Brownlee and New York medical investigative journalist Jeanne Lenzer wrote specifically about the FDA and its approval and follow-up process for the Cyberonics vagus nerve stimulator—VNS—a device meant to prevent or minimize seizures in epileptics not responsive to medication, explained HealthDay.

According to Brownlee and Lenzer, the FDA is to blame for some 900 deaths they allege are linked to this device. Approved in 1997, the VNS Therapy System was approved for so-called "treatment-resistant partial seizures," said MedPage Today. But, despite the overwhelming number of deaths reported in patients implanted with the device since its approval, the device remains on the market and, according to the investigative team, neither the agency nor the manufacturer have looked into VNS' potential part in the fatalities.

"Although Cyberonics conducted post-approval studies, none of the studies submitted to the FDA included mortality data. The FDA did not specifically require Cyberonics to submit mortality data as part of the follow-up study, merely to 'characterize morbidity and mortality,'" they wrote, quoted MedPage Today.

The VNS sends electrical stimulus to the neck's vagus nerve by implantation under the skin; 60,000 patients throughout the world have been implanted for its use as a vagus stimulator and about 5,000 have been implanted for depression not treatable with medication, an approved use as of 2005, noted MedPage Today, citing Cyberonics. Of note, said MedPage Today, Brownlee wrote that the VNS was approved for depression despite the FDA's scientific panel's objection; Cyberonics maintains that the device is also appropriate for an array of other health issues from obesity to stroke and that patents are underway.

According to the authors, said HealthDay, it remains unclear what role the device had in their deaths. While post-marketing studies were conducted by Cyberonics, the agency never mandated a study into the connection between the device and the 900 deaths, said HealthDay, which the authors believe points to larger issues at the agency, added MedPage Today.

Last month, the FDA issued an apology for incorrectly approving the Menaflex knee implant despite its scientists' objections and admitted—following a Congressional investigation and internal agency probe—to succumbing to pressure from New Jersey senators and a congressmen, said HealthDay. The reviews revealed that key officials at the agency, even the FDA commissioner, pressured FDA staff to confer positive approval on the device, said MedPage Today. The FDA is working on quashing that approval, said HealthDay.

Also previously, MedPage Today wrote about issues with a spinal fusion device heavily hyped for disc degeneration, but which was linked to dangerous, sometimes near-deadly, complications in some patients.