Intervertebral disc herniation

　　(I) Basic etiology

　　1. The degenerative change of the lumbar intervertebral disc is the basic factor

　　The degeneration of the nucleus pulposus is mainly manifested by a decrease in water content, which can cause slight pathological changes such as instability and loosening of the vertebral segments; the degeneration of the annulus fibrosus is mainly manifested by a decrease in tenacity.

　　2. Injury

　　Long-term repeated external forces cause slight damage, which aggravates the degree of degeneration.

　　3. Weaknesses of the intervertebral disc's own anatomical factors

　　The intervertebral disc gradually lacks blood circulation after adulthood, and its repair ability is poor. On the basis of the above factors, certain triggering factors that can suddenly increase the pressure on the intervertebral disc may cause the nucleus pulposus, which has less elasticity, to penetrate the less tenacious annulus fibrosus that has become less tenacious, causing the nucleus pulposus to protrude.

　　4. Genetic factors

　　Lumbar disc herniation has been reported to have a familial onset, and the incidence rate of this disease is low in people of color.

　　5. Congenital lumbar sacral abnormality

　　Including lumbosacral ossification, sacral lumbosacralization, hemivertebra malformation, articular malformation, and asymmetry of articular processes. These factors can change the stress borne by the lower lumbar spine, thus constituting increased intradiscal pressure and the tendency to degenerate and be damaged.

　　(II) Triggering factors

　　On the basis of intervertebral disc degeneration, certain factors that can suddenly increase the intervertebral disc pressure can lead to nucleus pulposus prolapse. Common triggering factors include increased abdominal pressure, incorrect posture of the waist, sudden weight-bearing, pregnancy, cold and dampness, etc.

　　Clinical typing and pathology

　　Based on pathological changes and CT, MRI manifestations, combined with treatment methods, the following types can be classified.

　　1. Bulging type

　　The annulus fibrosus is partially ruptured, while the surface is still intact. At this time, the nucleus pulposus rises locally into the vertebral canal due to pressure, but the surface is smooth. This type can usually be relieved or cured by conservative treatment.

　　2. Herniated type

　　The annulus fibrosus is completely ruptured, the nucleus pulposus protrudes into the vertebral canal, and is covered only by the posterior longitudinal ligament or a layer of fibrous membrane, with an uneven surface or cauliflower-like appearance. This often requires surgical treatment.

　　3. Prolapsed and free type

　　The broken and herniated intervertebral disc tissue or fragments fall into the vertebral canal or become completely free. This type can not only cause root symptoms but also easily lead to symptoms of cauda equina, and non-surgical treatment is often ineffective.

　　4. Schmorl node

　　The nucleus pulposus enters the cancellous bone of the vertebral body through the fissures of the superior and inferior end plates of the cartilage, generally only with lumbar pain, without root symptoms, and most do not require surgical treatment.

　　1. Central herniation often leads to bladder and rectal symptoms (urinary and fecal incontinence). Incomplete bilateral lower limb paralysis.

　　2. Surgical treatment for lumbar disc herniation, common complications include the following categories:

　　(1) Infection: It is a relatively serious complication. Particularly, intervertebral disc infection brings great pain to patients, with a long recovery period, and the general infection rate is about 14%. The main manifestations are: the original neuralgia and lumbar leg pain symptoms disappear, and severe lumbar pain with buttock or lower abdominal pulling pain and muscle spasm occurs 5 to 14 days later. Patients cannot turn over and suffer greatly.

　　(2) Vascular injury: Vascular injury during lumbar intervertebral disc herniation surgery mainly occurs during the removal of intervertebral discs through the posterior approach. If the intervertebral discs are removed through the anterior peritoneal or extraperitoneal approach, it is less likely to injure these large blood vessels due to the exposure of the abdominal aorta and inferior vena cava or common iliac arteries and veins. The cause of vascular injury is often due to the use of pituitary forceps too deeply in the anterior direction to remove intervertebral disc tissue, resulting in the forceps piercing the anterior annulus fibrosus, clamping the large blood vessels, and causing vascular laceration.

