21.What lesion signs will be seen on CT films of patients with lumbar disc herniation? The common lesion signs are roughly as follows: (1) Lumbar disc bulge: outside the vertebral body edge, there is a circle of low-density soft tissue shadow. The posterior edge is medially straight or mildly posteriorly convex, but does not compress the dural sac of the nerve root. (2) Posterior or posteromedial protrusion of the nucleus pulposus: at the posterior edge of the vertebral body medially or posterolaterally, there is an irregularly shaped mass of medium-density shadow whose base continues with the intervertebral disc, and sometimes calcification of the protrusion is visible. (3) Free body in the vertebral canal: sometimes a mass-like medium-density shadow can be found in the vertebral canal, and it is not connected to the intervertebral disc. This mass may be a broken disc after protrusion, forming a free body in the spinal canal. (4) Dural sac and nerve root compression or displacement: the fatty layer between the disc and the dural sac disappears, the dural sac is compressed and flattened, and the nerve root disappears or is displaced. (5) Other signs: narrowing of the lumbar spinal canal, hypertrophy of the ligamentum flavum, narrowing of the lateral saphenous fossa, degeneration of the articular eminence, and many other signs may be seen. 22.What are the characteristics of MRI images in patients with lumbar disc herniation? In patients with lumbar disc herniation, the MR signal is diminished due to dehydration and degeneration of the nucleus pulposus. In the sagittal film, the size and shape of the nucleus pulposus as well as the signal strength can be clearly reflected. Under normal conditions, the posterior edge of the nucleus pulposus should not exceed the edge of the corresponding nucleus pulposus, and the signal intensity should be uniform. When the disc degenerates and herniates, the MR signal will be weakened. The lower the intensity of the signal, the more severe the degeneration of the disc. In mild degeneration, the nucleus pulposus shows reduced MR signal intensity with uniform disc bulging forward or backward, but generally not beyond the posterior edge of the vertebral body, and with smooth edges. As degeneration worsens, the MR signal of the nucleus pulposus is further reduced in the sagittal view, the intervertebral space is narrowed, and the disc protrudes posteriorly beyond the posterior edge of the vertebral body. On sagittal images in some patients, the fatty white line in the posterior spine can be seen to be interrupted by compression. The high resolution of MRI imaging has greatly improved the rate of confirming the diagnosis of lumbar disc herniation by imaging. At present, in some hospitals, experienced doctors can accurately determine the surgical plan for patients with lumbar disc herniation by relying on clinical examination and MRI images, avoiding the patients’ pain of making a spinal canal imaging again before surgery. However, for some patients whose lumbosacral angle is not obvious, or who have lumbar sacralization or sacral lumbarization, there are some difficulties in localization, and they must still be carefully analyzed in combination with lumbar spine plain film or CT film. 23.What are the special imaging methods for lumbar disc herniation? Special imaging is a method that needs to be used carefully when the X-ray diagnosis is still not clear. When CT, MRI, etc. were not yet carried out, it was the main method for clear diagnosis of this disease. Even now, when CT and MRI are not yet popular in some primary hospitals, they are still the main method for imaging diagnosis of this disease. Special imaging examinations have a higher diagnostic accuracy and are similar to CT. Myelogram, disc myelogram, venogram, epidural imaging, etc. are commonly used. 24.What are the characteristics of myelography in patients with lumbar disc herniation? Myelography has a high accuracy rate, generally greater than 90%, and can be the method of choice when the diagnosis of lumbar disc herniation is suspected. Myelography methods include iodine oil imaging, iodine water imaging and air (oxygen) imaging, etc. (1) Iodine oil imaging: Iodine oil imaging of the spinal cord is generally used for patients with lumbar disc herniation requiring surgical treatment, with the purpose of clarifying the site of the herniated lumbar disc and the type of pathology, and its accuracy rate is quite high. The specific operation is: the patient lies on the X-ray examination table on his side, with the affected side underneath and hands on the knees. After routine disinfection and towel laying, a lumbar puncture is performed in the lumbar 3 to lumbar 4 or lumbar 4 to lumbar 5 intervertebral space to the subarachnoid space and about 6 ml of iodine oil-based contrast agent is injected, then the lumbar puncture needle is withdrawn and the wound is covered with a sterile dressing. The patient is placed in a supine position and fluoroscopy is performed. If a filling defect is found during fluoroscopy, a film