title: Cross friction algometry (CFA): Comparison of pressure pain thresholds between patients with chronic non-specific low back pain and healthy subjects.
abstract: Palpation is widely used to assess muscular sensitivity in clinical settings but still remains a subjective evaluation. This cross-sectional study assessed a newly developed cross-friction algometry making palpation measurable. The objective was to investigate the reliability of pressure pain thresholds obtained using Cross-Friction Algometry (CFA-PPTs) measured at the level of Erector spinae and Gluteus maximus central muscle parts, and to compare the CFA-PPTs between patients with chronic nonspecific low back pain (nCLBP) and matching healthy subjects.
  
  
  METHODS
  Patients presenting nCLBP to GP's and send into a Pain Center and healthy subjects recruited via university ad valvas & flyers distribution.
  
  
  METHODS
  30 patients with nCLBP were measured for cross-friction algometry. Other evaluations consisted of the Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI).
  
  
  RESULTS
  The inter- and intra-reliability were tested and found to be sufficient. The mean CFA-PPT values of the Erector spinae at levels T8, T10, L1 & L3 and the Gluteus maximus of the nCLBP group were significantly lower (p ≤ 0.001) when compared to the CFA-PPT values of the healthy group. The greatest difference (-58%) was found at L1 Erector spinae level and at the superior part of the Gluteus maximus measuring point (-59%). Within the group of patients with nCLBP it was surprising to notice that there was no significant correlation between all the reference points measured using CFA-PPTs and the outcomes of the VAS and ODI scores.
  
  
  CONCLUSIONS
  With the aid of CFA, the importance of local muscular disorder in the lumbar part of the Erector spinae and Gluteus maximus in patients with nCLBP is obviously demonstrated, but also reveals the very large inter-individual differences in muscular fibrosis sensitivity and/or pain behavior in daily life. This possibly re-opens the debate on which influences can be put forward as the most important: the central or the peripheral sensitization system.
authors.affiliation: Vrije Universiteit Brussel (VUB), Faculty of Physical Education & Rehabilitation Sciences, Laarbeeklaan 103, BE 1090 Brussels, Belgium. Electronic address: andre.farasyn@vub.ac.be.
authors.forename: Andre
authors.initials: A
authors.lastname: Farasyn
authors.affiliation: Vrije Universiteit Brussel (VUB), Faculty of Physical Education & Rehabilitation Sciences, Laarbeeklaan 103, BE 1090 Brussels, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Lassat
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D017276:Friction / Q000502:physiology*; D006801:Humans; D017116:Low Back Pain / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010147:Pain Measurement; D017288:Pain Threshold; D010173:Palpation / Q000379:methods; D011312:Pressure; D015203:Reproducibility of Results; D064746:Therapy, Soft Tissue / Q000379:methods*
keywords: Algometry; Cross-friction algometry; Low back pain; Trigger point