Lumbar disc herniation is a condition with low back pain or low back pain with sciatica as the main clinical manifestation. And there are more diseases that manifest as low back pain and combined sciatica or femoral neuralgia, which have great similarity with the manifestation of lumbar disc herniation and are not easy to distinguish clinically, and are easily misdiagnosed and mistreated. I. Bone development abnormalities (a) occult spina bifida Spina bifida is very common, accounting for about 5% to 29% of the population, which mostly occurs in the 1st and 2nd sacral vertebrae and the 5th lumbar vertebrae. Among them, simple bony fractures are called “occult spina bifida”. In occult spina bifida, more than 80% of them have no clinical symptoms and signs, and are mostly found during physical examination. For those who have symptoms, most of them are chronic lumbago with strain, and sometimes localized pain or unilateral or bilateral radiating pain in the lower extremities may occur when forward flexion or backward extension. The diagnosis of simple occult spina bifida is confirmed by spinal X-ray plain film. If clinically significant signs of nerve root localization are present, the possibility of a combined lumbar disc herniation should be considered. (B) Third lumbar transverse process syndrome The third lumbar vertebra is, under normal circumstances, significantly longer than the transverse processes of the other four lumbar vertebrae, so that the muscles and ligaments attached to it can effectively maintain the stability and normal activities of the spine. Since the role of this transverse process is stronger than that of other transverse processes, it is susceptible to strain and causes peri-transverse fibrillitis, resulting in lumbago and significant pressure pain in the deep part of the transverse process of the third lumbar vertebra. If the transverse process is too long or too large, the lateral femoral cutaneous nerve that passes deep in front of the third transverse process is easily involved, causing radiating pain to the lateral thighs and knees. The longer the transverse process, the higher its incidence, and it is more common unilaterally. The main differentiation point between third lumbar transverse process syndrome and lumbar disc herniation is: 1. pressure point The location of lumbar pain in third lumbar transverse process syndrome is higher and the pressure point is 5-6 cm from the midline, while the location of lumbar pain in lumbar disc herniation is mostly lower, because it is mostly seen in lumbar 5 sacral 1 disc herniation and the pressure point is 2-3 cm from the midline. 2.Radiation pain The radiation pain of the third lumbar transverse process syndrome is only in the lateral thigh and knee, and the area is blurred, not accompanied by sensory and motor disorders; while the innervation areas of the affected nerve roots in lumbar disc herniation each have specific sites, and the areas are obvious, mostly accompanied by sensory and motor disorders. 3.Closure test In the third lumbar transverse process syndrome, local closure (1% procaine, 10-20 ml) is applied around the third lumbar transverse process, and the lumbar pain and radiating pain of the lower limbs can be truncated and the pain can be stopped immediately; while the same method is invalid for lumbar disc herniation in the pressure pain point. 4.X-ray plain film The third transverse process syndrome may show longer than normal and more asymmetrical bilaterally. (C) Arthroglossal deformity The small joints in the posterior part of the lumbar spine have a vertical articular surface. It is prone to asymmetry during development and leads to asymmetry in lumbar function, which can easily cause strain on one side and result in injurious arthritis. It is especially likely to occur between lumbar 4 and sacral 1. The main manifestation is pain in the lumbosacral region, with pressure points located at the joint protrusions, mostly unilateral, especially when bending and flexing to the same side. If the hyperplastic and deformed articular protrusion is directed toward the spinal canal, secondary spinal canal or root canal stenosis may occur, and radiating sciatica in the lower limbs may appear. The characteristics of this disease are: 1. limited lumbosacral pain Except for the secondary spinal stenosis mentioned above, there is mostly limited lumbosacral pain without radiating pain in the lower extremities. 2.X-ray plain film shows increased local bone density of the articular eminence, mostly with irregular appearance. 