Lumbar spinal canal, root canal expansion and decompression

A typical vertebra consists of a anterior vertebral body and a posterior vertebral arch. The vertebral body and the vertebral arch form a vertebral foramen, and the vertebral holes of all the vertebrae are connected together to form a spinal canal. The vertebral arch is arched and consists of a pair of pedicles, a pair of vertebral arches, a spinous process, a pair of transverse processes and two pairs of articular processes. The pedicle is short and thin, horizontal, connected to the posterior aspect of the vertebral body; its upper and lower edges each have a depression, called the upper vertebrae and the subvertebral notch. The upper and lower notch of two adjacent vertebrae, which are intervertebral foramen, have spinal nerves and blood vessels. The nerve root channel at the exit from the spinal canal to the intervertebral foramen is the root canal, bounded by the isthmus and the lower part of the arch, and the root canal can be divided into the entrance zone, the middle zone and the exit zone. There are bony lateral crypts on the inside of the intervertebral foramen at the level of the lumbar and ankle. In the narrow sense of lumbar spinal stenosis: the sagittal diameter and transverse diameter of the lumbar spinal canal cause morphological changes of the spinal canal, causing symptoms and signs of compression of the cauda equina. Broadly speaking: it also includes the narrowing of the intervertebral foramen tunnel of the nerve root canal. The formation of the stenosis may be bony or soft tissue, or a mixture of the two. The cause can be congenital (developmental), acquired (degenerative) and iatrogenic. In short, any change in the diameter of the spinal canal due to the above reasons, or narrowing of the diameter of the nerve root canal, causing spinal cord and nerve root compression symptoms, are lumbar spinal stenosis. The cause of the disease does not include spinal stenosis caused by space-occupying lesions such as tuberculosis, tumor and lumbar disc herniation. Verbiest proposed that the median diameter of the lumbar spinal canal was less than 12 mm as the standard for diagnosis of stenosis on the x-ray film. The median diameter was relatively narrow between 10 and 12 mm, and the absolute diameter was less than 10 mm. Non-surgical therapies include: massage, hot compress, physiotherapy, traction, rest, etc. Only for mild lumbar spinal stenosis. Surgical treatment should be performed for typical cases. Surgery should enlarge the spinal canal and nerve root canal to relieve compression of the cauda equina and lumbar nerve roots. In order to determine the surgical site, the location should be clearly defined before surgery, and can be used for myelography, ct and magnetic resonance examinations. Treatment of diseases: lumbar spondylosis, spinal trauma Indication 1. There are symptoms of lumbar spinal stenosis, and those who have been treated for non-surgical treatment for more than 3 months are invalid. 2. Typical clinical symptoms, such as limited lumbar extension, intermittent claudication, complaints of multiple signs, ct tablets showed a sagittal diameter of less than 12mm. Preoperative preparation 1. Clear positioning through the myelography, x-ray film and ct film to measure the median diameter value, combined with clinical signs, determine the plane of the spinal canal and root canal stenosis. 2. Conventional preoperative skin preparation and medication before anesthesia, with blood for use. Surgical procedure 1. Position: prone position or lateral position. The operation is convenient in the prone position, and the surgeon and the assistant can better cooperate. The patient's waist area is best placed at the waist bridge of the operating bed, which can make the waist kyphosis for operation. The crotch pads on both sides are made of thin pillows to make the chest and abdomen overhead, so as to facilitate the patient's breathing; it is also possible to avoid abdominal pressure and avoid blood flow restriction and increase intraoperative bleeding. 