When the back goes "pop"

What does it mean for the pain outcome if you hear a "pop" in connection with spinal manipulation? Nothing, according to a study published in CMT.

An audible "pop" is the sound that may originate from an adjustment during spinal manipulation; it is often seen as a sign of successful treatment, even though a 1998 literature review concluded that there was little scientific evidence of any therapeutic benefit from the audible sound. Since then, research methods have developed considerably, and this has created opportunities for new evidence to emerge. Therefore, the researchers behind the current study decided it was time to review the evidence.

The researchers conducted an electronic literature search to find relevant studies on the effect of audible "pops" during spinal manipulation and found five original research articles that were included in the review; four were prospective cohort studies and one a randomized controlled trial. The included studies included a total of 303 participants between the ages of 18 and 65, of which 38.7% were men and 61.3% were women.

All studies reached the same conclusion: 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 of the studies even reported a hypoalgesic effect on external pain stimuli after spinal manipulation, regardless of whether there was an audible “pop” or not.

Although the factors underlying clinical improvement associated with treatment that includes spinal manipulation are still unclear, the sound of a “pop” during spinal manipulation does not appear to be an important factor in the hypoalgesic effect. In terms of clinical practice, the study supports the notion that an audible "pop" is not an indicator of successful treatment.

Annelieke Cesanne Moorman & David Newell . Impact of audible pops associated with spinal manipulation on perceived pain: a systematic review. Chiropractic & Manual Therapies (2022)