Frequently Asked Questions
This section is geared towards the healthcare professional
Q.
Why are lumbar spine problems thought to be
mostly ligamentous in nature? Doesn't the musculature play an important role in lumbar
spine disorders?
A.
Some of the most important structural elements of the
spine are ligamentous in nature. These include the annulus fibrosus, capsular ligaments of
the facets, lumbodorsal fascia, supraspinous, interspinous and intertransverse ligaments.
These collagenous structures largely determine the mechanical properties of the joint and
a local abnormality in intervertebral joint motion must involve damage to the ligamentous
tissues. Muscle spasms are a mechanism for stabilizing damaged joints and thus are a
consequence of the injury, not the cause.
This does not mean that muscular strains of the lumbar spine do not exist.
However, ligamentous injuries are more frequent and more serious because of the long
recovery time necessary for collagen to repair.
Low back pain patients exhibit more back muscle activity than normal
patients. It is thought that injury forces the muscles to increase firing to substitute
for the action of the injured components. Since there are basically three components
(bone, muscle and ligaments), it follows that the injured element is likely to be
ligamentous.
Q.
What is the clinical significance of the estimated intersegmental
mobility if the patient has good range of motion?
A.
Having good range of motion (ROM) does not mean that the motion is
executed properly. For example, a typical torsional injury may affect the lower lumbar
levels, such as L4/5. A restriction at L4/5 may be compensated by a hypermobile
thoracolumbar junction. In this case, "normal" ROM is achieved through two
abnormal motions compensating each other: a hypomobile L4/5 and a hypermobile T12/L1.
Low ROM does not necessarily indicate mechanical dysfunction. A
biomechanically normal subject may exhibit a small ROM because of fear of re-injury or of
experiencing pain. Thus the reduction in ROM is not a consequence of mechanical
dysfunction. It does not affect the overall pattern of motion of the lumbar spine and the
relative contributions of all spinal segments to the spinal motion remain normal.
Voluntary physiological parameters (ROM, trunk velocity) are distinct from
involuntary parameters (the relative contribution of spinal segments or coordination
between spine and pelvis). Whereas the voluntary parameters are influenced by the
patient's feelings about their condition, the involuntary parameters are not, and as such,
represent a more robust and objective source of functional information.
Q.
What is the clinical significance of measuring the spine/pelvis
contribution to the gross ROM?
A.
As a rule, proper transmission of forces from the hip extensors to the
shoulders requires proper coordination between spine and pelvis. If coordination cannot be
maintained (for example, in condtions such as spinal fusion or ankylosing spondylitis),
the spine's performance is suboptimal. When spinal structures are overstressed, the
probability of injury increases. Therefore, the relative spine/pelvis contribution is one
element which should be considered in the diagnostic process.
Q.
What happens to the spine/pelvis coordination when the patient
lifts weights?
A.
In general, the spine/pelvis coordination is normal as the load is
increased to near the individual's maximum comfortable limit. As the load increases beyond
that which can be comfortably managed, certain changes occur in the coordination. The
maximum safe load for an individual is defined to be the maximum load that may be lifted
with normal spine/pelvis coordination. The presence of an injury then begins to interfere
with normal function.
The Spinex International can detect abnormal spine/pelvis coordination.
Q.
What is the clinical significance of the lumbar lordosis graph?
A.
The lumbar lordosis graph shows an approximation of the lumbosacral angle
between T12/L1 and L5/S1. The change in lordosis during flexion and recovery from flexion
reflects the mechanism by which forces are transmitted from the legs to the upper
extremities. A reduction in lordosis is necessary to tighten the lumbodorsal fascia. The
inability to tighten the fascia is associated with an increase in muscular activity and an
increase in compressive forces on the disks.
Q.
How can an electrode placed on the skin’s surface measure the
EMG activity of multifidus?
A.
In the L5/S1/S2 region, multifidus is not deep-seated. It is just below
the skin and surface EMG can readily detect its activity.
In the middle and upper lumbar spine, the situation is quite different. At
these levels, multifidus is deep-seated and next to the longissimus and iliocostalis
lumborum and skin-surface EMG electrodes cannot distinguish between the different muscle
groups. During flexion/extension, the erectores spinae complex (multifidus, longissimus,
iliocostalis) behaves more or less as a single muscle mass, and the EMG of multifidus is
representative of the response of the lumbar back muscles.
Spinoscopy uses EMG only to detect the absence of electrical activity,
indicative of the muscle relaxation phenomenon that occurs when stresses are properly
transmitted to the ligaments.
Q.
Can skin markers accurately record lumbar spine motion?
A.
The ability of external markers to track lumbar spine kinematics was
investigated by X-raying patients in various postures and comparing the measured motion of
the markers with the measured motion of the underlying anatomical structures. These
studies showed that, while the skin does shift over the anatomical structures, the
movement of the markers is not random. Skin marker motion is correlated with both the
intervertebral joint kinematics and the total spine and pelvic motion.
Q.
Is it important that the skin markers accurately track the motion
of the vertebrae?
