¹⁾

As we can read with wide open eyes in some disbelief, the academics were at it again [1].

To start with, let us keep one truth in mind:

Everyone that confuses correlation with causation will die.

While that seems to be some really bad news, the other bad news is that everyone else also will die. Eventually. And so while we wonder whether the pesky “Last Christmas” tune is meant to also remind us that climate change may be real, the phantom pains are real, hence their name.

What is not happening so much in reality is the imaginary correlation-causation sharknado that is being pulled of while we watch in awe as these Last Christmases all pass in front of our eyes and the academics recommend we get our brains rewired. The recommendations are not them theirs, which would anyways be something I’d submit to the ethics committee first. No. We. Ours. Rewired. And their conclusions weren’t checked whether they were ethical. Or, correct. Because they will die while confusing correlation and causation to their end. Which is tragic in its own way. While we keep wondering, to our own end, tragically as well. What we are dealing with therefore is no less than a classical drama: everyone loses. We lose the illusion of academia providing “the” therapies, and they lose the illusion of always being right.

Let us get the facts straight first.

Being asymmetric does cause pain

Asymmetry, which one has, as right below elbow amputee or as other unilateral amputee, is to be regarded as a direct cause of serious orthopedic problems due to asymmetry on one hand and due to overuse on the other. Maybe not right away, but, also depending on the type of sports and training that one does, depending on daily and singular activities, in due time. The average active myoelectric prosthesis user (a contradiction in terms) will probably have five to eight years before problems tend to start to hit hard.

The unilateral reduced load of the spine on the amputated side due to lighter weight of amputated arm and underuse of that arm, and the unilateral overload of the spine on the other side due to unilateral use and overuse of the arm does not just (immediately, now) cause asymmetric spine loading and an increased risk of falling – it also leads to an increased risk of orthopedic problems over time.

These include significant neck pain, which affects about 39% of the population with arm amputations and increases with age, with a prevalence of approximately p ∼3.5+0.884×Age  [2].

Unilaterally upper limb amputees are more prone to developing musculoskeletal manifestations and overload syndromes due to heavy loads on one hand and due to repetitive movements on the other, and overuse of the unaffected side during daily activities ensues.

This overuse furthermore may lead to more adaptive and compensatory movements, resulting in changes in the shoulder girdle complex and spinal kinematics. These alterations in body mechanics may cause chronic back and neck pain, which in turn significantly affect functional performance, overall health, and quality of life. Additionally, they can interfere with prosthesis adaptation and impair both physical function and psychosocial well-being, negatively impacting long-term patient outcomes [3].

Asymmetry and related cervical spine issues are prevalent in unilateral arm arm amputees: “in upper limb amputees pain in the cervical spine was commoner than in the other groups” [4].

Musculoskeletal pain radiates and refers as phantom pain

Asymmetry induced musculoskeletal pain will exacerbate phantom pains, often massively. The bouts of phantom pain I had with severe hard tense back pains were absolutely ridiculous.

A lot of referred pain zones related to particular muscles are described in relevant literature [5]. Thereby, neck muscles (scaleni, trapezius) are to be considered with priority. Degenerative changes are less likely to be at the root than myofascial issues [6].

Muscle trigger points from overly tense muscle contractures are typical causes for referred pain [7, 8, 9]. A subset of that may be nerve compression, which is a typical source of neuropathic pain [10].

I use my mechanical massager to hammer down on these muscles’ cervical spine attachments and their muscle bellies as far as possible, for as long as possible – and these massive jolts of phantom pains tend to be – at once – gone.

No one else tells you that, certainly not the doctors or researchers.

Wearing a prosthesis proactively reduces phantom pain if it levels out asymmetry, compresses the stump and does not cause skin irritation

Compression

First of all, a good prosthetic socket compresses the stump.

One study of 31 amputated limbs [11], excluding amputations for vascular disease, only containing tumor and trauma as indications for the amputation, reported a high correlation of vascular abnormality and phantom pain. When they then raised body temperature without treating or removing the vascular problems, as my experience above, phantom pains would rise.

“The vascularization of the stumps was found to be profuse, sparse, or of an intermediate form. In some instances, the arteriographic appearances were probably pathologic, consisting of sinuous vessels and persisting venous networks. Pathologic vessels of this type were seen only in patients with pain. In those without any form of discomfort, the vascularization was as a rule sparse-unless skin infection was present or the stump had been treated with skin grafting. Skin temperature measurement showed the skin of the stump to rise in temperature when body temperature was raised in patients with phantom pain, while in those without current phantom pain the skin temperature usually did not rise” [11].

One interesting other paper to recommend is that of Reinhardt (1972) [12].

There, it appears that an overarching pathology seemingly is found in arteriovenous anastomoses. People with these in their stump, regardless of other vessel abnormalities, almost always had complaints of pain in their residual limb. That paper also summarizes that the majority of people without symptoms of phantom pain have normal vasculature in their stump, whereas the majority of people with phantom pains have pathological vasculature in their stump.

