Neurosurgeons Studying Bone Graft Substitute

Neurosurgeons at the University of Pittsburgh are studying a bone graft substitute to determine if it can promote bone growth following spinal fusion surgery for lower back pain caused by degenerative disc disease. The randomized, multi-center research study will enroll 370 patients nationally with about 40 patients being enrolled at UPMC Presbyterian Hospital.

The material is called Healos® Bone Graft Substitute. Healos is a mineralized collagen matrix manufactured by Orquest, Inc., with Sulzer Spine-Tech as distributor and sponsor of the clinical study.
“This study will determine the safety and efficacy of this new osteoconductive material,” said William Welch, M.D., associate professor in the Department of Neurological Surgery at the University of Pittsburgh School of Medicine and primary investigator of the study at UPMC.

Between each of the 24 vertebrae of the human spine is a vertebral disc, made of cartilage-like material that separates the vertebrae and allows flexibility of movement. Injury, aging, or repeated stress can produce degenerative disc disease — drying out or collapse of the disc — which can lead to excessive motion in the spine; inflammation of the nerves in and around the spine; nerve dysfunction; and severe, debilitating pain in the back, arms, and legs.

Spinal fusion is an accepted surgical method of treatment for lower back pain. Over the past five years, manufacturers have developed FDA-approved titanium alloy cage-like products, which have been shown to alleviate lower back pain through the promotion of fusion between the vertebrae.

“These devices are placed between the lumbar vertebral bodies after the discs have been surgically removed. The cages are essentially hollow screws with holes drilled into the walls, which are then filled with bone taken from the iliac crest of the patient’s hip. Over a period of months to years, bone grows across the vertebrae and through the cages to form a solid fusion,” Welch said. “Healos, if found to be safe and effective, would potentially eliminate the need to take bone from the patient’s own hip for use during spinal surgery, and may accelerate the bone fusion process. The process of removing a patient’s own bone from its hip can be very painful during the post-operative healing process. Avoiding this pain is one of the goals of this study.”

During surgery, a needle is placed into the iliac crest and a small amount of bone marrow is withdrawn. The Healos sponges are coated with the marrow before inserting the sponges into the cages. The Healos/marrow combination is then used instead of autograft bone, according to Welch.

—Frank Raczkiewicz