Risk assessments of explantations

Decisions on whether or not to explant require that the positive and negative effects of the available options are weighed against each other. If explantation is risky, it may be better to leave the implant in the body even if it does not function as desired or is for some reason no longer needed. Even if an implant has been recalled by the manufacturer, it is not self-evident that it should be removed. If explantation (with or without replacement) is a risky procedure, then it may be preferable to leave the recalled device in place [3]. After the Bjork-Shiley convexo-concave heartvalve was recalled in 1986, difficult decisions had to be made on which patients should have the implant explanted and replaced. Unfortunately, both options were connected with risks, which had to be weighed against each other [4]. A similar problem can arise for old pacemaker leads. Both alternatives—abandoning or removing the leads—can give rise to complications, and a decision on whether or not to explant the leads must therefore be based on an individual assessment of the risks associated with each of the options [5]. If an implant can put the patient at risk in magnetic resonance imaging (MRI), then that speaks in favour of explanting the implant when it is no longer needed [6, 7]. It is important that the risk assessments of explantations are wide enough, and not limited to immediate effects at the site of surgery. For instance, in decisions whether breast implants with manufacturing defects should be explanted, the risk of rupture or leakage from a retained implant may have to be weighed against negative psychological effects on the patient’s body image [8, 9].

When new and better implants become available, it can in some cases seem reasonable to explant and replace an old implant although it is still functioning. The potential advantages of a successful replacement will then have to be weighed against the risks of the intervention. These include the risk that the new device will not work satisfactorily, so that the operation results in worse rather than improved functionality. When this situation arises for patients with old cochlear implants in both ears, the risk can be mitigated by making the replacement in only one of the ears [3]. For implants that do not have a duplicate, the decision may be more difficult.

You are viewing: What Is Explantation

Some implants are intended only for temporary use, and may have to be explanted to avoid complications. This applies for instance to ureteral stents, for which complications can ensue if they are kept longer than the recommended indwelling time. Routines are needed to ensure that ureteral stents are not forgotten, and patients who do not keep appointments for removal will have to be contacted for a new appointment [10]. Similarly, orthopaedic implants that guide bone growth in children have to be explanted when they are no longer needed [11]. In some cases it may be an open question at the time of implantation whether the implant will be temporary or not. One example is LVADs (left ventricle assist devices), which have traditionally been used as bridge devices in patients waiting for a heart transplantation. In some patients an LVAD can function as a bridge to recovery, which means that the LVAD can be explanted when it is no longer needed [12].

In a letter to a plastic surgery journal in 1992, a surgeon criticized colleagues for unnecessarily removing breast implants due to “unfounded rumours” of a risk of immunological or malignant disease. He maintained that “[s]ome leaders of organized plastic surgery” condoned medically unjustified explantations as a means to “placate the legal profession and protect ourselves from litigation” [13]. If true, this would be ethically highly problematic, since it is hardly possible to defend that a medical intervention that does not benefit the patient is performed in order to benefit the physician.

The responsibility of manufacturers

Manufacturers of implants have a considerable responsibility for reducing the need for explantations. Improvement is needed in two major areas, namely service time and quality control.

In practice, the major issue concerning service time is battery depletion. More and more patients receive battery-driven implants such as pacemakers, cardioverter defibrillators, ventricular assist devices, and a wide variety of neurostimulators, chemical sensors, and drug delivery systems. Batteries are an increasing portion of the volume of implants, since the other components have become smaller [14]. Implant replacement or battery exchange usually entails invasive surgery and therefore also a risk of infection. This makes it important to prolong the service time of implanted electrical devices [15]. There are several ways to achieve this. Batteries can be improved, and devices can be made more energy efficient. Furthermore, several methods have been proposed for wireless power transfer from outside the body to medical implants. Potential means of power transfer include electromagnetic induction, radio waves, and ultrasound waves [14]. An enzymatic glucose/oxygen fuel cell that draws its fuel from the blood stream has also been proposed [16].

