The audible pop from high-velocity thrust manipulation and outcome in individuals with low back pain

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 or 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 in immediate or longer-term follow-up.