Updates in Research: Manual Lymphatic Drainage

 By Michelle Vallet, May 1, 2023

Few people think about their lymphatic system on a regular basis. Still, this network of vessels, tissues and organs is there each day chugging along as part of our immune system, protecting us against illness-causing invaders and removing cellular waste, as well as maintaining body fluid levels and absorbing digestive tract fats.

Approximately 20 liters of plasma flows through the body every day, 17 liters of which make it back into our circulatory system via our veins after nutrients are delivered and waste removed. The three liters or so left over seep into the body’s tissues, where it’s collected by our lymphatic system.

The Cleveland Clinic describes the lymphatic system this way: “The lymphatic system collects the excess fluid, now called lymph, from tissues in your body and moves it along until it’s ultimately returned to the bloodstream.”

Parts of the Lymphatic System: A Basic Overview

Lymph. Lymphatic fluid, often called lymph, is the excess fluid in cells and tissues that is not reabsorbed into the capillaries. Lymph is also comprised of other substances, like proteins, minerals, fats, nutrients, cellular waste, and foreign invaders like bacteria and viruses.

Lymph nodes. A person has roughly 600 lymph nodes throughout their body, which are bean-shaped glands that help cleanse lymph, filtering out damaged cells and cancer cells. Either single nodes or connected groups or chains are connected to one another via lymphatic vessels. Some common areas where lymph nodes are located include a person’s armpits, groin and neck.

Lymphatic vessels. This network of capillaries and tubes—located throughout a person’s body—help transport lymph away from tissues. These vessels function similarly to veins, and have a series of valves that keep fluid moving in one direction under very low pressure.

Collecting ducts. Lymph is emptied into the right lymphatic duct and left lymphatic duct by the lymphatic vessels. Lymph is returned to the bloodstream by the subclavian vein, which runs through a person’s collarbone and is connected to the collecting ducts. The process of returning lymph to the bloodstream is integral to maintaining blood volume and blood pressure, and also helps protect against edema.

Lymphatic organs. Lymphatic organs include the spleen, thymus, tonsils and adenoid, bone marrow, appendix, and Peyer’s patches (small patches of lymphatic tissue that line the mucous membrane of a person’s small intestine). These organs function in a variety of ways, from producing white blood cells to fight infection and disease to trapping pathogens to monitoring and destroying bacteria.

The Benefits of Manual Lymphatic Drainage: Latest Research Around Edema & Lymphedema

For years, manual lymphatic drainage has been used to help people with conditions like edema and inflammation. The Mayo Clinic describes edema as the body’s general response to injury or inflammation, where fluid from “leaky” blood vessels gathers in nearby tissue, causing the tissue to swell. Often, this condition is the result of an acute or new injury.

Alternatively, lymphedema commonly occurs after the removal of lymph nodes or when they’ve been damaged, like during cancer treatment or because of infection. Whereas edema is mostly water, the fluid that accumulates in lymphedema contains proteins, which are often too heavy to be efficiently moved by the lymphatic system. “Water gets pulled out, but the protein is too heavy and is left behind by a sluggish lymphatic system,” explains Carmen Thompson, BS, CMT. This leftover protein continues to pull water toward it, creating a cycle of lymphedema that is difficult to break.

Manual lymphatic drainage has long been thought to be an effective way to relieve both edema and lymphedema. Especially in the case of lymphedema—where some of the more conventional intervention methods primarily focus on moving the water—manual lymphatic drainage can also move the protein, according to Thompson. And some early research bears out those claims^1,2.

More current research, however, is starting to pinpoint when and how manual lymphatic drainage can help for conditions like lymphedema.

New research on timing. A 2022 study considering the effects of manual lymphatic drainage on upper limb lymphedema after surgery for breast cancer suggested manual lymphatic drainage had a positive effect during the maintenance phase of lymphedema, and participant questionnaires showed significant improvement in hand and arm symptoms.³

The maintenance phase of lymphedema typically involves daytime use of compression garments, according to The Mayo Clinic’s Dr. Andrea L. Cheville. This phase follows the reductive phase, where the primary goal is decreasing swelling and discomfort, and reducing the risk of cellulitis.

Frequency of sessions. Some researchers are still trying to answer the question around just how effective manual lymphatic drainage really is for lymphedema. A 2023 meta-analysis of randomized controlled trials on the effect of manual lymphatic drainage on cancer-related post-mastectomy lymphedema suggests that frequency is a potential indicator of effectiveness.⁴

The meta-analysis included a total of 457 patients and found that although the effect of manual lymphatic drainage was limited when looking at the amount of upper extremity edema when compared to control groups, when the treatment course was greater than 20 sessions, there was significant reduction in upper extremity volume. “There was also significant reduction in the extremity volume when treatment duration was greater than two weeks,” researchers noted.