3.CT examination may show abnormal and hyperplastic variation of the articular prominence, or visible hyperplastic spinal stenosis. (D) Lumbosacral migratory vertebrae (lumbosacralization, sacral lumbarization) Each segment of the vertebrae (cervical, thoracic, lumbar, sacral, caudal) that migrates to each other at the junction and has the characteristics (morphology) of another segment is called “migratory vertebrae”, also called “transitional vertebrae”. Although all segments can occur, most of them occur in the lumbosacral region, and their forms are lumbosacralization and sacral lumbarization, and they are difficult to identify, so they can be collectively called lumbosacral migrating vertebrae. The occurrence rate of lumbosacral migrated vertebrae is very high, accounting for about 5% to 10% of the normal population. In general, this type of deformity does not cause any symptoms, and the number of cases in which symptoms are actually caused by this type of deformity is very small. The symptoms occur mainly due to degeneration and strain of the vertebrae, especially in those with bilateral asymmetry of the lumbosacral migrating vertebrae, or those with pseudo-articulation of the transverse process and the iliac bone on one side, which can easily form arthritis in the strain and cause chronic low back pain. In rare cases, due to the above-mentioned pseudarthrosis, the marginal hyperplasia stimulates the nerve roots of lumbar 4 and lumbar 5, which travel from the front, or the peripheral nerves are stimulated and cause sciatica. Therefore, it must be distinguished from lumbar disc herniation. The differential diagnosis of the two mainly has two points: first, the lumbar pain of this disease is mainly in the lumbosacral region, appearing as muscle tonicity, and generally the pain does not radiate to the lower leg; second, by X-ray plain film, except for vertebral fusion, the lumbar spine of this disease generally does not appear lateral convexity. In clinical practice, if the typical signs of lumbar disc herniation appear, lumbar disc herniation should be considered first rather than this disease. Even if sciatica occurs, painful point closure can be differentiated, and the pain of this disease disappears, while lumbar disc herniation is not lost. Second, paravertebral musculofascial injury disease (a) lumbar myofasciitis lumbar myofasciitis is also known as lumbar myofibrositis or myofascial rheumatism. The cold, humidity, acute or chronic injury, certain viral infections and rheumatic metabolic reactions, resulting in lumbar fascia and muscle tissue edema, exudation and fibrous changes and the emergence of low back pain as the main symptoms of a class of disease. The main differentiation points between the disease and lumbar disc herniation are: 1. Characteristics of low back pain The disease presents diffuse low back pain, which is obvious in both sides of the lumbar region and above the iliac crest. The pain is severe in the morning and slightly decreases after activity, but increases in the evening after overexertion, while the symptoms of lumbar disc herniation decrease in the morning after rest and increase after activity. 2, pressure pain point The disease has a clear pressure pain point, which can be a point or several points. When pressure is applied, the nerve fiber endings distributed at the pain point can be transmitted upward, and pain in the adjacent tissues can appear radiologically. In contrast, in most cases, there is only one pressure point in lumbar disc herniation, and the range is more limited, and only radiating sciatica occurs in the area innervated by the nerve root at that level. 3, pressure point closure test with 1% procaine for pressure point local closure, the low back pain and pressure point of this disease caused by reflex pain in the buttocks, thighs and calves are disappeared; while lumbar disc herniation is not disappeared. 4, history and etiology This disease has clear triggering factors, mostly due to cold, moisture and overwork, or a past history of such. There can be an acute attack and remission period, which can be prolonged for a long time, and some of them can be self-healed; while lumbar disc herniation mostly has no clear triggering factors, and the triggering factors are often inconsistent with the past medical history, even if there is a certain remission, but it is difficult to be self-healed. 5.X-ray and other imaging examinations This disease generally has no special display; while lumbar disc herniation has typical imaging performance. 6, laboratory tests Some cases of this disease may show increased erythrocyte sedimentation rate, anti-hemolytic streptococcus “0” or positive rheumatoid factor, etc., confirming that the cause is rheumatic or rheumatoid disease. In contrast, lumbar disc herniation is generally absent. (B) Sciatic nerve pelvic outlet syndrome The early pathological changes of sciatic nerve pelvic outlet syndrome are traumatic reactions to local trauma, mostly due to acute sprains of the lower limbs during extreme abduction and external rotation or standing up from a squatting position. The late pathological changes of sciatic nerve pelvic outlet syndrome are mostly caused by repeated injury to the pear-shaped muscle, or improper treatment after injury, combined with cold, moisture and other stimuli, forming a chronic process and secondary changes. Due to the special relationship between the anatomical position of the pear-shaped muscle and the sciatic nerve, the late pathological changes after injury of the pear-shaped muscle, on the one hand, make the pelvic outlet of the sciatic foramen narrow, and may cause the sciatic nerve to be embedded in the outlet, when walking is pulled and may produce intermittent claudication; on the other hand, the hypertrophy, contracture and spasm of the pear-shaped muscle compress the sciatic nerve and cause irritable sciatica. At the same time, there may be motor, sensory and reflex disorders in the area innervated by the sciatic nerve, and even calf muscle atrophy and foot drop. Since sciatic nerve pelvic outlet syndrome and lumbar disc herniation both have similar symptoms of sciatica, differential diagnosis is required. The main points of differential diagnosis are as follows: 1. Medical history This disease has a clear cause of lower limb sports injury; while lumbar disc herniation is mostly due to lumbar injury. 