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.