Lymphovenous Canada: Measurement Standards

Without scientific protocol and standardized measurements, we cannot truly evaluate the effectiveness of treatments for persons with lymphatic disorders. Lymphovenous Canada looks at the efforts of two researchers who have tried to raise the bar in this area.

Tonette Megens: Measures of Upper Extremity Volumes in Women Following Axillary Dissection for Breast Cancer

I am a physical therapist who graduated from the University of Toronto in 1994. I worked for a short period at the Hospital for Sick Children with children with lymphedema. When I came to the University of British Columbia to do my Master of Science degree, I worked on a study with Professor Susan Harris from 1996 to 1998. The study involved 25 women at risk for lymphedema due to breast cancer treatments.

The women were randomized into an exercise group and a control group, and we were looking at whether there would be an additional risk for the exercising women to develop lymphedema. As a component to the study, we also wanted to compare calculated volume using circumferential measurements with volumetric measurements. We measured the circumferences of the upper extremities using tape measures since it is a quick and easy method for determining the size of a limb, and we also used volumetry since it is considered the gold standard for limb volume measurement. Volumetry is also referred to as the water displacement method, since it is performed by placing a limb into a container of water and measuring the displaced volume of water.

We had two therapists performing each measurement, and we did try to clearly define each method of measurement. We found very good reliability for both the circumferential measurements and the volumetric measurements. When the circumferential measurements were used in a calculation of volume, we found that the calculated volume consistently over-estimated volumetry, occasionally by as much as 300 mL.

I reviewed the literature to see how research groups were measuring limbs with lymphedema. There was a lot of inconsistency in how arms were being measured. Water displacement volumetry is time consuming and can be unhygienic, while circumferential measurements are easy to perform. This is probably why most studies incorporated some form of circumferential measurement technique to determine arm size. Often different sites and varying numbers of sites were used, however. This makes it pretty difficult to compare across studies.

Unlike in the study in which I was involved, most studies using circumferential measurements do not involve a calculation for limb volume. The arm measurements are compared directly from side to side at various points along the arm. Using this particular method makes it especially important to have consistency in the number and location of sites to be measured. This way, research studies could be better compared.

Results of the study, entitled: Measures of Upper Extremity Volumes in Women Following Axillary Dissection for Breast Cancer have been submitted to the Archives of Physical Medicine and Rehabilitation.

Ms. Megens is project co-ordinator of a U.B.C. study involving a new developmental assessment for infants. For more informatiaon she can be reached at: stfowler@direct.ca.

Note to readers: The recently published Canadian Medical Association Journal Clinical practice guidelines for the care and treatment of breast cancer: Pre- and postoperative measurements of both arms are useful in the assessment and diagnosis of lymphedema., January, 2001, makes the following recommendation re: measurements for breast cancer-related lymphedema:

"Circumferential measurements should be taken at 4 points: the metacarpal-phalangeal joints, the wrists, 10 cm distal to the lateral epicondyles and 15 cm proximal to the lateral epicondyles." For the on-line version of these guidelines see: http://www.cmaj.ca/cgi/content/full/164/2/191

Neil Piller: Establishing Australasian measurement standards

I work at the Flinders University Medical Center in South Australia and specialize in clinical and experimental research on primary and secondary lymphoedemas and oedemas, their assessment, treatment and management. I belong to the Australasian Lymphology Association and the Lymphoedema Association of Australia and am the Patron of the Lymphoedema Support Group of South Australia.

Last year the ALA undertook the challenge last year of identifying areas of concern regarding the treatment of lymphedema and then coming to agreement on each area one by one. Consumers, professionals and health care researchers were involved in providing input.

We used the Delphi technique, which allows people to give people feedback on an anonymous basis, to reach consensus on these issues. Issues that 80% of people wanted to take further were the ones that we focussed on.

We collected was about 40 pages of information - but within those pages there were about 9 major theme (domains) areas that emerged, of which measurement was one. We widely sought everyone's views and those which were similar were grouped and then got other people's views on those. We then distributed those views to get further feedback on them.

At the March 2000 meeting of the ALA, we started working on those topics, beginning by attempting to reach a consensus on the standards of measurement. To get some kind of agreement on these measurements was a major step in the right direction.

You can't force people to use standards, but the bait to encourage people to use the standard is that you can talk to someone else about how what they are doing compares with what you are doing. Most importantly, you can get a much better quality of result for your patient, you can collaborate in a research sense to in the end achieve a better understanding and better outcomes for the patient.

In terms of circumference, measurements had to be accurate and reproducable, there had to be enough positions to calculate volume, there had to be enough positions to provide information for garment manufacturers, and there had to be enough information for scientific research if people in smaller centres were going to be involved in multi-centre studies.

We started out with the questions:

• Could we get some sort of consensus on a starting point for measurement?
• Would it be a measurement board - the tip of the middle finger?
• Could we reach some consensus on the use of a tape measure - a narrow one, a wide one or what?
• What measurement position and distance should we be using - a four-centimeter one or a ten-centimeter one.
• What would be the minimal separation between circumference measurements?
• How important is volume clinically and scientifically?
• How do we determine that volume - through perometry (a form of opto-electronic volumetry), by plethysmography or by calculation from circumference.

We wanted to use standards that would evolve over time; that would flexible enough to be modified to maximize relevance and usability. The most important issue that came out was that we must balance reliability and accuracy with efficiency and ease of use.

Through extensive group discussions here's what we came up with:

• Tape measurements should start from the tip of the middle finger. Measurements should be taken using the narrow tape.
• There should be so minimal pressure in using that tape that there is no indent mark.
• Only take one measurement should be taken unless therapists feel unsure about the measurement in which case we should take two and then average them.
• Measurements should be taken at 10-centimeter measurement intervals.
• Calculation of volume was considered to be very important for scientific study. Most respondants thought volume should be calculated from tape measurements of circumference. Some persons thought it should be calculated from immersion in water and perometry if available for the high level or accuracy and repeatability it gives.

Ensuring that the limb and patient was in the same position during the measuring process was considered critical.

Other issues which remain to be resolved include: what firm pressure on skin entails, the use of transparent tape, the arm position, whether patients should be sitting or lying while measurements are taken.

Measurement of legs:

• The sole of the foot should be placed against the measurement board
• A narrow tape should be used
• Measurements should be taken at right angles to the limb
• Measurements should be taken at 10-centimeter intervals
• Firm pressure should be applied while taking measurements.

Agreeing to these standards in Australia represented a major accomplishment in getting better outcomes for our patients.

Professor Piller's full presentation on the establishment of measurement standards was made at the Sept. 2000 National Lymphoedema Network conference in Orlando, Florida. For a tape and full transcript of his presentation please contact the National Lymphedema Network at: http://www.lymphnet.org

Neil Piller is a Lymphologist and the Team Leader of the Lymphoedema Assessment Clinic at Flinders Surgical Oncology and professor at the Flinders University Medical Center in South Australia. He is also one of the leaders of the large microcirculatory and lymphological laboratories along with Professors Bren Gannon and Colin Carati. Neil can be reached at: neil.piller@flinders.edu.au.

Since this page was first posted, the Hospital for Sick Children has added the following comment: it is more difficult to develop standardized measurements for children because of their constant growth. For this reason water displacement volumetry is often a more effective way to measure change in this group.

Several new measurement techniques have also been drawn to our attention. These include a type of bioimpedence apparatus which is being tested at Flinders University and a new product, called a Perometer, manufactured by Juzo, which provides circumferential measurements by using infra red light beams.