2. pressure point The pressure point of this disease is at the outlet of the sciatic nerve pelvis, and its body surface projection is at the ring jump point of the foot Shaoyang gallbladder meridian of the Chinese medicine meridian (buttock), or slightly higher than 1 to 2 cm here; while the pressure point of lumbar disc herniation is on both sides of the lumbar spine. 3. Lower limb rotation test When the lower limb is rotated internally or externally automatically, the pain of the disease is aggravated, or sciatic nerve symptoms are induced; whereas in lumbar disc herniation, there is none. 4.Local anesthesia test of pressure point The local and radiological sciatica of this disease is significantly reduced or disappeared when using 1% procaine for local closure of the pressure point; but there is no such effect in lumbar disc herniation. 5. Imaging examination The sciatic nerve pelvic outlet syndrome alone has no special display, while lumbar disc herniation has typical imaging manifestations. III. Tuberculosis (a) Lumbar spine tuberculosis Lumbar spine tuberculosis accounts for about 50% of spinal tuberculosis. Tuberculosis of the spine is mostly secondary to infection and is therefore often associated with tuberculosis of other sites. In the early stage of the lesion of lumbar spine tuberculosis, persistent dull pain in the lumbar region or lumbosacral pain may occur. When a tuberculous abscess invades the lumbar intervertebral disc or invades the spinal cord, it can produce symptoms of nerve root irritation, restricted movement of the waist and lower limbs, lumbar deformity, and even motor, sensory, and reflex dysfunction below the lesion plane, so it should be distinguished from lumbar disc herniation. The main points of differentiation are as follows: 1. Systemic symptoms The disease is caused by secondary infection in other parts of the body, so most cases have persistent fever and night sweats (early symptoms may not be typical); while lumbar disc herniation is not. 2, laboratory tests The number of lymphocytes is elevated in this disease, and the number of neutrophils can also be elevated in cases of co-infection; the erythrocyte sedimentation rate is increased; smears of abscess puncture fluid or fistula secretions, bacterial culture, etc., can be seen in antacid bacilli. The lumbar disc herniation is mostly absent. 3, imaging X-ray plain film can determine the nature of the disease, the size of the scope, the presence of dead bone and cold abscess, and clearly show pathological fracture dislocation, etc.; while lumbar disc herniation shows typical signs of vertebral degeneration, osteophytes, and narrowing of the intervertebral space. Therefore, X-ray plain film is an important basis for differentiating the two. CT examination is more capable of showing the degree and extent of early vertebral destruction, the size of paravertebral abscesses and spinal cord compression in this disease. And the exact localization of the dead bone; while the examination of lumbar disc herniation can more clearly understand the location, size, direction and the compression of the nerve root or spinal cord of the herniated disc. Especially in the early stage, when X-rays cannot yet show obvious signs, CT is the best means of differentiation between the two. 4, medical history This disease can generally have a history of primary disease or contact with the population of tuberculosis; while lumbar disc herniation is mainly a history of trauma, cold and cold. (B) Sacroiliac joint tuberculosis Sacroiliac joint tuberculosis is also mostly a secondary lesion, often combined with other parts of the tuberculosis. In the early stage, it only shows mild back and leg pain, and its course develops slowly, and it is more common in women. Patients often complain of hip pain, which is relieved after rest and aggravated after activity, and is worse after sacroiliac joint torsion, and the pain is aggravated by coughing. As the nerve roots of lumbar 4 and 5 pass in front of the sacroiliac joint, they are stimulated by the swollen joint capsule due to tuberculosis inflammation, causing sciatica. Therefore, it should also be differentiated from lumbar disc herniation. Imaging examination can reveal blurred sacroiliac joint space, low bone density and dead bone. Tumor (a) Spinal tumor The early symptoms of lumbosacral tumor are mainly pain and discomfort in the lumbosacral region, which is persistently aggravated at night and not relieved after rest. When the lower lumbar spine is invaded, when the spinal cord, nerve