Lower lumbar instability

Introduction to lower lumbar instability Lumbar instability refers to the ability of the lumbar intervertebral joint to maintain its physiological anatomical relationship under normal load. The so-called normal physiological load, that is, the load does not cause damage to the spinal cord or nerve roots, and does not cause pain and development of spinal cord deformity. Low back pain caused by instability of the lower lumbar spine is a common and frequently-occurring disease that affects normal life and work of human beings. Lumbar degeneration is common, but instability occurs only when degeneration develops to abnormal displacement, and is called instability when it develops clinical symptoms. basic knowledge The proportion of illness: the incidence rate is about 0.0003%-0.0005% Susceptible people: no specific population Mode of infection: non-infectious Complications: meniscus injury

Causes of lower lumbar instability

(1) Causes of the disease

Most of the causes are caused by degeneration.

(two) pathogenesis

1. Overview Because the water content in the nucleus pulposus is as high as 90%, the intervertebral disc has good elasticity under normal conditions, but with the increase of age, its water content decreases year by year, and the intervertebral space decreases with the decrease of water content. The height is lowered, which causes lumbar instability due to such retreat. It is generally believed that lumbar instability is one of the early manifestations of degenerative changes of the lumbar spine, and trauma and strain are closely related to degeneration, and at the same time, small The articular surface, joint capsule, and cartilage disc of the intervertebral disc are most susceptible to damage, resulting in fibrosis of the cartilage, reduced thickness and densification of the bone, and varying degrees of damage, which can cause microfractures of varying degrees, and are mostly found under the cartilage. At the same time, the synovial membrane may have an acute inflammatory reaction, with fluid exudation, gradually thickening of the synovial membrane, and may lead to fibrosis around the joint, such as relatively light damage, which can be quickly restored by tissue repair. Repeated damage accumulation or heavier injury can cause a series of changes: as the height of the intervertebral disc decreases, the degree of overlap of the facet joints increases, and the ligamentum flavum can thicken or relax. Induced by spinal nerve root canal narrows, repeated injury lumbar instability will extend the time, easy to restore the original stability.

2. In addition to the traumatic cases, the disease is a gradual occurrence and development of chronic diseases. Under normal circumstances, lumbar instability is divided into the following three stages:

(1) Early degeneration period: that is, the initial stage of the disease, which is mainly caused by dynamic instability, so it is also called dysfunction stage. At this time, the small joint capsule is slightly slack, and the articular cartilage can show early fibrotic changes. If an external force is applied, the vertebral body may be displaced; however, the general clinical symptoms are mild in this period, and even if there is an acute symptom onset, it can quickly return to normal.

(2) Unstable period: As the lesions intensify, the sagging of the small joint capsules is increased, the articular cartilage and intervertebral discs are degenerated obviously, and various clinical symptoms are prone to occur. The vertebral body is abnormally displaced by dynamic imaging, biomechanics Tests have shown that at this stage, unstable segments are most prone to disc herniation.

(3) Fixed period of deformity: With the further development of the lesion, the segmentation of the spine is stabilized due to the formation of the small joint and the epiphysis around the intervertebral disc. At this time, a relatively fixed deformity appears, and the pathological examination shows that the articular cartilage degeneration In the advanced stage, there may be obvious rupture and dead bone in the annulus fibrosus and nucleus pulposus, bone spurs can be seen at the edge, and the hyperplasia of the fixed deformity and epiphysis often changes the caliber of the spinal canal. At this time, since the vertebral ganglion is no longer loose, The diagnosis of vertebral instability is also replaced by "spinal stenosis".

3. Stimulation and compression symptoms Intervertebral disc degeneration and vertebral ganglion loosening can cause symptoms by directly compressing the cauda equina nerve or stimulating the sinus nerve. The related symptoms are characterized by dynamic characteristics in the early stage, and pathological changes over time. The role of development and various additional factors is increasing, but once converted to vertebral hyperplasia of the vertebral canal, the original symptoms of vertebral instability disappeared and were gradually replaced by symptoms of spinal stenosis.

Lower lumbar instability prevention

1, to maintain good living habits, to prevent cold waist and legs, to prevent overwork.

