title: Changes in pressure pain threshold in patients with chronic nonspecific low back pain.
abstract: METHODS
  Cross-sectional study.
  
  
  OBJECTIVE
  The purpose of this study is to compare pressure pain threshold (PPT) values between patients with chronic nonspecific low back pain (CLBP) and healthy individuals and correlate PPT values of the structures investigated with demographic and clinical data from patients with CLBP.
  
  
  BACKGROUND
  Chronic pain may decrease pain tolerance of almost the entire spinal cord segment; however, previous studies on PPT in patients with low back pain have limited their focus to evaluating only patient complaints.
  
  
  METHODS
  Forty subjects participated in the study: 20 with a clinical diagnosis of CLBP and 20 healthy individuals. Outcome measures were PPT values of myotomes, sclerotomes, and dermatomes corresponding to segments L1 to S3; demographic, clinic, and social data; visual analogue scale, and Roland and Morris Questionnaire.
  
  
  RESULTS
  Most analyzed structures had lower PPT values in patients with CLBP than in healthy individuals on both sides (bilaterally). PPT correlated positively with height and pain duration (P < 0.05) and negatively with body mass index in the suprainterspinous ligament between L2 and L3 and dermatomes L5 to S2 (P < 0.05).
  
  
  CONCLUSIONS
  Our results showed that individuals with CLBP have lower PPT values than healthy individuals in almost all assessed structures. We propose a simple approach that can differentiate patients with CLBP whose hyperalgesia in the painful area may be the result of several mechanisms that should be further investigated, such as sensitization of the central nervous system.
  
  
  METHODS
  N/A.
authors.affiliation: *Division of Physical Medicine and Rehabilitation, Department of Orthopaedics and Traumatology, Clinical Research Center at the Institute of Physical and Rehabilitation Medicine, University of Sao Paulo School of Medicine, Sao Paulo, Brazil; †Center of Acupuncture, Department of Orthopaedics and Traumatology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil; ‡Center of Acupuncture, Department of Orthopaedics and Traumatology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil; §São Paulo Adventist University Center, Physical Therapy and Master in Health Promotion, and Clinical Research Center, Institute of Physical Medicine and Rehabilitation, University of São Paulo School of Medicine, São Paulo, Brazil; ¶University of São Paulo School of Medicine, São Paulo, Brazil; and ‖Department of Pathology and Director of the Center of Acupuncture, Department of Orthopaedics and Traumatology, University of Sao Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Marta
authors.initials: M
authors.lastname: Imamura
authors.forename: Janini
authors.initials: J
authors.lastname: Chen
authors.forename: Suely Reiko
authors.initials: SR
authors.lastname: Matsubayashi
authors.forename: Rosa A
authors.initials: RA
authors.lastname: Targino
authors.forename: Fábio Marcon
authors.initials: FM
authors.lastname: Alfieri
authors.forename: Daniel Kamura
authors.initials: DK
authors.lastname: Bueno
authors.forename: Wu Tu
authors.initials: WT
authors.lastname: Hsing
mesh_terms: D000328:Adult; D001827:Body Height; D015992:Body Mass Index; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000502:physiology*; D011795:Surveys and Questionnaires