roots and nerve plexus are compressed or invaded, radicular neurological symptoms and signs may appear within the distribution of damaged nerves, such as typical sciatica, weakness of lower limbs, muscle atrophy, sensory and reflex impairment (weakening, disappearance), and even paraplegia, which are sometimes misdiagnosed as lumbar disc herniation and only found to be caused by spinal tumor during surgery. Therefore, the differential diagnosis between the two is extremely important. The main points of differentiation are as follows: 1. symptoms The lumbar pain of spinal tumor is continuous and progressive, and cannot be relieved by rest or bed rest, while the lumbar pain of lumbar disc herniation is intermittent and relieved by rest or bed rest; malignant tumors of the spine often appear early with cachexia and anemia, and the age of onset of metastases is generally higher than that of lumbar disc herniation. 2.Laboratory examination Routine examination of blood and biochemical examination have positive significance for the differentiation of the two. For example, anemia, decrease in white blood cells and platelets, increase in prothrombin time, increase in sedimentation, increase in alkaline phosphatase and acid phosphatase, increase in total protein and globulin, increase in cerebrospinal fluid protein, etc. are of great significance for the diagnosis of spinal tumors. 3.Imaging examination (1)X-ray examination: X-ray plain film can have characteristic performance for certain solitary tumors, and the lesions show swelling bone defect, degeneration, pathological fracture, etc.. However, its resolution is low and cannot clearly show the bone lesions and soft tissues, and its diagnosis has great limitations. x-ray body layer photography can show the scope of lesions and smaller lesions more correctly than plain film. (2) CT examination: Because it can display cross-sectional images of tissue structure, it can directly and clearly show the vertebral bone and soft tissue structure, and show the compression of the spinal canal by the tumor, mild edge destruction of the vertebral body, and abnormalities of each protrusion, etc. This has significant differences with the images of lumbar intervertebral disc herniation. (3) MRI examination: Its imaging can show the morphological changes of intervertebral discs, ligaments, spinal cord and bones of the spine more clearly than X-ray plain film and CT images. However, it is not as good as X-rays and CT examinations for changes in vertebral body bone quality. (B) Intraspinal tumors Intraspinal tumors refer to tumors growing in the spinal cord, nerve roots and their accessory tissues. Clinically, there are mainly intradural nerve sheath tumors, intradural spinal meningioma and spinal cord glioma, which account for about 65% of intradural tumors. Among them, the first symptom of intradural nerve sheath tumor and spinal cord glioma is nerve root pain, and lesions in the lumbosacral region may cause radiating or severe pain in one or both extremities. The pain in spinal cord glioma is more intense, burning or stabbing pain. In the advanced stages of the disease, sensory and motor deficits and even paralysis may occur. In intravertebral spinal meningioma, although the first symptom is usually abnormal sensation (numbness of extremities, etc.), lumbosacral pain, such as burning or cutting pain, can also appear in the later stages and cause radicular pain. Due to the above characteristics of intravertebral tumor, the pain caused by compression of nerve root is similar to the radicular pain of lumbar disc herniation, and the cauda equina syndrome caused by tumor compression of spinal cord is also similar to the cauda equina syndrome of central type lumbar disc herniation. Therefore, the two need to be distinguished. The main points of differentiation are as follows: 1. Symptoms Intravertebral canal tumor, because the growth of tumor is continuous, so its symptoms are also gradually aggravated and not reduced by rest. The numbness in the foot can develop quickly from bottom up and extend from one leg to the other leg, eventually leading to bottom-up numbness in both legs and rectal bladder dysfunction, which is different from the cauda equina nerve dysfunction in central type lumbar disc herniation. 2. Signs The intravertebral tumor affects the spine less, the pressure pain area is not obvious, the sciatic nerve pull test is not typical, and the sensory, motor and reflex disorders are often not limited to one nerve root innervation area. In contrast, lumbar disc herniation mostly has obvious pressure pain points, and most of them only show motor, sensory and radiological disorders in the area innervated by the nerve root. 3.Laboratory examination Because most of the tumors in the spinal canal are benign tumors, the laboratory examination is not significant for the differential diagnosis of the two. 4.Imaging examination X-ray plain film has certain significance for the differentiation of the two. About 30% of the intravertebral tumors can be seen in the advanced stage of destruction, degeneration, defect, scoliosis and enlargement of intervertebral foramen. CT and MRI can