Book Review: The Danger Within Us: America’s Untested, Unregulated Medical Device Industry and One Man’s Battle to Survive It

In The Danger Within Us: America’s Untested, Unregulated Medical Device Industry and One Man’s Battle to Survive It, investigative journalist Jeanne Lenzer, outlines what she perceives as corruption within the medical device industry. Lenzer emphasizes that the FDA lacks stringent guidelines for proving safety and efficacy prior to device approval, and that significant publication bias exists given that private industry funds much of its own device research.

Throughout the book, Lenzer focuses on an anecdotal account in order to emphasize the case she makes – that of a man with epilepsy named Dennis Fegan, and report of his near death experience as he experienced intermittent episodes of asystole (heart stoppage) following Vagus Nerve Stimulator (VNS) device malfunction.  Lenzer reports that Cyberonics (the company that introduced VNS in the U.S.) failed to report this patient’s experience until years later, and assumes this was purposeful.


For those who aren’t familiar, the VNS device is surgically attached to the left vagus nerve. The vagus is the tenth of the twelve cranial nerves in the human body, and controls parasympathetic innervation (aka the ‘rest and digest’ nervous system) of the heart, lungs and digestive tract. More specifically, the parasympathetic system serves to conserve energy in the body, and so is involved in lowering heart rate and promoting intestinal activity. It also sends feedback information from the body to the brain about certain aspects of the body’s state. VNS devices are commonly used for people with severe epilepsy who do not respond to treatment with medications and who are not candidates for epilepsy surgery (in which the part of the brain causing seizures is surgically removed). In 1997, the FDA approved VNS use in patients with drug-resistant epilepsy who were not candidates for epilepsy surgery.

Lenzer points to a huge discrepancy of reported deaths in patients with VNS between the FDA’s reporting system and a private reporting system created by a former FDA consultant. Between 1997 and 2016, the FDA reported approximately 2,006 deaths while the private program recorded 11,223 deaths. Given this large discrepancy, Lenzer assumed Cyberonics has something to hide from the medical community regarding the risks of VNS. Although that may be the case, she insinuates that the VNS is causing the deaths (although she points out briefly that causality should not be implied). She doesn’t mention that patients who are implanted with VNS are those with severe epilepsy, who are already at a high risk of death because of their uncontrolled seizures. Moreover, despite all the VNS studies she references in her book, she fails to reference a large cohort study published in 2000 that showed no difference in mortality from unexplained death between medically refractory epilepsy patients implanted with VNS and those without VNS.


Lenzer writes that the only primary outcome measured in initial clinical trials was a reduction in seizure frequency and that trials failed to provide data on secondary markers including death and adverse reactions. However, she fails to mention that the studies clearly reported that monitoring revealed no heart rhythm/rate abnormalities or severe complications in any of the patients. Lenzer does make a good point however by pointing out that the initial trials were flawed in that they did not have a control group that consisted of patients receiving medical therapy only.

Ms. Lenzer strongly enforces the importance of statistics and de-emphasizes the power of human anecdotal experience, but fails to recognize that she herself emphasizes an anecdotal experience to highlight her arguments.  Never once does she acknowledge that the patient’s experience with his VNS (although still important and not to be taken lightly) is exactly that - an anecdotal account of a rare event that is already cited in the literature as a rare complication of VNS. Furthermore, Lenzer reports that Mr. Fagan discovered through his own research that 20-33% of VNS patients have worsening of seizures, but she fails to confirm where he found this data or mention any references to these findings. Despite emphasizing the importance of hard evidence and data, Lenzer’s lack of confirmed support for such statements seems contradictory.

Lenzer's writing about epilepsy management makes it clear that she lacks formal training in the field of epilepsy.  She suggests that the seizure-reducing effects seen in the initial VNS studies might be due to chance because a ‘sizable number of patients with epilepsy undergo spontaneous remission.’ What she doesn’t comment on is that patients who are implanted with VNS devices are those with severe epilepsy whose chance of spontaneous remission is infinitesimally low. Thus, while the effects of VNS still may be due to chance statistically, it is unlikely that sudden spontaneous seizure remission in VNS patients is attributable to the phenomena she mentions above.  Furthermore, VNS is implanted in patients with severe, drug-resistant epilepsy who already are at a high risk of death from their seizures. VNS is implanted when benefits of reducing seizures are deemed to outweigh the risks of rare complications and for many patients, VNS has served as a very effective tool that has saved lives and improved quality of life.

Nonetheless, Lenzer does make a few valid points in her book. She discusses the potential for corruption within the FDA, especially with regard to medical device oversight and approval. While the FDA should be an agency that is not biased or influenced by the private medical industry, she points out that this is often not the case. Specifically, she comments on how the medical device industry has been allowed to lobby and influence FDA decision-making. She also points out that political leaders, who can be influenced by financial interests from the medical industry, have replaced civil servants in FDA leadership positions. Some of these appointed politicians who have no expertise in medical research have overridden unanimous votes of FDA scientists in order to approve medical devices.

I found the book to be a useful reminder to clinicians of the importance of evaluating scientific literature with a critical eye, and that not all FDA-approved devices are appropriately tested for safety prior to being placed on the market. While Lenzer makes valid arguments about the potential for corruption within the medical device industry and the FDA, she could have used a better example than VNS, as the negative experience of the patient described throughout the book is extremely rare and there is no literature to suppport her claims that VNS commonly causes cardiac arrhythmias. Instead, her emphasis of this anecdotal report and her invalid assertions about epilepsy management lessen the credibility of her arguments.

Despite these shortcomings, I think she touches on some very real problems within the medical device industry that are of particular importance to the neurology community given the rise in implantable stimulation devices being used for a number of neurological disorders.