| OBJECTIVE: The purpose of this study was to document applied forces by the manipulator to the lumbar spine, lower torso and lower extremities on the subject during side posture lumbar manipulation. It was hypothesized that the location of the forces applied to the recipient of side posture lumbar manipulation influence the ability to achieve cavitation. BACKGROUND: Clinicians utilizing side posture lumbar manipulation claim to emphasize using their contact hand on the patient's spine to cause spinal joint cavitation. METHODS: This study was reviewed and approved by the Institutional Review Boards of Canadian Memorial Chiropractic College and University of Waterloo. Seven asymptomatic participants, ranging in age from 16 to 32 years, volunteered to act as subjects. Ten clinicians performed side posture lumbar manipulation. The range of clinical experience was 1 to 24 years. All asymptomatic subjects received side posture lumbar manipulation. The subjects were mounted with pressure mats covering their spine, posterior pelvis (PSIS & iliac crest) and upside lateral thigh. Accelerometers were secured to the subject's skin over the spinal column and each accelerometer detected vibration from the cavitation associated with side posture lumbar manipulation. The location and magnitude of applied force was noted at the time of peak force during side posture lumbar manipulation and assumptions were made to estimate the lumbar axial moment. RESULTS: Subjects exposed to axial lumbar moments equal or in excess of 109.8 Nm invariably generated cavitation. Conversely, less than 82.8 Nm of lumbar axial moment failed to achieve cavitation among all subjects. Directing 25% or more of the total force to the lumbar spine, as opposed to more peripheral sites, invariably generated no cavitation. There was an inverse linear relationship between pelvis and thigh applied force only when cavitation was achieved as those manipulators emphasized either thigh or pelvis force, not both. There was no relationship when cavitation did not occur. CONCLUSIONS: Successful generation of cavitation during side posture lumbar manipulation requires emphasizing forces to areas on a patient remote from the spine such as the pelvis and/or lateral thigh. This would produce a sufficient lumbar axial moment. Students learning side posture lumbar manipulation should be taught to utilize contact points on the posterior pelvis and/or lateral thigh if lumbar cavitation is a desired outcome of the manipulative procedure. This abstract is reproduced with the permission of the publisher. |
