title: The audible pop from high-velocity thrust manipulation and outcome in individuals with low back pain.
abstract: OBJECTIVE
  To determine the relationship between an audible pop with spinal manipulation and improvement in pain and function in patients with low back pain.
  
  
  METHODS
  In this pragmatic study, 70 patients from a multicenter clinical trial were randomly assigned to receive high-velocity thrust manipulation and included in this secondary analysis. Patients were managed in physical therapy twice the first week, then once a week for the next 3 weeks, for a total of 5 sessions. A single high-velocity thrust manipulative intervention purported to affect the lumbopelvic region was used during the first two sessions. Therapists recorded whether an audible pop was heard by the patient or therapist. Outcome was assessed with an 11-point pain rating scale, the Oswestry Disability Questionnaire, and measurement of lumbopelvic flexion range of motion. Repeated measures analyses of variance were used to examine whether achievement of a pop resulted in improved outcome.
  
  
  RESULTS
  An audible pop was perceived in 59 (84%) of the patients. No differences were detected at baseline or at any follow-up period in the level of pain, the Oswestry score, or lumbopelvic range of motion based on whether a pop was achieved (P > .05). The odds ratios and 95% confidence intervals for achieving a successful outcome at each of the follow-up periods all approximated a value of 1, suggesting no improvement in the odds of successful outcome among patients in which an audible pop occurred.
  
  
  CONCLUSIONS
  The results of this pragmatic study suggest that a perceived audible pop may not relate to improved outcomes from high-velocity thrust manipulation for patients with nonradicular low back pain at either an immediate or longer-term follow-up.
authors.affiliation: Department of Physical Therapy, Regis University, Denver, CO 80221-1099, USA. tflynn@regis.edu
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Flynn
authors.forename: John D
authors.initials: JD
authors.lastname: Childs
authors.forename: Julie M
authors.initials: JM
authors.lastname: Fritz
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology* / Q000628:therapy*; D008297:Male; D026882:Manipulation, Chiropractic / Q000379:methods*; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000592:standards*; D016896:Treatment Outcome