Now, a 'smart' tool to aid shake-free surgery

Doctors specialising in fine-scale surgery, such as operating inside the human eye or repairing microscopic nerve fibres, freehand tremors can pose a serious risk for patients.

Even the steadiest hand trembles naturally, about the thickness of a sheet of paper, several times each second.

By harnessing a specialised optical fibre sensor, a new "smart" surgical tool can compensate for this unwanted movement by making hundreds of precise position corrections each second, fast enough to keep the surgeon's hand on target.

Researchers from the Johns Hopkins University Whiting School of Engineering and Johns Hopkins School of Medicine in Baltimore, have combined the Optical Coherence Tomography (OCT) imaging technique as a distance sensor with computer-controlled piezo-electric motors to actively stabilise the tip of a surgical tool, according to a Johns Hopkins statement.

"Microsurgery relies on excellent motor control to perform critical tasks," said Cheol Song, postdoctoral fellow in the electrical and computer engineering department at Johns Hopkins.

"But certain fine micro-manipulations remain beyond the motor control of even the most skilled surgeon," Song said in a statement.

Various optomechatronics techniques, including robotics, have been developed to help augment stability and minimise the impact of hand tremors.

None has been able to seamlessly merge simple fibre-optic rapid and fine-grained sensing with hand-held automated surgical tools.

Researchers compared the effectiveness of the system by testing its ability to compensate for hand tremors during five and 30-second intervals.

These time periods were sufficient to determine the different characteristics between short and long-term hand tremors.

"A 30-second time period is enough to evaluate a surgeon's basic physiological hand tremor characteristics," said Song.

For complete characterisation, however, a record of a full surgical procedure, which typically lasts more than three hours, will be needed.

The findings are published in the journal Optics Express.