Impact of audible pops associated with spinal manipulation on perceived pain: a systematic review

Abstract

Objectives An audible pop is the sound that can derive from an adjustment in spinal manipulative therapy and is often seen as an indicator of a successful treatment. A review conducted in 1998 concluded that there was little scientific evidence to support any therapeutic benefit derived from the audible pop. Since then, research methods have evolved considerably creating opportunities for new evidence to emerge. It was therefore timely to review the evidence. Methods The following electronic databases were searched for relevant studies pertaining to the impact of audible pops in spinal manipulative therapy: PubMed, Index to Chiropractic Literature (ICL), Cumulative Index to Nursing & Allied Health Literature (CINAHL) and Web-of-Science. The main outcome was pain. Two reviewers independently selected studies, extracted data, and assessed risk of bias and quality of the evidence using the Downs and Black checklist. Results of the included literature were synthesized into a systematic review. Results Five original research articles were included in the review, of which four were prospective cohort studies and one a randomized controlled trial. All studies reported similar results: regardless of the area of the spine manipulated or follow-up time, there was no evidence of improved pain outcomes associated with an audible pop. One study even reported a hypoalgesic effect to external pain stimuli after spinal manipulation, regardless of an audible pop. Conclusions Whilst there is still no consensus among chiropractors on the association of an audible pop and pain outcomes in spinal manipulative therapy, knowledge about the audible pop has advanced. This review suggests that the presence or absence of an audible pop may not be important regarding pain outcomes with spinal manipulation.

The effect of a spinal thrust manipulation’s audible pop on brain wave activity: a quasi-experimental repeated measure design

“…The lack of correlation between the presence of an audible pop and pain reduction was further supported by the findings of Cleland et al. (2007) and Moorman & Newell (2022) . In summary, there is currently no evidence that the audible pop impacts clinical ( e.g.…”

“…Joint manipulation is commonly used by a variety of healthcare practitioners when managing musculoskeletal disorders ( Moorman & Newell, 2022 ). Joint manipulation has been defined as a maneuver in which the joint is passively moved through various ranges.…”

“…Currently, the most accepted theories explaining the audible pop are the cavitational collapse and tribonucleation theories ( Bereznick et al, 2008 ; Kawchuk et al, 2015 ). The cavitational collapse theory hypothesizes that the rapid reduction in intraarticular joint pressure, caused by the HVLA manipulation, releasing nitrogen gas from the synovial fluid, causing the audible pop ( Sillevis & Cleland, 2011 ; Moorman & Newell, 2022 ). Currently, the acoustic signature of cavitation bubble collapse is consistent with experimentally observed sounds, thus lending support for cavitation bubble collapse as a potential source of the sound ( Chandran Suja & Barakat, 2018 ).…”

“…, pain and self-reported disability) or physiological ( e.g. , inflammatory markers and autonomic nervous system) outcomes ( Cleland et al., 2007 ; Sillevis & Cleland, 2011 ; Moorman & Newell, 2022 ; Flynn et al, 2003 ). Therefore, this study aimed to identify and quantify any changes that were present in the brain EEG signals in the presence or absence of an audible pop directly following a posterior to anterior (PA) HVLA manipulation at the thoracic seven vertebrae (T7).…”

Factors that contribute to the perceived effect of spinal manipulative therapy: A qualitative study

“…Evans and Lucas proposed a novel de nition of SMT which includes the production of cavitation as a requirement for an intervention to be considered SMT [14]. Despite this, a recent systematic review found that the presence of an audible pop does not appear to impact the hypoalgesic effect attributed to SMT [15]. Similarly, it is common practice to select a speci c target site for SMT via static or motion palpation of bony landmarks or joint segments.…”