title: A comparison of physical and psychological features of responders and non-responders to cervical facet blocks in chronic whiplash.
abstract: BACKGROUND
  Cervical facet block (FB) procedures are often used as a diagnostic precursor to radiofrequency neurotomies (RFN) in the management of chronic whiplash associated disorders (WAD). Some individuals will respond to the FB procedures and others will not respond. Such responders and non-responders provided a sample of convenience to question whether there were differences in their physical and psychological features. This information may inform future predictive studies and ultimately the clinical selection of patients for FB procedures.
  
  
  METHODS
  This cross-sectional study involved 58 individuals with chronic WAD who responded to cervical FB procedures (WAD_R); 32 who did not respond (WAD_NR) and 30 Healthy Controls (HC)s. Measures included: quantitative sensory tests (pressure; thermal pain thresholds; brachial plexus provocation test); nociceptive flexion reflex (NFR); motor function (cervical range of movement (ROM); activity of the superficial neck flexors during the cranio-cervical flexion test (CCFT). Self-reported measures were gained from the following questionnaires: neuropathic pain (s-LANSS); psychological distress (General Health Questionnaire-28), post-traumatic stress (PDS) and pain catastrophization (PCS). Individuals with chronic whiplash attended the laboratory once the effects of the blocks had abated and symptoms had returned.
  
  
  RESULTS
  Following FB procedures, both WAD groups demonstrated generalized hypersensitivity to all sensory tests, decreased neck ROM and increased superficial muscle activity with the CCFT compared to controls (p < 0.05). There were no significant differences between WAD groups (all p > 0.05). Both WAD groups demonstrated psychological distress (GHQ-28; p < 0.05), moderate post-traumatic stress symptoms and pain catastrophization. The WAD_NR group also demonstrated increased medication intake and elevated PCS scores compared to the WAD_R group (p < 0.05).
  
  
  CONCLUSIONS
  Chronic WAD responders and non-responders to FB procedures demonstrate a similar presentation of sensory disturbance, motor dysfunction and psychological distress. Higher levels of pain catastrophization and greater medication intake were the only factors found to differentiate these groups.
authors.affiliation: Division of Physiotherapy, NHMRC Centre of Clinical Excellence Spinal Pain, Injury and Health, University of Queensland, Brisbane, Australia. ashley.smith2@uqconnect.edu.au.
authors.forename: Ashley Dean
authors.initials: AD
authors.lastname: Smith
authors.forename: Gwendolen
authors.initials: G
authors.lastname: Jull
authors.forename: Geoff
authors.initials: G
authors.lastname: Schneider
authors.forename: Bevan
authors.initials: B
authors.lastname: Frizzell
authors.forename: Robert Allen
authors.initials: RA
authors.lastname: Hooper
authors.forename: Michele
authors.initials: M
authors.lastname: Sterling
mesh_terms: D000328:Adult; D000765:Anesthesia, Conduction; D016022:Case-Control Studies; D002574:Cervical Vertebrae; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007270:Injections, Intra-Articular; D008297:Male; D008875:Middle Aged; D059225:Nociception; D017288:Pain Threshold; D016059:Range of Motion, Articular; D017211:Treatment Failure; D014911:Whiplash Injuries / Q000523:psychology / Q000628:therapy*; D021801:Zygapophyseal Joint