The effect of instrument assisted spinal manipulation on mechanical pain sensitivity in healthy population compared to control: A feasibility randomised trial

This trial involves using a small hand-held spring-loaded device that delivers an instrument assisted spinal manipulation (The Activator IV), a sham (Activator IV calibrated to produce no force) and a control group. Qualified Chiropractors with a minimum of 3 years experience will deliver the Activator treatment, Sham activator or control to a prone patient in a University research setting. The clinicians will deliver the randomly treatment either to the left or right of the L4 vertebra (targeted to the L4 pedicle). This is applied randomly in order to decrease bias due to participant's dominant side hand and will not be part of the analysis. Patients are required to meet the inclusion/exclusion criteria and will be assessed by the Clinicians. Pre-treatment baseline testing will be performed using a Wagner Pain Test algometer with a 1cm2 rubber probe. Each patient will receive one treatment with testing performed by a different clinician. The Activator or sham procedure involves placing the small hand-held spring-loaded device at the level of L4, producing a high-velocity low amplitude thrust (121-211.6N). This procedure including locating the L4 pedicle and delivering the thrust lasts only a few seconds. The sham is designed to simulate the Activator treatment without producing any force(0N). Post-treatment testing will be performed immediately after the intervention with blinding between assessors and clinicians. Following treatment and assessment, patients will be required to adhere to a questionnaire to investigate whether they believed they received one of two treatments (sham or intervention). This will investigate the believably of the sham. The entire procedure is estimated to be 60-90 minutes.