However, the current economic incentives structure impedes the development of devices with a longer lifetime. Implants that last longer, thereby reducing the risks associated with explantation and replacement, could reduce the profits of manufacturers and profit-driven healthcare providers. This may be the reason why pacemakers are not built to last as long as would be technologically possible [15, 17]. The major manufacturers put new pacemaker models on the market about every 6 or 12 months, often with new, not very urgent functionalities that draw upon the battery [18, 19]. It has been proposed that pacemakers should have “only the pacemaker generator features that have proven clinical benefit” in order to increase their service time [17]. This would seem to require a change in the incentives for development and marketing of these devices.

Read more : What Kind Of Lumber Is Good For Rainy Weather

The other major responsibility of manufacturers is to minimize the number of implants that have to be explanted and (usually) replaced due to device failure. In order to achieve this, the quality assurance system for implants has to be improved. What is needed is essentially the same process as for pharmaceutical drugs, namely the combination of (1) a series of pre-market clinical trials on a limited number of patients, showing that the device actually works and does not have frequent serious side effects, and (2) continued post-market studies in order to discover problems that were not observed in pre-market trials, for instance due to rarity, patient selection, or the limited time of observation. Full transparency of these studies is needed to ensure that independent researchers can analyze the data and compare the patient benefit of different products. But unfortunately, these procedures are still much less developed for implanted devices than for drugs. This applies not least to the European Union, whose regulatory system delegates approvals to pro-profit certification firms and keeps injury and malfunction reports secret with the justification that they are commercially sensitive for manufacturers [1].

In 1993, a group of orthopaedic surgeons complained that manufacturers “scarcely let a year go by without introducing a ‘new improved’ joint replacement which offers hitherto undreamt of (and unproved) advantages over the older designs”. Some of these are later “quietly withdrawn from the market” when they have proven to be substantially inferior to previously available models. The authors called this a “fashion trade” that “is causing patients unnecessary pain and distress” through early failures that lead to explantation and replacement of the defective implants [20]. The “fashion trade” still persists because the economic incentives still encourage it. Fewer but more thoroughly tested models of joint replacements would have increased patient safety. The situation is similar for other implants, not least pacemakers, which also have a short production life-cycle due to frequent changes [21]. Just as for follow-up drugs (“me-too drugs”), it is important for regulators to distinguish between products that contribute to incremental improvement and products that offer no demonstrable advantages over already available models [22].

The need for registers of patients with implants became acute after the Poly Implant Prothèse (PIP) breast implant scandal in 2010. Due to the lack of such registers, it was difficult to collect epidemiological data to determine what risks these implants were associated with. It was also difficult and sometimes impossible to identify affected women in order to offer them medical check-ups and, if needed, explantation. In several countries this experience led to the introduction of registers of patients with breast implants [2, 23]. There is a similar need of registers for other implants, such as artificial joints [20], growth rods for childhood scoliosis [24], and intraocular lenses [25].

Elective explantations

Some patients have required explantation of an implant despite being told that this would be detrimental to their health and perhaps even life-threatening. Such cases appear to be rare, but they tend to be difficult to deal with ethically. They involve a conflict between two basic principles of medical ethics. From the viewpoint of patient autonomy, a patient with decisional capacity should be able to decline or discontinue a treatment. If only this principle is taken into consideration, then it can be argued that a patient always has the right to have an implant removed, whatever the consequences. However, according to the principle of non-maleficence, physicians should not perform harmful interventions on patients. If a patient asks for a medically harmful explantation, then the two principles will clash. The conflict is exacerbated by the fact that the explantation of an implant is both an intervention (as is all surgery) and the discontinuation of an intervention. Qua intervention it is disallowed since it harms the patient, but qua discontinuation it is required since the patient has a right to end her treatment. In the most extreme cases, such as a wish to have a total artificial heart removed or deactivated, complying with a patient’s request would be tantamount to killing her [26].