　　(3) Nerve injury: During lumbar intervertebral disc herniation, the compressed nerve root itself may suffer from varying degrees of nerve injury due to the compression of the intervertebral disc tissue, chemical stimulation of the nucleus pulposus, leading to congestion, edema, adhesion, etc. Therefore, there is a possibility of exacerbation of neurological symptoms after surgery, and some may be due to nerve injury caused by surgical manipulation. Nerve injury can be classified into: extradural single or multiple nerve injuries, intradural cauda equina or nerve root injuries, and anesthesia medication injuries.

　　(4) Organ injury: It is rare to have simple organ injury during lumbar intervertebral disc removal, and almost all cases involve vascular injury accompanied by injury to other organs, such as the ureter, bladder, ileum, appendix, etc.

　　(5) Lumbar instability: In some patients undergoing lumbar intervertebral disc removal, sciatica disappears while low back pain persists. Some of the reasons for this include lumbar instability, manifested as abnormal movement of the lumbar spine during flexion. Therefore, for patients with severe low back pain symptoms, and for those with明显 abnormal spinal movement on functional motion lumbar radiography, spinal fusion surgery should be performed to resolve low back pain caused by spinal instability.

　　(6) Cerebrospinal fluid fistula or pseudocyst of the spinal meninges: This is often due to inadequate closure of the dura during intradural surgery, or failure to suture the dural incision and instead covering it with gelatin sponge.

　　(I) Clinical symptoms

　　1. Low back pain

　　It is the first symptom to appear in most patients, with an incidence of about 91%. Due to the stimulation of the annulus fibrosus outer layer and the posterior longitudinal ligament by the nucleus pulposus, referred pain in the lower back is produced through the sinus nerve, and sometimes accompanied by buttock pain.

　　2. Radiating pain in the lower limb

　　Although high lumbar intervertebral disc herniation (L2-3, L3-4) can cause sciatica, it is rare in clinical practice, accounting for less than 5%. The majority of patients have herniation at the L4-5 or L5-S1 interspaces, presenting as sciatica. Typical sciatica is a radiating pain from the lower back to the buttocks, the back of the thigh, the lateral side of the calf, and finally to the foot. The pain may worsen in situations where abdominal pressure increases, such as during a sneeze or cough. The limb affected by the radiating pain is usually one side, and only a few cases with central or paracentral nucleus pulposus herniation present with symptoms in both lower limbs. There are three causes of sciatica: ① The broken intervertebral disc produces chemical substances that stimulate and cause an autoimmune reaction, leading to chemical inflammation of the nerve roots; ② The protruding nucleus pulposus compresses or stretches the already inflamed nerve roots, causing venous return to be obstructed, further increasing edema, and increasing the sensitivity to pain; ③ The compressed nerve roots are ischemic. These three factors are interrelated and mutually reinforcing.

　　3. Cauda Equina Syndrome

　　The nucleus pulposus that protrudes posteriorly or the prolapsed, free disc tissue compresses the cauda equina, mainly manifested as urinary and fecal incontinence, and abnormal sensation around the perineum and perianal area. Severe cases may present with incontinence of urine and feces and incomplete paralysis of both lower limbs, which is rare in clinical practice.

　　(II) Signs of Lumbar Disc Herniation

　　1. General Signs

　　(1) Lumbar Scoliosis It is a postural compensatory deformity to alleviate pain. The direction of the spine bend depends on the relationship between the location of the nucleus pulposus and the nerve root. If the nucleus pulposus is located on the medial side of the spinal nerve root, the spine bends towards the affected side to reduce the tension of the spinal nerve root. Conversely, if the protrusion is located on the lateral side of the spinal nerve root, the lumbar spine tends to bend towards the healthy side.

　　(2) Limited Lumbar Movement Most patients have varying degrees of limited lumbar movement, which is especially pronounced in the acute stage. Among them, the restriction of flexion is most obvious because the nucleus pulposus can be further displaced posteriorly and the traction on the compressed nerve root can be increased in the flexed position.