clearly understand the shape and scope of the tumor, its longitudinal section and the extent of tumor involvement. V. Lumbar joint injury (a) Lumbar isthmus collapse and lumbar spine slippage The real cause of lumbar isthmus collapse is not yet completely certain, but is mainly thought to be due to congenital developmental defects and fatigue fracture or chronic strain. Arch rupture and lumbar spondylolisthesis are not necessarily symptomatic. Where symptoms occur, they are mainly lower back pain. Low back pain occurs mainly due to local activity of the isthmus disintegration and radicular irritation of nerve endings caused by the proliferation of fibrous tissue. Most of its low back pain symptoms are mild, aggravated after exertion, and can be slightly alleviated after rest, but cannot be completely relieved, and most of them are persistent low back pain. If the lumbar spine is severely slipped, compression of the nerve root or cauda equina nerve may occur and produce lumbago with leg pain, i.e., radiation to the sacrococcygeal region, buttocks or the back of the thighs, or sensory disorders of the lower extremities of different degrees may occur. Differentiation points: 1. Symptoms The disease is a chronic long-term low back pain or low back and leg pain, generally without obvious aggravation or remission period, unlike lumbar disc herniation which has more obvious features of symptom reduction after rest; whether low back pain or leg pain, it is lighter than lumbar disc herniation, and rarely has typical signs of sciatic nerve pain, if accompanied by sciatica, the possibility of combined lumbar disc herniation should be considered. 2.Signs The disease has protective ankylosis in the lower lumbar segment, increased physiological pronation, posterior protrusion of the spinous processes of the diseased vertebrae, while the spinous processes above them move to the front, thus causing the upper and lower spinous processes not to be on a plane, local depression, and increased sacral retrotrusion; pressure pain between the lumbar vertebrae or lumbosacral spines, and pressure pain in the spinous process, paraspinous or sacrospinous muscles; whereas in lumbar disc herniation the spinous processes may appear to be oblique, but there is no spinous process depression, and pressure pain is mostly in the spinous paraspinous. (1) Orthopantomogram: it is difficult to show the collapse of the vertebral arch and lumbar spine slippage, so there is no specific performance; while lumbar disc herniation can be seen as intervertebral space narrowing, vertebral osteophytes, and vertebral body deviation. (2) Lateral radiographs: there is often no positive finding in the case of arch collapse, while the degree of lumbar slippage can be observed and measured in the case of lumbar slippage; while lumbar disc herniation can show variation in the physiological curvature of the lumbar spine (reduction or disappearance of physiological convexity), variation in the vertebral space (equal width, narrowing, or even narrowing in front and wide in back), and osteophytes at the edge of the vertebral body or the hook vertebral joint. (3) Oblique radiographs: Oblique radiographs (45 degrees) of this disease are an important basis for diagnosis and can clearly show images of the vertebral arch isthmus. The type of isthmus fracture and disintegration can be shown on the oblique film; whereas there is no specific performance for lumbar disc herniation on the oblique film. (II) Degenerative lumbar instability Degenerative lumbar instability refers to a clinical condition in which abnormal displacement of the vertebral body occurs on the basis of degenerative changes of the lumbar spine and produces lower back pain as the main manifestation. This disease and lumbar disc herniation have great similarity in clinical manifestations, so they need to be carefully distinguished. The main differentiation points are: 1. symptoms Both have lower back pain, hip pain and lower limb pain. However, in the acute attack of the disease, there are often obvious traumatic factors, and pain may occur and dare not bend, and in the forward flexion position to the straight position is completely blocked and the phenomenon of “interlock”. In the acute attack, the pain is more intense, but the duration is short, and the pain is easily relieved within 4-5 days, and the pain is bilateral, and the degree of pain can be different on both sides, and the pain in the lower limbs rarely spreads below the knee, and the increase in abdominal pressure when coughing or sneezing does not aggravate the pain. 2.Signs There are no specific signs for this disease. If it is found that the sacrospinous muscle is tense and striated when standing, but relaxed when lying down, it has important value for the diagnosis of this disease. 