AS ilium fixations may occur in three primary ways. They may occur as a result of a compensatory or reactive mechanism to other spinal mechanical disorders, such as hypermobile dysfunctions. They may also occur as a result of trauma to the pelvis or spine. Compensatory mechanisms produce AS fixations more slowly or gradually, while trauma produces a more rapid AS sacroiliac fixation. A third mechanism of AS ilium fixation is compensatory reaction to body curves, such as thoracic hyperkyphosis or lumbar hyperlordosis.
AS ilium fixations of a compensatory or reactive nature can occur on the right and/or left sides. When a left AS ilium fixation of nontraumatic origin occurs, it has been my observation that the cause or causes can be found in proximal and/or distant spinal hypomobile dysfunctions.
Nontraumatic, gradually occurring left AS ilium fixations are quite common. An example of this is a posturally caused spinal dysfunction causing left AS ilium compensatory reactions. The nontraumatic AS ilium fixations also may be produced due to trauma to other spinal levels, and may occur rapidly in these cases, such as with automobile collisions.
When I speak of a left-sided sacroiliac AS fixation, I am referring to an ilium fixation in which there is no downward motion of the left ilium (as monitored at the PSIS) during standing left hip flexion. Also, in this particular situation or model, the right ilium is fully functional and moves in the PI direction during standing right hip flexion. Based upon tests of such PI motion during standing hip flexion, while monitoring the PSIS of the ilium during hip flexion, good or healthy motion is represented by one inch to 1-1/4 inches of downward PSIS motion during standing hip flexion on the same side.
The spinal levels, according to my experience, which may become functionally hypomobile and lead to reactive left-sided AS ilium fixations while the right SI joint is free, are:
- lower lumbar levels, mostly the last lumbar. Next common in causing the left AS fixation would be the second-to-last and third-to-last lumbars. Such lumbar fixations reflect left posterior or extension restrictions. As you move higher in the lumbar spine from L-2 to L-1, there is a tendency for spinal fixations to influence the right SI joint more, causing bilateral or right AS ilium fixes.
- C-6 and C-7 spinal levels. A very common cause of reactive compensatory left AS ilium fixation is the hypomobile operational status of C-6/7 and C-7/T-1 levels. Most commonly, the left side is fixated with rotation and lateral flexion restriction. That is, the left side is restricted in rotation to the right, and left lateral bending. Most commonly, it is a coupled restriction involving rotation and lateral flexion. With the correction by adjustment of the C-6 and/or C-7 left sided dysfunctions, there is a partial and often complete release of the left-sided AS ilium fixation, as monitored with left hip flexion, standing.
- C-1 and C-2 spinal levels. A very common cause of reactive compensatory left ilium fixation is the hypomobile operational status of C-1/2 and C-2/3 levels. Most commonly, C-1 and C-2 are fixated on the left side in some combination of rotation and lateral flexion. When one or both levels (C-1 or C-2) are fixated on the left, and the most fixated segment is adjusted, I have found that the left-sided AS ilium fixations will become partially or totally released. This is monitored by pre- and post-standing PSIS palpation during left hip flexion. This assumes that other spinal levels have been excluded as problems.
The release of left ilium AS fixation, with the adjustment of C-1 laterality, appears to work very well in the side posture position with the left laterality up. I have had considerable success correcting it with the multithrust Arthrostim instrument, although it may also be adjusted traditionally, by hand. Pre- and post-motion palpation results following the use of the Arthrostim for correction of C-1 left lateral flexion restriction also are remarkably good.
4. T-11, T-12, L-1, and L-2 levels. Fixations at these levels definitely affect the SI joints. Because this is a transition zone, the correction of primary extension restriction (the most common finding, usually coupled with some rotation blockage) at these levels will occasionally bring left-sided release of AS ilium fixation (when the right SI joint is free). Most often, these levels (T-11, T-12, L-1, L-2) will release bilateral or right-sided AS ilium fixations when adjusted, not left-sided AS fixes.
Quite often, reactive compensatory AS ilium fixations are the result of combined multilevel spinal problems, such as two or more levels of hypomobile dysfunction. The release of each level will bring increased sacroiliac motion if previously fixated. However, these are frequent occasions when the entire left-sided AS ilium fixation is the result of a C-1, C-2, C-6 or C-7 problem.
As a final note, I have, on previous occasions, advocated caution in the direct approach of adjusting the ilium as an AS fixation on the left side. Such a direct approach may be useful occasionally when all else has failed, but is may cause iatrogenic problems.
Joseph D. Kurnik, DC
Torrance, California
Dr. Joseph Kurnik practices in Torrance, Calif. He is a former columnist and longtime contributor to DC; previous articles are available online at www.dynamicchiropractic.com.