Values of a Patient and Observer Scar Assessment Scale to Evaluate the Facial Skin Graft Scar

BACKGROUND The patient and observer scar assessment scale (POSAS) recently emerged as a promising method, reflecting both observer's and patient's opinions in evaluating scar. This tool was shown to be consistent and reliable in burn scar assessment, but it has not been tested in the setting of skin graft scar in skin cancer patients. OBJECTIVE To evaluate facial skin graft scar applied to POSAS and to compare with objective scar assessment tools. METHODS Twenty three patients, who diagnosed with facial cutaneous malignancy and transplanted skin after Mohs micrographic surgery, were recruited. Observer assessment was performed by three independent rates using the observer component of the POSAS and Vancouver scar scale (VSS). Patient self-assessment was performed using the patient component of the POSAS. To quantify scar color and scar thickness more objectively, spectrophotometer and ultrasonography was applied. RESULTS Inter-observer reliability was substantial with both VSS and the observer component of the POSAS (average measure intraclass coefficient correlation, 0.76 and 0.80, respectively). The observer component consistently showed significant correlations with patients' ratings for the parameters of the POSAS (all p-values<0.05). The correlation between subjective assessment using POSAS and objective assessment using spectrophotometer and ultrasonography showed low relationship. CONCLUSION In facial skin graft scar assessment in skin cancer patients, the POSAS showed acceptable inter-observer reliability. This tool was more comprehensive and had higher correlation with patient's opinion.