title: An objective device for measuring surface roughness of skin and scars.
abstract: BACKGROUND
  Scar formation remains a major clinical problem; therefore, various therapies have been developed to improve scar quality. To evaluate the effectiveness of these therapies, objective measurement tools are necessary. An appropriate, objective measuring instrument for assessment of surface roughness is not yet available in a clinical setting. The Phaseshift Rapid In Vivo Measurement of the Skin (PRIMOS) (GFMesstechnik GmbH, Teltow, Germany) could be such an instrument. This device noninvasively produces a 3-dimensional image of the skin microtopography and measures surface roughness.
  
  
  OBJECTIVE
  The aim of this study was to investigate the reliability and validity of the PRIMOS for objective and quantitative measurement of surface roughness of skin and scars.
  
  
  METHODS
  Three observers assessed skin and burn scars in 60 patients using the PRIMOS and a subjective scale, the Patient and Observer Scar Assessment Scale. Reliability was tested using the intraclass correlation of intraobserver and interobserver measurements. An intraclass correlation coefficient of 0.7 or greater was required for reliable results. To test validity, scores of the PRIMOS were compared with scores of the subjective scale (Pearson correlation). A Pearson correlation coefficient greater than 0.6 was considered a strong positive correlation.
  
  
  RESULTS
  All 3 surface roughness parameters of the PRIMOS showed good intraobserver and interobserver reliability for skin and scars (intraclass correlation coefficient arithmetic mean of surface roughness > 0.85, mean of 5 highest peaks and 5 deepest valleys from entire measuring field > 0.88, peak count > 0.86). The parameter arithmetic mean of surface roughness showed a strong correlation with the subjective score (Pearson arithmetic mean of surface roughness 0.70; mean of 5 highest peaks and 5 deepest valleys from entire measuring field 0.53; peak count 0.54).
  
  
  CONCLUSIONS
  The reliability and validity of the PRIMOS were only tested on skin and burn scars, not in other dermatologic diseases.
  
  
  CONCLUSIONS
  The PRIMOS is a valid and reliable tool for objective noninvasive evaluation of surface roughness of both skin and burn scars.
authors.affiliation: Association of Dutch Burn Centers, Beverwijk, The Netherlands.
authors.forename: Monica C T
authors.initials: MC
authors.lastname: Bloemen
authors.forename: Maaike S
authors.initials: MS
authors.lastname: van Gerven
authors.forename: Martijn B A
authors.initials: MB
authors.lastname: van der Wal
authors.forename: Pauline D H M
authors.initials: PD
authors.lastname: Verhaegen
authors.forename: Esther
authors.initials: E
authors.lastname: Middelkoop
mesh_terms: D002056:Burns / Q000473:pathology*; D002921:Cicatrix / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000592:standards; D015588:Observer Variation; D010781:Photography / Q000295:instrumentation* / Q000592:standards; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology; D012871:Skin Diseases / Q000473:pathology*