Diabetic foot amputation and thermography: study case

29/06/2021 By: Alejandro del Estal Home

Amputation is one of those pathologies that we do not see so commonly in thermography, but that deserves special attention. In this study case we have a 94-year-old patient, very kind and yet experiencing pain of 10/10 on the Visual Analogue Scale. The reason is a diabetic foot neuropathy that requires a surgical amputation of four toes.

Diabetes affects millions of people around the world. With a rapidly increasing prevalence in the last thirty years (Singh et al., 2014), the trend is expected to continue increasing from the current 5.1% to 7.7% in 2030 (Faruque et al., 2017). It is estimated that around 5% of all diabetes patients end up needing an amputation (Walsh et al., 2016).

The study case:

This is the case of this patient, who, after a long life of problems associated with diabetes, finally decided to have the regions of the foot with the worst prognosis amputated. Therefore, all the left foot’s toes, except the second, were sectioned, as you can see in image 1:

amputation thermography diabetes diabetic foot — **Image 1:** superior view of the patient’s foot, where the operated region can be seen. The second finger can be seen, still intact.

Studies in different populations (Hambleton et al., 2009; Tseng et al., 2008) show that amputations caused by diabetes have a high mortality rate with a 5-year survival rate of 41% to 48%. For this reason, our obligation as healthcare personnel is to make sure that we make the best assessment of the pathology.

Among other diagnostic tools, thermography has become a particularly useful instrument.

Why thermography?

A patient that suffers from diabetic foot feels a decrease in thermoception (sensation of temperature), nociception (sensation of pain), as well as vibratory sensitivity and superficial touch (Cruciani et al., 2013). For this reason, these patients tend to suffer accidents and develop ulcers without realizing it, since their sensitivity is decreased. In this sense, thermography provides a different view than other tools, since we can assess the surface temperature of the skin in wounds and scars, as we saw in this other study case. In image 2, we can see an ulcer and how the thermography allows us to make an assessment of it compared to the rest of the foot:

Image 1: superior view of the patient's foot, where the operated region can be seen. The second finger can be seen, still intact. — **Image 2:** left: digital view of the foot, showing an ulcer on the inner side. Right: thermographic evaluation of the foot, where we can see the ulcer with a lower temperature than the rest of the foot (-1.4º C).

Excrutiating pain after amputation…

But this patient does not come for consultation just for the ulcers. Since the operation, the pain he experiences is so excruciating that he describes it as “hell on earth.” Absolutely EVERYTHING hurts her: moving around, sitting still, having her dressings done, when the bandage is tight, when it is too loose, when it gets dark, etc. She reaches a point where she decides never to sit down again, lying down or lying down day and night.

One of the therapies so likes the most is mirror therapy. We put a mirror so that it reflected his right foot. and automatically she felt less pain, which allowed us to work standing up for a few minutes. Although the evidence does not support its therapeutic use (Barbin et al., 2016), we use it for its short-term placebo analgesic effect.

Phantom limb syndrome in Thermography?

One of the main risks of an amputation is developing the so-called “phantom limb pain” (Limakatso et al., 2020). It has a prevalence of between 29 and 85% of all amputations (Clark et al., 2013; Yin et al., 2017). It is a well-recognized phenomenon after amputation that the patient experiences in his missing limbs, even though it does not physically exist.

The mental image of that region continues to exist and this produces a dissonance that the brain manages, producing pain (Makin & Flor, 2020). However, the etiology and pathogenesis of phantom limb pain is complex and not well understood, although there is agreement that peripheral and central mechanisms are involved (Alviar et al., 2016).

Hence, another of the most interesting assessments is precisely the vascular one, which gives us very useful information. Thanks to thermography, we can better understand how a certain region is irrigated.

Vascular applications of thermography in this study case

If there were arterial compressive phenomena, the region would cool down. Therefore, nutrition and oxygenation would be compromised.
If there were venous failures, such as varicose veins, the superficial region of the thickened vein would be warmer. This is normally related to systemic problems.

In image 3 we can see a small venous thickening on the inner side of the leg. The superficial path of this vein can be seen with the naked eye, which a priori in the qualitative analysis does not indicate any problem.

Conclusion of this amputation study case

Let us go to the end of this study case: amputation and thermography. Fortunately, after almost three months of negotiation and a lot of work to gain trust, the first progress is seen. She tells me all the stories about when she left home when she was 14 years old, how she lived through WWII during the Nazi invasion of Paris and about her three husbands, 7 children and she doesn’t even know how many grandchildren. But finally, I get him to sit up while she eats, walk 8 steps with a walker and an orthopedic shoe and do 20 squats in a row !! And all this is the result of talking, doing mirror therapy and a very gentle manual treatment. And, of course, of making progressive increases in load.