Clinical symptoms of lumbar disc herniation According to the site and size of the nucleus pulposus (prolapse) and the size of the sagittal diameter of the spinal canal, the pathological characteristics, the state of the body and the individual sensitivity, etc., the clinical symptoms can vary greatly. Therefore, the recognition and determination of the symptoms of this disease must be comprehensively understood and inferred from the perspective of its pathophysiology and pathologic anatomy. The common symptoms of the disease are described as follows. (1) Lumbar pain: more than 95% of patients with lumbar intervertebral disc protrusion (prolapse) have this symptom, including vertebral body type. ①Mechanism: mainly due to the degeneration of the nucleus pulposus into the vertebral body or the posterior longitudinal ligament, the adjacent tissues (mainly for the nerve roots and sinus-vertebral nerves) caused mechanical stimulation and compression, or due to the nucleus pulposus glycoprotein, β-protein overflow and histamine (substance H) release, so that the neighboring spinal nerve roots or sinus-vertebral nerves, etc., suffered from the stimulation of the cause of the chemical and (or) mechanical radiculitis. ② performance: clinically persistent dull pain in the lower back is common, lying down to alleviate, standing is aggravated, in general can be tolerated, and allow moderate lumbar activity and slow walking, mainly due to mechanical compression. The duration is as little as 2 weeks, and can last for months or even years. Another type of pain for the lumbar spasm-like pain, not only the onset of acute and sudden, and more intolerable, non-bed rest. This is mainly due to ischemic radiculitis, that is, the nucleus pulposus suddenly protrudes and compresses the nerve root, resulting in the root blood vessels at the same time, presenting a series of changes such as ischemia, bruising, lack of oxygen and edema, and can last for days to weeks (and spinal stenosis can also appear this sign, but the duration is very short, only a few minutes). Lying on a plank bed, closed therapy and various dehydrating agents can provide early relief. (2) Lower extremity radiating pain: more than 80% of the cases of this syndrome, of which the latter type can reach more than 95%. Mechanism: The same mechanism as the former, mainly due to mechanical and/or chemical stimulation of the spinal nerve roots. In addition, through the affected section of the sinus nerve can also appear reflex sciatica (or called “pseudosciatica”). ② performance: light manifestations from the waist to the thighs and calves of the back of the radioactive tingling or numbness, up to the soles of the feet; generally tolerable. Severe cases are manifested by the waist to the foot of the electric shock-like pain, and more accompanied by numbness. Although the mild pain can still walk, but the gait is unstable, limping; the waist more to take a forward leaning position or hands to support the waist to relieve the tension stress on the sciatic nerve. In severe cases, bed rest, and prefer to take the hip flexion, knee flexion, side lying position. All factors that increase abdominal pressure aggravate radiating pain. Since flexion of the neck can aggravate the stimulation of the spinal nerves by pulling on the dural sac (i.e., flexion of the neck test), the patient’s head and neck tend to take the tilted position. Radiation pain of the limb is mostly lateral, only a very small number of central or paracentral herniated nucleus pulposus manifested as symptoms of both lower limbs. (3) Numbness of the limbs: mostly accompanied by the former, and only about 5% of the patients showed numbness without pain. This is mainly due to the stimulation of proprioceptive and tactile fibers in the spinal nerve roots. The scope and location depend on the number of nerve root sequences involved. (4) Cold sensation in the limbs: a few cases (about 5%~10%) feel cold and chilly in the limbs, mainly due to the stimulation of the sympathetic nerve fibers in the spinal canal. Clinical often found that the day after surgery patients complained of limb fever cases, and this is the same mechanism. (5) Intermittent claudication: its mechanism and clinical manifestations are similar to those of lumbar spinal stenosis, mainly because in the case of herniated nucleus pulposus, secondary lumbar spinal stenosis can occur on the basis of pathology and physiology; for those with congenital developmental narrowing of sagittal diameter of the spinal canal, the herniated nucleus pulposus aggravates the narrowing of the spinal canal, so that it is easy to induce this symptom. (6) Muscle paralysis: paralysis caused by lumbar disc prolapse is very rare, but it is mostly due to root damage, resulting in different degrees of paralysis of the innervated muscles. In mild cases, the muscle strength is weakened, and in severe cases, the muscle loses its function. Clinically, foot drop caused by the involvement of anterior tibialis muscle, peroneus longus shortus, extensor digitorum longus and extensor digitorum longus innervated by lumbar 5 spinal nerves is common, followed by quadriceps (lumbar 3~4 spinal nerves innervated) and gastrocnemius muscle (sacral 1 spinal nerves innervated), etc. The most common