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Peter B. O’Sullivan, PhD et al ABSTRACT Proprioception is the sensation of position and movement at the joints in the body, along with an understanding of the degrees of force and effort of muscular contraction, and even the timing of the contraction. Injury to peripheral joints have been shown to cause reductions in position sense and proprioception, and this may cause abnormal loading across the joint, resulting in pain and damage to the articular surfaces. While some studies have indicated that persons with chronic LBP have deficits to lumbar spine position sense, others have not. This study sought to determine if persons with a specific spinal instability syndrome (LSI, or lumbar spine instability, flexion pattern) have alterations in their ability to reproduce a pelvic neutral position when compared to an age/sex/weight matched normal control group. Subjects with LSI, a total of 15,
were carefully chosen by experienced manual therapists.
Exclusion criteria included: past
history of training in motor control, recent back surgery, neurological
involvement, and pain that prohibited them from performing the test.
All had a history of low back pain for at least 3 months, and a
confirmed diagnosis of LSI flexion pattern.
This was defined as a history of chronic/recurrent LBP secondary to
a flexion injury, with trivial movements related to flexion,
flexion/rotation, and sustained flexion causing symptoms.
These subjects had full range of movement with pain going into or
returning from flexion, loss of segmental lordosis at the involved level,
increases segmental mobility at the involved level, and difficulty
assuming and maintaining a neutral lordotic curve.
The control group consisted of 15 subjects who were age, sex,
height and weight matched, with no history of LBP. The patients were seated, hips and
knees at 90 degrees, with surface sensors placed at T12, L2, L4, and S2.
The device used to measure spinal position was a 3-Space Fastrack
Model 3SF00002. This device
uses an external recorder that is able to measure the space and location
of the electrodes. Patients
were placed into a pelvic neutral position, which was then recorded as a
baseline. They assumed a
fully flexed position while seated, and then had to return to the neutral
position for a total of 5 trials. Each
seated flexions stretch was held for 5 seconds. Results showed that the patients
with LSI had significant reductions in the ability to return to the
previously chosen neutral position. This
indicates that there may be deficits in both motor control of specific
muscles, along with reduced coordination between muscle groups. It has already been determined that unisegmental muscles in
the spine have 2-6 times the density of muscle spindles that polysegmental
muscles have. The
unisegmental muscles may act to control specific segments, but most likely
also work in tandem with the polysegmental muscles.
The data from this study found that no specific level revealed
problems, and it was uniform across all 4 of the sensors. COMMENTS A good baseline study that can be
used to determine the effectiveness of specific lumbar training exercises,
and to also determine if subjects with no pain but having deficits in
proprioception, end up with LSI and other spinal conditions.
Once this is determined, use of specific exercises is warranted and
justified, especially with the increasing scrutiny of insurers. The surface electrodes were an area
of fault in this study, and the authors recognize this fact.
Having specific PT’s choose the subjects for the study always
presents the possibility of bias. It would have been nice if the authors did a better job of
describing the neutral they chose, instead of just saying it was between
end range flexion and end range extension.
Taking the 15 problematic patients, putting them through an
exercise regime, and then re-testing would have been a nice addition to
the study.
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