2. Stand or sit in the right position. If the spine is not correct, it will cause uneven force on the intervertebral disc, which is the hidden source of the disc herniation. The correct posture should be stationary like a loose, sitting like a bell, the chest is upright and the waist is straight. The same posture should not be kept too long, and proper in-situ activities or lumbar back activities can relieve the fatigue of the back muscles.

3, the degree of bending the leg when exercising is not too large, otherwise it will not achieve the intended purpose, but also cause the disc to protrude.

4. Don't bend over when lifting heavy objects. You should take down the heavy objects first, then slowly get up and try not to bend over.

Lower lumbar instability complications Complications meniscus injury

Can be complicated by pseudo spondylolisthesis and lumbar intervertebral lock.

Symptoms of lower lumbar instability symptoms Common symptoms Lumbar instability and interlocking phenomenon Sciatica Lumbar instability Neuralgia Lumbar disc herniation fear standing, hi relying on radiation pain tension and cough

1. The symptoms of mild symptoms are not obvious, but the severe cases show the phenomenon of spondylolisthesis, but because it does not have the spondylolisthesis, it is called "pseudo-spine spondylolisthesis". Among them, low back pain and sciatica are lumbar vertebrae. The main symptoms of stability are characterized by:

(1) General symptoms:

1 waist acid, swelling and weakness: In addition to the main lower waist acid, swelling and weakness, the patient feels that his waist seems to be "broken", especially after standing too long.

2 fear standing, happy relying: due to the relaxation of lumbar intervertebral joints, patients are more willing to stand for a long time, or rely on the site to rely on the site when standing, to reduce the load on the waist.

3 may have an acute attack: the patient may have a history of chronic low back pain, often with obvious causes of trauma, with or without neurological symptoms.

4 refuse weight bearing: due to instability of the lumbar spine, and more with atrophy of the lumbar muscle, so patients are reluctant to carry heavy objects to reduce the waist load.

(2) Pain:

1 general pain: light and heavy, short duration, after rest, braking and physical therapy can be relieved within 4 to 5 days, but easy to relapse.

2 symptoms of pain: If the degree of looseness of the vertebrae is large, it is easy to cause the roots of the spinal nerve roots to be stretched and the symptoms of root radiation pain, but the symptoms disappear immediately after the supine.

(3) Bilateral: The pain is often bilateral, but the degree of pain on both sides can be different. The pain is radiated from the lower back and buttocks to the groin and legs, but rarely spread below the knee. Coughing and sneezing make the abdominal pressure Increased does not increase the pain, but sometimes causes pain due to abnormal activity between the vertebral bodies.

(4) Interlocking phenomenon: the patient does not dare to bend because of the looseness and pain of the vertebral ganglia, and can change the lumbar spine when the lumbar vertebrae changes from the anterior flexion position to the extension position. At a certain angle, a little activity is required to "unlock" and return to normal.

All of the above characteristics are more common in every patient with lumbar instability. In addition, patients with diagnosed lumbar disc herniation, such as recurrent episodes of low back pain, accompanied by severe sciatica, suggest that lumbar instability is present.

2. Observe the following phenomena when physically checking the physical examination:

(1) The shape of the sacral spine: If the patient is standing, the tendon of the sacral muscle is strip-like, but the hardness of the sacral muscle is significantly decreased when the patient is lying down, indicating that the degenerative segment is not normally loaded, and only supported by the adjustment of the voluntary muscle, the patient When the standing position is taken, the sacral muscles are tense, while in the lying position, the sacral state is relaxed. This sign is of great value for diagnosis.

(2) Observing the whole process of lumbar flexion and extension activities: combined with the patient's age, occupation and other factors, if the performance is hip flexion or sudden hip shaking, or sudden stop of activity, etc., the degenerative segment has become very weak. The loose ligament and posterior joint capsule have not been able to play a normal role in the lumbar flexion.

(3) Others: The load of the lumbar vertebrae in different positions is not equal. From sitting, standing, walking to walking fast, the lumbar load is gradually increasing, and a segment with a sharp decrease in hardness is obviously unable to withstand increasing load. It can be seen clinically that the patient has almost pain when his position changes, and the pain is significantly increased after a short run.

In short, a normal vertebral segment will change from the beginning to the development to instability, and some signs specific to it will be found in clinical examinations.