cause of foot drop is paralysis caused by root damage. (7) Cauda equina symptoms: mainly seen in the posterior central type and the central paracentral type of medullary protrusion (prolapse), so clinically rare. Its main manifestations are perineal numbness, tingling, defecation and urination disorders, impotence (male), and sciatic nerve involvement in both lower limbs. In severe cases, symptoms such as loss of bowel control and incomplete paralysis of both lower limbs may occur. (8) Lower abdominal pain or anterior thigh pain: in high lumbar disc herniation, when the lumbar 2, 3, 4 nerve roots are involved, there is pain in the inguinal area of the lower abdomen in the innervation area of the nerve root or the anterior medial thigh. In addition, some patients with low-level lumbar disc herniation may also experience pain in the groin area or anterior medial thigh. With lumbar 3~4 disc herniation, 1/3 of them have groin area or anterior medial thigh pain. Its rate of occurrence in lumbar 4~5 and lumbar 5~sacral 1 intervertebral disc herniation is basically equal. This kind of pain is mostly involving pain. (9) Lower skin temperature of the affected limb: similar to the cold sensation of the limb, it is also due to the pain of the affected limb, which reflexively causes sympathetic vasoconstriction. Or due to provoke the paraspinal sympathetic nerve fibers, triggering sciatica and lower leg and toe skin temperature, especially toes. Such hypothermia is more pronounced in sacral 1 nerve root compression than in lumbar 5 nerve root compression. On the other hand, after nucleus pulposus removal, the limb is warm. (10) Others: Depending on the location of the compressed spinal nerve root and the degree of compression, the extent of involvement of neighboring tissues and other factors, some rare symptoms may occur, such as excessive sweating of the limbs, swelling, sacrococcygeal pain and radiating pain in the knees and other symptoms. Signs of lumbar disc herniation (1) General signs: mainly refers to lumbar and spinal signs, which are common manifestations of the disease, including: ① Gait: in the acute stage or nerve root compression is obvious, the patient can appear claudication, a hand to support the waist or the affected foot is afraid of weight-bearing and jumping gait, etc. The mild type can be the same as normal. And lightweight people can be no different from normal people. Lumbar curvature changes: general cases show that the physiological curve of the lumbar spine disappears, flat back or anterior convexity decreases. A few cases even have posterior convex deformity (mostly due to the combination of lumbar spinal stenosis). (iii) Scoliosis: this sign is generally present. Depending on the relationship between the protruded nucleus pulposus and the nerve root, the spine is curved to the healthy side or to the affected side. If the protruded nucleus pulposus is located in the medial side of the spinal nerve root, the lumbar spine bends to the affected side because bending the spine to the affected side can reduce the tension of the spinal nerve root, so the lumbar spine bends to the affected side; on the contrary, if the protruded material is located in the lateral side of the spinal nerve root, the lumbar spine bends more to the healthy side (Figure 1). In fact, this is only a general rule, there are many factors, including the length of the spinal nerves, the degree of traumatic inflammatory reaction in the spinal canal, the distance of the protrusion from the spinal nerve root, and a variety of other reasons can change the direction of scoliosis. Pressure and percussion: The location of pressure and percussion basically corresponds to the diseased vertebral segment, and is positive in about 80% to 90% of the cases. Knocking pain is obvious at the spinous process, which is caused by knocking and vibrating the lesion. Pressure points are mainly located in the paravertebral area equivalent to the sacrospinal muscle. Some cases were accompanied by radiating pain in the lower limbs, mainly due to the stimulation of the dorsal branch of the spinal nerve root. In addition, percussion on the bilateral heels can also cause conductive pain. When combined with lumbar spinal stenosis, there is also obvious pressure pain in the interspinous space. (5) Range of lumbar motion: depending on whether the disease is acute or not, and the duration of the disease, the degree of limitation of the range of lumbar motion varies greatly. In mild cases, the range of lumbar motion may be close to normal, while in acute episodes, the lumbar motion may be completely limited, and even refused to test the lumbar mobility. In general cases, lumbar forward flexion, rotation and lateral movement are limited; in combination with lumbar spinal stenosis, posterior extension is also affected. (6) Lower limb muscle strength and atrophy: Depending on the location of the damaged nerve roots, the muscles innervated by them may show signs of muscle weakness and atrophy. Clinically, thigh and calf circumference measurements and muscle strength tests should be performed routinely in this group of cases, and the muscle strength of each group should be compared with that of the healthy side and recorded, and then compared again after