SMT 1 - Kinematics/Kinetics HVLAT

Question 1

Research showing popping sound isn’t necessary.

Answer 1

The notion that a “cracking” sound is not necessary is based on just one study published twice. Flynn’s 2003 and 2006 study using the Chicago HVLAT that is usually done for SI joint. He had 4 attempts, 2 on each side.

Question 2

Beffa and Mathews (2004)?

Answer 2

Microphones taped to 3rd, 4th, 5th facets, and PSIS (SI) and L5/S1 or SI HVLAT performed. L5/S1 thrust cavitated the L3/L4 upside facet most often. SIJ thrust cavitated the L5/S1 upside facet more often.

Question 3

What is the mean cervical thrust duration?

Answer 3

Ngan (2005) - 158 ms with range of 117 to 250 ms
Triano (1992) - 135 ms
Herzog (1993) - 80 to 200 ms

Question 4

How long from start of contact to thrust for cervical spine?

Answer 4

Klein (2003) - Took mean of 7 seconds from contact/start of movement of head to thrust

Question 5

Purpose of pre-load and thrust phases?

Answer 5

Herzog (1993) - Pre-load: to move joint of interest to NEAR the end of passive motion. Thrust: Aimed at restoring joint integrity and joint range of motion, will immediately relax hypertensive muscles surrounding treatment area.

Question 6

How much pre-thrust rotation is needed for cervical HVLAT?

Answer 6

Ngan (2005) - For C5/C6 rotary chin hold: Rotation 54, flexion 30, sidebend 6 degrees
Triano and Schultz (1994) - Rotation 40, Flexion 18
Klein (2003) - For C3 and C5 Levels: Rotation 30, lateral bending 46, flexion 2 degrees

Question 7

De-Rotation Displacement for the cervical spine?

Answer 7

Ngan (2005) found that the more de-rotation displacement you put on, the more thrust displacement, velocity, and acceleration occurs

Question 8

3D Kinematics of Cervical HVLAT?

Answer 8

Klein (2003) found that side/level did not influence 3D ROM. Angular displacements were not larger for C3 than C5, Thus, you don’t rotate or SB down to the level, components are applied to the level to be manipulated.

Rotation and SB were always opposite, this heterolateral coupling contrasts with normal homolateral coupling of the lower cervical spine.

Question 9

Largest and lowest ranges for cervical thrust?

Answer 9

Klein (2003) - Largest ranges: rotation 46, SB 62, flexion 23. Lowest ranges: rotation 12, SB 31, flexion 0.

Except for SB, which was close to active range, the motion ranges obtained were well below active ROM, so is it mid-range or end range??? This study only done by one researcher though.

Question 10

Reggars (1996)?

Answer 10

For C3/C4 HVLAT there were cavitations with every subject, average of 2.5 per thrust. Only 9 (18%) had a single crack, 82% had 2 or 3 distinct cracks. Seven subjects had 4 cracks, two subjects had 5 cracks. C3/C4 HVLAT results in 1-5 cracks.

Question 11

Force needed for thoracic HVLAT?

Answer 11

Herzog and Symons (2001) - Preload mean force 24 N. Mean peak force 238 N, average rate of force application 1368 N/sec.

Preload force showed a decrease just before thrust and reached peak (x10) in 150-200 ms.

Question 12

Bolton (2007)?

Answer 12

Investigated side of pop with rotational or SB C3/C4 HVLAT. Mounted microphones at C2. Rotational HVLAT the pop was more likely to occur on the contralateral side, SB was more likely to occur on ipsilateral side. Subjects perception of the side that popped were in limited agreement with the actual side that popped.

Question 13

How far into the range do you thrust for cervical spine?

Answer 13

Ngan (2005) - Mean thrust displacement 11.4 degrees with range from 6 to 22.5 degrees
Triano and Schultz (1994) - Mean displacement 13 degrees

Question 14

Talk about movement of bones during HVLAT.

Answer 14

Gal (1997) looked at thoracic vertebral movements in unembalmed cadavers, first time this was done. 2 77 y/o unembalmed cadavers had PA thrusts to right T.P. of T10, 11, or 12. Bone pins were placed in these levels. All 3 vertebrae moved 6-12 mm anteriorly and 3-6 mm left lateral translation. Axial rotations of 0.4 to 1.2 degrees, sagittal rotations of 0.5 to 1.8 degrees. These measurements were taken after the pre-load force.

Question 15

Force needed for cervical HVLAT?

Answer 15

Kawchuck (1992) - Mean peak force 118 N, mean duration of force 102 ms, time to peak force 48 ms.

Mean joint compliance of joint manipulated increased by 0.5 mm from pre to post thrust compared with 0.1 mm for non-thrust side.

Question 16

How much do you come off the barrier before thrusting cervical spine?

Answer 16

Ngan (2005) - Mean de-rotation displacement is 4.8 degrees with a range from 0.5 to 16 degrees.

Question 17

Herzog 1993 Comments (Thrust Duration and Forces)?

Answer 17

Thrust duration: Cervical = 80-200 ms Thoracic/SIJ = 120-200.
Peak thrusting force is very closely associated with preload force. A stiff joint requires more pre-load force and larger peak thrusting force than a soft joint

Question 18

Ross (2004) for thoracic spine?

Answer 18

Average error was 3.5 cm. Only 3/17 HVLAT resulted in single cavitation. Most thrusts produced 2-6 cavitations. When getting 1-2 cavitations have less likelihood of cavitating target joint, when getting 4 or more have high liklihood of cavitating target joint.

Question 19

Frictional properties of thoracic skin-fascia interface?

Answer 19

Bereznick (2002) - Without removing skin slack 1st, prone PA HVLAT on TP’s showed the average displacement of the hands was 38.75 mm, when on the spinous procss it was 33.25 mm. The vertebrae didn’t move that distance, so the skin did. Therefore, you can’t hook on these processes.

Question 20

What is thrust velocity and acceleration for the cervical spine?

Answer 20

Ngan (2005)
Average peak velocity 127 deg/sec
Mean thrust velocity 72 deg/sec
Mean thrust acceleration 2183 deg/sec squared

Question 21

Peak pressure movement during thoracic HVLAT?

Answer 21

Herzog and Symons (2001) - Peak pressure moved an average of 9.8 mm during course of HVLAT, nearly 1 cm

Question 22

Ross (2004) for lumbar spine?

Answer 22

For lumbar spine. Only 36.5% of HVLAT resulted in single cavitation, remaining 63.5% produced 2-6 pops. Only 57/124 thrusts deemed accurate to target vertebrae. Average error was 5.29 cm (0-14). When thrust only produced one cavitation, average error was 3.9 cm (0-19 cm).

Question 23

How fast is the “high-velocity” in thrust for cervical spine?

Answer 23

Triano (1992) - Mean time from onset of HVLAT to peak force was 0.135 seconds (nearly 1/10th of second)