes piezoelectric motors, which move a mount that accepts attachments such as scalpels and forceps. As the computer detects tiny movements of the tool, caused by hand tremors, it compensates for them by activating the motors to move the attachment accordingly. If the surgeon’s hand inadvertently moves the whole tool ten microns to the left, for instance, SMART automatically makes up for it by moving the scalpel (or other attachment) ten microns to the right.
The system makes its adjustments at a rate of 500 per second, which is far faster than the typical tremor frequency of up to 15 per second.
So far, the technology has been tested on both a “dry” model and on a live chicken embryo, for periods lasting up to 30 seconds – these were reportedly sufficient “to evaluate a surgeon’s basic physiological hand tremor characteristics.” In order to better test its real-world viability, however, it will have to be used in an operating suite for periods of over three hours. The researchers hope that such trials could take place over the next few years.
A paper on the SMART device was recently published in the journal Optics Express.