The locations of these nodes often make fluid and proteins collect in the arm, so treatment consists of compression sleeves that seek to restore normal flow. However, current techniques are expensive and inconvenient.
In Biomicrofluidics, researchers from the University of Waterloo’s Microfluidics Laboratory and DIESEL Biomechanics Laboratory, Breast Rehab, and Myant, Inc. developed a soft robotic sleeve controlled with a microfluidic chip that reduces treatment cost, weight, and power consumption. The prototype is more portable than previous devices, and the underlying mechanisms can extend to other treatments, such as prosthetics.
The microfluidic chip has 16 channels, each acting as a sort of pipeline. Just as pipelines with different diameters create different flow speeds, the channels each have a different resistance. The differing resistances create a time delay between the flow through each channel, causing balloons in the sleeve to sequentially inflate and push fluid upwards, out of the arm.
The design requires only two miniature valves, which take the place of eight bulky, energy-consuming valves. As a result, the cost is cut from thousands to hundreds of dollars. It operates using a 3.7-volt lithium-ion battery within a control box weighing less than an iPhone 13, in contrast to previous technology that required a wall outlet.
“My definition of wearable is you can wear it and do whatever you want, and not be plugged into a wall,” said author Carolyn Ren. “Bringing in the microfluidics field, we wanted to make the system battery-powered but without compromising the performance.”
By placing a sensor between the sleeve prototype and the arm, the team measured and optimized the sleeve pressure to encourage fluid flow.
The researchers are currently recruiting for patient testing. They intend to use their device patent to develop a commercially viable product.
Microfluidic chips could also be incorporated into prosthetics for lower leg amputees.
Pressure is unevenly distributed around the leg during walking, and the leg swells to change sizes throughout the day, but traditional prosthetic sockets cannot adjust accordingly. A balloon system like the lymphedema sleeve could apply the correct amount of pressure to the leg dynamically and inflate or deflate to change size on demand.
“We look at these problems from different angle, but I think there are a lot more things microfluidics can contribute to these areas,” said Ren.
Several approaches to lymphedema treatment have been reported in the literature. Among conservative treatments, complex decongestive therapy (CDT) (also known as complex decongestive physiotherapy, combined physical therapy, and complex physical therapy, among others) is backed by longstanding experience and is noteworthy as the best approach for reducing upper limb lymphedema volume after breast cancer and lower limb lymphedema volume after gynecological cancer, as well as in lymphedema of other etiologies.1 – 3
Other conservative approaches have been proposed for treatment of lymphedema, mainly as adjuvants to CDT, including intermittent pneumatic compression (IPC),4 taping,5 extracorporeal shock wave therapy,6 photobiomodulation therapy,7 and acupuncture,8 among others.
In this paper, we will discuss conservative and non-pharmacological treatments that can be used to reduce the volume of limbs with lymphedema and maintain the reductions.
COMPLEX DECONGESTIVE THERAPY (CDT)
CDT consists of two treatment phases and four components, namely skin care, manual lymphatic drainage (MLD), compression therapy, and exercises. The first phase of this treatment aims at the maximum reduction of limb volume, with skin care, MLD, multilayer wrapping, and exercises performed in daily sessions lasting from four to six weeks. The maintenance phase (second phase) begins immediately after this phase. Its objective is to conserve and optimize the results obtained in the initial phase and it consists of fitting of elastic garments, exercises, skin care, and MLD when necessary.9
Studies carried out with different lymphedema etiologies have shown that CDT reduces limb volume and symptoms and improves quality of life and patients report satisfaction with the treatment received, so this therapy is currently considered the gold standard treatment.10 – 13
In women with breast cancer-related lymphedema (BCRL), the response to CDT treatment is associated with weight control, lymphedema grade, physical activity, and adherence to the use of compression therapy.14 , 15 Quality of life and social support were not predictors of better therapeutic response in this population.16 , 17
Manual Lymph Drainage
MLD consists of a specific manual therapy performed on the superficial lymphatic system, by means of precise, light, smooth, slow, and rhythmic maneuvers, which obey lymphatic system anatomy and physiology (Figure 1).
