Scientists under Dr. Robert Howe, professor of engineering at Harvard BioRobotics Laboratory, are developing a robotic system for transmyocardial repairs of mitral valves (for now, probably, stenotic ones), reports the MIT Technology Review:
Unlike traditional mitral-valve repair, Howe’s procedure does not involve opening up the heart itself. Instead, a hollow needle is inserted into the organ. The needle is used to introduce small anchors into the heart and affix them to the tissue around the mitral valve. The anchors can then be pulled together by a suture wire to decrease the size of the valve opening. “The challenge here is that [to affix the anchors] we need to keep track of where the heart tissue is, as the heart moves continuously,” Howe says. Howe’s team opted to use 3-D ultrasound to visualize heart movement because with other imaging techniques, such as video, the internal structures of the organ would have been concealed by circulating blood.
Data from the 3-D ultrasound images is analyzed using special software written by the researchers. The software can predict where heart tissue will be approximately 70 to 100 milliseconds in the future, so the position of the tip of the handheld surgical tool can be adjusted accordingly. Sensors in the tool also detect whether it comes in contact with the tissue. “We can detect very quickly if things deviate greatly from what’s predicted and then pull back the [instrument] to get it out of the way,” Howe says.
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Abstract: An active motion compensation instrument for beating heart mitral valve surgery