A Tissue Dielectric Constant Evaluation of Knee Edema: A Retrospective Intra-rater Reliability and Association Study of Repeated Measures.

BACKGROUND: This research compared the reliability and association of tissue dielectric constant (TDC) measures of knee edema to circumferential measurements of knee girth recorded as part of a physical therapy examination. METHODS: Twenty adults having observable unilateral knee edema were enrolled. A single examiner measured edematous knee swelling with a TDC device and a tape measure across two visits. The presence of edema was recorded as a positive number in reporting side-to-side differences and a positive percentage in documenting change over time. Intra-rater reliability of the measures was assessed with an intra-class correlation coefficient (ICC). Percent change in edema was evaluated independently for both methods using a paired t-test, and the association between measures was assessed by a Pearson's statistic. RESULTS: Both measures were reliable (ICC ≥ 0.81), and both detected a significant percentage decrease (p < 0.05) in edema across visits. The TDC measure changed by 8.3%, an amount nearly four times larger compared to knee girth (2.4%). The subsequent follow-up comparison revealed an inverse relationship (p = 0.049; r = -0.44) between the two percent change measurements of edema. CONCLUSION: The two methods capture different physical attributes of edema. The TDC records the water content of the tissue, while the use of a tape measure records circumferential limb girth. The TDC measurement was reliable and more responsive in detecting a percentage decrease in knee edema in comparison to a circumferential measure of knee girth. The TDC method may have wider use in directly measuring edema in other tissue structures and regions of the body.

Tissue Dielectric Constant Measures in Women With and Without Clinical Trunk Lymphedema Following Breast Cancer Surgery: A 78-Week Longitudinal Study.

OBJECTIVE: Following breast cancer surgery with lymph node removal, women are at risk of developing lymphedema in the upper extremity or trunk. Currently, trunk lymphedema diagnosis relies on a clinical assessment because no quantifiable standard method exists. Tissue dielectric constant (TDC) values are quantifiable measures of localized skin tissue water and may be able to detect trunk lymphedema. The goal of this study was to (1) compare parameters derived from TDC measurements with those derived from clinically accepted criteria for trunk lymphedema in women following breast cancer surgery and (2) explore the potential utility of TDC to detect trunk lymphedema early in its progression. METHODS: This prospective longitudinal study, a secondary analysis from a larger study, observed women with and without clinically determined truncal lymphedema following breast cancer surgery. TDC was measured on the lateral trunk wall at post-surgery weeks 2, 4, 12, and 78 in women who had surgical breast cancer treatment with lymph node removal. Clinical assessment for trunk lymphedema was determined at 78 weeks by a lymphedema expert. Comparison of TDC measurements in women with and without clinical trunk lymphedema was analyzed. RESULTS: Clinical assessment identified trunk lymphedema in 15 out of 32 women at 78 weeks. These women had TDC ratios statistically higher than women without truncal lymphedema. CONCLUSION: The overall findings indicate that TDC has the ability to quantify trunk lymphedema and might be valuable in early detection. IMPACT: TDC may be a beneficial tool in the early detection of breast cancer-related trunk lymphedema, which could trigger intervention. LAY SUMMARY: A new device may help recognize trunk lymphedema in patients with breast cancer so they could receive appropriate treatment.

Spatial and Temporal Variability of Upper Extremity Edema Measures After Breast Cancer Surgery.

Background: Tissue dielectric constant (TDC), as an index of local tissue water, and girth measurements are quantitative methods to measure and characterize lymphedema. Objective: To describe the spatial and temporal variability in arm girth and TDC values in women surgically treated for breast cancer and to describe the relationship between these measures. Methods and Results: This was a prospective longitudinal study that observed 36 women for 78 weeks after breast cancer surgery with lymph node removal. Arm circumferences and TDC values, as indices of local tissue water, were measured on both arms at multiple sites at postsurgery weeks 2, 4, 12, and 78 in women undergoing surgical breast cancer treatment with one or more axillary lymph nodes removed. TDC and girth values remained relatively uniform from visit-to-visit for both at-risk and contralateral control arms with no overall statistically significant difference in values (p > 0.05). There was a strong inverse correlation between arm girth and the TDC value in both the at-risk and control arms (p < 0.001). Overall, there was no statistically significant difference in TDC interarm ratios among visits or anatomical sites. TDC values for at-risk and control arms tended to significantly decrease with increasing distance from the wrist (p < 0.001). Conclusion: TDC arm values and girth measures remained relatively uniform in women after breast cancer surgery. The fact that TDC values are higher distally than proximally provides new information from which TDC measurements may be interpreted and also provides a better understanding of arm spatial variability in relation to girth measures.

