The neuromythology of silicone breast implants

To define neurologic problems that may occur in women with silicone breast implants.

The association between silicone breast implants (SBIs) and certain rheumatologic disorders has been discussed since the 1980s. Recent uncontrolled case series have reported neurologic problems believed to be associated with SBIs.

Case series based on a retrospective data analysis of medical records from 131 women diagnosed as having a neurologic problem related to SBIs.

Data extracted from the medical records and analyzed included neurologic symptoms, neurologic examination findings, and a variety of laboratory studies. Symptoms, examination findings, and laboratory studies were analyzed using methods that would purposely overreport false-positive results in order to negate possible bias accusations. Finally, prior diagnoses made by evaluating physicians and thought to be related to SBIs were also recorded. An independent assessment was also made for alternative diagnoses using standards accepted by the medical and neurologic communities which did not necessarily accept a causative link between SBIs and their alleged complications.

Neurologic symptoms were frequently endorsed, including fatigue (82%), memory loss and other cognitive impairment (76%), and generalized myalgias (66%). Despite multiple complaints, most patients (66%) had normal neurological examinations. Findings reported as abnormal were mild and usually subjective, including sensory abnormalities in 23%, mental status abnormalities in 13%, and reflex changes in 8%. No pattern of laboratory abnormalities was seen, either in combination or in attempts to correlate them with the clinical situation. Laboratory studies appeared to be random without an attempt to confirm or correlate with a particular diagnosis. Diagnoses by physicians endorsing the concept that SBIs cause illness included "human adjuvant disease" in all cases, memory loss and other cognitive impairment ("silicone encephalopathy") and/or "atypical neurologic disease syndrome" in 73%, "atypical neurologic multiple sclerosis-like syndrome" in 8%, chronic inflammatory demyelinating polyneuropathy in 23%, and some other type of peripheral neuropathy in 18%. There was no coherence in making these diagnoses; the presence of any symptoms in these women was sufficient to make these diagnoses. Alternatively, after review of the data, no neurologic diagnosis could be made in 82%. Neurologic symptoms could be explained in some cases by depression (n=16), fibromyalgia (n=9), radiculopathy (n=7), anxiety disorders (n=4), multiple sclerosis (n=4), multifocal motor neuropathy (n=1), carpal tunnel syndrome (n=1), dermatomyositis (n=1), and other psychiatric disorders (n=3).

There is no evidence that SBIs are causally related to the development of any neurologic diseases. Methods of diagnosis that have been used to make the diagnosis of neurologic disease in these patients are contrary to standards accepted by the neurologic community. Several possible explanations exist for the neurologic and other symptoms in women with breast implants.