Where does “evidence” come from?

Recent reviews have pointed out that most of our treatment-techniques are likely based on individual ‘convictions’ vs. valid, widely accepted protocols i.e. established evidence. Through studies (of numerous types) data is collected then eventually synthesized into reviews; meta-analysis or systematic. Theoretically these reviews create as definitive a representation of the knowledge available as is possible. Many times our interventions feel the sting of the relative dearth of high-quality studies or perhaps less optimistically our procedures have difficulty demonstrating their superiority. In 2004 and 2007 Cochrane review summaries states:

“There was little or no difference in pain reduction or ability to perform everyday activities between people with LBP who receive spinal manipulation and those receiving other therapies”.

“Traction added to a PT regimen offered no additional benefit to those with LBP”.

 In 2010 a systematic review (Sportschaden Mar;24) concludes:

“For LBP spinal segmental stabilization is more effective than a minimal intervention but no more effective than any other PT intervention”.

Ann of Int Med Oct;2(14) 2007:

“There is good evidence for a moderate benefit to the use of heat for acute LBP”.

“Spinal manipulation shows fair evidence for a small benefit in acute back pain”.

“Chronic LBP & neck pain show moderate effect with cognitive behavior therapy, manipulation, acupuncture, massage & yoga”.