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 skins 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 subjects 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 spines 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 spines 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.