Function, Shoulder Motion, Pain, and Lymphedema in Breast Cancer With and Without Axillary Web Syndrome: An 18-Month Follow-Up.

Background: Axillary web syndrome (AWS) can develop following breast cancer surgery and presents as a tight band of tissue in the axilla with shoulder abduction. Objective: The objectives were to determine the prevalence and natural history of AWS and the association between AWS and function, range of motion, pain, lymphedema, and body mass index (BMI). Design: This study was a longitudinal prospective cohort study utilizing a repeated measures design. Methods: Axillary web syndrome, function, shoulder range of motion, pain, and lymphedema (using circumference, bioimpedance spectroscopy, tissue dielectric constant) were assessed in women at 2, 4, and 12 weeks and 18 months following breast cancer surgery. Prevalence of AWS and the association with the measured outcomes were analyzed. Results: Thirty-six women agreed to participate in the study. The cumulative prevalence of AWS was 50% (18/36) at 18 months following breast cancer surgery. AWS was identified as a risk factor for reduced function. Women with AWS had statistically reduced range of motion, lower BMI, and higher number of lymph nodes removed compared to the non-AWS group. Forty-one percent (13/32) of women had AWS at 18 months. AWS reoccurred in 6 women following resolution, and a new case developed beyond the early postoperative period. The overall prevalence of physical impairments ranged from 66% to 97% within the first 18 months following surgery regardless of AWS. Limitations: Limitations include a small sample size and potential treatment effect. Conclusion: AWS occurs in approximately 50% of women following breast cancer surgery. It can persist for 18 months and potentially longer, develop beyond the early postoperative time period, and reoccur after resolution. Clinicians need to be aware of the chronicity of AWS and its association with reduced range of motion and function.

Movement, Function, Pain, and Postoperative Edema in Axillary Web Syndrome.

BACKGROUND: Axillary web syndrome (AWS) is a condition that may develop following breast cancer surgery and that presents as a palpable axillary cord of tissue. OBJECTIVE: The purposes of this study were: (1) to determine the clinical characteristics of AWS related to movement, function, pain, and postoperative edema and (2) to define the incidence of and risk factors for AWS within the first 3 months following breast cancer surgery. DESIGN: This was a prospective cohort study with a repeated-measures design. METHODS: Women who underwent breast cancer surgery with sentinel node biopsy or axillary lymph node dissection (N=36) were assessed for AWS, shoulder range of motion, function, pain, and postoperative edema (using girth measurements, bioimpedance, and tissue dielectric constant) at 2, 4, and 12 weeks. Demographic characteristics were used for risk analysis. RESULTS: Seventeen women (47.2%) developed AWS, and AWS persisted in 10 participants (27.8%) at 12 weeks. Abduction range of motion was significantly lower in the AWS group compared with the non-AWS group at 2 and 4 weeks. There were no differences between groups in measurements of function, pain, or edema at any time point. Trunk edema measured by dielectric constant was present in both groups, with an incidence of 55%. Multivariate analysis determined lower body mass index as being significantly associated with AWS (odds ratio=0.86; 95% confidence interval=0.74, 1.00). LIMITATIONS: Limitations included a short follow-up time and a small sample size. CONCLUSION: Axillary web syndrome is prevalent following breast/axilla surgery for early-stage breast cancer and may persist beyond 12 weeks. The early consequences include movement restriction, but the long-term effects of persistent AWS cords are yet unknown. Low body mass index is considered a risk factor for AWS.