The problem of such vascular abnormalities has been studied more extensively in lower leg varicosis [13]. There, congestion, and burning pain, are all there, described in detail.

Activating the stump by using its muscles helps to reduce stasis as well [14, 15].

There is no other way than to regard vascular problems as one highly relevant clear peripheral cause for stump problems.

No skin irritation

Skin damage, rashes, irritation, particularly also as conveyed unto the stump by the suspension, is painful and a known problem that exacerbates also phantom pains.

Functionality

The theoretically protective function of an arm prosthesis can only become manifest if it is strictly functional with regard to the specific application such that it effectively relieves the other arm [16].

There, and for all real work, body-powered prostheses also and simply are just better at accomplishing such work [17] [link].

Daily wearing of a weight-balancing prosthesis is reported to be a technical prerequisite: “an abnormal body posture is particularly noticeable during clinical examinations of the arm when the amputee does not wear their prosthesis” [18].

“The asymmetries that occurred, which were significant in the depicted muscle groups, were completely reversible with full weight-loss compensation” [18].

“The type and use of the prosthesis impacted clinical changes insofar as patients who wore heavier prostheses exhibited higher weight-loss compensation and consequently lower manifestations of clinical parameters. This must be considered before deliberations on orthopedic technical care” [18].

In this context, it should be added that myoelectric arm prostheses have demonstrably no effect on improving postural damage in arm amputees [19].

Also, arm amputees themselves do not seem to believe that wearing a prosthetic arm every day helps them too much [20], most likely until they hit overuse and neck/pain a few years later, so an early medical prescription, clear and understandable explanations to the patient, and accompanying users through difficult times, to improve compliance and adherence, may be relevant adjuncts to starting off with a prosthetic arm, whereas it must be so it that can be worn every day for months and years, not just hours or days.

Reverse causality?

What our blood young academic shooting stars [1] seem to have overlooked are simple well argued competitive correlations for their own correlation-causation sharknado.

• People with bad posture and bad stump skin cannot wear a prosthesis comfortably. They would have to go through a phase of closely supervised mini steps.
• People with bad phantom pains will be less likely to wear a prosthesis. A frequent problem, neuroma, will easily add to any asymmetry caused phantom pain exacerbations. Just wearing a prosthesis may result in a bad fitting. So that is a vicious circle as well.
• Stumps are not per se load-bearing or good for a prosthesis. People who have stumps that are difficult to fit due to skin, shape, or other issues, are more likely to not wear a prosthesis, and thus suffer consequences of asymmetry and overuse and report phantom pains.

What is suggested in academic study and how that is problematic:

The authors claim that a natural appearance of a prosthesis that necessarily is electric in that it has electric feedback systems built in such as described in another study [21] is the requirement for reducing phantom pains.

Although the direction of effects has to be examined in prospective studies, there is some evidence that more naturalistic prosthetic devices equipped with sensory feedback both enhance prosthesis ownership experiences and reduce PLP levels. Identification of the underlying mechanisms of the relationship of pain, prosthesis use, and body perception could facilitate the development of better prosthetic devices that potentially reduce postamputation pain.

The reduction I get from phantom pain is that I wear a hard body-powered mechanic arm that provides minimal but sufficient tactile feedback and that protects and encases my stump, and that otherwise performs beautifully for that one goal that justifies that prosthesis’ existence: the disability can take a back seat and not be important. I can occupy myself with other things, all day long, for weeks and months on end. The prosthesis is there to serve, not to be the center of everyone’s attention. That is the huge fundamental aspect that generates the difference that we have, me, and these junior researchers with their study where they seem to think that only the most human like appearance with a maximum of electronic parts can be of use for the amputee that permanently focuses on their amputated arm. The goal I see as relevant is that the whole thing needs to move out of the attention core, it needs to stop blocking everyone’s vision. And that is where academic work generally blocks prosthetic arm development: every little true academic achievement strives to be a narcissistic perversion in its own right, as that is how the whole academic system works. There, we push towards an idiosyncratically egotistic definition of truth and innovation, we tag achievements to single people that then are awarded single people awards such as becoming professor, and while all professors are hired as individuals, they even have a further degree of excellence, the professor “ad personam” (mind you, there is no professor “ad cohortem”). So in order to provide the necessary stepping stones that are planted into free air, that allows such an academic career to elevate itself, a disjunction from realities is a quintessential necessity. The reason why they can always have new ideas is that they have removed the locking belt that so far if ever has tied them to our sad sweaty smelly and fragile realities.

The authors persevere in claiming and promoting that the center point for their cause is the brain of the amputee that is rewired due to that, whereas the prosthesis that is welcomed by that brain as own body part remedies that. This is neither new [link] [link] nor is it anywhere near our realities [link].

From [1]: Interestingly, experiences related to the mirrored limb have been identified as predictor for treatment success: the more participants were able to relate the visual image to their phantom, the less PLP they reported after a treatment period of 4 weeks. Although this finding as well as the present results is of correlative nature, there might be a causal relationship. It has been shown that the experimental induction of ownership in terms of the rubber limb illusion or related paradigms can reduce acute pain perception, although there are contrary findings.

