SHORT-TERM RESPONSIVENESS OF MANUAL THORACIC END PLAY ASSESSMENT TO SPINAL MANIPULATION - A RANDOMIZED CONTROLLED TRIAL OF CONSTRUCT-VALIDITY

Objective: To evaluate the short-term responsiveness of rotatory thora cic end-play assessment to spinal manipulation and, thereby, motion pa lpation construct validity. Design: Prospective, single-blind, randomi zed, controlled trial (randomized blocks design). Setting: Laboratory, Center for Technique Research. Participants: Sixty first-year chiropr actic college student volunteers; seventy-three possible candidates we re screened. Interventions: The treatment group received manual high-v elocity, low-amplitude rotatory manipulation. The control group receiv ed no intervention to minimize nonspecific effects of sham treatment. Main Outcome Measures: End-play response, defined as the change from r estricted to normal end play immediately after intervention. Responsiv eness, defined as the percentage of the end-play response attributable to spinal manipulation: relative response attributable to the maneuve r, RRAM = (treatment group response - control group response)/treatmen t group response. Results: Ten percent of the tests were positive for restriction of end play in left or right rotation from T3-T4 to T12-L1 , the average rate was 2.1 restrictions per subject (SD = 1.4). End-pl ay response was 60% in the treatment group, in contrast to the 37% res ponse in the control group (z = 1.86, p = .04). More than a third of t he response in the treatment group was attributable to spinal manipula tion (RRAM = 39%). For one examiner, RRAM = 51%. Mild symptomatology d id not affect responsiveness. Conclusions: The data suggest a moderate short-term responsiveness of rotatory thoracic end-play restriction t o spinal manipulation, hence it has utility as a posttreatment evaluat ive test. This study was the first to use an external standard (manipu lation) to demonstrate that segmental end-play restriction changes, he nce end-play restriction itself, are detectable in human subjects with manual palpation by chiropractors. Further research is required to de termine the generalizability of the study findings.