In May, researchers at Stanford University released a study that finds strong evidence linking the medical product Infuse to male sterility. Infuse, produced by the company Medtronic and used in spine surgeries, is a biological protein that is used to stimulate bone growth. Research now indicates that it may have an inflammatory effect on the nerves and tissues surrounding the spine, specifically those that determine the flow of semen. It is believed that Infuse causes retrograde ejaculation, which occurs when sperm and semen enter the bladder instead of the urethra. The retrograde ejaculation condition is known to cause male sterility.
The study carried out at Stanford University involved 243 patients who underwent spinal fusion surgery between 2002 and 2004, in the timeframe after Infuse was approved for use. The researchers compared rates for complication between patients who had received Infuse and those who had not. More than 7% of patients who had received Infuse suffered retrograde ejaculation whereas only 1% of patients who had not receive Infuse treatments suffered the same complication. These results mirror data that was originally submitted to the FDA by Medtronic, the maker of Infuse, itself.
The findings of the Stanford research team are particularly troublesome because they provide independent support to a long-held suspicion about the sterility risk that Infuse creates. It appears that doctors using Infuse over the last 10 years actually knew of the possible complication, based on Medtronic’s own FDA reporting, yet did not advise patients of the risk and failed to include information about it in their own research articles.
For example, over nearly 10 years, Dr. Thomas A. Zbedlick and his company, Taz Consulting, have benefited enormously from their use of Medtronic products, receiving more than $23 million in royalties and other payments from Medtronic. While these payments were not directly connected to Infuse, they are directly related to a product used with Infuse. Zbedlick and other doctors deny that there is any relationship at all between Infuse and retrograde ejaculation. Zbedlick is also the editor of a medical journal which published research articles on Infuse that neglected to highlight the possible complications and risk of male sterility it presents.
Medtronic is now under investigation by the U.S. Department of Justice in relation to its marketing of Infuse.