　　(3) Pain on Palpation, Tapping Pain, and Spasm of the Sacrospinalis Muscle The sites of palpation and tapping pain are basically consistent with the vertebral interspaces of the lesion, and 80% to 90% of cases are positive. Tapping pain is most pronounced at the spinous processes, caused by the vibration of the lesion. The points of palpation are mainly located 1cm beside the vertebra, and pain can radiate along the sciatic nerve. About 1/3 of patients have lumbar sacrospinalis muscle spasm.

　　2. Special Signs

　　(1) Straight Leg Raising Test and Reinforcement Test The patient lies on their back, extends their knees, and the affected limb is passively raised. Normal nerve roots have a 4mm degree of mobility, and the lower limb starts to feel discomfort in the popliteal fossa when raised to 60° to 70°. In patients with lumbar disc herniation, the nerve roots are compressed or adhered, reducing or eliminating mobility. Pain in the sciatic nerve can occur when raised within 60°, known as a positive straight leg raising test. In positive cases, slowly lower the height of the affected limb until the radiating pain disappears. At this point, actively flex the affected ankle joint, and if it triggers the radiating pain again, it is called a positive reinforcement test. Sometimes, due to a large nucleus pulposus, raising the healthy limb can also stretch the dura mater and trigger radiating pain in the affected sciatic nerve.

　　(2) Sciatic Nerve Stretch Test The patient assumes a prone position with the knee of the affected limb fully extended. The examiner lifts the extended lower limb upwards, placing the hip joint in an exaggerated extension position. Pain in the anterior thigh area over the distribution of the sciatic nerve is considered positive when this extension reaches a certain degree. This test is mainly used to check for lumbar disc herniation at levels L2-L3 and L3-L4.

　　3. Neurological Manifestations

　　(1) Sensory Disturbance Depending on the location of the involved spinal nerve root, sensory abnormalities occur in the area innervated by the nerve. The positive rate is over 80%. Early symptoms often include increased skin sensitivity, followed by numbness, tingling, and decreased sensation. Since the involved nerve roots are mostly single and unilateral, the range of sensory disturbance is relatively small; however, if the cauda equina is involved (central and paramedian types), the range of sensory disturbance is more extensive.

　　(2) Decreased Muscle Strength 70% to 75% of patients experience decreased muscle strength. When the L5 nerve root is involved, the strength of the ankle and toe extensors decreases, and when the S1 nerve root is involved, the strength of the toes and plantar flexors decreases.

　　(3) Reflex Changes are also one of the typical signs that are prone to occur in this disease. When the L4 nerve root is involved, knee-jerk reflexes may be impaired, initially manifested as hyperactivity, and then quickly become reflex减退. When the L5 nerve root is damaged, there is usually no effect on the reflex. When the S1 nerve root is involved, the Achilles reflex is impaired. Reflex changes have great significance for the localization of the involved nerve.

　　Lumbar disc herniation is caused by the accumulation of injuries on the basis of degenerative changes. Accumulated injuries will further aggravate the degeneration of the intervertebral disc, so the focus of prevention is to reduce the accumulation of injuries. One should maintain good posture when sitting and the bed should not be too soft when sleeping. Workers who sit for long periods of time should pay attention to the height of the desk and chair, and change their posture regularly. Workers who need to bend over frequently during their professional work should stretch their waist and chest regularly, use wide belts, and strengthen the training of the lumbar and thoracic muscles to increase the intrinsic stability of the spine. Those who use lumbar corsets for a long time should pay special attention to the exercise of the lumbar and thoracic muscles to prevent the adverse consequences of disuse muscle atrophy. When picking up objects, it is best to use a flexed hip and knee squatting method to reduce the pressure on the posterior part of the lumbar intervertebral disc.

　　1. Lumbar X-ray Film

　　Plain X-ray films cannot directly reflect whether there is intervertebral disc herniation, but sometimes there may be narrowing of the intervertebral space and hyperplasia of the vertebral body margin, indicating degenerative changes, which is an indirect clue. Some patients may have spinal deviation or scoliosis. In addition, X-ray films can detect the presence of bone diseases such as tuberculosis and tumors, which has important significance for differential diagnosis.

