Tissue tonometry is the measurement of change within tissue or the in the case of lymphedema measurement of the resistance of the lymphedematous tissues to compression. It does this by measuring the “softness” of the skin and the change in fibrosis.
It can be an important tool to mesure the success of a lymphedema treatment and management program.
Presented here for informational purposes is a review of the literature available.
Lymphatic Research and Biology Volum 2, Number 2, 2004
Ali Mirnajafi, B.Eng, Ph.D.; Amanda Moseley, B.N.,R.N.,B.H.Sc. (HONDS) and Neil Piller, B.Sc. Ph.D.
Objectification of lymphedema progress and the effect of treatment continues to be a problem in patients. Female patients who have had axillary clearance and radiotherapy are at a considerable risk of developing lymphedema at some time of their life. Therefore it is critical to diagnose and treat lymphedema at an early stage before the swelling of the limb becomes significant. This study postulated that the torsional rigidity of the skin of the lymphedematous limb differs from the normal limb and may be used as a diagnostic tool.
Methods and Results
A device was designed and constructed that enabled the measurement and comparison of the skin’s torsional rigidity. Seventeen females (40-65 years-old) with a history of chronic secdonary arm lymphedema were tested. The torsional rigidity of the skin of both normal and lymphedematous arms were measured in the same area at a rotation of 15 degress. The result indicated that the required power to rotate the normal skin is 46.34(Plus/minus)23.57 percent more than lymphedematous skin of the same subject.
The mechanical properties of skin change due to lymphedema. It is proposed that skin torsional rigidity may be a beneficial tool in the diagnosis of lymphedema.
Developed in Australia at Flinders Biomedical Engineering in collaboration with the Lymphoedema Assessment Clinic at Flinders Medical Centre, the Tissue Tonometer is an easy- to-use, fast, accurate and reproducible method of assessing pitting edema and fibrotic changes in edematous and lymphedematous tissues.
Pitting edema results when there is a displacement of extracellular fluid and is present in stage 1 lymphedema (ISL 1995). Over time, chronic inflammatory changes result in the progressive fibrotic indurations of tissues (Stage 2 lymphedema – ISL Grade 2).Assessing the rate of this change and the impact of your treatment and the patient’s management of this fibrosis is crucial since fibrosis is one of the major factors that can lead to poor lymph drainage and poor treatment outcomes.
The Tonometer has a weight of 200 grams that gently pushes a plunger onto the skin.The depth of penetration of the plunger is accurately recorded on a dial, to a resolution of 0.01mm.
This tool is quick and easy to use in any clinic setting. It is a mechanical device and does not require electricity or batteries. It is approx.11 cm (4 inches) in height and 5cm (2 inches) wide. It is made of stainless steel with a plastic base and is easy to clean. It comes with a full set of instructions. Flinders Biomedical Engineering will provide a limited warranty for one year against mechanical defect, including free return shipping for the first three months of the warranty period if defective
Appropriate treatment for lymphedema requires accurate objective, diagnosis of the pathophysiologic changes.
These changes can be monitored by the use of tonometry. Tonometry measures the resistance of tissues to compres- sion, in the major lymphatic territories.This provides a sensitive measure of fluid and fibrous accumulation within the tissues and of the progress of the territory or the limb from the initial fluid-rich stage through the fatty middle stage to the fibrous end point stage.
Tonometry is able to monitor the effect of treatment and progression of lymphedema.With fibrosis, tissue resistance to compression increases, resulting in low plunger penetra- tion and a low numerical indication
Routine measurement through a course of treatment may indicate an increasing plunger penetration due to a softening of the sclerotic tissue.Accurate charting of lymphedema and the course of treatment is essential in order to provide objective data to patients, referring physicians, insurers and research projects and provides evidence for your actions.
In using the Tonometer, there are two important points to be aware of: Firstly, it does not measure absolute amounts of fiber or changes in it.The measure is a relative one. That is why its best information comes when you are able to get a baseline (pre-treatment) indication of tonometry of the affected lymph territories or limbs and track the changes as the patient is treated. Secondly, it is also important to try to get a contralateral reference point on a normal limb.This will allow you to see how other apparently normal lymphatic territories are progressing and allow you to assess the progress of the affected limb against the non-affected limb.
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Lymphat Res Biol. 2008
Moseley A, Piller N. Department of Surgery and Lymphedema Assessment Clinic, Flinders University and Medical Centre, South Australia, Australia.
Abstract Background: Measuring the female breast, especially after breast cancer treatment, is problematic due to breast size, texture, and patient positioning. However, being able to accurately measure changes in the breast is important, as it may help in the earlier diagnosis and treatment of early breast edema and later lymphedema.
