A surgical tool to reduce complications associated with spinal revision surgery

Every year, there are more than one million spinal surgeries in the United States targeting nerve problems that occur mainly in senior patients. 32 percent require a revision surgery due to a degeneration of the initial condition. Of these 320,000 surgeries, 18 percent result in a serious clinical complication called a cerebrospinal fluid leak, which is any sort of tear or puncture in the thin membrane, known as the dura mater, that surrounds the spinal cord. Each of these 57,600 incidences extends patient hospitalization by 3-5 days, incurs an average cost of $6,500 per patient, increasing the financial burden on the U.S. health care system by around $375 million annually. There is currently no device on the market that deals specifically with the separation of scar tissue, bone, and dura in the spinal area. Instead, doctors use a variety of instruments called periosteal elevators, which generally have a spatula-shaped end designed to scrape tissue from the bone. However, these are general surgical tools that are not designed to tear tissue gently and can easily damage the dura if the surgeon creates too much sheer force or makes contact with the dura due to lack of visibility. To address these issues, we have designed a tool that employs ultrasonic vibrations concentrated on a thin, flattened tip in order to separate the scar tissue from bone. The tip design features an L-shaped curvature that conforms to the geometry of the spine, sharp edges on either side of the tip that enable it to cut laterally through scar tissue, a dull tip that offers protection for the spinal cord membrane underneath, and a means of cooling through water ejected from an irrigation hole located on the distal end of the tip. We have demonstrated that our device will reduce the force applied during scar/ bone separation by 45 percent and will perform force testing and dural characterization experiments in rabbit spines in the coming year.