HIGH OCTANE Researchers say a "granular jamming cap" (left) does a better job of tracking patient head movements than current methods.

Robert Webster, PhD, loves coffee and had an idea brewing: What if the grounds that make his daily caffeine fix could also be used to track how a patient's head moves during image-guided ENT surgery? That might seem farfetched, but it made perfect sense to Dr. Webster after his morning cup of joe kicked in.

His java-inspired solution to improve the accuracy of delicate sinus and throat surgeries involves 6 cups of ground coffee and optical sensors attached to the surface of a silicone "granular jamming cap," which resembles a latex swim cap. Dr. Webster, an associate professor of mechanical engineering and otolaryngology at Vanderbilt University in Nashville, Tenn., and a team of researchers placed loose coffee grounds in the silicone cap. Once the cap is placed on the patient's head, a vacuum pump is used to suck air out of the cap to pack the grounds together. The cap solidifies and forms a hard layer that conforms to the contours of the skull and won't budge during surgery, says Dr. Webster.

Before procedures begin, surgeons use a specially designed reflective scanner to register dozens of optical markers on the outside of the cap to anatomical landmarks in the patient's head. The system then combines the registered landmarks with CT images of the patient's skull to create a real-time, 3D intraoperative display of how bones and soft tissue are positioned in relation to the surgeon's instruments.

Dr. Webster's team looked into the reported inconsistencies of conventional image-guided systems and discovered that variations in the spatial relationships between the patient's head and fiducial markers, not the systems' image-guided hardware, can cause surgeons to miss their mark by approximately 2 millimeters during procedures that demand high levels of precision.

The researchers have sought a patent on the innovative design and are looking for a commercial partner to help them obtain FDA approval for the technology.

Daniel Cook