October 29, 2019

We continue to receive many inquiries from women who have had Filshie clips implanted as a form of sterilization who complain that they suffered various allergic reactions to the materials contained in Filshie clips, including but not limited to fatigue, pain, and what has been deemed as post implant syndrome (PIS) that includes autoimmune syndromes and hypersensitivity reactions. A recent publication by the FDA (September 2019) entitled “Biological Responses to Metal Implants” may shed some light on the biological basis for such claims.

In the Introduction to the report, the FDA states: “In the past several years, FDA has undertaken extensive postmarket reviews of data associated with specific metal-containing implants after safety concerns were raised including for metal-on-metal (MoM) total hip arthroplasty (THA) systems and the Essure System for permanent birth control … For the latter (Essure System), the patient-reported associations with broad systemic signs/symptoms (considered by some to represent “allergic” or “hypersensitivity” reactions) are less clear. Together, these issues have raised questions about how an implant or insert recipient’s immune system may respond to the presence of metal in/from the device and to what degree, if any, that response may produce clinically significant signs, symptoms or adverse outcomes. This paper presents FDA’s review of currently available scientific information related to metals and their uses in medical implants, with focus on how metal materials are impacted by a physiological environment, expected and potential immune system responses to the metal associated with an implant, as well as subsequent clinical manifestations.”

The report states: “Some metals which are commonly found in implants, such as copper, zinc, iron, manganese, and cobalt are examples of elements that are essential to our normal biological functions. These metals are required only in small amounts and are critical to the structure and/or function of many proteins and enzymes. Abnormal function may occur, along with associated signs or symptoms, when there is too little (deficiency) of an essential metal. Other metals used in metallic implants such as nickel, titanium and aluminum are nonessential for human health. Both essential and nonessential metals when present at sufficiently high concentrations can disturb normal biological functions and result in cellular stress responses known as metal toxicity. Metal toxicity may affect various tissues including the kidney, liver, heart, the immune and nervous systems.”

“It should be noted that the toxicity information is typically based on exposure to the element through dietary intake and/or occupational/environmental exposure (e.g., dermal contact, inhalation). However, since the in vivo implant environment and the form/composition the metal appears in that environment (e.g., chemical form (valence), physical form (particulate vs ionic), dose released over time, etc.), may be different or unknown (Brown et al. 2015), the degree to which published toxicity data can be extrapolated to a patient implanted with a metal-containing device is not known.”

“A patient’s overall response to a metal implant consists of responses both at the implant location as well as systemically. Immune cells are primarily responsible for these responses. Immunological cell responses are either innate (requiring no prior exposure) or adaptive (acquired only after an antigen is encountered). Both cell responses are involved with adverse reactions associated with metal implants … Specific local tissue responses depend on the device or biomaterial and peri-implant tissue type as well as patient-related characteristics. Further research is needed to understand the underlying molecular mechanisms. Understanding the underlying molecular mechanisms is the first step to develop pre-operative screening to distinguish patients at greater risk for adverse reactions. It is also essential for identifying clinically-detectable signs that can predict post-operative metal implant failure.”

“The typical response to metal implants is characterized by rapid inflammation and innate immune response that equilibrates to steady state within one to two weeks following implantation. This resolution is critical to limiting tissue pathology and precluding subsequent implant failure.”

“The clinical response to metal implants is complicated and no simple explanation for the wide variety of reported adverse responses is available. Despite commonly used terms such as “metal allergy” or “metal hypersensitivity”, current published evidence suggests that allergic mechanisms alone do not explain most responses to metal implants. Harmful responses, when they do occur, are likely the result of device, biomaterial, and patient-related factors. Individual patient susceptibility plays an important role in the outcome. Recent issues with metal-on-metal orthopedic implants and gynecological metal implants highlighted concerns about the potential safety of certain types of metal implants. A broad spectrum of clinical responses have been reported and often more than one response can arise in the same patient … recent issues with metal-on-metal (MoM) orthopedic implants and gynecological fallopian metal implants has heightened concerns about the potential safety of metal implants in general.”

While Filshie clips are not specifically discussed in the report, the FDA does discuss the Essure device, which is inserted transvaginally into the fallopian tubes and is intended to induce a moderate inflammatory response resulting in fibrosis and subsequent tubal occlusion: “Unlike the lack of definitive evidence on autoimmune conditions, there is evidence linking Essure to Allergic Contact Dermatitis (ACD) … these data might suggest that Essure-related “hypersensitivity” is not necessarily allergic by nature and that a true allergy is rarely a cause for device removal (Zurawin and Zurawin 2011), thus implying different – non-allergic – pathogenetic mechanisms underlying pain and other Essure-attributed adverse outcomes. However, the significant limitations of a passive reporting system such as the MAUDE database should be considered in interpreting the authors’ conclusions … With the increasing awareness and concerns about possible reactions to constituent metals, a more nuanced evaluation of the entire spectrum of device/biomaterial-specific ARMDs [adverse reaction to metal debris] is needed as a prerequisite for developing adequate diagnostic and therapeutic measures aimed to improve long-term implant safety.”

The FDA report states: “Gaps exist in both our knowledge base and the available tools that are necessary to understand and assess biological responses to metal implants in clinical and regulatory contexts. One of our fundamental challenges is that the mechanisms underlying the biological responses to metal implants are not fully understood. Because of this, it is difficult to distinguish between the device- and patient-related factors in addressing safety and effectiveness concerns. Overcoming this challenge is necessary to help manufacturers design appropriate pre-market studies and develop appropriate acceptance criteria. Further, there are only a few validated tests that assess adverse responses to metal implants and currently there is no clear evidence or agreement on how these tests should be used for clinical and regulatory decisions … The clinical response to metal implants is complicated and no simple explanation for the wide variety of suggested responses is available. These contexts are highly diverse: patient history, genetic background, variations in environment and lifestyle, and underlying disease and comorbidity … Although local and systemic responses are known to manifest in patients with metal implants it remains unclear if metal “allergy” is a cause or consequence of device failure … Harmful responses are often the result of device, biomaterial, and patient-related factors. Individual patient susceptibility likely plays an important role in the outcome … Additional characterization of the nature and frequency of adverse reactions to metal implants is needed.”

“The main challenge in both pre- and post-market phases of regulatory review is the lack of adequate study endpoints and diagnostic and/or prognostic tools which reliably predict clinical responses. The threshold for detecting subtle but consequential biological responses which may constitute signals in our post-market surveillance systems remains to be determined. Currently, it is extremely difficult to determine whether symptoms are related to the implanted device or other causes. Predictive assessment of the proinflammatory potential and subsequent tissue remodeling remains a major challenge affecting real-world performance of implantable devices and biomaterials. Real world evidence and patient registries may be helpful in this regard.”


If you or a loved one suffered injury or other harm from Filshie clips in the United States, you should promptly find a medical malpractice lawyer in your state who may investigate your Filshie clip claim for you and represent you in a Filshie clip medical malpractice and/or product liability case, if appropriate.

Visit our website or call us toll-free in the United States at 800-295-3959 to find medical malpractice attorneys in your U.S. state who may assist you with your Filshie clip claim.

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