Forces required to cause cavitation during spinal manipulation of the thoracic spine

The Effects of Thoracic Manipulation on Posteroanterior Spinal Stiffness

“…30 Mechanical changes in PA spinal stiffness following spinal manipulation may be affected by the properties of the manual forces that are applied. Manipulation force parameters that have been measured include preload force, 27 peak force, 18,22,27 thrust duration, 18,22,27 thrust rate, 11,18,22 and the production of cavitation. 27 Cavitation describes the audible crack heard during manipulation, which is hypothesized to occur as the joint surfaces separate, creating a gas bubble which is collapsed by the surrounding fluid.…”

“…Preload force maximum is defined as the highest force during the 500 milliseconds prior to the beginning of the thrust phase and represents the therapist moving the spinal level to the end of normal range of movement. 11 Preload force minimum is the minimum force immediately preceding the manipulative thrust and represents the release of force prior to thrust. 27 Peak force is the maximum force produced during the manipulative thrust.…”

“…18,22,27 Thrust rate is the difference between peak force and preload force minimum divided by the thrust duration. 11,18,22 Total thrust force (N) was calculated to quantify the amount of force that was applied during the thrust phase of the manipulation and is defined as the difference between preload force minimum and peak force. The starting point (baseline zero) for the identification of these data points was defined as the point of lowest force preceding the thrust technique, because it was identifiable as the period where the subject expired immediately prior to the thrust technique (FIGURE 2).…”

The biomechanics of spinal manipulation

“…High-velocity, low-amplitude (HVLA) manipulations are more frequently used by chiropractors than other treatment modalities, and they are of special interest, as force magnitudes and the rates of force application are high. HVLA treatments cause deformations of the spine and surrounding soft tissues and often elicit a cracking sound that has been identified as cavitation of spinal facet joints (Cascioli et al, 2003;Conway et al, 1993;Haas, 1990;Herzog et al, 1993c;Meal and Scott, 1986;Miereau et al, 1988;Reggars, 1996). Despite the acknowledged nature of mechanical force application as a treatment modality (Triano, 2000), and the accepted idea that HVLA treatments produce mechanical effects (e.g., Triano and Schultz, 1997) at the treatment site, little is known about the biomechanics of spinal manipulation.…”

A functional pre-manipulative spinal orthopedic assessment maneuver

“…2 However, most orthopedic tests that are used for spine related presentations [3][4][5] do not adequately assess functional, coupled end-range limitations that reflect the specific forces commonly associated with those that are delivered when a manual adjustment is performed. [6][7][8][9][10][11][12][13][14][15][16] Orthopedic and functional examination procedures are used widely yet there is little research that adequately investigates the reliability, sensitivity, and specificity of the majority of them. Doctors who use manual therapies as one of their primary interventions may additionally use a variety of specific technique protocols.…”