Lumbar isthmus rupture and spondylolisthesis

Introduction to lumbar isthmus shredding and spondylolisthesis In the past, the causes of spine cracking were classified into congenital and traumatic; but in fact, the most common is due to degenerative changes, accounting for more than 60% of all spine crackers. Anatomically, the lumbar isthmus refers to the narrow part between the superior and inferior articular processes, where the bone structure is relatively weak, the normal lumbar vertebrae have physiological lordosis, the atlas vertebrae are physiologically kyphosis, and the lumbar vertebrae junction becomes a turning point. . The upper lumbar vertebrae are tilted forward, and the lower lumbar vertebrae are tilted backwards. Therefore, the negative gravitational force of the lumbar vertebrae naturally forms a forward component, which causes the waist 5 to have a tendency to slip forward. However, under normal circumstances, due to the limitation of the lower 5 articular processes and the surrounding joint capsules and ligaments, the waist 5 isthmus is at the intersection of the two forces, so the isthmus is prone to cracking, which is the reason for the most cracking of the waist 5 isthmus. After the isthmus is cracked, the vertebral arch is divided into two parts. The upper part is the upper articular process, the transverse process, the pedicle, the vertebral body, and still maintains normal connection with the upper spine; the lower part is the lower articular process, the lamina, the spinous process, and the lower part. The atlas maintains contact, the bone joint is lost between the two parts, and the upper part is displaced forward due to the loss of restriction. The vertebral body slides forward on the lower vertebral body, called spine slip, which is named by Killam. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: lumbar disc herniation

Lumbar isthmic spondylolisthesis and spondylolisthesis

(1) Causes of the disease

The true cause of lumbar spondylolysis is still uncertain. Over the years, a lot of research has been carried out, and it is found that congenital developmental defects and chronic strain or stress injury are two possible important reasons. It is generally believed that the latter is the main one, but so far Inconclusive.

(two) pathogenesis

The reasons that most scholars agree with now are as follows:

1. Traumatic factors The lumbar isthmus can cause acute fractures due to acute trauma, especially after extensor trauma. Patients can hear the sound of fractures. After the local shock period, there is severe pain and limited activity. This situation is more common in competitive sports scenes. Or a strong labor porter, the site of which is more common in the 4th or 5th lumbar vertebrae, but can also be found in other vertebrae.

2. Congenital genetic factors There are vertebral body and vertebral arch ossification center in lumbar vertebrae. Each vertebral arch has two ossification centers, one of which develops as superior articular process and pedicle, and the other develops into lower articular process. Half of the lamina and spinous processes, if there is no healing between the two, it forms a congenital spondylolysis, also known as isthmus non-continuous, local can form a pseudo-articular changes, when starting to walk, due to standing, Factors such as weight bearing can occur, especially in the case of bilateral isthmus cracking, which can make the upper spine slide forward, called spondylolisthesis, and can also cause spondylolisthesis due to abnormal development of the upper part of the humerus or the lumbar vertebral arch. There is no crack in the isthmus, and this congenital cause is also more genetically predisposed. The same family has more morbidity. There are reports in the literature that the parents and their children have the disease, and the ethnic factors are also obvious, such as the Inuit. The incidence rate is as high as 60%, while the incidence rate of the average person is 5% to 5.7%. This person is often accompanied by other lumbosacral deformities, such as transitional lumbar vertebrae and recessive spina bifida.

3. Fatigue or chronic strain factors So far, most experts believe that most patients are caused by fatigue fractures in the lumbar isthmus due to chronic strain or stress damage. It is obvious that the lumbar vertebrae are extremely vulnerable to injury because When the person is in the standing position, the lower lumbar spine bears most of the weight. The lumbosacral joint is the pivot of the trunk flexion and extension, and the physiological curvature of the lumbar vertebrae makes the waist 5 at the junction of the turning point. The biggest, especially for some manual workers, dancers and athletes, must bear a large load every day, and increase the possibility of lower waist injury. From the mechanical analysis, it is known that the upper part of the spine is transmitted to the negative gravity of the waist 5 Divided into two components: one is the compressive component acting downward on the intervertebral joint; the other is the component that acts on the isthmus to cause dislocation, and the isthmus with relatively weak bone structure is prolonged and broken. The disease is mostly caused by the stress of long-lasting repeated action, so it is actually a fatigue fracture. When the spine is flexed, the resistance acting on the spinous process compresses the underside of the joint. The upper part is subjected to the pulling force. Contrary to the former, when the lumbar vertebrae are stretched, the resistance acts on the lower articular process, so that the inter-articular part is subjected to the pulling force, while the upper part is subjected to the compressive force (Fig. 1). The stress is the largest, followed by the waist 4, so the clinical incidence rate is 5 with the waist and 4 times with the waist.