Methods: 14 women who had undergone breast conserving surgery for breast cancer (> 12 months ago) were recruited to assess the between subject reproducibility of tonometry and bioimpedance spectroscopy (BIS). With the participant supine, two repeat measurements of the resistance of the tissues to compression (tonometry) and fluid levels (BIS) of the treated and normal breast were taken for each of the four quadrants of the breast.
Results: The between subject reproducibility for both measurement techniques was high, with covariance ranging from 1.29% to 3.25% for tonometry and 0.20-0.86% for BIS.
Conclusions: The reliability of these two measurement techniques provides an opportunity for researchers and clinicians to easily quantify breast tissue and fluid changes which in turn may lead to the earlier diagnosis and targeted treatment of breast edema and lymphedema.
Am J Phys Med Rehabil. 2007 Oct 29
Chen YW, Tsai HJ, Hung HC, Tsauo JY. From the School of Occupational Therapy, College of Medicine, National Taiwan University, Taiwan (YWC); Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Bei-Hu Branch, Taipei, Taiwan (HZT); School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taiwan (HCH, JYT). Chen Y-W, Tsai H-J, Hung H-C, Tsauo J-Y:
OBJECTIVE: Water displacement, circumference measurement, and tissue tonometry are important methods to evaluate the status of lymphedemous limbs in breast cancer patients. The purpose of this study was to investigate the reliabilities, and define the limits for clinical change indicative of clinical improvement with respect to these three measures.
DESIGN: Fourteen patients were recruited for water displacement and circumference measurement, and 17 for tissue resistance by tonometry. All had been treated for breast cancer and subsequently developed lymphedema. Two physical therapists conducted the measurements to determine intra- and interrater reliability.
RESULTS: All measures had fair to excellent reliability (water displacement and circumference measurement, intraclass correlation coefficient [ICC] >0.99, P < 0.05; tissue tonometry, 0.66 < ICC < 0.88, P < 0.05). There was no systematic change in the mean for any of the measures. The variation, as determined by standard error of measurement (SEM), SEM%, smallest real difference (SRD), and SRD% was greatest for tissue tonometry.
CONCLUSIONS: Water displacement and circumference measurement (but not tonometry) are reliable techniques for assessing lymphedema in clinical practice. The effect of modifying the tonometry protocol and increasing the amount of rater training should be studied to determine whether the reliability of this method can be improved.
PMID: 17993983 PubMed - as supplied by publisher
Shirin Bagheri, M.D. Lund University, Lund University Hospital, Lund, Sweden; Lund University, Malmö University Hospital, Malmö, Sweden. Karin Ohlin, OTR Department of Plastic and Reconstructive Surgery, Lund University, Malmö University Hospital, Malmö, Sweden. Gaby Olsson, RPT, LT Department of Plastic and Reconstructive Surgery, Lund University, Malmö University Hospital, Malmö, Sweden. Håkan Brorson, M.D., Ph.D. Department of Plastic and Reconstructive Surgery, Lund University, Malmö University Hospital, Malmö, Sweden.
Background: Arm lymphedema is a common complication after breast cancer treatment. Different conservative and surgical treatments have been used to reduce the arm swelling, but most have failed as chronic edema eventually transforms from a state of accumulated lymph fluid into increased deposition of subcutaneous fat, i.e. a non-pitting lymphedema.
Objective: To evaluate changes in tissue tonicity with an electronic tissue tonometer before and after liposuction. To validate the tonometer, outcome of surgery, and aspirate content. If tonometry can discriminate between “soft” and “hard” edema/swelling, it can be used to differentiate these types, as treatment differs. Subjects and Methods: Twenty women with non-pitting unilateral postmastectomy arm lymphedema were operated on. The following measurements were performed: Tissue tonicity with a tonometer, its sensitivity on five different foam-polyethers by ten subjects, arm volumes, and adipose tissue aspirate content.
Results: Tissue tonicity values showed that the upper lymphedematous arm was harder than the normal one. After surgery it became softer, and at one year it was as soft as the normal arm. Polyether tonometries could clearly differentiate the various properties. A sample of three measurements was as good as ten. Horizontal vs. vertical measurements did not differ in the high-density polyethers. Complete reduction of the lymphedema was achieved. Adipose tissue content of the aspirate was 89%.
Conclusion: The tonometer could register postoperative changes in tissue tonicity in the upper arm, but not in the forearm, which also showed significantly higher absolute values. Probably this is caused by the high adipose tissue content with little or no free fluid, thus resembling the normal arm in tonicity. Possibly also the thinner subcutaneous tissue in the forearm plays a role. Tonometry can differentiate if a lymphedematous arm that is softer or harder than the normal one. A harder swelling is dominated by adipose tissue and can be treated with liposuction, while the softer one is treated conservatively. Mary Ann Liebert, Inc.