ABSTRACT
BACKGROUND: The Patient and Observer Scar Assessment Scale (POSAS) v2.0 is a widely used instrument to evaluate postsurgical scars. Its two subscales respectively investigate the patient's and clinician's opinion on the scar quality. However, psychometric studies of the POSAS have indicated that its metric performance is suboptimal, and structural adjustments may be appropriate. The authors aimed to verify through Rasch analysis the measurement properties of the POSAS v2.0, and propose eventual structural refinements for an easier and more confident use of the scale in clinical practice and research. METHODS: Consecutive patients admitted to two rehabilitation centers for postsurgery rehabilitation over a 2-year period underwent scar assessments with the POSAS v2.0. We performed Rasch analysis to examine the scale's dimensionality, rating categories, item fit, reliability indices, local item independence, and differential item functioning. RESULTS: The study population consisted of 115 patients. The 10 response options of the POSAS showed malfunctioning, and thus were collapsed, forming a parsimonious five-level rating scale, which helped to improve the measurement accuracy. After that, unidimensionality of both subscales was confirmed. Then, internal construct validity of the POSAS v2.0 was demonstrated (through item fit to the Rasch model). Reliability indices were high (≥0.80). No significant differential item functioning was detected concerning age or sex. CONCLUSION: This study demonstrates the good psychometric properties of a simplified Rasch-based version of the Patient and Observer Scar Assessment Scale with five response options (POSAS v2.1) in patients with postsurgical linear scars, and provides insights for future refinement of the tool.
Subject(s)
Cicatrix/pathology , Postoperative Complications/pathology , Severity of Illness Index , Adult , Aged , Humans , Male , Middle Aged , Musculoskeletal Diseases/rehabilitation , Musculoskeletal Diseases/surgery , Observer Variation , Patient Reported Outcome Measures , PsychometricsABSTRACT
The Patient and Observer Scar Assessment Scale (POSAS) is one of the most robust instruments to assess scar quality, but there is no Italian version, and no other competing instruments are available in Italian. The aim of this study was to translate and validate an Italian version of POSAS (POSAS-I). POSASv2.0 was culturally adapted in accordance with international standards. The psychometric assessment included acceptability/feasibility, internal consistency, reproducibility, construct validity and sensitivity to change. Cultural equivalence of POSAS-I with the English version was confirmed. The validation study included 102 subjects with surgical scars. Both subscales demonstrated acceptable internal consistency (Cronbach's α = 0·72-0·80). Reproducibility of the OSAS-I (ICCs = 0·93-0·94; SEM = 1·8 points; MDC95 = 5·1 points) was superior to that of PSAS-I (ICC = 0·65; SEM = 5·7 points; MDC95 = 15·7 points). OSAS-I showed moderate to good correlations with the Vancouver Scar Scale (VSS), Global Rating of Change Scale (GRCS) and PSAS-I. Sensitivity to change was large for PSAS-I (effect size = 1·08; standardised response mean = 0·96) and moderate to large for OSAS-I (ES = 0·69; SRM = 0·92). This study confirmed that POSAS-I can be used to assess patients with surgical scars in the Italian population. OSAS-I is useful for clinical and research purposes, while PSAS-I should be better used to capture patients' own opinions and symptoms in clinical settings.
Subject(s)
Cicatrix/classification , Patient Participation , Reference Standards , Adult , Aged , Aged, 80 and over , Cross-Cultural Comparison , Female , Humans , Italy , Male , Middle Aged , Psychometrics , Reproducibility of Results , Surveys and Questionnaires , TranslationsSubject(s)
Anti-Inflammatory Agents/therapeutic use , Cervical Vertebrae/diagnostic imaging , Cysts , Musculoskeletal Manipulations/methods , Neck Pain , Osteoarthritis, Spine , Aged , Cysts/complications , Cysts/diagnostic imaging , Cysts/physiopathology , Cysts/therapy , Female , Humans , Neck Pain/diagnosis , Neck Pain/etiology , Osteoarthritis, Spine/complications , Osteoarthritis, Spine/diagnosis , Osteoarthritis, Spine/physiopathology , Osteoarthritis, Spine/therapy , Tomography, X-Ray Computed/methods , Treatment OutcomeABSTRACT
BACKGROUND AND PURPOSE: Scarring after surgery can lead to a wide range of disorders. At present, the degree of scar adhesion is assessed manually and by ordinal scales. This article describes a new device (the Adheremeter) to measure scar adhesion and assesses its validity, reliability, and sensitivity to change. DESIGN: This was a reliability and validity study. SETTING: The study was conducted at the Scientific Institute of Veruno. PARTICIPANTS AND METHODS: Two independent raters, a physical therapist and a physical therapist student, used the Adheremeter to measure scar mobility and contralateral normal skin in a sample of 25 patients with adherent postsurgical scars before (T1) and after (T2) physical therapy. Two indexes of scar mobility, the adherence's surface mobility index (SM(A)) and the adherence severity index (AS), were calculated. Their correlation with the Vancouver Scar Scale (VSS) and its pliability subscale (PL-VSS) was assessed for the validity analysis. RESULTS: Both the SM(A) and the AS showed good-to-excellent intrarater reliability (intraclass correlation coefficient [ICC]=.96) and interrater reliability (SM(A): ICC=.97 and .99; AS: ICC=.87 and .87, respectively, at T1 and T2), correlated moderately with the VSS and PL-VSS only at T1 (r(s)=-.58 to -.66), and were able to detect changes (physical therapist/physical therapist student): z score=-4.09/-3.88 for the SM(A) and -4.32/-4.24 for the AS; effect size=0.6/0.4 for the SM(A) and 1.4/1.2 for the AS; standard error of measurement=4.59/4.79 mm(2) for the SM(A) and 0.05/0.06 for the AS; and minimum detectable change=12.68/13.23 mm(2) for the SM(A) and 0.14/0.17 for the AS. LIMITATIONS: The measurement is based on the rater's evaluation of force to stretch the skin and on the patient's judgment of comfort. DISCUSSION AND CONCLUSION: The Adheremeter showed a good level of reliability, validity, and sensitivity to change. Further studies are needed to confirm these results in larger cohorts and to assess the device's validity for other types of scars.
Subject(s)
Cicatrix/complications , Physical Examination/instrumentation , Physical Therapy Modalities/instrumentation , Postoperative Complications/diagnosis , Tissue Adhesions/diagnosis , Adult , Aged , Cicatrix/physiopathology , Humans , Infant , Male , Middle Aged , Pilot Projects , Postoperative Complications/etiology , Reproducibility of Results , Severity of Illness Index , Statistics, Nonparametric , Tissue Adhesions/etiologyABSTRACT
PURPOSE: Complications of surgical incision include pathological scars with functional, cosmetic or psychological consequences. Postsurgical scar assessment is fundamental for a complete functional evaluation and as an outcome measure. Scar assessment scales are here reviewed and discussed from a clinical and psychometric point of view, with a clear definition of different scar parameters. METHOD: An extensive review of the English-language literature was conducted using the Medline database. RESULTS: Four scales that satisfy psychometrical criteria were identified: Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (POSAS), Manchester Scar Scale (MSS) and Stony Brook Scar Evaluation Scale (SBSES). CONCLUSIONS: To date, VSS is the most widely used rating scale for scars but POSAS appears the most comprehensive, taking into account the important aspect of patient's perspective. The MSS has been never used for research, while SBSES has only been very recently proposed.
