CHICAGO - Products used to stimulate bone growth in spinal fusion surgery worsen the risk of complications and boost overall hospital costs, U.S. researchers said on Tuesday.
They said spinal fusion surgery using bone growth products such as those made by Medtronic Inc and Stryker Corp resulted in higher rates of complications than conventional spinal fusion procedures, and increased total hospital charges by 11 to 41 percent.
When used in certain spinal fusion operations in the neck, an unapproved use, complications rates were double those found in conventional surgery, Dr. Kevin Cahill of of Brigham and Women's Hospital in Boston and colleagues reported in the Journal of the American Medical Association.
Last July, the U.S. Food and Drug Administration warned unapproved or off-label use of bone growth products had been linked with life-threatening complications.
The U.S. Justice Department is investigating Medtronic's marketing practices for InFuse. Last week, the company said U.S. prosecutors are seeking documents related to a study by a former U.S. Army surgeon accused of fabricating data about InFuse.
InFuse and Stryker's OP-1 Implant and OP-1 Putty contain recombinant, or genetically engineered, human bone morphogenetic protein or BMP, an artificial protein used to promote bone growth.
Medtronic spokeswoman Marybeth Thorsgaard said the JAMA study only looked at hospital-related costs and complications. "Other studies have demonstrated reduced complication rates and reduced associated costs with the use of BMP long term," she said by e-mail.
She said the company in 2005 asked the FDA for a label change warning of complications linked with neck fusion procedures.
In conventional spinal fusion, surgeons fuse one or more vertebrae to reduce pain and stabilize the spine, using chips from a patient's pelvic bone. It is painful and can extend recovery time. BMP allows doctors to perform the surgery without harvesting bone from the patient.
Cahill and colleagues looked to see how the product was used after its 2002 approval. They studied 328,468 patients who had spinal fusion procedures from 2002 to 2006, including more than 17,000 performed with BMP in 2006.
BMP was used in 25 percent of spinal fusion procedures done in the United States.
They found no differences in rates of overall complications based on BMP use for fusions of the lower back or lumbar spine, or the upper back or thoracic spine. They also found no increased complications in neck surgery in which the incision was done in the back of the neck.
But they did find higher complication rates associated with anterior cervical fusion - spinal fusion surgery in which the incision was done through the front of the neck.
Complication rates in these procedures were about 7.09 percent in BMP-treated patients, compared with 4.68 percent in those who got spinal fusion without BMP.
Spinal fusion surgery was also linked with longer hospital stays, and higher costs across all kinds of fusion surgery, the team reported, with anterior cervical fusion accounting for the highest increases.
