INFUSE Bone Grafts are synthetic proteins that help grow new bone. But they may come with side effects such as nerve pain, infection and an increased risk of cancer.
What are Bone Grafts?A growing number of people suffer from crippling back pain because of arthritis or other forms of degenerative disease, and it is estimated that 84 percent of bone grafts are used in a type of back surgery to relieve back pain called spinal fusion. Surgeons in the United States perform about 432,000 spinal fusions a year, and the average cost for this surgery is more than $34,000. In spinal fusion, doctors surgically fuse together the individual damaged bones of the spine, called vertebrae. After the fusion, the individual vertebrae form one solid bone and this eliminates the irritation of nerves in the spine. When doctors perform spinal fusions, they typically take bone from another part of the patient's body or use donated bone. However, the surgery to harvest the bone from the hip can come with complications like pain at the harvest site, infection, bruising and pelvic fracture. Donated bone carries a risk of infection or disease, and the quality of the bone cannot be controlled. In response to these concerns, medical implant companies like Medtronic and Stryker Biotech have developed what they claim is a safer alternative to traditional bone grafts using synthetic versions of bone morphogenetic protein (BMP). BMP occurs naturally in the body and was first discovered by Dr. Marshall R. Urist in 1965. These proteins have a large role in forming cartilage and bone in the body. While this synthetic bone graft technology is a significant advance in medicine, it also comes with a hefty price tag. Using BMPs adds several thousand dollars to the average cost of spinal surgery. Packages of INFUSE can range from $2,500 to $5,000.
Medtronic and the INFUSE Bone Graft ControversyOver the years, Medtronic has faced increased scrutiny for the INFUSE Bone Graft. In 2011, Dr. Eugene J. Carragee and several colleagues published an editorial in The Spine Journal revealing that a number of Medtronic-sponsored studies failed to disclose possible side effects associated with rhBMP-2, the synthetic protein component of the INFUSE Bone Graft system. It also revealed that a number of the researchers in these studies received between $1 million and $23 million a year from Medtronic in royalties and consulting fees. In June 2011, the U.S. Senate launched an investigation into the allegations that journal entries written by doctors who were paid by the company failed to reveal dangerous, life-threatening side effects. The Senate is considering legislation called the Physician Payment Sunshine Act that forces drug companies to make all doctor payments public. Even before Dr. Carragee's article was published, the U.S. Department of Justice (DOJ) was already investigating Medtronic. In a civil suit, the DOJ accused the company of paying kickbacks to doctors as an incentive to use INFUSE and other spinal products between 1998 and 2003. Medtronic reportedly set up sham consulting agreements and royalty agreements and even paid for "lavish trips to desirable locations," according to the suit. In 2006, the company paid $40 million to settle the civil case.
Specifics of the INFUSE Bone GraftIn 2002, the FDA approved the INFUSE Bone Graft/LT-CAGE Lumbar Tapered Fusion Device system. The system is designed for use in people with degenerative disc disease, including Grade I Spondylolisthesis, more commonly known as a slipped disc in the spine. It is only approved for use in the lower back (lumbar spine). The only surgical technique that is FDA approved for use with the INFUSE Bone Graft is the anterior lumbar interbody fusion (ALIF). In ALIF surgery, the surgeon operates on the spine by going through the abdomen instead of through the lower back. This procedure minimizes injury to the back muscles and nerves. The INFUSE Bone Graft system is made up of two parts: the synthetic bone morphogenetic protein (rhBMP-2) and a sponge manufactured from cow collagen. The protein comes in powder form and is mixed with sterilized water to form a solution. The solution is then applied to the collagen sponge and the sponge is placed inside a pair of LT-CAGES, metallic devices that resemble thimbles. The LT-CAGES are implanted into the spine, in between the vertebrae. This implant stabilizes the vertebrae and holds the sponge in place until new bone can form. The sponge releases the rhBMP-2 over time and then dissolves. INFUSE is mainly used in spinal surgery, but it has also been approved for other uses. In 2004, INFUSE was approved for use in open fractures of the tibia, and in 2007 the device received approval for use as a bone graft alternative in sinus augmentations.
Serious INFUSE Bone Graft ComplicationsEarly clinical studies, including those reviewed by the FDA, showed that INFUSE has the potential to inflame nearby tissues and bone, cause urinary problems and even stimulate cancer growth. In fact, BMP products are associated with a 43 percent higher overall complication rate. Until Dr. Carragee and his colleagues published their 2011 review, these adverse events were unpublished. In the review, Carragee accused companies like Medtronic of paying off doctors to intentionally hide these severe complications. Some of the common side effects associated with Infuse Bone Grafts include:
- Inflammatory reactions
- Back and leg pain
- Radiculitis (pain that spreads through the spinal nerves)
- Implant displacement
- Retrograde ejaculation (occurs when semen enters the bladder)
- Male sterility
- Osteolysis (degeneration of bone tissue)
- Ectopic bone formation (unwanted bone in the spinal canal)