title: Do severity score and skin temperature asymmetry correlate with the subjective pain score in the patients with complex regional pain syndrome?
abstract: BACKGROUND
  The diagnostic criteria of complex regional pain syndrome (CRPS) have mainly focused on dichotomous (yes/no) categorization, which makes it difficult to compare the inter-patient's condition and to evaluate the intra-patient's subtle severity over the course of time. To overcome this limitation, many efforts have been made to create laboratory methods or scoring systems to reflect the severity of CRPS; measurement of the skin temperature asymmetry is one of the former, and the CRPS severity score (CSS) is one of the latter. However, there has been no study on the correlations among the CSS, temperature asymmetry and subjective pain score. The purpose of this study was to evaluate whether there is any correlation between the CSS, skin temperature asymmetry and subjective pain score.
  
  
  METHODS
  Patients affected with CRPS in a unilateral limb were included in this study. After making a diagnosis of CRPS according to the Budapest criteria, the CSS and skin temperature difference between the affected and unaffected limb (ΔT) was measured in each patient. Finally, we conducted a correlation analysis among the CSS, ΔT and visual analogue scale (VAS) score of the patients.
  
  
  RESULTS
  A total of 42 patients were included in this study. There was no significant correlation between the ΔT and VAS score (Spearman's rho = 0.066, P = 0.677). Also, the CSS and VAS score showed no significant correlation (Spearman's rho = 0.163, P = 0.303).
  
  
  CONCLUSIONS
  The ΔT and CSS do not seem to reflect the degree of subjective pain in CRPS patients.
authors.affiliation: Department of Anesthesiology and Pain Medicine, KEPCO Medical Center, Seoul, Korea.
authors.forename: Seung Gyu
authors.initials: SG
authors.lastname: Jeon
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Choi
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Pyung Bok
authors.initials: PB
authors.lastname: Lee
authors.affiliation: Kirin Pain Clinic, Seoul, Korea.
authors.forename: Young Jae
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Min Soo
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Joung Hwa
authors.initials: JH
authors.lastname: Seo
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Francis Sahngun
authors.initials: FS
authors.lastname: Nahm
keywords: complex regional pain syndrome; infrared thermography; severity of illness index; visual analogue pain scale