3.Imaging examination (1)X-ray plain film: except for the displacement of unstable segments and the degree of displacement, it is difficult to distinguish from lumbar disc herniation in other aspects. (2) CT examination: this disease can clearly show calcification of the joint capsule, hypertrophy of the ligamentum flavum, narrowing of the nerve root canal, narrowing of the lateral saphenous fossa, degeneration or narrowing of the spinal canal, as well as post-traumatic paravertebral hematoma, injury, disorder and interlocking of the small joints. In contrast, CT examination for lumbar disc herniation can clearly show the signs of disc protrusion, the location, degree, size, shape of the protrusion and the signs of compression on the surrounding nerve roots and spinal cord. (3) MRI examination: The diagnosis and classification of vertebral slippage in this disease are more refined, and the degree and extent of degeneration of the degenerated tissue and the damage to the surrounding soft tissues, their nature and extent can be understood more clearly. It plays an important role in the differentiation of the two. (C) Lumbar spine small joint disorder Lumbar spine small joint disorder is also called lumbar spine small joint misalignment or misalignment. It is mostly caused by trauma, degenerative changes and congenital deformities, which can cause lumbar pain and lumbar leg pain. Therefore, it must be distinguished from lumbar disc herniation. The main points of differentiation between this disease and lumbar disc herniation are as follows: 1. Symptoms Patients with this disease are mostly young adults, mostly with acute attacks, and in the process of twisting or bending to straight back immediately produce unilateral or bilateral lower back pain or with radiation to the buttocks, thighs and sacrococcygeal area, the pain is so intense that the patient is in a forced position, afraid to move and afraid of others’ touch. However, its nerve root irritation symptoms, generally involving a small area, do not spread according to the nerve root distribution area, and the Achilles tendon radiation may be weakened or disappear when the sacral 1 nerve root is involved. However, it should be noted that the possibility of acute attack of lumbar disc herniation cannot be ruled out even in the presence of the acute attack of low back pain mentioned above. 2.Signs During the acute attack of this disease, the lumbar region is tense, and there is obvious percussion pain and pressure pain in the small joint part of the lesion. Generally, there is no abnormality in the muscle strength and sensation of the lower limbs, and the straight leg raising test is normal or close to normal. Local closure of the small joints of the affected vertebrae can immediately block the neurotransmission function of the small joint capsule area and reduce the pain symptoms. In the case of lumbar disc herniation, the straight leg elevation test is positive, and the local closure cannot block the nerve root stimulation in the spinal canal, so it cannot reduce the symptoms of lumbar pain. 3, imaging examination X-ray plain film examination, the disease is mostly no abnormal performance, lumbar spine physiological curvature exists, or increase. In the acute attack, the physiological curvature disappears. Mild small joint disorder is not easily observed on plain film, and if there is obvious misalignment, asymmetry of small joint protrusion on both sides is seen. In left and right oblique films, the articular processes are sometimes seen to be embedded in the isthmus. In contrast, the frontal and lateral radiographs of lumbar disc herniation show flattening, loss of lumbar physiological curvature or even lordosis, lumbar lordosis, narrowing of the intervertebral space, equal width or even narrowing of the front and back, osteophytes at the edge of the vertebral body, and other specific manifestations. If it is really suspicious, it can be identified by CT or MRI examination. Lumbar spinal stenosis Lumbar spinal stenosis is one of the common conditions that cause low back pain or low back pain. Due to the narrowing of the lumbar spinal canal, the spinal cord and nerve roots are compressed and the corresponding neurological dysfunction occurs. The causes of lumbar spinal stenosis are primary and secondary, with primary lumbar spinal stenosis accounting for about 3% and the rest being secondary. Secondary lumbar spinal stenosis has the following four common causes: 1. degenerative changes osteophytes of the spine, hypertrophy of the ligamentum flavum, calcification of the posterior longitudinal ligament, stenosis of the lateral saphenous fossa, and intervertebral disc lesions, etc. 2, trauma deformity of the vertebrae after fracture caused. 3, vertebral body slippage arch collapse and vertebral body slippage due to spinal degeneration can narrow the spinal canal. 4.Other bone diseases, such as fluorosis, Paget’s disease and scoliosis, etc. According to the characteristics of clinical symptoms, there are three types: central, lateral saphenous and mixed. Central lumbar spinal stenosis is often similar to or coexists with posterior central lumbar disc herniation, while lateral saphenous lumbar spinal stenosis is similar to or coexists with posterior lateral lumbar disc herniation. Therefore, the issues related to its differential diagnosis are discussed as follows: (a) Central lumbar spinal stenosis 1. It is generally believed that intermittent claudication is the specific symptom of this disease. In lumbar spinal stenosis, this symptom is present in more than 70% of cases. In contrast, the chance of intermittent claudication in lumbar disc herniation is extremely rare and only occurs in the presence of lumbar spinal stenosis. In addition, the onset of the disease is slow, while central lumbar disc herniation mostly develops suddenly, except for low back pain or lumbar leg pain accompanied by intermittent claudication, and the cone bundle sign rarely appears due to compression of the cauda equina. 