Its main objectives are to increase absorption of liquid and proteins from the interstitium by the lymphatic capillaries, increase the contractility of the lymphatic collectors, and increase liquid lymph node absorption, thus increasing the amount of liquid that returns to the venous system through the lymphatic system.18 In addition, because they are maneuvers that involve superficial touching, MLD can also promote quality of life improvement, sleep improvement, and reduction of pain, anxiety, and other symptoms.19 – 21
However, the effectiveness of manual lymphatic drainage for reducing lymphedema is not yet clear in the scientific literature.19 A clinical trial was conducted in Brazilian women with BCRL who underwent CDT and were randomized into two groups: with or without MLD. Both groups displayed reduction in limb volume at the end of the first treatment phase, with no difference between them.22 Other randomized clinical trials have reported similar results, with no difference in response to CDT with or without MLD.23 – 24
Studies have shown that MLD is a safe treatment and, when performed, can offer additional benefits to CDT, promoting better maintenance of the effects of compressive therapy, better quality of life, and improvement of symptoms resulting from lymphedema and areas of lymphostatic fibrosis.11 , 25 – 27
Compression therapy is performed using multi-layer bandaging (Figure 2), adjustable compression devices, and elastic garments. It is considered the main resource for lymphedema treatment, both in the volume reduction phase and in the maintenance phase.9
The effects of compression therapy on the lymphatic system include reduction of excess interstitial fluid due to decreased blood ultrafiltration, greater resorption, and improved muscle pumping.28 In the venous system, compression therapy reduces reflux and improves venous return, decreases venous hypertension, improves the calf muscle pump, and can improve the clinical conditions of venous ulcers. In addition to these effects, compression therapy also acts on trophic changes, by releasing anti-inflammatory mediators, minimizing areas of interstitial fibrosis.28 Compression therapy can have favorable results, improving pain, functionality, and quality of life.28
When the therapeutic objective is to reduce limb volume, the multi-layer bandage treatment leads to the best clinical response. The pressure exerted on the limb during muscle contraction (working pressure) will depend on the type of material, the degree of extensibility or stretching (tension applied during the bandaging), the force exerted by the bandage (the number of layers), and the conditions of the material (usage time, washing method).
For lymphedema treatment, use of short extensibility bandages is recommended because they produce greater working pressure. The greater the tissue pressure in the interstitium imposed by compression, the better the absorption of interstitial fluid.29 However, continuous high pressure can lead to blood capillary occlusion, resulting in pain and skin damage.30 Determination of the ideal pressure must take into account lymphedema type and severity, presence of any fibrosis, and skin conditions.31
In the second lymphedema treatment phase, wearing of elastic garments is indicated. For each clinical situation, it is necessary to assess the appropriate compression class, which depends on the physical and dynamic aspects of the fabrics (elasticity and stiffness) and also on the specific characteristics of each patient (skin texture, limb size, edema location, presence of lymphostatic fibrosis, and functionality of the affected limb).28
Another option for compression therapy that can be used both in the reduction of limb volume phase and in the maintenance phase is adjustable compression devices. These consist of a garment made of low elasticity fabric that wraps around the limb with lymphedema, attached with adjustable VELCRO®. These self-adjusting devices allow patients to maintain great compression as the limb volume decreases.32 Although VELCRO® devices are not better than bandage wrapping, they may be an alternative option for patients who do not adhere to other forms of compression, those with significant wounds or skin changes, or for financial reasons.33 – 37
reference link : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8565523/
More information: Run Ze Gao et al, A novel air microfluidics-enabled soft robotic sleeve: Toward realizing innovative lymphedema treatment, Biomicrofluidics (2022). DOI: 10.1063/5.0079898