One problem here is that the requirements for wearing a prosthesis are not included in this vague correlation mix.

If someone has a difficult if not impossible to fit stump, and given the personalities and funding schemes of prosthetic technicians, chances are good that such a person just won’t ever wear a prosthesis. As consequence they may eventually suffer sequels of asymmetry and overuse, their pains eventually blow out of proportion, and that’s it. So the first focus should be on developing suspension methods for difficult and impossible to fit stumps that aren’t extreme, painful, strange or dangerous. Swiss disability insurance law restricts the duty to support rehabilitation efforts only to a degree where it is tolerable, and having to deal with an osseointegration is not something that can  expected as tolerable. On the path towards tolerating a prosthesis, non-disabled researchers should have to go through 4 months of daily arm wrapping and immobilization as an attempt to develop insight and empathy [link].

If the prosthesis causes skin irritation and breaks often, it is one to not wear, point blank. It can only be worn all the time, if it works and if it does not irritate. Also such a person, eventually, will stop wearing their problem arm and end up having all sorts of pains. They do not lack an own extra body part, they simply lack a prosthesis they can actually wear. I do not need to regard my cell phone or car as extension of my bodily self and still want, need, to keep these charged, serviced, functional. So the second research focus must be on the skin prosthesis interface [link][link] and on making real life requirements and technical prosthetic design match also in terms of specifications and testing [link][link][link].

And if the prosthesis adds to, or does not remedy, asymmetry problems and overuse issues, or if it causes skin problems, or, if it breaks all the time, or, if it doesn’t deliver pure function all the time, then it may be the wrong prosthesis to begin with.

The other fundamental problem is that a prosthetic arm does not have to be an owned body part. Because with that, a whole bunch of real world problems come into existence that no one wants. It is absolutely sufficient to use that money for prosthetic arm research that there is, not waste it on correlation sharknando as exemplified here, and instead, build prosthetic arms that can be used in the sense as described above. Arm amputees may not embody any hand-like, or anatomical extremity-like, representation of their prosthetic arm, as an own body part at all, but, instead, it appears that they actually embody a prosthetic arm as a distinct entity such as a tool [22].

Once a prosthesis has become a “body part” and if only in the brains of Herta Flor, Robin Bekrater Bodmann and of course the amputee, we have a minimum of three in set S that believe the prosthesis to be a body part in a true sense. The rest of the population will populate set P that knows these prosthetic arms are built for obsolescence parts that may on occasion actually be CE compliant but that risk to not be on any other occasion, so they break all the time, also on Christmas. Now do you for a second believe that they open 24h-emergency clinics for prosthetic arms? If Otto Bock does not even “allow” users to sell their (functionally useless, sorry, OB) myoelectric devices to other users (not that Otto Bock is in the business to allow things here on earth)? Is that a world where you see the hospital doctor run around with oil can, screw driver and USB dongle in order to “fix” a body part consisting of a prosthetic arm? What, mentally, does it do to you to lose a body part, and, what does it do to you to lose it over and over again? Do you have experience along that river of tears? No, you don’t.

The summary problem may be that almost all of these academic researchers lack own skin in the game. However, “in relation to [..] performance, is possible to distinguish between board of directors with and without skin in the game” [23]. In that context, the total lack of Cybathlon’s true innovative performance appears to perfectly correlate with what from the outside clearly looks like a total lack of skin in the game of virtually all people with even minimal responsibilities there [link].

You do not take actual responsibility, we all know. You, as academic researchers, in your own world, need to write scientific papers that have high impact (like, here or here or here). Your peers also lack skin in the game. If you can research isolated problems, then you are in heaven. No need to deal with amputees trying to get their life back. Smelly stumps with friction rashes, eww. Hard testing? Nope (here and here and here). I once had a researcher in his lab tell me his accelerometer based control was perfect. I should try it at home. So I grabbed and hovered the paper cup with water in it, wearing his prosthetic device, over his laptop and asked him, sure about that? He went pale and said no, but, he said that in a split second he learned more about real prosthetic arm use than in years of academia before. Skin in the game, whaddayaknow. So also, they now use “healthy” study subjects, because amputees are increasingly hard to come by (here). And so with a massive level of detachment looming from all anecdotal evidence that we can ever have, I more specifically know that all of y’all are like “oyks?”. I spoke to far too many of you over the years. And so thus I built/build my own parts, simply because you would not want to depend on yourself as actual provider of prosthetic arm technology either (that is when you look at yourself in the mirror and go, oh, he’s right). In terms of body scheme, I can wear my prosthetic arm, and I like to do that, and in fact I do that, and still I do not feel less of a full person myself if I don’t. How do you like them apples.

Now go, stroll, enjoy the fact you have no skin in this game but learn to keep your fingers away from pretending that you do.

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