University Of Illinois At Chicago Pioneers Large-Skull Implant Design And Surgery

UIC neurosurgeons recently performed large-skull implant surgery on a 35-year-old man who had been missing the front of his skull from above the eyes and from ear to ear (115 square centimeters). The man, injured by a bullet more than five years ago, had to wear a helmet for protection.

This procedure, available only at UIC, draws on a combination of medical advances made by experts in neurosurgery, radiology, biomedical visualization and computer engineering. Among the new developments that have made this procedure possible is the ability of UIC biomedical visualization experts to design cranial implants using computed tomography (CT) and magnetic resonance (MR) data taken directly from the patient. They design and manufacture the implant before neurosurgeons operate on the patient.

A local manufacturer makes a model of the patient's skull using a laser that instantly transforms liquid into plastic. UIC experts design the final implant from this plastic mold and cast it in medical-grade plastic. Another advance critical to the success of the cranial implant surgery is the ability of experts to obtain an exact measurement of patients' brain blood flow, using UIC's Xenon gas CT technology. Blood flow in the frontal lobes of the gunshot victim improved 40 percent following closure with the implant.

When a portion of the skull is missing, numerous complications can arise depending on where the injury is located. Headaches, blindness, thought impairment and behavioral disorders are among the problems associated with this condition. The brain, in general, sinks because gravity pressing down on brain tissue is greater than the fluid pressures that surround the brain and hold it in place. These fluids, plus blood pressure in veins, arteries and capillaries, maintain the brain's shape.

Scientists can use several materials, including titanium mesh and hydroxy apatite cement, to repair small holes in the skull, but these methods are ineffective with large holes. Experts at UIC have been using this technique for over a year, performing the surgery on a dozen patients.