Dr. James Dunning has a recent article published in BMC Musculoskeletal Disorders examining both the side(s) and number of cavitation sounds during upper cervical thrust manipulation. You can access it here through Open Access.
For the sake of this ‘By the Numbers’ post, 3.57 is the mean number of pops per C1-2 rotatory HVLA thrust manipulation in this study compared to 2.46 in a 1996 study by Reggars JW. So what does this mean?
Simply, it shows that he was able to get more cavitation/pops through the technique he teaches in his courses than previously studied by Reggars. There are difference in the technique as he describes in the article that can make this assumption, but be cautious that Reggars targeted C3-4 instead of current study of C1-2.
Also, we know that multiple cavitations typically are more optimal if you are targeting a joint as the degree of error is much higher than you would expect (such as we may try to target C3-4 but majority of the time if you only get ‘1 pop’, it will not be at that targeted joint). However, what we don’t know and he points out in the article, is if more cavitations leads to improved function and disability.
I don’t have the answer for this, as it has not been studied but I would typically say yes, it tends to lead to improved pain and movement within-session, which has been shown to have higher rates of improvement between-sessions.