should be taken promptly. There should be one ortho and one lateral radiograph, and the lateral position should be taken as the horizontal lateral position. Note that during the imaging process, the patient should be turned as little as possible because the contrast medium can flow and cause the film results to be inaccurate. The following contrast patterns are often seen during imaging: pressure marks in the dural sac, mostly in a semi-arc shape, which indicate a herniated disc to one side; pressure in the middle of the dural sac, with the contrast agent stagnating in one segment (or with the contrast agent flowing downward in a filamentary pattern on one side), which indicates a central type of lumbar disc herniation; fading of the contrast agent in one segment with low density, which is probably due to disc bulge This sign is probably due to bulging discs. In short, the results of imaging vary from person to person, and should be carefully analyzed in conjunction with the specific situation while mastering certain rules. There are four common types of imaging patterns: ① When the lumbar disc is herniated laterally, the dural sac is concave and indented, and the root cuff shadow is elevated or disappears. (2) In the case of median herniation, the dural sac is compressed medially, and there are thin lines of contrast flowing from both sides or one side to the distal end when the spinal canal is completely obstructed. The contrast agent is stagnant in one plane. ③Protruding disc with the fibrous ring not yet completely ruptured: the local image is veil-like or bead-like. ④The herniated material causes nerve root congestion and edema, and a filamentous cauda equina shadow appears. Evaluation: easy to perform, repeatable and inexpensive. There is no reaction other than headache. In addition, it is not easily absorbed and can be used for long-term observation after treatment. (2) Iodine water contrast: Since the main complications of spinal iodine oil contrast have not been completely eliminated so far, iodine water is currently used as the contrast agent for myelography at the lumbar level. The main advantages are: ① Satisfactory contrast: the specific gravity of water-soluble iodine contrast agent is similar to that of cerebrospinal fluid, which can fill the nerve roots and root sleeves in the subarachnoid space and clearly show the morphology and course of the spinal cord, cauda equina, nerve roots and root sleeves, which can improve the correctness of diagnosis. ②Accurate localization: Because of the low viscosity of iodine contrast agent, it can pass through the stenosis and reveal the panoramic view of the spinal canal, so the localization is accurate and multi-segmental lesions can be detected, which is conducive to the selection of clinical treatment plan. (3) Rapid absorption: Since iodine aqueous contrast agent can be completely absorbed, there is no need to withdraw the contrast agent, avoiding the possible arachnoiditis after iodine oil imaging. The biggest disadvantage of iodine-water contrast agent is that it is irritating to both the spinal cord and nerves. In the early stages, this test can be performed under lumbar anesthesia to prevent pain. A small number of patients have adverse effects such as headache, nausea, and increased sciatica after contrast. With the continuous updating of iodine contrast agent, these complications have been decreasing. Contrast pattern: ①Central type protrusion: Dural sac compression. (2) Lateral type protrusion: compression of the nerve sheath cuff or compression of the dural sac. Evaluation: The imaging is clearer than iodine oil imaging, and the filling of the spinal cord and nerve roots is complete because the contrast agent can show the area of compression more clearly. However, there are more side effects, shorter imaging time and more expensive. (3) Air contrast; air contrast is filtered air or oxygen as a contrast agent, injected into the subarachnoid space after lumbar puncture, and shows the state of the spinal canal with the help of low-density shadow of gas. It is also known as negative contrast. Although the air contrast method has the advantages of low irritation, easy absorption, cheap, etc., but because of its poor clarity, incomplete obstruction of the spinal canal, it is difficult to identify the lesion site, so it is no longer the preferred imaging method. The procedure is as follows: after a successful lumbar puncture, about 10 ml of cerebrospinal fluid is released and an equal amount of air is injected. The procedure is then repeated so that the amount of air injected reaches approximately 40 ml, leaving the patient in a head-down position, which fills the subarachnoid space of the lumbosacral segment due to the lightness of the air. At this point, X-ray frontal and lateral films are taken and then observed. Defects in the front of the air column can often be seen in the orthopantomograph of patients with lumbar disc herniation Imaging morphology: at the site of lumbar disc herniation, a filling defect in the air column with reduced