2. Incision, exposure (for thoracic laminectomy, spinal exploration as an example): the median incision of the back, generally should include 1 to 2 laminas above and below the lesion, the length depends on the extent of the lesion. Cut the skin, subcutaneous tissue and fascia, reveal the supraspinous ligament, and cut the supraspinous ligament along the middle of the spinous process to reach the bone. Because the spinous process is sacral, when the muscle is attached along the bone edge, the blade should be close to the bone edge and slightly outward. When cutting to the edge of the spinous process, the blade is slightly inward to avoid cutting into the muscle, causing unnecessary Bleeding. Then insert the periosteal stripper, close to the spinous process and lamina, peel off the sacral spine muscle under the periosteum, reach the articular process, and then use dry gauze to fill the hemostasis. Use a relatively wide periosteal stripper when peeling off, always peel the laminectomy, hold the stalk of the periosteal stripper in the right hand, and stabilize the anterior segment of the periosteal stripper with the left hand to prevent the periosteal stripper from breaking into the ligamentum and inserting into the spinal canal. Cause accidental injury. Those who have had laminar damage should pay more attention. In this order, the side of the spinous process is first removed, and then the opposite side is peeled off until the spinous processes in the incision are all peeled off. Then, the dry gauze is taken out in order, the sacral spine muscle is retracted by the periosteal stripper, the residual muscles on the lamina are cut, and the large gauze is stuffed to stop bleeding. Wait a few minutes, after the hemostasis, use an automatic dilator to open the muscles and reveal the lamina. If there is still residual muscle or adipose tissue on the lamina, it can be cut off. If the muscle still has oozing blood, it can be stopped by hot saline gauze to stop bleeding or electrocoagulation. 3. Excision of the lamina: The spinous process of the thoracic spine is inclined downward, and the upper spinous process is pressed against the next lamina, and the upper and lower laminae are covered in a tile-like shape. Therefore, when the thoracic lamina is removed, one spine should be bitten up and down, and the lamina should be removed from the bottom up. The interspinous ligament is first cut, and then the spinous process is used to bite the spinous process at the root of the spinous process, so that the lamina in the midline is thinned and easy to be removed. First use the side angle head double joint rongeur to identify the ligament of the ligamentum flavum from the lower edge of the lowermost lamina to be removed, and bite a lamina outside the ligamentum flavum. The ligamentum flavum connects the superior and inferior vertebral arches, and the outer edge reaches the posterior edge of the intervertebral foramen. The ligamentum flavum is cut transversely with a knife, and the dura mater is placed in front of the lamina to separate the gap between the ligamentum flavum and the epidural fat. In order to avoid accidental injury to the dura mater when the lamina is removed. Then, the rongeur is placed from the gap, and the lamina is bitten down and up, and generally 2 to 3 are bitten first. It is best not to damage the joints on both sides of the lamina. Otherwise, spinal instability and low back pain will occur after surgery. If the articular process must be removed due to the removal of the lesion, it should not exceed 1 or 2, and try to keep the other joint. Sudden. The lamina adjacent to the articular process can be trimmed with a mastoid rongeur to achieve total laminectomy. If the lesion is estimated to be on one side or lateral side, it can also be treated with unilateral laminectomy and enlarged if necessary, so that some patients may preserve spinous processes and part of the lamina. No matter what kind of rongeur can not penetrate into the spinal canal when biting off the lamina, it will easily damage the spinal cord. The rongeur should be fully opened and placed in the spinal canal. The surgeon holds the forceps in one hand and holds the rongeur with one hand and bites with the upward force to prevent the rongeur from sliding down the bone edge and damaging the spinal cord. Bone bleed with bone wax to stop bleeding, epidural venous plexus bleeding can be used to stop bleeding by bipolar coagulation or gelatin sponge, generally easy to control. 4. Detection and expansion of spinal canal: During the operation, the pathological anatomy of the lesion and the influence on adjacent tissues should be observed at any time. The lamina of lumbar spinal stenosis is mostly thickened and hardened, the ligamentum flavum is obviously thickened, and some even calcified, the extradural space is small, the fat disappears, or there is a heavier extensive adhesion. Therefore, care should be taken when removing the lamina. It should be separated by a hard stripper, then the vertebral plate should be bitten with a small vertebral plate bite clamp. Do not use a large rongeur to protrude into the dura or ponytail. . The thickness of the lamina and the ligamentum flavum should be measured during surgery and the values recorded. After the lamina is removed according to the design range, the