Just hours after Roy Horn was mauled by one of his tigers, doctors reportedly removed a portion of the Las Vegas illusionist's skull. Recent reports note that the fragment was implanted in a pouch in Horn's abdomen. Why place a piece of skull in someone's stomach?
So it can be returned to the patient's head when the moment is right. The procedure that Horn reportedly underwent has alternately been referred to as either a decompressive craniectomy or a hemicraniectomy. The former is considered a slightly less risky surgery since a smaller section of the skull is removed. However, both procedures are intended to accomplish the same goal: to prevent injury or death due to brain swelling. After severe trauma like Horn experienced, the brain can swell to such a degree that it squeezes against the cranium. This can block blood flow or warp the brain stem, two potentially fatal situations.
In a decompressive craniectomy, doctors remove a portion of the skull in order to relieve the pressure associated with swelling. The skin of the scalp is then sewn together with the dura mater, a tough membrane that covers the brain. With the bony skull gone, the scalp and dura can stretch to accommodate an enlarged brain. Doctors typically wait six to 20 weeks for the swelling to subside, then replace the skull fragment. In the interim, the patient wears a protective helmet.
But the skull cannot simply be placed in a bedside jar. Fragile bone marrow will wither and die unless preserved under optimal circumstances—either frozen, or kept close to a warm, circulating blood supply. Some doctors choose to freeze the skull bit because it requires one less incision. But others prefer to place the skull piece within a subcutaneous pouch that's implanted in the abdomen, between the muscle and the fat. This is an ideal location since there is ample storage space and little danger of interfering with essential body functions. Also, keeping the skull nestled within the body is a good way of keeping the bone sterile; the second you start toting vital body parts around, there's always the danger they might pick up airborne germs or, worse, be misplaced.
Despite the delicateness of the surgery, as well as the grave conditions of many patients selected for such procedures, success rates are fairly high. A 1998 study at the University of Heidelberg found a mean survival rate of 72.1 percent, and of the 43 patients studied, none of those who survived were left in comas.
Explainer thanks Dr. Ghassan K. Bejjani of the University of Pittsburgh Medical Center and Heather Monroe of the American Association of Neurological Surgeons.