Lumbar degeneration, compensatory and unstable appearance is a long and complicated process. When the recurrent episodes of low back pain gradually increase, this is actually a signal of tissue damage. Patients with degenerative lumbar instability are almost All have the same main complaint, that is, low back pain accompanied by ambiguous buttocks and thighs, soreness, fatigue, and postural changes or exacerbation after fatigue, thus proving that the degenerative segment can not be normally loaded.

Examination of lower lumbar instability

X-ray examination is of great significance for the diagnosis of lumbar instability. Especially for dynamic imaging, it is more valuable. It can be found that the vertebral instability is earlier than MRI. The conventional radiography also has certain reference significance.

1. Conventional lumbar X-ray film

(1) General findings: In the case of lumbar vertebral instability, the main manifestations are: small joints, asymmetric arrangement of spinous processes, small joint hyperplasia, hypertrophy and subluxation.

(2) Traction spur: This spur is generally located in front of or lateral to the vertebral body, and protrudes horizontally. The base is about 1 mm from the outer edge of the disc. This is because the adjacent vertebral body is unstable when the lumbar spine is unstable. Abnormal activity occurs, the outer fiber of the annulus fibrosus is caused by stretched strain, and its clinical significance is also different from the common claw-shaped bone spur. Small distraction spurs mean that lumbar instability is present, and large traction Tensile spurs only suggest that the segment has been unstable. When the lumbar spine is regained, the distraction spur can gradually disappear.

(3) Intervertebral space stenosis: Intervertebral space stenosis is a common sign in lumbar disease, which is an indirect basis for nucleus detachment, displacement and degeneration of the entire intervertebral disc. Changes in the facet joint often coincide with stenosis of the intervertebral space because the vertebra The narrowing of the gap increases the pressure on the facet joint and is susceptible to injury and pain.

2. Dynamic film

(1) Overview: The abnormal increase of relative displacement between adjacent vertebral bodies is one of the important manifestations of lumbar instability, and it is also the essence of lumbar instability. Clinically, for patients suspected of lumbar instability, doctors always hope X-ray examination is used to find reliable evidence of lumbar instability, but the general lumbar X-ray film is taken in the upright position when the patient does not perform flexion and extension. Due to the tension of the sacral spine and the rest of the motion segment, the degenerative section The change of the position of the posterior margin of the segmental vertebral body is difficult to show. At this time, the kinetic observation of the full flexion and extension of the lumbar spine is needed. The continuous improvement of dynamic X-ray photography and measurement technique contributes to the diagnosis of lumbar instability.

(2) Filming method: Firstly, the ruins of the Luscka joint are confirmed on the lumbar X-ray. On the normal motion segment, the position of the Luscka joint remains remains unchanged during the movement (Fig. 4); and when the motion segment is unstable At the same time, their relationship will change. Secondly, it is necessary to have an arch frame of appropriate height and length. The patient is lying or lying on his back, and the lesion gap is placed at the highest point, so that the psoas muscle is completely relaxed. Under the goal of complete flexion and full extension, when the lumbar vertebral power piece is photographed on the arch frame, since the tibia and the tibia overlap, it is necessary to control the filming conditions. Generally, the center of the tube is horizontally oriented. Align the highest point of the arched bracket into the center of the dark sputum, the projection distance is 100cm, and the exposure condition is 95kV, 200ms.

(3) Measurement and calculation of shift value: On the X-ray film, find the segment with abnormal positional relationship between the vertebral bodies. On the next vertebral body, make the connection line A of the posterior superior edge and the posterior lower edge, and then pass the upper line. The posterior upper edge of a vertebral body is the parallel line C of A, and the vertical distance between the straight lines A and C is measured. The backward shift is represented by RO, the forward shift is represented by AO, and the sagittal diameter W of the previous vertebral body is measured. The position value = RO (or AO) / W × 100%, when the supine displacement position value > 9%, or the prone position value > 6%, can assist clinical diagnosis of degenerative lumbar instability.

