An overview of Manual Lymphatic Drainage
Manual lymphatic drainage (MLD) is a technique whereby gentle pressure is applied to the lymphatic drainage system by a trained specialist.
Manual Lymphatic Drainage is used in the treatment of patients with conditions such as lymphedema or lipedema, or following some surgical procedures (MLD UK, 2024a).

Lymphedema of any origin is usually treated with complex physical de-congestive therapy, which comprises Manual Lymphatic Drainage and other methods, including compression therapy, exercise therapy, skincare and patient education (Kasseroller and Brenner, 2024).

What is the Lymphatic Drainage system and how does it work?
The lymphatic system is a network of vessels, tissues and organs that work together as part of the immune system to remove cellular waste and toxins. The lymphatic system helps to maintain body fluid levels and absorb fats from the digestive system.
About 20 liters of plasma flows through the body on a daily basis, 17 liters of which return into blood circulation through veins following the delivery of nutrients and removal of waste from the body (Vallet, 2023). The remaining 3 liters transfer into the body’s tissues for the lymphatic system to collect (Vallet, 2023).
If the lymphatic system is not functioning as usual, this fluid is not adequately removed and seeps into the tissues, causing a buildup of fluid over time. This excess fluid is called ‘lymph’, and would normally be returned into the  bloodstream as part of a functioning lymphatic system. Lymph typically comprises proteins, minerals, fats, nutrients, cellular waste, bacteria and viruses (Vallet, 2023).
A human being has 600 lymph nodes located throughout the body (Vallet, 2023). These are glands that help to cleanse the lymph, aiding the process of filtering out toxins, such as damaged cells or cancer cells. Lymph nodes can exist independently or connect in a chain via lymphatic vessels.
Lymph nodes are commonly found in the neck, armpits and groin (Vallet, 2023). When a person has a viral infection, lymph nodes may cause swelling in the infected areas while ridding excess toxins from the body. Lymphatic vessels consist of capillaries and tubes in the body, which transport lymph from the tissues. Vallet (2023) noted that these networks of vessels function in a similar way to veins, and contain valves to prevent the backflow of fluid and aid the movement of fluid in one direction under low pressure. Lymph is emptied into the right and left lymphatic ducts by lymphatic vessels, then returned to the blood via the subclavian vein, which is connected to the collecting ducts (Vallet, 2023).
Maintenance of blood pressure and volume depend on effective lymphatic drainage, as each can be significantly affected by inadequate clearance of lymph (Vallet, 2023). Excess volume in areas of the body where lymph is not adequately cleared will cause swelling.
Edema is typically found in the ankles and legs, but can also occur in other areas of the body, such as the arms after breast cancer surgery. Organs involved in the lymphatic system include the spleen, thymus, tonsils, adenoid, bone marrow, appendix and Peyer’s patches (areas of lymphatic tissues lining the mucous membrane of the small intestine) (Vallet, 2023). These organs produce white blood cells, which are used in the immune response to fight against infections and diseases. Lymphatic organs also work to trap pathogens, as well as monitor and destroy bacteria.

How does Manual Lymphatic Drainage work?
Manual Lymphatic Drainage is a technique designed to move fluid away from areas with swelling to a place where there is normal function of the lymphatic system, in people with lymphedema or other conditions as indicated (CRUK, 2023).
It is a non-invasive technique involving a range of rhythmic movements that stimulate the lymphatic system (MLD UK, 2024a). The movements involve applying light pressure, as the lymphatic system is located in a shallow area in the dermis layer of the skin. For example, the massage may target the chest if aiming to remove fluid from the arm, given the location of the lymphatic vessels (CRUK, 2023). The specialist chooses the type of Manual Lymphatic Drainage and the number of sessions to conduct depending on the patient’s condition. Manual Lymphatic Drainage is an effective technique for many patients, achieving outcomes in lymphedema, improving areas with venous insufficiency (eg leg ulcers), speeding up postoperative healing time, reducing fluid congestion (eg in pregnant women with swollen legs, for swollen ankles or puffy eyes) and promoting healing time following injuries such as fractures, sprains and torn ligaments (MLD UK, 2024b). Burns and other wounds may also benefit from Manual Lymphatic Drainage, as can chronic conditions such as sinusitis, scleroderma or rheumatoid arthritis (MLD UK, 2024b).

Contraindications
Despite the wide array of benefits offered by the therapy, there are contraindications for Manual Lymphatic Drainage in some cases. The Lymphedema Framework (2006) lists the following general contraindications:
• Acute cellulitis/erysipelas
• Severe cardiac insufficiency
• Ascites
• Unstable hypertension
• Renal failure
• Untreated tuberculosis or malaria
• Superior vena cava obstruction
Such conditions can put the person at a higher risk of mortality if they receive Manual Lymphatic Drainage, because blood pressure or renal pressure is increased, or the heart has poor cardiac output and cannot cope with additional fluid. Manual Lymphatic Drainage moves fluid from one part of the body to another, so it can be contraindicated for a patient whose diagnosis would leave their body unable to cope with the pressure of fluid being moved in this way.
Other possible contraindications include untreated thyroid dysfunction, metastases and primary tumors (Lymphedema Framework, 2006).

References
Excerpts and/or language from Sarah Jane Palmer / Department of Work and Pensions, Nursing and Midwifery Council, London, UK:
"An overview of manual lymphatic drainage", Published by The British Journal of Community Nursing, September 2024 Vol 29, No 9.
https://doi.org/10.12968/bjcn.2024.0101