What are the findings. Then continue with the next series. The most striking finding is a intermediate intensity structure posterior to the L3 vertebra (blue arrow). It has the same signal intensity as the disc. This is a hernia that has migrated cranially compressing the L3 nerve on the right side. Here another example of disc migration. Notice how the disc herniation at the L3L4 level migrates caudally behind the body. Notice that at the L4L5 level the migrated disc simulates a nerve root (green arrow while in fact the nerve is compressed posteriorly and subsequently moves to the foramen (yellow arrow).
Listhesis, treatment, lateral, listhesis and Scoliosis
Click to enlarge them. The findings are: Herniation of the L3L4 disc. Compression of the L3 nerve in the foramen. Click to enlarge The signal intensity of a hernia on T1W-images is usually intermediate, while on T2W-images it can be a high signal fresh herniated nucleus pulposus or a somewhat older low signal intensity hernia. Here a herniation with high signal (yellow arrow on transverse images) sliding through the annular tear and compressing admin the left L5 nerve (blue arrow). Here sagittal T1W-images demonstrating a structure of very low signal intensity at the L4L5 level (arrow) and at the L5S1 level. Continue with the T2W-images. T2W-images Also on the T2W-images the signal intensity is very low. A ct-scan was performed to see if this could be a calcified herniated disc or some artifact. Continue with the ct-images. The low signal intensity could finally be explained by the vacuum phenomena due to nitrogen gas within the herniated disc both on L4L5 (red arrow) and L5S1 level (blue arrow) First scroll through these sagittal T1W-images.
There is also an annular tear (high signal) through which the disc herniates (yellow arrow) At the level of biography the lateral recess, there is a focal herniation of disc material compressing the L5 nerve (yellow arrow). This is called an extrusion, because the distance between the edges of the disc material is greater than the distance at the base. Compressed L5 nerve (blue arrow) within the lateral recess. The herniated disc has migrated caudally and is seen as an oval structure anterior to the nerve. The herniated disc is uncontained,. Not covered by fibers of the annulus. First study the images.
Extrusion is present when the distance between the edges of presentation the disc essays material is greater than the distance at the base. Read Spine - disc Nomenclature for more information about disc herniation nomenclature. Here a focal protrusion at the L5S1 level. The S1 nerve is compressed (arrow). Scroll through the images and describe the findings. The findings at the different levels 1-4 are: At the level of the disc there is minimal spinal canal narrowing by bulging of the disc and facet arthrosis. At this level there is severe spinal canal stenosis due to bulging disc and facet arthrosis.
Here another patient with widespread lymphadenopathy in the mesenterium and retroperitoneum. Here a patient, who presented with severe low back pain. Notice the aortic dissection. Sometimes these aortic abnormalities are incidental findings. Disc herniation Disc herniation is displacement of disc material like nucleus pulposus, parts of the annulus fibrosus and cartilage, beyond the limits of the intervertebral disc space. It can be focal ( 90 broad-based ( 90-180) or caused by bulging of the disc ( 180). Protrusion indicates that the distance between the edges of the disc herniation is less than the distance between the edges of the base.
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When you online examine multiple levels with different angulation like in the example on the right, you will not be able to follow the whole nerve tract and you will not get the whole picture. Interpretation The sagittal T1W-images give you the most diagnostic information. Before you start looking for any hernias, first take a good look at the prevertebral tissues and bone marrow. Once you have detected any abnormality, correlate these findings with the T2W-images (figure). Use of a marker When you notice an abnormality, it can be helpful to use a marker that correlates with the same location on the other series. If you enlarge the image, you will see the small yellow cross, which indicates that you are looking at the exact same spot on the other series.
Here the L5 nerve on the right is compressed by a synovial cyst, which is the result of facet arthrosis with effusion within the intervertebral joints. Prevertebral tissues Here a 25 year old patient who presented with low back pain. Notice multiple small masses in the abdomen surrounding the mesenteric vessels and abnormal low signal intensity of the bone marrow. The signal intensity of the discus is a little bit higher compared to the bone marrow (bright discus sign). This examination was the first indication of an abnormality in this patient. This proved to be bone- and lymph node metastases of a carcinoma of the colon.