dural sac can be seen to be narrowed or hyacinth-like stenosis. In severe cases, there is no pulsation. After the posterior dural sac is exposed, it should be enlarged laterally to the inner edge of the facet, and fully decompressed at the rear. If the exploration reveals that the hyperplasia of the articular process is compressed, the medial part of the facet joint should be removed. Sometimes the rongeur can't reach or accumulate too thick, you can use the small bone to cut the back part, then use a small bite clamp to bite off; can also be used for sneak resection, to achieve full side decompression. However, it is necessary to avoid accidentally injuring the cauda equina when using the osteotome (if the surgeon has insufficient experience, it is not advisable to use osteotomy). For patients with severe spinal stenosis, the thickened lamina or calcified ligamentum flavum can be removed by electric drill or pneumatic drill until the lamina is ground into a thin paper and then removed. When the posterior wall and side wall of the spinal canal are fully enlarged, the dura mater should be significantly enlarged, the shape of the gourd disappears, and there is pulsation. 5. Expand the decompression of the root canal: gently push the dura mater to one side with a dura mater to find the nerve root and explore the nerve root canal stenosis. If the nerve root does not move, the hard film stripper cannot extend, indicating that there is a stenosis. Apply a thin cotton pad (soaked saline) to protect the dura mater, pull it to the opposite side, gently pull the nerve root with a dura cutter, and probe the root canal. When the superior articular process is inward and forward, and the stenosis is caused, it is necessary to use a small mastoid chisel or a small thin flat chisel to excise the hyperplastic bone. It is best to use a micro drill to remove a layer of cortex. The lower bone, and then remove the residual layer of cortical bone, can safely remove the crypt stenosis. Then carefully excavate the posterior wall and anterior wall of the root canal along the nerve root. If the pedicle is moved down with the stenosis, the lower edge of the root should be removed. The thick yellow ligament may cause thickening of the posterior wall of the root canal and should be completely removed. Disc bulging in degenerative spondylitis can be one of the causes of root canal stenosis. It can compress the nerve root from the lower back, and if necessary, remove the bulging part and then implant the intervertebral bone. At this time, the nerve root canal can be fully expanded and decompressed, and the nerve root can have a considerable degree of movement. Sometimes when the nerve roots are stuck to the surrounding tissue, the surgeon can carefully separate them with a hard film stripper. Throughout the operation, the assistant should continue to use a 6 ° C ~ 8 ° C physiological saline for low temperature washing to protect the nerve roots and horsetail, and continue to suck with a suction device to maintain a clean surgical field. After the root canal is enlarged, if there is a rough bone defect in the bone wall, it needs to be smoothed with a curette; if the bone surface is oozing, the bone wax can be used to stop bleeding. 6. Dwarf anterior exploration and decompression: After the spinal canal, lateral and root canal decompression, the nerve root has a certain degree of motion, the dural sac can be pulled toward the midline to explore the front of the dura mater. If there is a herniated disc or a large callus, it should be removed. Avoid large veins when removing, and do not let bleeding. If bleeding occurs, do not blindly clamp, usually by using gelatin sponge plus cotton tablets for several minutes to stop bleeding. If the thin catheter is inserted from the subdural lamina of the spinal canal enlargement area to the proximal end and the distal end, if it is more than 5 cm, it means that there is no stenosis at both ends of the spinal canal, so that it is not necessary to extend up and down. 7. Stitching: Wash the wound with saline, remove the bone chips, carefully explore the residual lesions, and fully stop bleeding. The epidural is covered with a thin layer of free fat flakes. The 16th catheter was placed outside the dura mater, and a small incision was made next to the incision to lead the catheter out of the skin for negative pressure suction. The sacral spine, subcutaneous tissue and skin are layered and sutured without leaving a dead space. Both the superior and inferior articular processes are resected, and the spine will be unstable. It should be used for intertransplantation or interbody fusion.

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