{"id":1470,"date":"2017-09-21T19:33:02","date_gmt":"2017-09-21T19:33:02","guid":{"rendered":"https:\/\/www.mc.vanderbilt.edu\/vanderbiltmedicine\/?p=1470"},"modified":"2021-08-11T19:40:18","modified_gmt":"2021-08-11T19:40:18","slug":"how-six-cups-of-ground-coffee-can-improve-nose-throat-surgery","status":"publish","type":"post","link":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/how-six-cups-of-ground-coffee-can-improve-nose-throat-surgery\/","title":{"rendered":"How six cups of ground coffee can improve nose, throat surgery"},"content":{"rendered":"
\"\"<\/a>
The granular jamming cap, left, and the current elastic headband used for tracking the position of a patient\u2019s head during endonasal surgery, right. Photo by Joe Howell.<\/figcaption><\/figure>\n

Imagine plopping six cups of coffee grounds on the heads of patients just before they are wheeled into the operating room to have nose or throat surgery.<\/p>\n

In essence, that is what a team of Vanderbilt University engineers are proposing in an effort to improve the reliability of the sophisticated \u201cGPS\u201d system that surgeons use for these delicate operations. They have designed a \u201cgranular jamming cap\u201d filled with coffee grounds that does a better job of tracking patient head movements than current methods.<\/p>\n

The coffee grounds form a thin layer inside a stretchy silicone headpiece, which looks like a black latex swim cap decorated with reflective dots. After the cap is placed on the patient\u2019s head, it is attached to a vacuum pump that sucks the air out of the cap, jamming the tiny grounds together to form a rigid layer that conforms closely to the shape of the patient\u2019s head.<\/p>\n

Before surgery, a special scanner is used to map the location of the dots relative to key features on the patient\u2019s head: a process called registration. Then, during surgery an overhead camera observes the position of the dots, allowing the navigation system to accurately track the position of the patient\u2019s head when the surgeon repositions it. The computer uses this information to combine a CT scan, which provides a detailed 3-D view of the bone and soft tissue hidden inside the patient\u2019s head, with the position of the instruments the surgeon is using and displays them together in real time on a monitor in the operating room.<\/p>\n

\u201cThese are very delicate operations and a sophisticated image guidance system has been developed to help the surgeons, but they don\u2019t trust the system because sometimes it is spot on and other times it is off the mark,\u201d said Robert Webster, Ph.D., associate professor of Mechanical Engineering and Otolaryngology, who is developing a surgical robot designed specifically for endonasal surgery.<\/p>\n

Webster and his research team discovered it wasn\u2019t the hardware or the software in the guidance system that was causing the problem. It was the way the reflective markers were attached to the patient\u2019s head that was at fault. Typically, these \u201cfiducial markers\u201d are attached by an elastic headband and double-backed tape and are subject to jarring and slipping, which produced large tracking errors.<\/p>\n

\u201cThe basic assumption is that, after registration, the spatial relationships between the patient\u2019s head and the fiducial markers remains constant,\u201d said Patrick Wellborn, the graduate student who is making the presentation. \u201cUnfortunately, that is not the case.\u201d<\/p>\n

Previous research has found that when everything goes well, the guidance system produces targeting errors of about 2 millimeters, but in about one operation out of seven, the target error is much larger, forcing the surgeon to redo the registration process.<\/p>\n

\u201cActually, we do have a solution to this problem but it involves drilling and attaching the markers directly to the skull, which we don\u2019t like to do because it is painful and it\u2019s a step backward from the majority of what we are doing,\u201d said associate professor of Otolaryngology Paul Russell, M.D., who is collaborating with the engineers on the project.<\/p>\n

So the team began thinking up alternative, non-invasive methods to attach these critical markers. In the last three years, they have gone through a number of designs. They began with headbands that had coffee ground-filled bags over the temples. Their tests showed that these models could reduce the targeting error by about 50 percent. But the engineers still weren\u2019t satisfied.<\/p>\n

Then, Wellborn had a brainstorming session with fellow graduate student Richard Hendrick. Among the materials that his predecessor had left behind was a latex bald cap. \u201cThat sparked the idea of caps in general,\u201d Wellborn recalled. \u201cWe wanted something elastic that was form fitting, which led to the idea of a swim cap.\u201d<\/p>\n

In addition to fitting extremely tightly to the head, the new design had another advantage. The headband system has only three fiducial markers attached on the ends of three thin rods to form a triangle. The new design allowed them to attach several dozen markers directly to the surface of the cap, which the researchers believe will also contribute to improving the guidance system\u2019s accuracy.<\/p>\n

They designed three tests to determine how well this \u201cgranular jamming cap\u201d performed relative to the current headband in reducing targeting error.<\/p>\n

On the strength of these results, Vanderbilt University has applied for a patent on the design and the technology is available for licensing. (Interested parties should contact the Vanderbilt Center for Technology Transfer and Commercialization.)<\/p>\n","protected":false},"excerpt":{"rendered":"

Imagine plopping six cups of coffee grounds on the heads of patients just before they are wheeled into the operating room to have nose or throat surgery. In essence, that is what a team of Vanderbilt University engineers are proposing in an effort to improve the reliability of the sophisticated \u201cGPS\u201d system that surgeons use…<\/p>\n","protected":false},"author":211,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"_links_to":"","_links_to_target":""},"categories":[11,25],"tags":[],"class_list":["post-1470","post","type-post","status-publish","format-standard","hentry","category-vm-around-the-medical-center","category-vm-summer-2017"],"acf":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pcDnub-nI","_links":{"self":[{"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/posts\/1470","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/users\/211"}],"replies":[{"embeddable":true,"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/comments?post=1470"}],"version-history":[{"count":1,"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/posts\/1470\/revisions"}],"predecessor-version":[{"id":3062,"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/posts\/1470\/revisions\/3062"}],"wp:attachment":[{"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/media?parent=1470"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/categories?post=1470"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medschool.vanderbilt.edu\/vanderbilt-medicine\/wp-json\/wp\/v2\/tags?post=1470"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}