A segmental instability may be symmetrical
(anterior or posterior) or asymmetrical (torsional or transverse). The degree
of slippage is dependent on the level of instability and the ability of the
patient to stabilize the segment, consciously or unconsciously. The stability
tests are actually tests to see if non-physiological (movement that should
not be present to any appreciable degree) motion is present.
Anterior
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The patient is in side lying with the spine in neutral
and the hips flexed to about 70 degrees (45 degrees for the lumbosacral
junction) making sure that the spine does not flex as the hips are flexed.
This is accomplished by pushing the legs posteriorly as the hips are flexed.
The therapist places the patient's knees between his/her thighs and reaches
over the legs to apply a lumbrical grip with the cranial hand to the superior
vertebra. The index finger of this hand palpates the spinous process of the
inferior vertebra. The hand is then reinforced by the caudal hand.
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| If any movement is perceived, the
segment is considered to be anteriorly unstable. The therapist uses a forward
pelvic thrust against the patient's knees to shear the femurs, pelvis and
lower vertebrae posteriorly against the stabilizing force of the therapist's
cranial hand. The index finger on the inferior spinous process palpates for
motion between the two spinous processes. |
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If instability is present, a second test can be carried out.
This test is used to determine the ability of the extra-segmental structures to
stabilize the segment. It is postulated that the posterior ligamentous system
will be able to stabilize the segment if the pelvis is tilted posteriorly
thereby tightening the system. Accordingly, the segment is re-tested with
same technique but now, the spine is kyphosed by posteriorly rotating the
pelvis. If the test is now negative, the patient can be instructed to use
this strategy for activities that move the spine into lordosis and the
segment into its unstable position.
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Posterior
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The patient sits over the side of the bed. The therapist stands in front of the
patient. The patient holds up both arms flexed at the elbows. The therapist
reaches around the patient so that the patient's forearms are pressed against
the therapist's chest. The therapist stabilizes the inferior vertebra of the
segment with both hands while using one or two index fingers to loosely palpate
the superior spinous vertebra. The patient is then asked to very gently push
against the therapist chest by protracting the scapulae. The therapist
feels for movement of the superior spinous process. If this occurs, the segment
is considered to be posteriorly unstable.
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Torsion
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A general torsion test can be carried out for the entire
lumbar spine. The paitent lays prone. The therapist stabilizes T12 spinous
process with the thumb or thenar region with one hand and grasps the iliac
crest with the other. The ilium is then pulled straight backwards. There
should be a small amount of motion only and the end feel should be hard and
abrupt. The patient should not experience any symptoms. The presence of
symptoms only would indicate joint effusion, lamina fractures, minor tearing
of the anulus etc. The presence of excessive motion would suggest torsional
instability.
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| For a more specific evaluation,
each segment can be assessed separately. The patient side lays with the
spine in neutral. The therapist can then either leave the spine in this
position and allow for the small degree of axial (pure) rotation that
exists or can very lightly rotate the spine. If the spine is rotated,
there will be a small amount of motion felt during the test but if lightly
rotated, there should be no rotation available. |
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The therapist pushes the superior spinous process towards
the bed and pulls the inferior process towards the ceiling thereby producing a
torsional force that would tend to produce axial rotation. The force must be
transverse and not through an oblique plane. If pre-rotated, there should be
no rotation available if not pre-rotated, a small amount of rotation must be
allowed for. In both cases, the end feel should be very hard almost bony.
There should be no slippage felt.
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Disclaimer:
The assessment and treatment techniques depicted or described in this
site are not intended to replace formal instruction in orthopedic manual
or any other type of physical therapy. They are intended to review,
augment and facilitate the knowledge and skills previously gained on
manual therapy or other course and to stimulate the untrained or trainee
physical therapist to increase the bounds of his or her knowledge and
skill base.
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