HVLA principles Flashcards
Definition of HVLA
Nicholas: direct technique which causes high velocity/low amplitude forces, also called mobilisation impulse treatment. In other words, a spinal manipulation with gentle stroking of the paraspinal soft tissues, named thrust treatment. High acceleration, low distance.
Explain spinal manipulation
- act 1991 stated that is a rapid application force by manual or mechanical means on part’s of person’s body, either joint or segment of the vertebral column.
Explain HVLA
HVLA engage barrier of motion restriction through quick and short thrust, generating sometimes a popping sound. The technique is always performed within the range of motion and little force. HVLA doesn’t exceed anatomical barrier.
How to perform a successful HLVA?
Physician must combine a rapid acceleration force with only a minimal movement of the articular segment that is being treated. The distance in this formula should be only enough to move the dysfunctional articular segment through the restrictive barrier, not to carry it through the barrier and beyond the physiologic barrier.
Explain the pop sound
To improve or restore motion loss at a joint level by using HVLA, an articular pop can occur. However different theory has been cited about the sound, including cavitation, a change in synovial fluid to a gaseous state. The Co2 and the gases dissolved in the synovial fluids releasing a gas that maintain pressure volume relationship. Or a vacuum phenomena, where the synovial fluid create a vacuum force with the articular segment.
Who can perform HVLA?
cervical manipulation can be only performed by registered osteopaths, chiropractor, physiotherapists or doctors. The law authorised HVLA to be performed only by registered health professional, students in approved program studies and clinical training (only within the course) with a supervisor authorised to perform the activities.
When can penalty occur?
When manipulation of the cervical spine occur without consent, understanding from the patient, registration and legal autorisation to practise. It is defined by moving the joints of the cervical spine beyond the individuals usual physiological range of motion using high velocity and low amplitude thrust.
What are the two types of mechanism of HVLA?
intra-articular / neurophysiologic.
Explain the 4 proposed theories behind HLVA
- released of entrapped synovial folds or entrapped menisci’s.
- relaxation of hypertonic muscle by sudden stretching.
- Disruption of articular and peri-articular region
- unbuckling motion segments that undergone disproportionate placements.
Explain the entrapped synovial folds or meniscoids
Nerves fibers course the synovial folds, remote from blood vessels, were most likely nociceptive. The synovial folds become pinched between articular facets surfaces at the ZA. Intraarticular entrapments within the ZA can be a potential sources of pain, leading to an acute locked back. theory of entrapment demands that the joint be in or near to a neutral position, to create the pinching. Pain occurs as distention of the joint capsule providing stimulus to the nociceptors to depolarise. Muscle spasm would occur to prevent impaction of the meniscoids by keeping them rotated.
What is the impact of HVLA on entrapped SF or menisci’s?
the manipulation, involved gapping of the ZA, reducing impaction and opens the joint, so encouraging the meniscoidal to return to its normal anatomic position in the joint cavity. This ceases the distention of the joint capsule thus reducing pain.
Explain the theory about HVLA creating relaxation of hypertonic muscle by sudden stretching.
Viscoelasticity properties are a property of soft tissues whereby the strain induced in the tissue is dependent on the rate of loading of the applied stress. The connective tissue in and around the muscle belly, tendons, joint capsules, and ligaments exhibits viscoelastic behaviour under loading, due to biochemical interaction between the collagen fibres and the ground substances.
Forces produced during HVLA of the ZA joint can be large. However applied properly, these forces shouldn’t be transferred to the soft tissues and should be dissipated into the SF, which is also viscoelastic. SF absorb the forces to cause cavitation.
Mechanoreceptors, proprioceptors, and nociceptors afferents of both joint capsules and musculotendinous structures have been viewed as a gate away through which the nervous system would be influenced by HVLA techniques.
Forces in HVLA are transferred around joint capsule and soft tissues nociceptive afferents, and therefore activated them. The protective role of the musculature against potentially harmful force to joints, is done by reflex arcs, creating a synergism btw the passive and active joint restraint.
HVLA can normalise abnormal motor tone by the stimulation of inhibitory afferents. Creating a reduction of paraspinal spontaneous EMG activity, hyperalgesia of paraspinal myofascial trigger points and generating a alterations of the sensitisation of the dorsal horn.
Neuropeptide release during cavitation, but cannot explained by simple mechanoreceptors mediated reflex arcs.
Explain the theory behind HVLA and the disruption of articular or peri-articular adhesions.
Normal range of mvt in a synovial joint is termed physiological zone. HVLA involves a pre-load taking the viscoelastic SF to a well defined elastic recoil, characterised by increasing stiffness. Impulses create mvt btw the articular surfaces of the joint is ultimately delivered to the SF.
Cavitation occurs when the articular surfaces are separated through the elastic recoil of the SF above a critical velocity, causing SF to fracture or crack open like solid. High rates shear, liquids begin to behave mechanically as solids. Removal of adhesion cannot explain pain related or non mechanical effects of zygapophyseal HVLA.
Possible injuries to the ZA joint can generate articular fibrosis and would need to be stretched at a slow rate.
Explain the theory of HVLA and unbuckling of motion segments that have undergone disproportionate displacements
Biomechanics studies show this positional theory to be false and merely demonstrate transient relative movements of the manipulated vertebrae associated with cavitation. Radiographs, computed tomography, and MRI imaging scans have been shown to be an unreliable method for diagnosis back pain.
Give few characteristic about taking a segment into a barrier in HVLA.
- should not take further than anatomical barrier.
- physiological barrier limit movement (no SD, no treatment)
- Elastic = passive stretching.
- Restrictive barrier =reduce ROM =articular dysfunction
