Biological Breakthrough Eases Spine Fusion Surgery
Nov. 7, 2001 -- New technology using genetically engineered messengers can make spine fusion surgery less painful and more likely to succeed.
Normally, these messengers exist in bone and other tissues and are called bone morphogenetic proteins, or BMPs for short. But when BMPs are placed in the body, they attract immature, shape-shifting cells from the blood, called stem cells, which then are able to turn into bone cells.
Researchers wanted to find out if BMPs could help the body form new bone and avoid the need for painful hip bone grafts currently needed for spine fusion surgery. Spine fusion surgery is used to treat people with severe back pain due to worn-out vertebrae -- due to arthritis or injury -- usually in the lower spine.
"It opens up a whole realm of treatment possibilities we haven't studied yet. That is very exciting," says Matthew F. Gornet, MD, of the Missouri Bone and Spine center.
But one of these possibilities has been studied -- and Gornet reported the findings at this week's meeting of the North American Spine Society (NASS).
Spinal fusion surgery has typically required removal of bone from the hip to be used as a graft to fuse the vertebrae together, thus relieving pressure on the spinal nerves. These bone grafts currently consist of bone taken from the hip in a separate operation -- often causing long-term hip pain. Gornet and colleagues at 16 spinal centers looked at whether BMP could be used in place of bone grafts.
Early trials showed it could work. Now Gornet's team shows that a specially shaped cage made of titanium -- a new product called "LT-CAGE" -- and loaded with BMP works at least as well as frames loaded with natural bone. (The LT-CAGE and BMP product are made by Medtronic, a WebMD sponsor.)
The 279 people in the study underwent the least traumatic form of spinal fusion surgery, in which the surgeon operates on the back through a relatively small cut in the abdomen. Half the people got the BMP-loaded frame, and half got frames loaded with hip bone grafts. People getting the natural bone grafts did better than expected -- about 89% of them had complete spinal fusion. But those getting the BMP material, called "InFUSE," did even a little better -- about 95% had complete spinal fusion.
People who received the InFUSE grafts spent less time in surgery and had less blood loss. And they completely avoided bone removal from their hip -- an extra operation that left about a third of the bone-graft people with lasting pain.
Both groups had more than a 50% improvement in their pain following surgery.
Studies are underway to compare the InFUSE system with bone graft in people who undergo the more traumatic spinal fusion surgery in which the surgeon must get to the spine from the back.
INFUSE Bone Graft(R)/LT-CAGE® Lumbar Tapered Fusion Device incorporates technology developed by Gary K. Michelson, M.D.