Indurometer

Mechanical tonometer

Limited stocks - No longer in production

The original mechanical device was made by Flinders Medical Centre Biomedical Engineering and has been used extensively in Lymphoedema assessment (see the Lymphoedema tab for publications). It is a robust tonometer that worked well despite shortcomings with the mechanical design:

Must be within 5 degrees of upright to measure correctly The resistance to indentation is difficult to read from a small dial and must be read before it is removed from the skin Clumsy to hold and operate to ensure the indentor moves freely Results are highly dependent on operator training and use

Electronic Tissue Indurometer

Undergoing clinical trial - expected 2011

This second generation indurometer is an electronic version of the mechanical tonometer with significant improvements. Advantages of this model include:

• Simple and quick operation
• Easy to read digital display
• Capture of reading
• Ability to use at any angle

The electronic indurometer is under clinical trial and is expected to be available at the end of 2010, early 2011. For information contact Mark.McEwen@fbe.com.au

Viscoelastic Indurometer

Under development

The next generation of indurometry under development is the viscoelastic indurometer. It measures the tissue’s resistance to indentation, like the electronic indurometer, as well as the fluid movement (viscoelastic properties) of the tissue. Fluid movement is particularly important in pitting lymphoedema. This indurometer is not currently available for purchase and is undergoing initial pilot trials.

View the comparison chart on the side bar for a summary of the range of indurometers available and under development.

Indurometry (or tonometry) is widely used in lymphoedema assessment for an objective estimate of pitting and fibrotic induration. Pitting results when there is a displacement of extracellular fluid.

Publications

Pallotta O, Woolford R, Smith AL, Piller NB. Mechanical, electronic and viscoelastic tonometry. Presented at International Society of Lymphology Congress, Sydney 2009.
(Abstract)

Moseley A, Piller N. Reliability of bioimpedance spectroscopy and tonometry after breast conserving cancer treatment. Lymphat Res Biol. 2008;6(2):85-7. (Abstract at PubMed)

Piller N. To measure or not to measure? What and when is the question. Journal of Lymphoedema, 2007;2(2):39-45. (Article)

Carati CJ, Anderson SN, Gannon BJ, Piller NB. Treatment of postmastectomy lymphedema with low-level laser therapy: a double blind, placebo-controlled trial. Cancer. 2003 Sep 15;98(6):1114-22. (Abstract at PubMed)

Bates DO, Levick JR, Mortimer PS. Quantification of rate and depth of pitting in human edema using an electronic tonometer. Lymphology. 1994 Dec;27(4):159-72. (Abstract at PubMed)

Casley-Smith JR, Morgan RG, Piller NB. Treatment of lymphedema of the arms and legs with 5,6-benzo-[alpha]-pyrone. N Engl J Med. 1993 Oct 14;329(16):1158-63. (Abstract at PubMed)

Liu NF, Olszewski W. Use of tonometry to assess lower extremity lymphedema. Lymphology. 1992 Dec;25(4):155-8. (Abstract at PubMed)

Piller NB, Clodius L. The use of a tissue tonometer as a diagnostic aid in extremity lymphoedema: a determination of its conservative treatment with benzo-pyrones. Lymphology. 1976 Dec;9(4):127-32. (Abstract at PubMed)

Clodius L, Deak L, Piller NB. A new instrument for the evaluation fo tissue tonicity in lymphoedema. Lymphology. 1976 Mar;9(1):1-5. (Abstract at PubMed)

Burns

Trials have been conducted on burn scar assessment using a indurometer/tonometer modified for this purpose.

Corica GF, Wigger NC, Edgar DW, Wood FM, Carroll S. Objective measurement of scarring by multiple assessors: is the tissue tonometer a reliable option? J Burn Care Res. 2006 Jul-Aug;27(4):520-3. (Abstract at PubMed)

Lye I, Edgar DW, Wood FM, Carroll S. Tissue tonometry is a simple, objective measure for pliability of burn scar: is it reliable? J Burn Care Res. 2006 Jan-Feb;27(1):82-5. (Abstract at PubMed)

Sclerosis

A trial has been conducted on sclerosis assessment using a indurometer/tonometer modified for this purpose.

Research devices

Flinders Biomedical Engineering have a history of tonometer development with many early prototypes measuring tissue properties in different ways.

Tonometer, 4mm This is a battery operated hand held tonometer to measure skin tension after 4mm depression.
Tonometer, Skin recovery This device measures time taken for skin to rebound after indentation (elasticity) measured by a reflective sensor. The low mass of the measuring head minimises disturbances to the tissue from application pressure.
Tonometer, Torsional In this tonometer a probe depresses tissue to a set depth or force, then rotates and measures linear and rotational force response over a user selected period of time. Strain gauge assemblies in the probe suspension measure the forces.