density is seen, and the air column manifests significant posterior displacement or interruption. Evaluation: The advantages are small reaction, no allergy, no sequelae, and no use of pharmaceuticals; the disadvantage is that the development is not as clear as iodine, and it is not suitable for people with intracranial hypertension. At present, the domestic application is less. 25.What are the characteristics of vertebral intravenous angiography in patients with lumbar disc herniation? As a diagnostic tool, vertebral vein angiography is comparable to myelography in terms of accuracy and superior to other angiograms, and is a more ideal method of intravertebral canal examination. The vertebral vein system is divided into an internal group of veins within the spinal canal and an external group of veins outside the spinal canal. The two groups of veins are connected by multiple collateral traffic. The intravertebral veins are located between the spinal canal and the dura, forming the epidural venous plexus. There are four groups of longitudinal veins. Two groups are located anterior to the dura and are called anterior internal vertebral veins. Two groups are located posterior to the dura and are called posterior internal vertebral veins. The intravertebral veins are connected to the extravertebral veins by intervertebral veins. The intervertebral veins accompany the nerve roots out of the intervertebral foramen and terminate in the lumbar ascending veins. The blood in the venous plexus can communicate with each other because there is no valve (there is no valve in the vertebral veins) to block it. Normally the blood in the vertebral vein flows into the inferior vena cava, so when pressure is applied to the lumbar region, the blood can flow backwards into the sacral plexus. The vertebral vein can be filled up, which provides the conditions for the vertebral vein to be visualized. The specific operation is that the patient is in supine position, a needle is inserted into the femoral vein and a catheter is inserted into the common iliac vein, generally from the affected side is better, if the side cannot be determined, the left femoral vein is inserted, because the left superior lumbar vein tube is larger, and after the injection of contrast medium, the filling of both sides can often be seen. After insertion of the catheter, the abdomen is pressurized with a balloon to compress the inferior vena cava to reduce blood reflux. About 30 ml of 60% Conray is taken and injected at a rate of 2 to 5 ml per second, and X-ray films are taken for observation. In the X-ray film of patients with lumbar disc herniation, the intervertebral vein of the anterior internal vertebral vein in the vertebral canal may be displaced posteriorly and externally or posteriorly and internally due to the compression of the herniated material. Complete obstruction of the intervertebral vein and anterior internal vertebral vein may even be seen. Common images include unilateral or bilateral interruption of the anterior internal vertebral vein; unrevealed, interrupted, or thinning of the medial segment of the intervertebral vein; thinning and dilution of the anterior internal vertebral vein; and abundant collateral circulation, among others. Vertebral vein angiography has the advantages of simple procedure, easy operation, small postoperative reaction and no serious sequelae. Since the drug is not injected directly into the spinal canal during the operation, there are no side effects on the spinal cord and arachnoiditis does not occur. At the same time, it is possible to perform intravenous spinal canal imaging even in the presence of infected foci in the spinal canal, which is its superiority over other imaging methods. Compared with myelography, intravenous imaging does not irritate the arachnoid membrane, does not damage the spinal cord and nerve roots, and does not cause sequelae such as arachnoiditis and post-puncture headache. Compared with myelography, intravenous angiography is less painful for the patient during the procedure and does not cause irritation of the lining of the spinal canal due to spillage of the contrast medium. The scope of observation is wider, not limited to one or two intervertebral discs. It is safer because the doctor does not have to operate under X-rays and is exposed to a smaller amount of radiation. Vertebral vein angiography is a less-invasive test with a greater range of spinal canal lengths examined and fewer side effects. It is inexpensive. The image quality is high, and there are certain requirements for radiology X-ray machine 26.What is myelography? Myelography is a method to diagnose whether the disc has rupture, protrusion and other pathological changes by injecting contrast agent directly into the nucleus pulposus. The procedure is performed by first performing a myelocentesis. The transdural puncture method and the transdural epidural puncture method are generally used. The transdural puncture method has the advantage of less damage because the puncture needle enters the intervertebral disc