The FDA is alerting health care professionals and patients about injuries and death associated with the use of an experimental procedure sometimes called “liberation therapy” or the “liberation procedure” to treat chronic cerebrospinal venous insufficiency (CCSVI).

Some researchers believe that CCSVI, which is characterized by a narrowing of veins in the neck and chest, may cause multiple sclerosis (MS) or may contribute to the progression of the disease by impairing blood drainage from the brain and upper spinal cord. However, studies exploring a link between MS and CCSVI are inconclusive, and the criteria used to diagnose CCSVI have not been adequately established.

“Because there is no reliable evidence from controlled clinical trials that this procedure is effective in treating MS, FDA encourages rigorously-conducted, properly-targeted research to evaluate the relationship between CCSVI and MS,” said William Maisel, M.D., M.P.H., chief scientist and deputy director for science in the FDA’s Center for Devices and Radiological Health. “Patients are encouraged to discuss the potential risks and benefits of this procedure with a neurologist or other physician who is familiar with MS and CCSVI, including the CCSVI procedures and their outcomes.”

The experimental procedure uses balloon angioplasty devices or stents to widen narrowed veins in the chest and neck. However, the FDA has learned of death, stroke, detachment and migration of the stents, damage to the treated vein, blood clots, cranial nerve damage and abdominal bleeding associated with the experimental procedure. Balloon angioplasty devices and stents have not been approved by the FDA for use in treating CCSVI.

Complications following CCSVI treatment can be reported through MedWatch, the FDA Safety Information and Adverse Event Reporting program.

The FDA also is notifying physicians and clinical investigators who are planning or conducting clinical trials using medical devices to treat CCSVI that they must comply with FDA regulations for investigational devices. Any procedures conducted are considered significant risk clinical studies and require FDA approval, called an investigational device exemption. In February 2012, the FDA sent a warning letter to a sponsor/investigator who was conducting a clinical study of CCSVI treatment without the necessary approval. The sponsor/investigator voluntarily closed the study.

The FDA will continue to monitor reports of adverse events associated with “liberation therapy” or the “liberation procedure” and keep the public informed as new safety information becomes available.