treatment. (7) Sensory impairment: the mechanism is consistent with the former, depending on the location of the affected spinal nerve roots and the occurrence of sensory abnormalities in the innervated area. The positive rate reaches more than 80%, among which the posterior type reaches 95%. In the early stage, it is mostly characterized by skin sensitization, which is gradually followed by numbness, tingling and hyperalgesia. Feeling completely lost is not rare, because the affected nerve root to a single section of unilateral as much, so the range of sensory impairment is small; but if the cauda equina is involved (central type and the central side of the type), the range of sensory impairment is more extensive. (8) Reflex changes: one of the typical signs of this disease. When the lumbar 4 spinal nerve is involved, knee-jerk reflex disorder can appear, the early performance is active, and then quickly become hyporeflexia, clinically, the latter is more common. Lumbar 5 spinal nerve damage has no effect on reflexes. The Achilles tendon reflex is impaired when the first sacral nerve is involved. Reflex changes are of greater significance to the localization of the involved nerves. (2) Special signs: refers to the signs obtained through various special examinations. Clinically significant ones are: ① Neck flexion test (Lindner’s sign): also known as Lindner’s sign. The patient is asked to stand, lie on his back or sit down, and the examiner puts his hand on the top of the head and bends it forward. If radiating pain occurs in the affected lower extremity, it is positive, and vice versa is negative. The positive rate is up to 95% or more in the vertebral canal type. The mechanism is mainly due to the fact that when the neck is flexed, the dura mater is displaced upward, resulting in the spinal nerve roots in contact with the protrusion being pulled. This test is simple, convenient and reliable, especially for outpatient and emergency. ② Straight leg raising test: the patient lies on his back, so that the affected knee is lifted upward in a straight state, measure the angle of passive lifting and compare it with the healthy side, which is called the straight leg raising test. This test has been recognized since it was first proposed by Forst in 1881. The more inferior the nerve root, the greater the effect of this test and the higher the positive detection rate (and the lower the angle of elevation). In addition, the larger the prominence and the more extensive the edema and adhesions in the root cuff, the lower the lifting angle. In normal conditions, the lifting angle of the lower limb can reach more than 90°, and the angle decreases slightly with age. Therefore, the smaller the lifting angle, the greater the clinical significance, but must be compared with the healthy side; bilateral, generally 60 ° for the normal and abnormal demarcation line. (iii) The healthy limb elevation test (also known as Fajcrsztajn’s sign, Bechterew’s sign, Radzikowski’s sign): when the healthy limb is elevated with straight legs, the nerve root sleeve on the healthy side can pull the dural sac to shift distally, thus making the nerve root on the affected side move downward as well. When the herniated disc on the affected side is in the axilla of the nerve root, the movement of the nerve root to the distal end is restricted, causing pain. If the herniated disc is in the shoulder, it is negative. When the patient is lying on his back during the examination, the presence of sciatica on the affected side is positive when the healthy side straight leg is raised (Figure 2). Laseque’s sign: some people combine this sign with the former into one category, while others advocate to describe it separately. The hip and knee joints are placed in a state of 90° flexion, and then the knee is straightened to 180°, and if the patient experiences radiating pain in the posterior part of the lower limb during this process, it is positive. The mechanism is mainly due to the stimulation and pulling of the sensitive sciatic nerve when the knee is extended. ⑤ Straight leg raising and strengthening test: also known as Bragard’s sign, i.e., when the operation of straight leg raising test reaches a positive angle (subject to the patient’s complaint of radiating pain in the limb), the foot of the affected limb is flexed to the dorsal side in order to aggravate the pulling on the sciatic nerve. Positive patients complain of increased sciatic nerve radicular pain. The purpose of this test is to exclude the influence of myogenic factors on the straight leg raising test. (6) Supine abdominal raising test: the patient takes the supine position, performs the movement of raising the abdomen and buttocks, so that the buttocks and back leave the bed surface. At this time, if the complaint of the affected limb sciatic nerve radiating pain, it is positive. (7) Femoral nerve pulling test: the patient takes the prone position, and the knee joint of the affected limb is completely straightened. The examiner will straighten the lower limb elevated, so that the hip joint is in the hyperextension position, when hyperextension to a certain degree of pain in the femoral nerve distribution area in front of the thigh, it is positive. This test is mainly used to examine patients