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The Somatic Connection  |   July 2015
Advances in Biomechanical Examination of Cervical Spine Manipulation
Author Affiliations
  • Hollis H. King, DO, PhD
    University of California, San Diego School of Medicine
Article Information
The Somatic Connection   |   July 2015
Advances in Biomechanical Examination of Cervical Spine Manipulation
The Journal of the American Osteopathic Association, July 2015, Vol. 115, 462-463. doi:10.7556/jaoa.2015.096
The Journal of the American Osteopathic Association, July 2015, Vol. 115, 462-463. doi:10.7556/jaoa.2015.096
Buzzatti L, Provyn S, Van Roy P, Cattrysse E. Atlanto-axial facet displacement during rotational high-velocity low-amplitude thrust: an in vitro 3D kinematic analysis. Man Ther. 2015:1-7. 
European researchers used high-resolution ultrasound-based motion tracking technology to measure motion at the atlantoaxial joint in 20 fresh human cadaver specimens. Their purpose was to expand the understanding of the biomechanical effects of high-velocity, low-amplitude (HVLA) manipulation of the upper cervical vertebrae and relate these data to the risk of vertebral artery dissection during HVLA procedures. 
The specimens were taken from 11 female and 9 male cadavers with a mean (SD) age of 81 (11) years. The specimens included the intact spinal cord from T2 to C2 and the head. T2 was stabilized in a mount, and the head was positioned on a head rest much like a treatment table. Sensors were mounted on the transverse processes of C1 and C2 and on the superior nuchal line of the occiput to allow for 3-dimensional analyses. The authors acknowledge that the in vitro preparations did not have all of the soft tissue elements typical of in vivo participants. 
Two experienced manual therapists, blinded from the data analysis results, each delivered 3 consecutive left rotation thrusts. A few specimens received right rotational thrusts. The rotational thrust was delivered with the head in flexion and contralateral sidebending. The manipulating hand was placed on the dorsal aspect of the C1 transverse process, the supporting hand was placed around the chin in a locking position, and slight traction was applied with the thrust. 
The data showed that the motion registered at the C2 facet ranged from 0.0 mm to 1.9 mm in all 3 axes, with means in each vector of 0.2 mm to 0.3 mm. Only on the x-axis were any notable and reliable induced displacements produced by either manual therapist. The authors concluded that “displacement during execution of HVLA thrust is unintentional, unpredictable, and not reproducible.” However, the authors suggest that the in vivo displacement of the C1-2 facet motion would be less than the mean of 0.2 mm found in their study and thereby would be unlikely to damage nearby spinal cord or vertebral artery structures. In discussions on the safety of cervical spine manipulation, the data reported in this study may be informative. 
Early in my training I was taught to do a rotational thrust without flexion and sidebending for the C1-2 joint so as to avoid any impact on the vertebral artery. It is surprising to me that this technique would still be done in clinical practice, and I would recommend additional investigations before implementing this technique in practice.