Of course, the occurrence of isthmus cracking is related to the isthmus's bone structure, curvature, and the magnitude, nature, and number of stresses. If the isthmus becomes relatively slender, it may be a precursor to the isthmus cracking. This is called the vertebral arch before the crack. Pre-spondylolisthesis, Hu Jingling measured the height of the isthmus of the spine, and found that the average height of the 689 cases of the isthmus without the isthmus was 9.035mm, while the average height of the isthmus of the 141 patients with isthmus was only 6.824. Mm, therefore, the thinning of the isthmus may be an intrinsic factor in the occurrence of isthmic cracking. The reason for the thinning may still be a congenital cause. Of course, it is directly related to acquired acquiredness. As for the magnitude and nature of stress, it is an important factor. Fu Shiru found that 80% of athletes suffering from isthmic disintegration have no obvious history of trauma, indicating that an acute trauma is not the main cause of the disease.

The training period of athletes is directly proportional to the incidence rate, and the incidence rate of male athletes is higher than that of females, suggesting that exercise may be a causative factor. The incidence of athletes in different sports is very different. The incidence of athletes engaged in volleyball and skill sports The rate is as high as 50%, and there is no such thing as long-distance running. The incidence of high jump and long jump athletes is also high. It can be seen that the athletes with long waist movements have a high incidence rate. Therefore, it can be considered that the waist stretches to the isthmus. The stress is the largest, which may be the cause of isthmic fracture. Lane, Nathan, Newman, etc. clearly stated that the lumbar 5 articular process and the upper axon joint oppression of the isthmus easily lead to isthmic fracture and spondylolisthesis. Fu Shiru uses lumbar vertebrae specimens for experiments. It is shown that the lower articular process is most likely to touch the isthmus when it is stretched behind the waist, which indicates that fatigue fracture is an important cause of its disease.

4. Degenerative factors After the human body matures, various loads increase, especially those with more than normal people, such as stronger sanders, porters, weightlifters and male ballet dancers, etc. Concentrated to the lower back and then to the lower limbs. In this state, due to the physiological lordosis of the lumbar spine itself, the lumbar 4 and lumbar 5 vertebral bodies are tilted forward and downward, so the two vertebrae, especially the fifth The lumbar spine has the largest bearing capacity. In this segment, the compressive stress transmitted from above is divided into two component forces. As mentioned above, one acts on the intervertebral joint to form the compressive component and the other acts on the joint isthmus. Dislocation component, at this time, through the lower articular process (tip) of the upper vertebral body, the compressive stress is concentrated to the isthmus of the next vertebral body, forming a shear force, which is easy to cause the smaller diameter of the vertebral isthmus to repeatedly suffer such shearing force. The wear and tear, combined with the weak tissue structure, is easy to cause fracture, and the disease is easy to occur after the middle age of labor intensity.

The shear force acting on the isthmus is proportional to the weight, load force, lumbar flexion and lumbosacral angle. Under normal circumstances, the intervertebral joints are slowed down, especially if they have been degenerated, especially When the stenosis is severe, it will aggravate. According to this mechanism, the 4th and 5th lumbar vertebrae below the lumbar vertebrae are most likely to be cracked, especially the waist 5 is more common. Statistics show that the waist 4 and waist 5 The incidence of vertebral arch ablation accounted for more than 90% of all cases, while those with a waist above 3 were rare.

In addition to the above factors, in the middle-aged and elderly people, due to the degeneration of the intervertebral disc, the nucleus pulposus water is reduced, the height is lowered, the elasticity is reduced, and the intervertebral space is narrowed and the intervertebral ligament is loose, which may easily lead to lumbar instability and spondylolisthesis. The isthmus can be normal without cracking, but its slipping direction is different from the former. The upper spine can not only slip forward or slip backward, which is called reverse slip.