with lumbar 2~3 and lumbar 3~4 disc herniation. However, in recent years, it has also been used to detect cases of lumbar 4~5 intervertebral disc herniation, and its positive rate can be as high as 85% or more. (8) Other tests: such as N nerve or peroneal nerve compression test, lower extremity rotation (internal or external rotation) test, etc., mainly used for other causes of sciatica disorders. Symptoms and signs of lumbar disc herniation with localization significance in common sites are listed in Table 1. Table 2 shows the clinical manifestations of central lumbar disc herniation. Types of lumbar intervertebral disc herniation (prolapse) According to the location and direction of the nucleus pulposus (prolapse), it can be categorized into the following two major types. (1) Vertebral body type: It refers to the nucleus pulposus protruding from the degenerated nucleus pulposus through the lower (common) or upper (rare) annulus fibrosus, and then through the cartilaginous plate vertically or obliquely into the middle of the vertebral body or vertebral body edge. This type was previously thought to be rare, but in fact, if a comprehensive examination of patients with low back pain can be carried out, this type of patients not less than 10%; autopsy materials show that the proportion of this type can be as high as 35%. This type can be divided into: ① anterior margin type: the nucleus pulposus penetrates into the edge of the vertebral body (the anterior superior margin of the next vertebral body is the most common), so that the edge of the appearance of a triangular-shaped bone (therefore, clinically misdiagnosed as vertebral body edge fracture from time to time). This type of clinical more common, Qu Mianwu (1982) in 102 gymnasts found that there are 32 cases, accounting for 31, 3%, higher than the general incidence of 3% to 9%, may be related to this group of athletes and the amount of training activities. The mechanism is mainly due to the posterior extension of the low back, increased pressure in the intervertebral space, and forward displacement of the nucleus pulposus and its protrusion into the vertebral body (Figure 3A). Depending on the course of the disease after prolapse, it presents different morphology, and in the later stage, it can form part of the vertebral body edge bone cumbersome. Orthomedial: The nucleus pulposus passes vertically or nearly vertically upward or downward through the cartilaginous plate into the vertebral body and forms a Schmorl’s node-like change (Figure 3B). It is not easy to diagnose because it is clinically mild or asymptomatic, and is found in about 15% to 38% of autopsies. The protrusions can be large or small, with large ones easily detected by X-ray or CT or MRI, while small ones are often missed. Under normal circumstances, the degenerated nucleus pulposus is not easy to pass through the small infiltration holes in the cartilage plate, but if it meets with acquired damage, thinning of the cartilage plate, or happens to pass through the remains of the vascular channel, then it can cause this type. (2) Vertebral canal type: or posterior type, refers to those cases in which the nucleus pulposus protrudes through the annulus fibrosus in the direction of the spinal canal. If the nucleus pulposus stops in front of the posterior longitudinal ligament, it is called a “herniated disc”; if it crosses the posterior longitudinal ligament and reaches the spinal canal, it is called a “prolapsed disc”. According to the different anatomical locations of the herniated disc, it can be categorized into the following 5 types (Figure 4). ①Central type: the prolapse is located in the center of the spinal canal and mainly causes irritation or compression of the cauda equina. In individual cases, the nucleus pulposus may pass through the wall of the dural sac and enter the subarachnoid space. The main clinical manifestations of this type are bilateral lower limbs and bladder and rectal symptoms. Its incidence is about 2%~4%. ② Paracentral type: refers to the protrusion (prolapse) is located in the center, but slightly to the side of the person. Clinical symptoms are mainly cauda equina symptoms, which can be accompanied by radicular irritation symptoms at the same time. Its incidence is slightly higher than the former. Lateral type: the protrusion is located in the center of the spinal nerve root in front of the spinal nerve root, which may be slightly shifted. It mainly causes radicular irritation or compression symptoms; it is the most common in clinic, accounting for about 80%. Therefore, when mentioning the symptoms, diagnosis and treatment of this disease, most of them are elaborated according to this type. Lateral type: the protrusion is located on the lateral side of the spinal nerve root, mostly in the form of “prolapse”, so not only is it possible to compress the spinal nerve root of the same segment (inner and lower), but the nucleus pulposus may also move up along the anterior wall of the spinal canal and compress the upper segment of the spinal nerve root. Therefore, if surgical exploration is performed, care should be taken to examine it. It is clinically rare, accounting for about 2%~5%. ⑤ Outermost lateral type: the prolapsed nucleus pulposus migrates to the anterior