Reliable and feasible evaluation of linear scars by the patient and observer scar assessment scale

Background: Although scar evaluation tools are necessary for an evidence-based approach to scar management, there is as yet no generally accepted tool. The Patient and Observer Scar Assessment Scale was developed recently and found to be a useful subjective evaluation tool for burn scars. The authors tested the Patient and Observer Scar Assessment Scale on linear scars, the largest category of surgical scars. Methods: One hundred linear surgical scars were assessed by three independent observers using the observer scale to evaluate vascularity, pigmentation, thickness, relief, pliability, and surface area. The patients evaluated their scars simultaneously and 2 weeks later using the patient scale for the following parameters: pain, itching, color, stiffness, thickness, and relief. Results: The internal consistency of the observer and patient scales was good (Cronbach's α = 0.86 and 0.90, respectively). The reliability of the observer scale was good for the total score (r = 0.96, p < 0.001) and separate items (r ≥ 0.86, p < 0.001) for three observers. Even a single observer evaluated scars reliably with respect to the total score (r = 0.88, p < 0.001) and the items vascularity, pigmentation, thickness, and surface area (r > 0.70, p < 0.001). The patient's intraobserver reliability was good for the total score (r = 0.94, p < 0.001) and separate items (r ≥ 0.89, p < 0.001). The coefficient of variation of the total score was 10.4 percent for the observer scale and 15.8 percent for the patient scale, indicating good agreement. Conclusions: The Patient and Observer Scar Assessment Scale is an appropriate subjective tool for the evaluation of linear scars.