These findings suggest that providing manual lymphatic drainage over an extended period of time may be the most beneficial and effective.

Emerging Understanding: How Recent Research Broadens How We Think About the Benefits of Manual Lymphatic Drainage

Manual lymphatic drainage has been talked about in terms of its benefit for lymphedema for decades, but more recent research is adding to our understanding of some of the benefits offered by this technique.

Axillary web syndrome. Another condition that can develop with breast cancer patients—most often during either diagnosis or treatment—is axillary web syndrome (AWS).

According to Healthline, AWS, also called cording or lymphatic cording, describes the rope- or cordlike texture that develops just under the skin under a person’s arm, though the cording can also extend down the arm and in rare cases down to the wrist.

An exact cause hasn’t been confirmed, but some experts think the condition may be the result of damage done to connective tissue surrounding lymph vessels during surgeries like mastectomy, lumpectomy, lymph node dissection and breast reconstruction, to name a few. This damage results in scarring and hardening.

AWS often causes pain and tightening, and can restrict range of motion, making some everyday activities difficult.

Two recent studies examine the benefits of manual lymphatic drainage for managing symptoms of AWS. The first considered the benefit of manual lymphatic drainage for AWS when combined with vacuum sealing drainage.⁵ Participants in the study group received manual lymphatic drainage combined with vacuum sealing drainage and the control group received health education and functional training.

Researchers noted the duration time to disappearance of cordlike nodules and tightness in the study group was significantly shorter than in the control group. At one month and three months post-intervention, the study group had a significantly lighter degree of pain, and better upper limb functionality and quality of life.

A 2022 study on manual lymphatic drainage with progressive arm exercises showed the study group, whose participants were assigned manual lymphatic drainage with resorption strokes along with arm exercises, showed significant and clinically relevant improvements in self-reported pain intensity at the primary and three-month follow up when compared to the control group, whose participants were assigned standard arm exercises.⁶

“To our knowledge, this is the first appropriately designed study to demonstrate the effectiveness of manual lymphatic drainage with progressive arm exercises for AWS,” the researchers noted.

Venous flow, fatigue and pain. A small narrative review⁷ focused on investigating the lesser known effects of manual lymphatic drainage, including increasing venous flow, decreasing fatigue and raising a person’s pain threshold.

A literature search of the 30 years starting at 1989 to 2019 yielded 20 studies that met inclusion criteria of identifying different effects of manual lymphatic drainage. What researchers found was that manual lymphatic drainage has been shown to help with symptoms and conditions beyond edema and lymphedema, mainly fatigue and pain tolerance.

“This study suggests that MLD can be used in symptomatic treatment of various diseases, like multiple sclerosis and Parkinson’s disease, considering the effects of MLD on the various systems,” researchers concluded.

Additionally, a 2022 study exploring integrative therapies for managing fatigue associated with long-COVID found that study participants who had face-to-face treatment sessions with Perrin technique practitioners, along with daily self-massage and gentle mobility exercises, realized an approximately 50 percent reduction in subscale scores for fatigue.⁸

“Our findings suggest that a specific manual lymphatic drainage intervention may help to reduce fatigue symptoms related to long-COVID,” researchers of this study concluded. “Perhaps preventing acute symptoms through early intervention.”

Pain and range of motion. Though past research focuses primarily on breast cancer, a 2022 study investigated the effects of early interventions of manual lymphatic drainage and rehabilitation exercises for oral cavity cancer patients.⁹

The study group participants received 30 minutes of rehabilitation and 30 minutes of manual lymphatic drainage compared to the control group, who just received 30 minutes of rehabilitation intervention. Clinical measures were assessed before surgery, before intervention and when participants were discharged from the hospital, and included the visual analog pain scale (VAS), range of motion of the neck and shoulder, ultrasonography and face distance for lymphedema, and the Foldi and Miller lymphedema scales.

Results indicated that the VAS pain score, neck range of motion and internal and external rotation of the right shoulder showed significant improvement. “Early intervention with MLD and the rehabilitation program were effective in improving ROM of the neck and controlling lymphedema in acute-phase rehabilitation,” researchers noted.

The massage profession is consistently evolving, and a major part of that evolution is the role new research plays in advancing our understanding of the more general benefits massage therapy provides, as well as specific benefits provided by the various techniques massage therapists use. Staying up-to-date on the latest research can help massage therapists better care for their clients by keeping them current on the growing benefits techniques like manual lymphatic drainage has to offer.

References