Can interventional MRI provide an insight into the mechanics of a posterior–anterior mobilisation?

Objectives. A pilot study aimed to investigate if interventional MRI could detect changes in the spine and surrounding soft tissues as a result of a posteroanterior mobilisation, and to determine if such an effect was specific to the level of application. Design. A prospective pilot study to investigate the kinematics of cervical spine mobilisation. Background. Posteroanterior mobilisation is a manual physiotherapy technique that is commonly used as an examination tool and a form of conservative treatment. The efficacy of this technique is controversial and little is known regarding the underlying mechanisms. Methods. Five control subjects were recruited and written informed consent obtained. Subjects were scanned, using a General Electric Signa SP10 Open Interventional MRI scanner, in the prone position with their necks in either a neutral or flexed position. In each position a posteroanterior mobilisation to the 2nd and 6th cervical vertebrae was performed. Sagittal images of the spine were obtained prior to, during and following the mobilisation. Results. Clear images of vertebral position could be obtained during the application of a posteroanterior mobilisation. Measurements of intervertebral angulation and translation demonstrated little if any motion during the application of a posteroanterior mobilisation, in both a flexed and neutral position. Changes were seen in terms of soft tissue compression and in some instances overall angulation of the cervical spine. Conclusions. Interventional MRI can produce images of posteroanterior mobilisation. Dynamic imaging of the procedure produced images of unsuitable quality for analysis. The quasi-static images of suggested that the application of a posteroanterior mobilisation to the cervical spine produces minimal if any intervertebral motion, but significant soft tissue deformation of the overlying structures.