side of the spinal canal and even enters the root canal or the lateral wall of the spinal canal. Once adhesions are formed, it is easy to miss the diagnosis, and may even be overlooked during intraoperative examination, so clinical attention should be paid to it, but fortunately, its incidence is only about 1%. Pathogenesis 1, the main etiology It is well known that the lumbar intervertebral discs are subjected to strong compressive stresses during spinal loading and movement. After the age of about 20, the intervertebral discs begin to degenerate and constitute the basic cause of lumbar disc herniation. In addition, lumbar disc herniation is associated with the following factors: (1) Trauma: Observation of clinical cases shows that trauma is an important factor in disc herniation, especially the onset of the disease in children and adolescents, with which it is closely related. During light load and rapid rotation of the spine, it can cause horizontal rupture of the annulus fibrosus, while compressive stress mainly ruptures the cartilage endplates. It is also believed that trauma is only the causative agent of disc herniation, and the original lesion lies in the painless nucleus pulposus protruding into the inner annulus fibrosus, while the trauma causes the nucleus pulposus to protrude further into the outer annulus fibrosus, which is innervated outside, thus causing pain. (2) Occupation: Occupation and lumbar intervertebral disc protrusion (prolapse) of the relationship is very close, for example, car and tractor drivers in a long-term sitting position and bumpy state, so that when driving a car, the pressure within the intervertebral discs is higher, up to 0, 5kPa/cm2, in the clutch when the pressure can be increased to 1kPa/cm2, which is prone to cause lumbar intervertebral disc protrusion. Engaged in heavy manual labor and weight lifting sports due to overload is more likely to cause disc degeneration, because in the stooping state, if you lift 20kg of heavy objects, the pressure in the intervertebral disc can be increased to more than 30kPa/cm2. (3) Genetic factors: lumbar intervertebral disc herniation has a familial incidence of reports, less material in the country; in addition, statistics show that the incidence of Indians, African blacks and Inuit incidence of other ethnic groups than the incidence of significantly lower, the reasons for which need to be further studied. (4) Lumbosacral congenital anomalies: lumbosacral malformations can increase the incidence rate, including lumbar sacralization, sacral lumbarization, hemivertebral deformities, small joint deformities and asymmetric articular eminence, etc. The above factors can make the lower lumbar vertebra bear the burden of the lumbar vertebra. The above factors can make the lower lumbar spine under stress change, thus constituting one of the factors that increase the internal pressure of the intervertebral disc and prone to degeneration and injury. 2, triggering factors In addition to the main causes of this disease, that is, the degenerative changes in the intervertebral discs, a variety of triggering factors also play an important role, for example, some of the factors that slightly increase the abdominal pressure can be made to herniate the nucleus pulposus. For example, some factors that slightly increase the abdominal pressure can cause the nucleus pulposus to protrude. The main reason is that, on the basis of degeneration of the intervertebral disc, some factors that can induce a sudden increase in the pressure of the intervertebral space can cause the nucleus pulposus to pass through the annulus fibrosus that has been denatured and thinned to enter the front of the spinal canal or pass through the vertebral plate to invade the edge of the vertebral body. Such triggering factors are as follows: (1) Increase in abdominal pressure: clinically about 1/3 of the cases before the onset of a clear increase in abdominal pressure factors, such as violent coughing, sneezing, breath-holding, straining to defecate, or even “false honor” action, which can make the abdominal pressure rise and destroy the equilibrium between vertebral segments and the vertebral canal. (2) Lumbar posture: Whether during sleep or in daily life, work, when the lumbar region is in a flexed position, such as sudden rotation, it is easy to induce nucleus pulposus protrusion. In fact, in this position, the pressure in the intervertebral space is also higher, which is easy to promote the herniation of the nucleus pulposus to the back. (3) Sudden weight-bearing: a well-trained person, more first to do preparatory activities, or start from a small weight-bearing (such as lifting weights, picking burdens, etc.) in order to prevent lumbar sprains or herniated discs, but if the sudden increase in the lumbar load, not only may cause lumbar sprains, but also prone to herniation of the nucleus pulposus. (4) pregnancy: during pregnancy, the whole ligament system is in a state of relaxation, and the laxity of the posterior longitudinal ligament is easy to make the intervertebral disc bulge. In this regard, the authors conducted a relevant research study and found that at this time, the incidence of low back pain in pregnant women is significantly higher than that of normal people.