Indurometer vs. Tonometer: Is the Indurometer Currently Able to Replace and Improve Upon the Tonometer?

Background: The Indurometer is a tool designed by the Flinders Biomedical Engineering Department to replace the Tissue Tonometer. It measures the resistance to an applied force to quantify the amount of fibrosis present within the epifascial compartment of tissue. The aim of the study was to compare the current model of the Indurometer with the Tonometer to determine the level of variability and repeatability between the two devices and how the variability differs when compared to an individual's ISL stage. Methods and Results: Data were gathered on a total of 180 participants with unilateral arm lymphedema as part of an international multicenter trial. For each participant three repeat measurements were obtained with the Indurometer and Tonometer at the anterior mid forearm and anterior mid upper arm. The Indurometer gave lower measurement values than the Tonometer. The Tonometer was found to be less variable than the Indurometer when measurements were taken from the anterior mid upper arm and the anterior mid forearm site. The Tonometer values were significantly less variable than the Indurometer values in ISL stages 1 and 2. No significant variability was found in stage 3. Conclusion: The Indurometer is easier to use as compared to the Tonometer. Modification of the Indurometer needs to take place in order to improve its variability before it can be considered as a replacement for the Tonometer in the assessment of lymphedema. The lack of understanding of the ISL classification system is a significant issue.