VNS
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A new report is renewing questions about the Food and Drug Administration's oversight of medical devices.

In a paper published in the British medical journal known as BMJ, investigative journalist Jeanne Lenzer and Shannon Brownlee of the Dartmouth Institute for Health Policy and Clinical Practice raise questions about the FDA's oversight, citing a device manufactured by Cyberonics, Inc., of Houston.

The device, known as a vagus nerve stimulator (VNS), is implanted under the skin and sends electrical impulses to stimulate the vagus nerve in the neck. It was approved in 1997 to prevent epileptic seizures on the condition that the company that Cyberonics carry out a post-approval study to examine the safety of the device. The company conducted a study, but did not include any information about deaths among patients who received the device, according to the report. In the 13 years since the device was approved 900 deaths have been reported, according to the report.

Lenzer and Brownlee say the device typifies the FDA's lax oversight of medical devices. In an editorial accompanying the paper, Jerry Avorn of Harvard Medical School calls on the FDA to strengthen its oversight of medical devices. Avorn said the agency should develop better ways to monitor their safety.

This is far from the first time questions have been raised about the safety of medical devices. In fact, in 2005 the FDA itself evaluated its post-approval studies and found more than one-fifth "couldn't be evaluated for quality because there was no record at the FDA showing they had ever been conducted," according to the report. The FDA has "since automated its records but many companies continue to submit data deemed 'inadequate' by the agency, while other studies remain unreported."

Cyberonics defended the safety of its device in a written statement, saying "VNS Therapy is an important treatment option for patients with epilepsy who have tried and failed multiple medications and for whom brain surgery is not an option." The company also said that none of the 900 deaths reported to the FDA were attributed to the device and that in fact patients who use the device are less likely to die than those who do not.

In a telephone interview, Karen Riley, a spokesperson for the FDA, agreed that there was no evidence that any of the 900 deaths were caused by the device, adding that the company's follow-up study also did not find any signs the device was causing any problems. Moreover, the agency had taken a number of steps in recent years to improve the monitoring of products after they had been approved, she said.