Two recent cases from the literature illustrate the dilemma. In one case, a patient with a unilateral cochlear implant asked to have it removed in order to strengthen her identity as a member of the Deaf culture. She was offered deactivation, or partial removal that would allow for later reimplantation, but neither of these alternatives would satisfy her. She was informed that the explantation she required would make reimplantation impossible, and that a later implantation in her non-implanted ear would be impossible due to ossification. In spite of this, she did not change her mind. After extensive consultations, the implant was removed [27]. The explantation surgery was fairly uncomplicated. The decision might have been different for an explantation that could pose larger risks of complications, such as the removal of a brainstem implant or vestibular implant.

The other case was a patient who asked to have his implantable cardioverter defibrillator (ICD) removed, since it was aesthetically unattractive and he did not believe he needed it. Many attempts were made to convince him that it had already saved his life twice and that without it, he was likely to die soon due to a cardiac arrest. Nevertheless, he insisted to have it explanted, and after extensive consultations, it was removed. Four months later, he had a cardiac arrest. He was lucky to have a person close by who could offer immediate assistance, and he was brought to an intensive care unit where his life was saved. He then demanded and received a new ICD [28].

No simple solution to the ethical dilemma illustrated in these examples seems to be available. The principles of autonomy and non-maleficence have to be weighed against each other, and the outcome of that weighing will be different depending on what is at stake in each individual case. However, it should be observed that in cases when an explantation would predictably lead to the patient’s death, the intervention is highly problematic even with the patient’s consent [29, 30]. In many countries it can be a criminal offence. The vast majority of patients whose life could by ended by explantation or some other intervention by a physician are in a position in which they could have ended their lives by their own means. A wish that a physician ends one’s life should be seen in that perspective [31, 32]. An adequate medical response to a wish to commit suicide should include a psychiatric assessment and, if indicated, an offer of psychiatric treatment. Consultation with a clinical ethicist is also highly advisable in this type of cases.

Although this dilemma has no general solution, measures can be taken to reduce the number of cases in which it has to be dealt with. Patients offered an implantation should receive adequate information about potential future interventions, including explantation. If it can be foreseen that explantation would be considered a breach of professional ethics, and would therefore be denied, then the patient should be informed of this. As noted by Owoc and coworkers, there is a need for explantation guidelines to “assist in clinical decision-making and patient counselling and education” [27]. Even with such guidelines, consultations with relevant specialties, including clinical ethics, will be needed before decisions are made on elective explantations that are medically contraindicated.

Ending clinical trials

Read more : What Is A Blue Warrant

Clinical trials with implants give rise to two complex issues involving explantation, namely (1) how to deal with a participant’s wish to leave the trial and have the implant removed, and (2) whether it is acceptable to remove an implant after the trial if the patient wants to keep it.

One of the generally accepted principles of research ethics is that participants in a clinical trial have the right to withdraw their informed consent at any time, and that the withdrawal should be respected and implemented by the researchers [33]. Just as a patient with decisional capacity has the right to end a clinical treatment, a subject in a trial has the right to end the experimental treatment. In a recent article, a group of clinicians and ethicists recognize that research participants “arguably have a right of self-determination to refuse the continued presence of an invasive device in their bodies”. However, they maintain that this must be weighed against “the feasibility of imposing additional burdens on the research enterprise”. They conclude that “researchers should not be obligated to cover costs related to device removal if it is incompatible with the sustainability of the research enterprise that initiates the relationship that grounds the obligation in the first place” [34]. This is a remarkable argument, since it makes the basic rights of research subjects in relation to researchers secondary to the economic viability of the research project. A clinical trial should not be performed if lack of economic resources would prevent participants from exercising the rights, including the right to leave the trial at any time, that are standardly required and implemented in clinical trials.

But there is an exception, namely the comparatively unusual case of trials of a life-sustaining technology. One example is trials of total artificial hearts. A request to withdraw from such a trial and have the device explanted would be equivalent to a request to have one’s life ended. This is essentially the same situation as when a patient requires the removal of a life-sustaining device that was implanted in a non-experimental setting. The above considerations of the latter case apply in a clinical trial as well. Current regulations and ethical principles that stipulate an exceptionless right to leave a trial do not seem to have taken this unusual case into account [35]. (However, clauses concerning explantation and deactivation are included in a published consent form for a trial with total artificial hearts [36].)