through the epidural cavity, but its operation is relatively more difficult than the transdural method. A 22-gauge needle (approximately 12 cm) is inserted into the annulus fibrosus by selecting one of the above-mentioned puncture approaches. Note that the tip of the needle can feel like rubber when it penetrates the fibrous ring, and then the resistance decreases when the needle is re-entered. Determine the puncture position is accurate, pull out the needle core, change to 27-gauge needle, to 22-gauge needle in the syringe into the fiber ring, and then take an X-ray to determine the location of the puncture needle. If the position is satisfactory, then inject 50% contrast agent (commonly used pantopamine or sodium vinblastine) 0.5 to 1.5 ml. when the intervertebral disc fibrous ring is not ruptured can accommodate about 0.5 ml of contrast agent, so the amount of contrast agent that can be injected into the normal intervertebral disc often cannot exceed 1 ml, and the resistance is very high, in the case of ruptured fibrous ring, the resistance is less when pushing injection, often after injecting 1.5 ml of contrast agent is still not significant. However, care should be taken not to inject too much contrast agent to avoid leakage into the spinal canal, which may cause pain and confusion in the visualization. The normal nucleus pulposus is oval, and the contrast agent does not leak out of the punctured needle channel when the lumbar spine is moved after the end of the imaging. In the case of disc herniation, abnormalities are seen. (1) Complete shape degeneration combined with posterior protrusion, split degeneration with lobulated multibranches, etc. in degeneration shadow. The nucleus pulposus image occupies the entire intervertebral space and may even extend beyond the vertebral body edge. There is narrowing of the intervertebral space and varying degrees of hyperplasia-like changes at both the anterior and posterior edges of the vertebral body. However, the contrast image is only slightly larger than the normal range. This indicates degenerative degeneration of the intervertebral disc, but the annulus fibrosus is still intact. (2) Posterior lateral rupture image: the intervertebral space is basically normal or mildly narrowed, and the anterior and posterior edges of the vertebral body may have hyperplasia-like changes. The nucleus pulposus image extends behind the annulus fibrosus to beyond the posterior edge of the vertebral body and may leak into the epidural space, forming an epidural image. This indicates that the disc annulus fibrosus ruptures posteriorly and externally. (3) Anterior rupture: the myelogram may show the flow of contrast to the underside of the anterior longitudinal ligament. This image is less common in clinical practice. It indicates an anterior rupture of the fibrous ring. (4) Rupture of the cartilage plate: Myelography shows the flow of contrast into the interior of the vertebral body, forming an elliptical translucent area. This indicates that the nucleus pulposus has broken through the cartilage plate and entered the vertebral body, forming a Hume’s node. This is the most common type of disc herniation. At this point the annulus fibrosus is intact. In the 1970’s and earlier, myelography, myelography, venography, and epidurography, all with approximately equal accuracy, were the special imaging methods that were often used. However, with the rapid development of technology today, the scope of application of myelography has been greatly reduced under the impact of CT, MRI and other advanced examination methods. Its main shortcomings are as follows: (1) complicated operation. Compared with myelography, the operational requirements of myelography are obviously much higher, which increases the possibility of its failure. (2) It may cause infection. Since the intervertebral disc is a bloodless tissue, it has a poor ability to resist infection, and once the intervertebral space is infected due to unclean aseptic conditions at the time of puncture, it is difficult to control. (3) Aggravating pain symptoms. When the contrast agent is injected, it may cause and aggravate the symptoms of the original disc herniation. If the contrast agent is injected into the annulus fibrosus, it may stimulate the sensory nerves in the annulus fibrosus and cause pain in the middle part of the low back. 27.What is epidurography? Epidurography is a contrast method in which contrast is injected into the epidural cavity to show changes in the epidural surroundings. Because the epidural space is filled with contrast, the extent of filling defects in the intervertebral space after disc herniation and the extent of occupying lesions in the intra-arachnoid space can be seen after imaging. Since the contrast agent is outside the dura, it does not affect the arachnoid membrane, and there are no sequelae such as arachnoiditis after contrast, so it is a safer imaging method. (1) Transsacral fissure puncture method: The patient is placed in prone position, the skin is routinely disinfected, and after local