The audible pop is not necessary for successful spinal high-velocity thrust manipulation in individuals with low back pain

Objective To determine the relationship between an audible pop and symptomatic improvement with spinal manipulation in patients with low back pain (LBP). Design: A prospective cohort study. Setting: Two outpatient physical therapy clinics located in military medical centers. Participants: A cohort of 71 patients with nonradicular LBP referred to physical therapy. Interventions: Participants underwent a standardized examination and standardized spinal manipulation treatment program. All patients were treated with a sacroiliac (SI) region manipulative technique and the presence or absence of an audible pop was noted. Main Outcome Measures: Subjects were reassessed 48 hours after the manipulation for changes in range of motion (ROM), numeric pain rating scale (PRS) scores, and modified Oswestry Disability Questionnaire (ODQ) scores. Results: An audible pop occurred in 50 of the 71 subjects during the manipulative procedure. Both groups-those who had an audible pop and those who did not-improved over time in flexion ROM, PRS scores, and modified ODQ scores; however, there were no differences between groups (P>.05). Nineteen of the 71 (27%) patients improved dramatically (mean drop in modified ODQ, 67.6%). In 14 of the 19 dramatic responders, an audible pop occurred. However, the odds ratio (1.2; 95% confidence interval, 0.38-4.04) suggested that the occurrence of a manipulative pop would not improve the odds of achieving a dramatic reduction in symptoms after the manipulation. Conclusion: There is no relationship between an audible pop during SI region manipulation and improvement in ROM, pain, or disability in individuals with nonradicular LBP. Additionally, the occurrence of a pop did not improve the odds of a dramatic improvement with manipulation treatment.