For some participants, a clinical trial can be a short period of improved health, followed by deterioration when the experimental treatment ends. This has been the case in some drug trials, such as trials of HIV/AIDS treatments in developing countries. It now seems to be generally agreed that this is an unacceptable practice, and that funders and organizers of clinical trials have to make sure that participants receive adequate post-trial treatment [37]. For implant trials the situation can be even more drastic, since terminating the treatment at the end of the trial will typically require either an explantation or abandoning a non-functional device in the body, both of which can involve risks.

One problematic example is the Dobelle project, which started around 1975 and ended in 2005 [38]. The subjects were blind people who had electrodes implanted on the surface of the visual cortex. These electrodes were connected to converted camera images that gave rise to phosphene patterns. Some of the subjects were able to use these patterns for orientation or object detection. They felt a profound loss when they were deprived of these abilities due to device failure or the termination of the study. (This study also had other questionable features from an ethical point of view. Subjects had to pay up to 200,000 USD for participation, and although the project was American, the implantations took place in Portugal due to lack of FDA approval.)

A recent article described a trial with deep brain stimulation against treatment-resistant depression. Some participants who had experienced an improvement with the implant wanted to retain it after the end of the trial, but this was only possible if they could pay for it themselves or some charitable donor could be found. The research project only covered the costs of explantation or a rechargeable battery. According to the authors, “[t]his is the norm, not the exception, in brain-implant trials. In fact, most sponsors do not cover the cost of device removal or a rechargeable battery” [39]. Thus, these trials have the withdrawal of beneficial treatments that patients desire as a planned and foreseen consequence. This does not seem to be compatible with the CIOMS/WHO guidelines, according to which researchers and sponsors of trials have to make plans for “providing continued access to study interventions that have demonstrated significant benefit” [40]. Joseph Fins has proposed that the neuromodulation community should adopt an ethical principle of non-abandonment. “After a subject is implanted” in a trial, he says, the investigors and sponsors “incur a clinical responsibility to provide on-going care and a fiscal responsibility for any associated costs. It is a breach of professional ethics to do otherwise” [41]. The same principle can be applied to other implants. An experimental implant can be explanted because the patient does not need or want it any more, but it is not ethically acceptable to explant it because the patient cannot pay for continued clinical use. A clinical trial with implants should not be performed if it would result in patients being abandoned, or forced to have functional implants explanted, for economic reasons. Performing such studies would be at variance with the Helsinki declaration, which requires provisions to be made for “post-trial access for all participants who still need an intervention identified as beneficial in the trial”. It would also endanger public trust in medical research [42].

Explanted implants

Just as removed organs or parts of organs are sent to pathology, investigations of explanted implants can provide useful information both in the individual case and for general medical and technological improvement. This applies in particular to failed implants, but also to devices that are explanted for other reasons than technical failure. The evaluation of an explanted device should be made on the basis of relevant clinical information about its functioning and the patient’s experiences [43]. Although detailed methods for the analysis of retrieved implants have been developed, such analyses are still not performed in the systematic way that removed tissues are sent to pathology [44,45,46].

Explanted but still functional implants can in some cases be reused [47]. In several industrialized countries, removed pacemakers with sufficient battery capacity are collected for use in low- and middle-income countries. Some of these pacemakers are explanted in the clinic, whereas others are removed post-mortem, which is necessary to avoid explosions in crematoria. After evaluation and sterilization, these pacemakers are sent to cardiology clinics in low- and middle-income countries [48]. The need for pacemakers is large; one charity organization estimates that about one million people a year die for lack of a pacemaker [49]. The ownership of used pacemakers has been cited as a problem that can prevent the reutilization of pacemakers. In the 1990s, when explanted functional pacemakers were reused domestically in industrialized countries, the legal situation shifted between countries. In Sweden, the implanting medical centre was considered to own the device, whereas in Canada and the Netherlands it was considered to be the property of the patient, or, after death, the patient’s heirs [50, 51]. Today, it is generally assumed that informed consent from the patient or family is required, and consent forms are collected for all pacemakers [48].

Source: https://t-tees.com
Category: WHAT