A.
A good correlation between skin markers and vertebral motion is not
necessarily required for Spinoscopy to be effective. The objective is to separate the
normal from the injured and not to assess vertebral motion per se. If the true
anatomical positions of the vertebrae were the key to diagnosising of low back complaints,
then radiology would have provided the answers long ago!
What is necessary is the existence of a relationship between
pathology (or the absence thereof), EMG patterns, and the motion of skin markers. This has
been demonstrated in blind clinical studies, which confirmed that data collected from skin
markers do permit the separation of the normal from the injured. In fact, if there were no
relationship between pathology and the motion of skin markers, there would be no reason to
look at the skin during the physical examination, as is frequently done with the Schober
test/lumbar elongation measurements.
Q.
Is Spinoscopy another form of Functional Capacity Evaluation?
A.
Spinoscopy is not an FCE, although some of its data can be used as part of
an FCE. Spinoscopy is a physiological lab test showing the biomechanical integrity of the
spine (normal or abnormal), patterns of abnormality (if present), and under what
conditions the abnormalities present themselves (functional limitations). It can be
likened to a stress test for the lumbar spine.
Q.
What is the difference between Range of Motion (ROM) and the Range
of Normality (RON)?
A.
The ROM describes how much the trunk can bend forward. It does not
indicate whether that motion is done normally. The RON indicates how much the subject can
move while remaining within the limits of normal biomechanical function.
For instance, suppose that a subject flexes his trunk by 75 degrees and that
all measured physiological parameters remain within +/- 2 SD of the zone of normal
function for only 40 out of the total 75 degrees. The subject’s RON is thus 40
degrees.
Q.
How does the Expert Vision Spinex International differ from equipment that
measure trunk muscle strength?
A.
Each individual intervertebral joint contributes to the spine’s overall
functional capacity. The spine has 24 centers of rotation in each plane, as well as a
strong coupled motion. However, muscle strength testing machines force the subject to
rotate about a fixed axis of rotation. Although some strength testing equipment permit
motion around three fixed axes, to isolate the lumbar contribution, most dynamometric
equipment anchor the pelvis and thorax. This interferes significantly with natural motion,
disrupting normal coordination of spine and pelvis.
The pelvis/spine coordination is an important diagnostic parameter. As the
pelvic action is an integral component of the spine’s overall functionality, it is
impossible to properly measure the biomechanical integrity of the spine while the pelvis
is anchored.
When the patient move free, as in the Spinex International exam, how the body naturally
alters the distribution of stresses to protect any injured components can be assessed. If
a rigid pattern of motion is imposed from the outside, such as with dynamometric
equipment, all this information is lost. The information obtained with Spinoscopy is
highly reliable and repeatable. There is very little voluntary control over the
coordinated movements of the spine, and in any case, the structural ligamentous tissues
are passive.
Muscle strength testing machines also require that the patient perform
maximum muscular contractions, which may be unsuitable for injured or disabled patients.
The Spinex International allows the patient to perform simple movements in his/her own way, without
exertion or strain.
Q.
Why use Spinoscopy instead of radiology (MRI, CT scan)?
A.
A physician may wish to know whether a disc herniation appearing on MRI
corresponds to mechanical dysfunction. This question is highly relevant because the
incidence rate for disc herniation in asymptomatic individuals has been shown to be as
high as 76%. As a result of this very high rate, a herniation detected by MRI should not
automatically be deemed responsible for the patient's complaints.
Spinoscopy will help the clinician decide whether an MRI finding is
functionally significant. If the herniation has no functional consequences, the clinician
may consider conservative care rather than taking more aggressive measures such as
surgery.
Q.
Can a patient have a negative MRI (and/or CT Scan) and a
positive Spinoscopy result?
A.
Yes, abnormal joint function can be associated with a negative MRI or CT. A
negative MRI scan of a disc does not mean that the disc is biomechanically sound, it
simply means that no anatomical anomalies were detected. How the biomechanical function of
the disc relates to the MRI image is not known. Furthermore, even if the disc image
appears normal, other components of the spine might not be.
Conversely, a positive MRI or CT can be associated with negative Spinoscopy
test. Functional loss associated with a disc anomaly may be compensated for by a facet
deformation, so that, in spite of the disc injury, the overall biomechanical function of
the spine is maintained. Or, a disc abnormality may, quite simply, be of no functional
consequence.
Q.
Does Spinoscopy conform to high scientific and clinical research
standards?
A.
All research on Spinoscopy has been peer reviewed and published in
well-respected scientific journals.
Q.
Is there independent scientific data substantiating the use of
Spinoscopy?
A.
All data validating Spinoscopy was collected independently, in a study
administered and funded by the Government of Quebec. None of the faculty members
executing the study had any vested interest in the technology. In this study, Spinoscopy
was shown to be both reliable and valid.
Q.
Does the Spinex International have FDA approval?
A.
The FDA does not approve devices, however, it classifies them and gives
permission for the device to proceed to market. The Spinex International has FDA 510(k) marketing
permission.
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