Surgeons study long and hard to perfect their technique, but one thing they can't control is the microscopic shifts that exist in even the steadiest of hands. Researchers have tackled this problem by creating a surgical tool that compensates for these shifts.
The tool, named SMART (Smart Micromanipulation-Aided Robotic-surgical Tool), determines its location by sending out tiny pulses of light via optical fiber; the harmless light hits the tissue and is picked up by the same fiber. SMART measures any motion of the surgical tool by calculating the time it takes for the light to bounce back.
SMART then uses motors powered by pressure and movement to shift its surgical tip. The hyper-accurate motors are able to move as often as 500 times a second, which more than compensates for the average, natural invisible shifts the human hand makes — some 50 to 100 microns several times a seconds, which is about the width of a human hair.
Researchers tested the motors with two surgeons and found when just holding the SMART with the motors off, they tend to move their hands 15 times fewer per second. When the surgeons were asked to hold their hands as still as possible with the motors switched on for five and 30-second periods, the team found the system's light sensors and motors helped keep the tool tip even steadier.
Correcting for these small shifts could make a big difference in delicate surgies, especially on the eye or nerves where the surface of the operation is microscopic to begin with.
While the prototype tool used a needle for the tip, the research team plans to create an interchangeable tip to allow for different surgical tools such as scalpels to be added to assist surgeons on a variety of surgical procedures.
Jin Kang, an engineer at Johns Hopkins University, led research on the new tool and describes the objective as being about making an existing tool "smarter." In other words, it's not about a deficiency in the operator of the tool, but using the evolution of technology to upgrade their tools to help them operate with more efficiency and precision.
Kang and the research team will publish a paper about SMART in an upcoming issue of the journal Optics Express.