When the lumbar spine is fully flexed, if the position of the Luscka joint remains in the diseased segment is broken, the previous vertebral body slips forward, generally indicating that the disc has only mild degeneration; when the lumbar spine is fully extended, if the lesion is in motion segment The location of the Luscka joint remains ruptured, and the previous vertebral body slips backwards, generally indicating moderate or severe degeneration of the intervertebral disc. Adams et al. proposed the concept of "dominant damage", which they believe is that when the lumbar spine is fully flexed, the interspinous and spine The upper torsion has the highest tension, and the anterior longitudinal ligament has the highest tension when the lumbar spine is fully extended. Therefore, when the intervertebral disc is moderately degenerated, the pre-condition factor - the anterior longitudinal ligament is loose, if the lumbar vertebrae are made at this time Fully stretched, then the relaxed anterior longitudinal ligament is incapable of limiting the posterior movement of the motion segment, which is the dominant damage of the pre-condition.

3. Significance of CT and MRI examination in diagnosis

(1) Overview: instability of the vertebral body can lead to excessive movement of the facet joints, which can produce wear and reactive bone hyperplasia of the small joints for a long time, and finally osteoarthritis, which reduces the function of restraining the anterior flexion of the vertebral body, Increased instability of the vertebral body, X-ray plain film can clearly show the degree of instability of the segmental displacement, can also show whether the small joints in most cases are symmetrical, with or without hypertrophy, whether the gap is narrow, and whether there is spur Or osteophyte formation, but due to the overlapping of bone structure, other pathological signs are often unclear on the X-ray film, so CT and MR examination will play a role.

(2) Diagnostic significance of CT examination: X-ray film can only reflect the two-dimensional structure of the examined part, and CT examination can display the degeneration signs seen by X-ray film in more detail, and can also clearly display Some changes related to nerve root and cauda equina compression, including joint capsule calcification, ligamentum flavum, nerve root canal stenosis, lateral recess stenosis, spinal canal deformation or stenosis, these signs help to explain clinical signs and symptoms and X The problem of line signs does not match, in the diagnosis of traumatic lumbar instability, CT examination can play a more superior role, because CT examination can not only show paraspinal hematoma, but also can show the damage of the posterior structure, you can also check the tiny The bone structure is disordered and the small joints are interlocked.

(3) The role of MRI examination: clinical observations show that MRI examination has the superiority of X-ray plain film and CT examination when used for analyzing spinal stability, and can also visually detect the change of spinal cord. The direct signs such as vertebral spondylolisthesis are difficult to display, so sometimes CT examination is not reliable in the diagnosis of lumbar instability. MRI examination of multi-directional imaging and direct display of the advantages of the spinal cord makes it a special advantage in evaluating spinal instability. Sex, mainly in the following aspects:

1 Diagnosis and indexing of vertebral spondylolisthesis.

2 to understand whether the spinal canal is narrow and its extent.

3 to understand whether the lumbar vertebrae have scoliosis, angle and direction.

4 shows the degree and extent of intervertebral disc and intervertebral joint degeneration.

5 shows the presence or absence of damage to the spinal cord and its nature and extent.

6 can show the soft tissue around the spine that affects the stability of the spine, and if necessary, can perform the imaging of the spinal dynamics.

On the MRI, the standard of X-ray film can be used, and the analysis of spinal instability can also be performed by the Denis standard.

Diagnosis and diagnosis of lower lumbar instability

The diagnostic criteria of this disease have different opinions. The author believes that the following points are of great significance:

1. Lumbar interstitial sign is often associated with other lumbar vertebrae diseases due to lumbar instability. Therefore, the clinical symptoms are more complicated and more specific. It is difficult to distinguish from low back pain caused by other causes, sometimes even without symptoms. When there is repeated acute attack and short-term severe low back pain, the possibility of lumbar instability should be thought of. The unstable interlocking of the waist has obvious specificity for the diagnosis of this disease and should be taken seriously.

2. Symptoms disappear after supine If the symptoms appear when the patient is active, there may be positive findings during the examination, but after a slight rest, the symptoms are obviously reduced or completely disappeared, and this dynamic change has diagnostic significance.

3. Dynamic photo positive is seen in the dynamic imaging, measuring the relative displacement between the vertebral bodies, not only can make a clear diagnosis of lumbar instability, but also the degree of lumbar instability can be evaluated quantitatively It is also the main means and basis for diagnosing lumbar instability. The authors believe that the relative horizontal displacement between lumbar vertebrae is greater than 3 mm on the lateral flexion and extension and greater than 2 mm on the lateral flexion. The objective performance, the determination of the lumbosacral joint can be increased by 1mm.

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