Lumbar isthmic spondylolysis and spondylolisthesis prevention

Be careful to maintain adequate sleep and avoid overwork.

Lumbar isthmic spondylolisthesis and spondylolisthesis complications Complications lumbar disc herniation

Severe isthmic collapse can be associated with spondylolisthesis, compression of nerve roots or cauda equina.

Lumbar isthmic spondylolisthesis and spondylolisthesis common symptoms sprained lumbar soft can not straight up tension lumbar disc herniation spinous process tenderness neuralgia dehydration

1. General symptoms Early vertebral arch fracture and spondylolisthesis are not necessarily symptomatic. Many people have no intention to find it because of other reasons, but if you understand it carefully, there may be some complaints, mainly the lower back pain, the degree Most of them are lighter, often intensified after exertion, or they can start with mild trauma. After a proper rest or taking painkillers, the patient's history is much longer. The back pain is intermittent, and it can be persistent in the future. Affect normal life, rest can not be relieved, pain can be radiated to the appendix, buttocks or thighs at the same time. If combined with lumbar disc herniation, it can manifest as symptoms of sciatica.

The cause of low back pain is mainly due to the abnormal activity of the isthmus in the isthmus or the fibrous root tissue to stimulate the root stimulation caused by the nerve endings; it can also stimulate the branch of the posterior branch of the spinal nerve, and the reflex pain (sinus-vertebral reflex) occurs through the anterior branch. Spontaneous spondylolisthesis may compress nerve roots or cauda equina, but it is quite rare.

2. Signs usually have few signs. The simple isthmus is cracked without slippage. There is no abnormality found in the body. The body examination is only tender in the spinous process, the spine or the spinous process, and the waist activity can be unlimited or slightly restricted. There are no abnormal objective signs on other hips.

Patients with spondylolisthesis may have a special appearance of lumbar forward convexity, hip kyphosis, abdominal drooping and short waist. At this time, the spinous process of the diseased vertebrae protrudes, and the spinous processes above it move toward the front, neither of which On one plane, the local part may have a sense of depression, the posterior humerus increases, the lumbosacral spine is tender, the dorsal extension muscle is mostly tense, the waist activity is limited to varying degrees, the lower extremity movement, sensory function and tendon reflex are more abnormal. .

3. Root symptoms Most cases have root pain, mainly due to root stimulation caused by local vertebral pedicle loosening, or pseudo-root symptoms through sinus-vertebral nerve reflex; it is characterized by disappearance or obvious after lying down Relieving, the severe root compression caused by the compression of the spinal nerves is not very common in clinical practice, and the compression of the cauda equina is even rarer.

Waist isthmus shredding and spondylolisthesis

No relevant laboratory tests.

1. X-ray film shows that the diagnosis and degree of the disease are mainly based on X-ray film examination. All patients who are suspected of the disease should be photographed in the normal position, lateral position and left and right oblique tablets. Repeated shooting, especially the oblique film is often difficult to faithfully reflect the lesion due to improper shooting angle.

(1) Orthotopic film: It is generally difficult to show vertebral arch fracture or spondylolisthesis according to the routine shooting of the lumbosacral segment. However, when the slippage is obvious, there may be overlapping lines of the vertebral body, also known as the Brailsford bow line. The presence or absence of intervertebral space degeneration and the presence or absence of other factors that cause low back pain on the orthotopic film are helpful for clinical diagnosis and differential diagnosis.

(2) Lateral film:

1 simple cracker: in the lower part of the pedicle of the diseased segment shows a transparent fissure from the upper rear obliquely forward and downward, or the isthmus becomes slender; the congenital factors cause a pseudo-articular appearance.

2 with slippery: In addition to the above-mentioned strip-shaped transparent cracks (the width is proportional to the degree of slippage), other abnormalities can be found, mainly the displacement and looseness of the vertebral segments, and can be compared.

A. Grading judgment: For Meyerding, the upper edge of the lower vertebral body is divided into 4 equal parts, and according to the degree of slippage, it is divided into the following 4 degrees.