anesthesia, a 16-gauge epidural needle is used to puncture the sacrococcygeal ligament at 45 degrees to the trunk, and then it is changed to 25 degrees to slowly penetrate the sacral canal. Since the subarachnoid space terminates in the plane of the second sacral vertebra, the puncture needle should not exceed this plane to ensure that it will not penetrate into the subarachnoid space, pull out the needle core, observe whether there is any cerebrospinal fluid spillage, insert the epidural anesthesia catheter into the interlumbosacral epidural space, and then withdraw the puncture needle. Before the injection of contrast agent, 80-120 ml of 0.5% procaine can be injected to observe the presence of spinal anesthesia to exclude dural penetration injury. The contrast agent should be injected only after confirming the absence of dural injury. (2) Transcatheter lumbar puncture for retrodural imaging: the patient is placed in the lateral position with the affected side underneath and the head slightly padded. The method is the same as epidural anesthesia, and the puncture is made from the lumbar 3 and lumbar 4 gap. After confirming that the tip of the needle is located in the epidural space, the contrast agent is slowly injected, and then the puncture needle is removed and X-ray films are taken. (3) Trans-lumbar puncture pre-dural imaging method: The patient is placed in the lateral position, and a 22-gauge puncture needle is inserted through the interspinous space of lumbar 4 and lumbar 5. When the tip of the needle breaks through the posterior wall of the arachnoid and enters the subarachnoid space, there is cerebrospinal fluid outflow, continue to puncture forward, and when the tip of the needle penetrates to the anterior dural space, there is no more cerebrospinal fluid outflow. X-ray is taken to confirm that the tip of the needle is at the posterior edge of the vertebral body, 2 ml of 0.5% procaine is injected, and 2 ml of contrast agent can be injected if there is no resistance, and X-ray is taken again to confirm that no contrast agent is overflowing into the subarachnoid space, 4 ml of contrast agent is injected, and the puncture needle is withdrawn. Epidurography can show the size of the spinal canal and the disc herniation outside the range of the dural sac. Its accuracy for the diagnosis of lumbar disc herniation is high, but the display of the spinal canal contour image is affected by the presence of an unconstant amount of fat, loose connective tissue and venous plexus in the epidural space of the spinal canal. When reading the film, a combination of frontal and lateral analysis is necessary. Epidurography: It can diagnose lumbar disc herniation, spinal stenosis, epidural tumor, etc., and can also be used as an objective basis for evaluating the efficacy of treatment. It is reported that the correct diagnosis rate is 100%. The imaging pattern: ①Orthopantomogram shows: filling defect in the center; peripheral filling defect; interruption of the nerve root profile. (ii) Lateral film shows: posterior aspect of the disc with a large posterior dural indentation; filling defect within the anterior contrast; foveal stenosis within the posterior contrast. Evaluation: simple and safe operation, little side effects, high diagnostic accuracy, no sequelae, large and clear visualization area. 28.What is the significance of nerve root angiography? Nerve root angiography is a direct examination method of injecting contrast into the damaged nerve root sheath to show the lesion status of the nerve root. The procedure is as follows: the patient is placed in prone position, the skin is routinely prepared, and the lumbar area is padded with soft pillows. The lumbar 5 nerve root imaging is used as an example. After sterilization, a 20-gauge needle is inserted at an angle of 45 degrees to the midline, and the tip of the needle is passed through the lower edge of the transverse process into the intervertebral foramen. When the puncture needle touches the diseased nerve root, it causes a sudden sharp pain. If the site of pain is consistent with the patient’s usual site of pain, the puncture location is accurate. 1 ml of 1% Xylocaine is injected, and after the pain is relieved, 1 to 2 ml of contrast agent can be injected. An X-ray is taken, and if the contrast is successful, the contrast agent travels linearly along the nerve root, which is in a striated shadow. In patients with disc herniation, the nerve root produces changes such as bending and interruption. Or the contrast may be seen to stagnate at the arch or lateral saphenous height. 