2. Signs The symptoms and signs of lumbar spinal stenosis are mostly inconsistent, that is, the symptoms are heavy but the signs are light, or there are no obvious signs, which is different from the cauda equina syndrome of central lumbar disc herniation. A positive straight leg raise test is less common in this disease, while a positive lumbar hyperextension test is an important sign of this disease. In contrast, patients with lumbar disc herniation have a positive test for both tests, while the straight leg raise test is overwhelmingly positive. In addition, although partial sensory impairment may occur in this disease, the impairment in the innervated areas is incomplete, and the Achilles tendon reflexes are weak or absent, which is a diagnostic sign of this disease. 3, imaging (1) X-ray plain film: It is important for the diagnosis of lumbar spinal stenosis, not only to see the degeneration of the vertebral body, the hypertrophy of the articular prominence, and the reduction of the lower joint spacing, but more importantly, to measure the sagittal diameter of the spinal canal, if the sagittal diameter is equal to or less than 15 cm, the diagnosis can be confirmed with the support of clinical symptoms, while the possibility of lumbar spinal stenosis should be considered when it is 16-17 cm. However, the accuracy and reliability of the figures are limited because of the magnification and body position of the x-ray visualization. (2) Spinal canal imaging: Spinal canal imaging for lumbar spinal stenosis may have varying degrees of contrast filling defects or obstruction, unlike lumbar disc herniation where only the anterior aspect of the spinal canal is obstructed, lumbar spinal stenosis may appear as a lateral, lateral or completely obstructed image. (3) CT examination: It can clearly show the bony structure of the transverse section of the spinal canal, has clear clinical value for hypertrophy of the ligamentum flavum and disc herniation, and can clarify the condition and etiology of lumbar spinal stenosis, but because of its low discrimination of soft tissues, the display of fibrous ring expansion is vague, and there are false positive cases, so it is not as clear as MRI examination to observe the fibrous ring expansion of the intervertebral disc, bone superfluous hyperplasia at the posterior edge of the vertebral body, posterior longitudinal ligament and (b) The lateral saphenous fossa is a very important part of the spinal canal, and the spinal cord, cauda equina, and nerve roots are in compression. (B) Lateral saphenous stenosis 1. Symptoms The lateral saphenous fossa is a narrow gap extending laterally in the vertebral canal. Nerve root compression and irritation due to lateral saphenous fossa stenosis is the cause of radicular neuralgia in lateral saphenous lumbar spinal stenosis. However, the radicular symptoms of lateral saphenous lumbar spinal stenosis tend to appear or increase in pain when moving in certain positions, and intermittent claudication does not usually occur. 2. Signs Clinical features similar to those of lumbar disc herniation, such as impaired sensation in the lower extremities, weakened muscle force, weakened or absent tendon radiation, and positive straight leg raise test, may occur in cases of severe nerve root impaction in lateral saphenous lumbar spinal stenosis and are difficult to distinguish. 3. Imaging examination (1) X-ray plain film: it can be found that the lateral saphenous lumbar spinal stenosis has hypertrophy and hyperplasia of the articular protrusion and outward expansion of the spherical joint, the upper articular protrusion rises, and the lower articular protrusion has reactive density increase. Sometimes the superior articular eminence is displaced and the hyperplastic bone extends into the intervertebral foramen. (2) CT examination: It can clearly show the bony structure of the transverse section of the spinal canal, and has a more accurate differential diagnosis for lateral saphenous fossa stenosis and intervertebral microarthrosis. It is an indispensable means for the differential diagnosis of lateral saphenous lumbar spinal stenosis and posterior lumbar disc herniation. (3) MRI examination: The diagnostic value of lumbar spinal stenosis is greater than that of CT and spinal canalography, and it is also superior to CT scan of spinal canalography (CTM). On T2-weighted images, the narrowing of the spinal canal and the compression of nerve roots caused by the protrusion of the vertebral body into the lateral saphenous fossa, the thickening of the ossified posterior longitudinal ligament, and the extension into the lateral saphenous fossa can be directly observed.