title: Tissue loading created during spinal manipulation in comparison to loading created by passive spinal movements.
abstract: Spinal manipulative therapy (SMT) creates health benefits for some while for others, no benefit or even adverse events. Understanding these differential responses is important to optimize patient care and safety. Toward this, characterizing how loads created by SMT relate to those created by typical motions is fundamental. Using robotic testing, it is now possible to make these comparisons to determine if SMT generates unique loading scenarios. In 12 porcine cadavers, SMT and passive motions were applied to the L3/L4 segment and the resulting kinematics tracked. The L3/L4 segment was removed, mounted in a parallel robot and kinematics of SMT and passive movements replayed robotically. The resulting forces experienced by L3/L4 were collected. Overall, SMT created both significantly greater and smaller loads compared to passive motions, with SMT generating greater anterioposterior peak force (the direction of force application) compared to all passive motions. In some comparisons, SMT did not create significantly different loads in the intact specimen, but did so in specific spinal tissues. Despite methodological differences between studies, SMT forces and loading rates fell below published injury values. Future studies are warranted to understand if loading scenarios unique to SMT confer its differential therapeutic effects.
authors.affiliation: Department of Physical Therapy, University of Alberta, Edmonton, AB, Canada.
authors.forename: Martha
authors.initials: M
authors.lastname: Funabashi
authors.affiliation: Department of Physical Therapy, University of Alberta, Edmonton, AB, Canada.
authors.forename: Gregory N
authors.initials: GN
authors.lastname: Kawchuk
authors.affiliation: Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada.|Glenrose Rehabilitation Hospital, Alberta Health Services, Edmonton, AB, Canada.
authors.forename: Albert H
authors.initials: AH
authors.lastname: Vette
authors.affiliation: Department of Mechanical Engineering, University of Calgary, Calgary, AB, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Goldsmith
authors.affiliation: Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Narasimha
authors.initials: N
authors.lastname: Prasad
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D006801:Humans; D007403:Intervertebral Disc / Q000502:physiology; D017116:Low Back Pain / Q000503:physiopathology / Q000628:therapy; D008159:Lumbar Vertebrae / Q000502:physiology; D020393:Manipulation, Spinal / Q000009:adverse effects / Q000379:methods*; D023421:Models, Animal; D016059:Range of Motion, Articular / Q000502:physiology; D012371:Robotics; D034421:Sus scrofa; D016474:Weight-Bearing / Q000502:physiology