I°: refers to the vertebral body sliding forward no more than 1/4 of the sagittal diameter of the vertebral body.

II°: More than 1/4, but no more than 2/4.

III°: More than 2/4, no more than 3/4.

IV°: more than 3/4 of the sagittal diameter of the vertebral body.

B. Newman grading method: In addition to the commonly used indexing, Newman proposed using the spine slip grade to determine the degree of slippage. As shown, the upper edge of the first atlas was divided into 10 equal parts, and then the same size and then the humerus. The front is also divided, and the evaluation grade is based on the position of the upper lumbar vertebral body leading edge, such as I=3+0, II=8+6, III=10+10. This classification method is more accurate.

C.Garland sign: draw a vertical line along the anterior border of the supracondylar joint. Under normal circumstances, the anterior lower edge of the lumbar 5 vertebral body should be 1~8mm behind the line. If it is on this line or in front of it, it is positive, indicating that there is Slip off, this vertical line can also be called the Ullmann line.

D. Others: The distance from the leading edge of the affected vertebral body to the surface of the spinous process can be measured, and the true slippage or pseudo-slip is determined by comparison with the adjacent segments. The former is obviously widened, while the latter is basically similar. Bosworth proposes The ratio of the spondylolisthesis to the sagittal diameter of the upper vertebrae is also determined. In addition, it is also proposed to determine the degree of the fifth lumbar spondylolisthesis based on the Meschan clip angle, but it has been used less.

(3) oblique position: the clinical significance of the diagnosis of this disease is the biggest. When the projection tube is tilted 40 ° ~ 45 ° film, you can get a clear image of the isthmus of the vertebral arch, and coincide with the formation of a pug-like image The spine anatomical landmarks represented by the various parts of the dog-like image are listed below:

Dog mouth - represents the ipsilateral transverse process.

Dog ears - upper joints.

Eye - vertebral arch longitudinal section.

Dog neck - the isthmus of the vertebral arch or the intertubule.

The body - the ipsilateral lamina.

Dog legs - the front leg is the ipsilateral inferior articular process, and the hind leg is the contralateral lower articular process.

Dog tail - contralateral transverse process.

When the vertebral arch is cracked, a band-like fissure can appear in the isthmus, which is similar to wearing a necklace (circle) on the dog's neck. The wider the "necklace", the larger the distance, the more the vertebral body slips away, even Appeared as if the dog's head was "cut"-like appearance, due to congenital factors, the bone density at both ends of the fissure increased, the surface was smooth, and typical pseudo-articular signs appeared. The traumatic factors could show clear fractures in the early stage. Line, but in some cases, some cases have a pseudo-articular appearance.

(4) Dynamic lateral radiograph: that is, the lateral lumbar vertebrae and lumbosacral vertebrae over-extension and underflexion are observed, and the stability of the vertebrae and the looseness of the vertebral segments are observed.

2. CT, MRI and myelography are generally not required. According to the above-mentioned positive, lateral, oblique X-ray film can be diagnosed, but must be diagnosed with other diseases or combined with neurological symptoms, still It is an essential diagnostic method.

Diagnosis of the isthmus of the lumbar isthmus and the diagnosis of spondylolisthesis

The diagnosis of lumbar spondylolisthesis and spondylolisthesis is consistent with clinical signs and X-ray examination, namely spine tenderness, push pain, paraspinal tenderness, posterior lumbar pain, and localization of lower limb neurological dysfunction and isthmus Non-continuous or spondylolisthesis is consistent, in order to determine the waist and leg pain caused by isthmus or lumbar spondylolisthesis, in addition to clinical signs of other low back pain, such as lumbar disc herniation, back muscles or ligaments Sprains and strains, X-ray films have other lower lumbar deformities, need to rule out other causes of lower back pain, in order to confirm the diagnosis of this disease, and as clear as possible the following relevant diagnosis:

1. Spondylolisthesis of small joints, with or without arthritic changes, such as lip-like hyperplasia, narrowing of the gap, marginal hardening or gap width, clinical symptoms of low back pain, rain and low back pain.

2. The exact location of the compression of the nerve root or cauda equina, which is often determined by MRI or myelography.

3. The degree of slippage, the degree of sacral tilt.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.