Optimizing Patient Positioning to Reduce Variation in the Measurement of Breast Cancer-Related Lymphedema

Sarah M. DeSnyder, MD,1 Parviz Kheirkhah, PhD,2 Marigold L. Travis, PT, CLT-LANA,3 Susan E. Lilly, PT,3 Isabelle Bedrosian, MD,1 Thomas A. Buchholz, MD,4 Mark V. Schaverien, MD,5 and Simona F. Shaitelman, MD, EdM4. Lymphatic Research Biology 2018

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Optimizing Patient Positioning to Reduce Variation in the Measurement of Breast Cancer-Related Lymphedema

Sarah M. DeSnyder, MD,1 Parviz Kheirkhah, PhD,2 Marigold L. Travis, PT, CLT-LANA,3 Susan E. Lilly, PT,3 Isabelle Bedrosian, MD,1 Thomas A. Buchholz, MD,4 Mark V. Schaverien, MD,5 and Simona F. Shaitelman, MD, EdM4. Lymphatic Research Biology 2018

Background: Prospective lymphedema screening is recommended for breast cancer patients. We observed interoperator variation in perometer-acquired arm volume measurements (P-AVMs) due to patient instability during measurements. We hypothesized that improved positioning during perometry would reduce P-AVM variability.

Methods and Results: Each arm was measured three times by each operator using a perometer. With the original configuration, P-AVM was performed by 2 operators in 30 patients and four cohorts of 5 to 6 operators in 5 volunteers. Repeatability, reproducibility, and gage precision/tolerance (P/T) ratio were calculated. A customized handlebar was installed to optimize patient positioning. P-AVMs were performed in 20 patients with both configurations. Student’s t-test was used to compare variation. With the new configuration, P-AVMs were performed by three operators in five volunteers and five operators in three volunteers. Repeatability, reproducibility, and gage P/T ratio were calculated. For the original configuration, gage P/T ratio was 19.9% for two operators and 35.9% for four cohorts of five to six operators. One operator using the new handlebar decreased P-AVM variability by 28% (p=0.02). For the new configuration, gage P/T ratio was 6.5% for three operators and 18.7% for five operators.

Conclusions: Optimizing patient setup improved P-AVM accuracy. P-AVM accuracy is critical as lack of accuracy results in either over diagnosis or under diagnosis of lymphedema, which in turn results in either over or under treatment of this dreaded condition. A higher number of operators were associated with greater P-AVM variability.

Main findings

  • This study tested the hypothesis that improving patient positioning would reduce variability in the perometer-acquired arm volume measurement (P-AVM) and thereby reduce both underdiagnosis and overdiagnosis of lymphedema. Their secondary hypothesis evaluated the impact of multiple operators on P-AVM.
  • An upright perometer was used. Their current protocol assessed both intra and inter therapist and then three new handlebars of various heights and a wall bar was created to improve the position of the person being measured.
  • The study revealed that use of a higher perometer handlebar as well as a wallbar perometer-acquired arm volume measurements with an upright perometer by 28%. Although rates of both underdiagnosis and overdiagnosis were higher at a 5% volume difference threshold than at a 10% volume difference threshold, both were reduced with the use of both a higher handlebar and a wallbar. As a result of this study, the perometers at the institution have been equipped with both a higher handlebar on the perometer and a wallbar to achieve the most accurate perometer-acquired arm volume measurements.
  • This study demonstrates the importance of maintaining stable patient positioning during perometer measurements and the need to quantify variability in arm volume measurements. For centers using multiple operators, attention should be paid to the impact this might have on measurement reliability and reproducibility.