Sometimes it can be difficult to clinically differentiate neurogenic claudication - which is caused by spinal stenosis - from vascular claudication - which is caused by arterial stenosis. The frequency-encoding should be in the ap-direction and consequently the phase-encoding feet-head. This has several advantages: The resolution is the highest in the frequency-encoded direction. We want the highest resolution in the ap-direction to look for small herniations and delineation of nerve roots. When you have the phase encoding in the ap-direction, you get breating artifacts.
That is why some use a saturation band or the rfov. With the frequency-encoding in the ap-direction you do not have these problems and you do not need a saturation band. Frequency encoding in the feet-head direction can result in poor deliniation of the vertebral endplates due to chemical shift artifact when the fat in the vertebral body meets the water in the disc. This is another reason to use a feet-head phase encoding and an ap frequency encoding. It is better to have continuous slices with the same angulation parallel to the level where nerve compression is suspected. This has the advantage, that you can follow the involved nerve along the four levels of possible compression.
Listhesis by medical dictionary
Hypertrophy of the flavum ligament is usually seen in combination with paper facet arthrosis and both result in stenosis of the lateral recess or when it is bilateral, in spinal stenosis. Epidural fat, this is the fat that surrounds the dural sac, that contains the nerves. Abundant fat can be seen in steroid therapy, extreme obesitas and rarely idiopathic. Abundant epidural fat can contribute to stenosis of the spinal canal. Mri protocol, the mri protocol for examination of the lumbar spine in patients with symptoms of nerve compression is quite simple. Basically we rely on the sagittal T1w- and T2W-images and correlate the findings with the transverse T2W-images of the levels of suspected pathology. Do not use a saturation band on the anterior side or a rectangular field of view (rfov because you also want to image the prevertebral diary soft tissues. Especially look for an aneurysm of the abdominal aorta, since this may also be the cause of low back pain.
have to study all these levels. Scroll through the images to see how the nerves run at the level of the disc, lateral recess, foramen and extra-foraminal. At each level specific pathology can be seen, but there is a lot of overlap. For instance a disc can herniate and cause nerve compression at the level of the disc, but can also migrate to a lower level and compress the nerve in the lateral recess or move upward and cause compression at the level of the foramen. In patients with facet arthrosis the bony spurs can move medially and narrow the lateral recess or move upward and narrow the foramen. When there is extreme facet arthrosis bilaterally, it can cause stenosis of the spinal canal and compress all the nerve roots at that level. Anatomy, the illustration demonstrates the structures that surround the nerves within the spinal canal. Flavum ligament, the flavum ligament is a strong ligament on the interior posterior side of the vertebral canal that connects the laminae of adjacent vertebrae. As a result of aging and instability of the vertebral column due to facet arthrosis there will be more stress on the flavum ligament resulting in hypertrophy and fibrosis.
Mostly by herniated discs and less frequently due to spinal stenosis. Level of lateral recess. This is the area below the disc where the nerve runs more laterally towards the foramen. Narrowing of the lateral recess is caused by facet arthrosis, usually in combination with hypertrophy of the flavum ligament and bulging of the disc. This is the area between two pedicles, where the nerve leaves the spinal canal. Narrowing of the foramen is seen in facet arthrosis, spondylolisthesis and foraminal disc herniation - usually a remote migrated disc from a lower level. This is the area lateral to the foramen. Nerve compression in this area is uncommon, but is sometimes caused by a laterally herniated disc. At these four levels there can be a lot of overlap of pathology.
Lateral, listhesis - quora
And other causes of nerve compression. Robin Smithuis, radiology department of the rijnland hospital in leiderdorp, the netherlands. Publicationdate december 14, 2014, in this article a systematic approach to patients shredder with nerve root compression in the lumbar region is presented. We wil discuss disc herniation, facet arthrosis, synovial cysts, spondylolisthesis and epidural lipomatosis. The images can be enlarged by clicking on them. Systematic approach, four levels of nerve compression. In patients with symptoms of nerve root compression, there are four levels that need to be studied: Disc level. This is the most common area where nerves are compressed.