The Inter- and Intra-rater Reliability of Subcutaneous Echogenicity (SEG) Grade and Subcutaneous Echo-free Space (SEFS) Grade in Postmastectomy Lymphedema

The clinical severity of lymphedema in an extremity is generally graded according to the International Society of Lymphology (ISL) stage. Stage 0 which refers to a latent or subclinical condition where swelling is not evident despite impaired lymph transport. It may exist months or years before overt edema occurs (Stages I-III). Stage I represents an early accumulation of fluid relatively high in protein content (e.g., in comparison with "venous" edema) and subsides with limb elevation. Pitting may occur. Stage II signifies that limb elevation alone rarely reduces tissue swelling and pitting is manifest. Late in Stage II, the limb may or may not pit as tissue fibrosis supervenes. Stage III encompasses lymphostatic elephantiasis where pitting is absent and trophic skin changes such as acanthosis, fat deposits, and warty overgrowths develop. Within each Stage, severity based on volume difference can be assessed as minimal (<20% increase) in limb volume, moderate (20-40% increase), or severe (>40% increase).

Because the ISL stage mainly consists of findings achieved by physical examinations and represents the most severely affected arm, it is subjective and may not reflect the distribution and mode of progression of the disease. The characteristic skin and subcutaneous tissue changes in extremities with chronic lymphedema are caused by changes in the extracellular matrix, such as connective tissue hypertrophy, fat accumulation resulting from both fat hypertrophy and an increased number of adipocytes, and interstitial protein-rich fluid accumulation. Ultrasound has been used to assess and diagnose lymphedema related changes. Subcutaneous echogenicity (SEG) and subcutaneous echo-free space (SEFS) grade systems for postmastectomy lymphedema are developed in order to grade lymphedema objectively and to delineate the disease status more clearly. However, the reliability of SEG and SEFS has not been evaluated. The aims of this study is to determine the inter- and intra-rater reliability of SEG and SEFS grade systems for postmastectomy lymphedema. Two physiatrist (one ten-year-experienced and one five-year-experienced in musculoskeletal ultrasonography) independently and alternately will assess the subjects once for each assessment. Three days later after the initial examination, one of the physiatrists reassessed the patients. The inter- and intra-rater reliability will be determined using kappa.