29. What is the clinical significance of cerebrospinal fluid examination for patients with lumbar disc herniation? Examination of cerebrospinal fluid and its kinetic test, the Quaker test, can estimate the presence or absence of inflammation and degree of obstruction in the subarachnoid space of the spinal cord, which is necessary for patients with lumbar disc herniation who have significant neurological symptoms because the clinical manifestations of certain intravertebral tumors and disc herniation are extremely similar. This is done by lying the patient on his or her side on the examination table with the knees and hips flexed so that the lumbar spine is posteriorly convex, while wrapping a blood pressure gauge cuff around the neck. The lumbar 3, lumbar 4 or lumbar 4, lumbar 5 gap can be selected as the puncture point, disinfected, and after applying a towel, the subarachnoid space is punctured with a 20- to 22-gauge puncture needle under local anesthesia, and after confirming entry into the subarachnoid space, the needle core is withdrawn, the cerebrospinal fluid clearness is observed, and a pressure measuring glass tube is attached. In normal adults, the initial pressure of cerebrospinal fluid in the lateral position is 0.6-1.5 kPa, while in children it is 0.4-0.8 kPa. When the cerebral fluid is clear, the water column plane fluctuates with the heartbeat. At this time, if the abdominal pressure is increased, the cerebrospinal fluid pressure can be increased; after decompression, the cerebrospinal fluid pressure drops rapidly. The blood pressure gauge was inflated to 2.6 kPa and this pressure was maintained. Every 5 seconds, the height of the water column rise was recorded and the time taken for the water column to rise to the apex was recorded. After maintaining the current condition for 15 seconds, the pressure was released, and the rate of water column descent was observed and its final plane and time were recorded. Release about 3 ml of cerebrospinal fluid, send it for biochemical examination, and then measure its pressure as the final pressure. 30.What types of lumbar disc herniation can be classified? According to the location, degree, direction of the herniated nucleus pulposus of lumbar disc, the relationship between the degree of degeneration and nerve roots and different imaging examinations, there are various typing methods, and there is no uniform standard so far. There are various reported typologies, mostly related to the researcher’s purpose of study. Some classify lumbar disc herniation into intact, subperiosteal rupture and intradiscal rupture, some into juvenile, migratory and mature, some into reversible and irreversible, and some into bulging, protruding and isolated. Mastering the typing of lumbar disc herniation is crucial to the selection of treatment, especially in non-surgical treatment, the correct application of typing can improve the treatment effect and prevent the occurrence of accidental injury. (1) Vertebral body type: The degenerated nucleus pulposus passes through the inferior (more common) or superior (less common) fibrous ring, and then passes through the cartilage plate in a vertical or oblique direction into the middle of the vertebral body or the vertebral body edge of the herniated nucleus pulposus. (1) Anterior margin type: the nucleus pulposus penetrates the vertebral body edge (the anterior superior edge of the next vertebral body is common), causing triangular bone block-like changes at this edge (clinically easy to misdiagnose as vertebral body edge fracture). Qu Jincheng (1982) found 32 cases (31.3%) among 102 gymnasts, and this type is a forward displacement of the nucleus pulposus and protrusion into the vertebral body. (2) Inferior medium size: the nucleus pulposus passes vertically or nearly vertically upward or downward through the cartilage plate into the vertebral body and forms Schmorl nodule-like changes. Autopsy findings account for between 15% and 38%. (2) Posterior vertebral canal type (posterior type): the nucleus pulposus protrudes through the fibrous ring in the direction of the vertebral canal. If the nucleus pulposus stops in front of the posterior longitudinal ligament, it is called “disc prolapse”; if it crosses the posterior longitudinal ligament and arrives in the spinal canal, it is called “disc prolapse”, and it is divided into the following five types according to the anatomical location of the protrusion (prolapse): ① Central type: mainly manifests as cauda equina (1) Central type: The main manifestation is irritation and compression of the cauda equina, accounting for 2% to 4%. (2) Paracentral type: clinical symptoms are mainly equine caudal nerve symptoms, and can be accompanied by root irritation symptoms. The incidence is slightly higher than that of the central type. ③Lateral type: It is located in the anterior median part of the spinal nerve root and may be slightly deviated. The main symptoms are nerve root irritation and compression symptoms, accounting for 80%. The main symptoms are nerve root irritation and compression, accounting for 80% of cases. ④Lateral type: the protrusion is located on the lateral side of the spinal nerve, mostly in the form of “prolapse”, and can compress not only the same (inner and lower) spinal nerve root, but also the upper nerve root. It accounts for about 2% to 5% of cases. (5) The most lateral type: the nucleus pulposus moves to the anterior side of the spinal canal, or even into the spinal canal or the lateral wall of the spinal canal, accounting for about 1%.