Manual Treatment of Lymphedema is Changing
Since the 1930's Lymphatic drainage massage techniques have been utilized to help move fluid from an area that is congested due to lymphatic dysfunction to an area that is thought to be working better. The most common techniques are light in nature and performed in a rhythmical fashion to mimic the pumping action of the lymphatic vessels. Since the initial skin lymphatic networks are close to the surface of the skin, it has been determined that the pressure needed to affect fluid movement within is light.  Deeper techniques were reserved for later stages lymphedema where tissue changes were making the underlying tissue harder (fibrosis). Lymphatic drainage massage for lymphedema has had a general nature to it where treatment protocols were similar for the various related conditions such as right-side lumpectomy or left-side mastectomy. Variations in the treatment protocol were established addressing the radiation field, scar massage, fibrosis techniques and others. These techniques have, of course, evolved somewhat over the years and remain the main protocols for most lymphedema training schools. A change is coming soon however due to some valuable insights from research within the past five to ten years.
What is Driving the Change?
Research about the anatomy and physiology of the lymphatic system
1. All edema is lymphedema 
In 2010, researchers Levick and Michel  published a paper changing the way we think about how fluid is transported into and out of the blood capillary network. For over 100 years Starling’s Principle, found in all anatomy texts and taught in all anatomy classes, showed us that due to differing pressures between the blood and tissues, most of the fluid that entered the tissues was reabsorbed back into the venous system and only a small percentage of fluid was taken up by the lymphatics within the tissues. Levick and Michel (2010) found that the venous end of the capillary had a lining of sorts call the EGL (endothelial glycocalyx layer). This layer was found to block fluid from re-entry and therefore it was determined that the lymphatic vessels within the tissues were responsible for the entire fluid load.  The difference between edema and lymphedema has been questioned for years. Lymphedema was thought to occur when the lymphatic vascular system was irreversibly overwhelmed, whether by genetic means or a secondary cause. [9,5] The work of Levick and Michel (2010) basically changed this definition to all edema is lymphedema. Whether short lived (acute as in sprains or strains) or long term (chronic or lasting longer than 3 months) it is due to lymphatic disruption. 
1. New knowledge about lymphatic pathways
Dr. Suami  used ICG (Indocyanine green) fluorescence technology to visualize lymphatic pathways in 2012. Subsequent research from Suami &Scaglioni (2018) led to the creation of a map of sorts that has zones of skin that drain to a similar lymph node group. Furthermore, Dr. Suami’s paper from 2020 involving breast cancer-related lymphedema also presented theories based on current research stating lymphatic pathways from the arm differ between women. Varying pathways included the axilla (armpit) on the same side of surgery, the chest and the opposite axilla.
The ALERT study from Australia published in 2021  expanded on Dr. Suami’s work to confirm that the arm has alternate pathways for drainage. They found three alternate ways the body compensates for obstruction and the most interesting is that the axilla on the same side of surgery was the main destination for fluid drainage. This is contrary to current beliefs. Other drainage pathways noted were by the collarbone (clavicle), the lymph nodes by the breastbone (sternum) and in a few, the opposite side axilla. They did however state that connections can be disrupted as lymphedema progresses. Even more reason to catch lymphedema in its early stages.
1. New knowledge about effective techniques
The study by the Australian Lymphedema Education, Research and Treatment Program  used ICG fluoroscopy during treatment sessions and found that in congested areas a slower and firmer technique was needed to move fluid out of a congested area. Lighter techniques worked well to stimulate lymph flow in less congested areas.
In this study no drainage was evident to the groin (inguinal) nodes on the same side as surgery. Traditionally pathways are opened to encourage fluid from the surgical side axilla to the inguinal nodes on the same side. With this new revelation, treatment could then spend more time draining to known pathways than on those that may not receive lymph fluid from the upper body.
WHY IS THIS RESEARCH IMPORTANT FOR YOU AND YOUR THERAPIST?
The landscape of lymphedema treatment is evolving as new research comes to light. Until recently, research has not focused on the anatomy and physiology of the lymphatic system to inform treatment. While the traditional method of lymphatic drainage massage, in use since the 1930's, has worked for so many years, therapists can use the zone maps for designing your treatment plan, they can utilize the newer techniques to better move fluid from the more congested areas and above all your treatment can be individualized to meet your specific needs. One thing to keep in mind is that this research, while exciting, is new and more research on these findings will only build on what has been found to either add to, prove or disprove what is known.
My Experience Utilizing These Concepts
Having taken a course from a forward-thinking school in the US a few years ago and utilizing newer assessment techniques, mapping to inform my treatment plans and similar treatment techniques as the ALERT study that I was taught by this school, I can tell you that it has made some big changes in my client’s lymphedema outcomes. As a lymphedema therapist, keeping up with the research, upgrading and thinking outside the box is vital to ensure you as a patient get the best care possible.
Koelmeyer, L. A., Thompson, B. M., Mackie, H., Blackwell, R., Heydon-White, A., Moloney, E., Gaitatzis, K., Boyages, J., & Suami, H. (2021). Personalizing Conservative Lymphedema Management Using Indocyanine Green-Guided Manual Lymphatic Drainage. Lymphatic research and biology, 19(1), 56–65. https://doi.org/10.1089/lrb.2020.0090
Brennan, A. (2019). Raising the Starling Principle: The importance of the glycocalyx. https://lymphaticnetwork.org/news-events/new-science-and-lymphedema- andrea-brennan
Lymphatic Education and Research Network (LE&RN). www.lymphaticnetwork.org
Levick JR, Michel CC. Microvascular fluid exchange and the revised Starling principle. Cardiovasc Res. 2010 Jul 15;87(2):198-210. doi: 10.1093/cvr/cvq062. Epub 2010 Mar 3. PMID: 20200043.
Hettrick, H., Aviles, F. (2022). All Edema is Lymphedema: Progressing Lymphedema & Wound Management to an Integrated Model of Care. Wound Management & Prevention, 68(1), 121-167
Suami H. (2020). Anatomical Theories of the Pathophysiology of Cancer-Related Lymphoedema. Cancers, 12(5), 1338. https://doi.org/10.3390/cancers12051338
Suami, H. & Scaglioni, M. F. (2018). Anatomy of the Lymphatic System and the Lymphosome Concept with Reference to Lymphedema. Seminars in plastic surgery, 32(1), 5–11. https://doi.org/10.1055/s-0038-1635118
Suami, Hiroo & Chang, D. & Skoracki, Roman & Yamada, Kiyoshi & Kimata, Y.. (2012). Using Indocyanine Green Fluorescent Lymphography to Demonstrate Lymphatic Architecture. Journal of Lymphoedema. 7. 25-29.
Zuther, J., E. and Norton, S. (2013). Lymphedema Management: the comprehensive guide for practitioners. 3rd Ed. Thieme Medical Publishers Inc. Stuttgart: New York