he unusual method comes from Vanderbilt University and the cap has been described as akin to placing six cups of coffee grounds onto the heads of patients, prior to the patients are taken into an operating theater for surgery of the nose or throat.
The aim of the device is to improve the accuracy of the global positioning system technology used by surgeons to locate the precise areas for operating on patients. Ensuing that the area selected for the operation is accurate is critical since the surgery often involves working on tiny areas of the nasopharynx (the nasopharynx connects the back of your nose to the back of your mouth).
The research showed the “granular jamming cap“, filled with coffee grounds, did a superior job to current methods (which generally consist of a cap made from a plastic material). The coffee grounds are treated so they act as a thin layer contained within a silicone headpiece. The finished cap resembles like a black latex swim cap, with reflective dots positioned on the top. Once the cap is positioned on the patient’s head, the headpiece is attached to a vacuum pump. The pump proceeds to suck the air out of the cap which compresses the tiny grounds together. The grounds then form a rigid layer, forming a shape that matches the dimensions of the patient’s head.
Prior to surgery, surgeons use a scanner that produces a map of the patient’s head based on the positioning of the reflective dots (fiducial markers) and a three-dimensional image is generated. During the surgical process the position of the dots is carefully observed, aiding in the surgeon in his or her task. Critical to the imaging is the differentiation between bone and tissue. Since movement alters the image, continually assessing the positioning of the head in real-time is critical for surgical success. Current guidance systems produce targeting errors of about 2 millimeters; the new cap containing the coffee grounds reduces the error rate significantly, by 83 percent.
Further information about the cap is presented in a short video:
Speaking with the Hindustan Times, one of the researchers, Paul Russell explains: “It’s a very clever way–that doesn’t involve drilling holes in patients’ skulls–to greatly improve the accuracy of the guidance system when we are operating in the middle of a person’s skull: a zone where the accuracy of the current system is inadequate.”
The novel device was recently presented to the International Conference on Information Processing in Computer-Assisted Interventions, which took place in Barcelona, Spain on June 20, 2017. The conference is an international forum for technical innovations, system development and clinical studies in computer-assisted interventions.
