Journal Article: "Phlebolymphedema–A Common Underdiagnosed and Undertreated Problem in the Wound Care Clinic"

The following is a discussion of an article related to the topic of secondary lymphedema (also known as phylebolymphedema) entitled "Phlebolymphedema - A common underdiagnosed and undertreated problem in the wound care clinic" by W. Farrow.

The article reference J. Am Col Certif Wound Spec 2010 2(1) 14-13 may be accessed at this link:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3601853/pdf/main.pdf

Secondary lymphedema develops as a result of damage to the lymphatic system unlike primary lymphedema that is a congenital disease.

Secondary lymphedema manifests itself as edema, a condition characterized by an excess of watery fluid collecting in the cavities or tissues of the body.  There are several origins of secondary lymphedema including radiation (women sometimes develop lymphedema in their arms after breast cancer radiation treatment) and parasitic infection known as filariasis, a condition that affects 100 million people worldwide.  

The article focuses on the most common form of lymphedema in the Western world that develops in patients with chronic venous insufficiency (CVI) and, as stated above, is identified as secondary lymphedema or phylebolymphedema.   

Journal article "The Effects of External Compression on Venous Blood Flow and Tissue Deformation in the Lower Leg"

This is a discussion of the journal article "The Effects of External Compression on Venous Blood Flow and Tissue Deformation in the Lower Leg" by Dai et al.  A co-author on this paper is Roger Kamm who has done extensive work on flow modeling of the venous system.

The journal article may be accessed at reseachgate.net at this link: 
https://www.researchgate.net/profile/Roger_Kamm/publication/12681713_The_Effects_of_External_Compression_on_Venous_Blood_Flow_and_Tissue_Deformation_in_the_Lower_Leg/links/0fcfd51236d6adf190000000.pdf

The article uses FEA (finite element analysis) to model venous flow and vein collapse when symmetric and asymmetric compression is applied. 
  A few important points that I have identified are the following:
1. The elastic modulus of skin is 2 x 10^6 Pa.  The elastic modulus of the fascia is 3.4 x 10^8 Pa.  Elastic modulus is the material's resistance to deformation (not permanent deformation). This means that skin is much more easily deformed than fascia.   

2. Asymmetric compression more effectively narrows the vein diameter than symmetric circumferential compression.  

From Fig. 4 of the article, for the same amount of compression, for example, 30 mmHg, asymmetric compression (designated as Anterior-Posterior Compression) effectively collapses the vein whereas circumferentially-uniform compression at 30 mmHg leaves the vein relatively open. 

3. Because asymmetric compression more effectively narrows the vein diameter, the blood flow velocity is higher with asymmetric compression. 

From Fig. 7 of the article, asymmetric compression causes a higher flow velocity peak than symmetric compression (as determined at the thigh location).  The article also looks at single versus two-compartment graded-sequential compression (Fig. 7 bottom plot).  There also, asymmetric compression shows a higher flow velocity.  Surprisingly, the two-compartment, graded-sequential pressure application does not show a higher flow velocity than a single chamber pressure application.  This suggests single-chamber compression devices are adequate.  

The article suggests that an effective compression device should deliver asymmetric (not uniform circumferential) compression and multi/gradient compression chambers may not be necessary.