　　2. CT Examination

　　It can clearly show the location, size, shape, and compression and displacement of the nerve roots and dural sac caused by intervertebral disc herniation. At the same time, it can also show the thickening of the vertebral laminae and yellow ligaments, the hyperplasia and hypertrophy of the small joints, the stenosis of the spinal canal and the lateral recess, and other conditions, which have great diagnostic value for this disease and have been widely used at present.

　　3. Magnetic Resonance Imaging (MRI) Examination

　　MRI has no radioactive damage and is of great significance for the diagnosis of lumbar disc herniation. MRI can comprehensively observe whether the lumbar intervertebral disc is diseased, and clearly show the morphology of intervertebral disc herniation and its relationship with the dural sac, nerve roots, and other surrounding tissues through sagittal images of different levels and the transverse images of the affected intervertebral disc. In addition, it can also differentiate whether there are other space-occupying lesions within the spinal canal. However, the display of whether the herniated intervertebral disc is calcified is not as good as CT examination.

　　4. Other

　　Electrophysiological examination (electromyography, nerve conduction velocity, and evoked potentials) can assist in determining the extent and degree of nerve damage, and observe the effectiveness of treatment. Laboratory tests are mainly used to exclude some diseases and play a role in differential diagnosis.

　　In daily life, patients with lumbar disc herniation can adjust their diet, and use food therapy to help recover from the disease.

　　1. Vinegar cooked eggs: Three fresh eggs, 500g of rice vinegar. Preparation: Boil the rice vinegar in a pot, add the eggs, and cook for 8 minutes, then remove. Patients can eat this before bedtime every day until cured.

　　2. Loofah root: An appropriate amount of loofah root and the old vine near the root, a little yellow wine. Preparation: Dry and grind the loofah root and vine into powder. Patients take 6g each time, taken with yellow wine, twice a day.

　　3. Sheep kidney and goji berry congee: One pair of sheep kidneys, 100g of mutton, 10g of goji berries, 80g of glutinous rice. Use: Remove the tendons from the sheep kidneys, cook with mutton, goji berries, and glutinous rice in water to make congee. Patients can eat this every day.

　　4. Sheep bone powder: One sheep shank bone, an appropriate amount of yellow wine. Use: Roast the sheep shank bone over a fire until it turns yellow, crush and grind into powder. Patients take 5g after each meal, twice a day with warm yellow wine.

　　5. Sanqi and Rehmannia瘦肉汤: 12g of Sanqi, 30g of raw Rehmannia, 4 jujube fruits, 300g of lean pork. Preparation: Place the materials in a pot, add water, bring to a boil over high heat, then reduce to low heat and cook for 1 hour until the pork is tender, add salt to taste. Patients can drink the soup and eat the meat, every other day, which can promote blood circulation and remove blood stasis, relieve pain. It is used to treat acute lumbar disc herniation with Qi stagnation and blood stasis.

　　6. Three-seven Stewed Frog: Two frogs, skin, head, and internal organs removed; 15g of Sanqi (Panax notoginseng), crushed; 4 jujube fruits with seeds removed. Preparation: Place all the materials in a pot and boil over high heat, then reduce to low heat and simmer for 1-2 hours. Patients drink the soup and eat the meat, once a day, which can invigorate the Qi and promote blood circulation, reduce swelling and relieve pain. It is used to treat lumbar disc herniation with Qi deficiency and blood stasis, and spleen and stomach weakness.

　　1. Non-surgical therapy

　　Most patients with lumbar disc herniation can be relieved or cured through non-surgical treatment. The treatment principle is not to return the degenerated and protruding intervertebral disc tissue to its original position, but to change the relative position of the intervertebral disc tissue and the compressed nerve root, or partially reposition the disc, alleviate the compression on the nerve root, resolve the adhesions of the nerve root, eliminate the inflammation of the nerve root, and thus alleviate the symptoms. Non-surgical treatment is mainly suitable for: ① Young patients with a first attack or a short course of disease; ② Patients with mild symptoms, whose symptoms can be relieved by rest; ③ No significant spinal canal stenosis in imaging examination.

　　(1) Absolute bed rest: During the first attack, strict bed rest should be observed, emphasizing that both urination and defecation should not be performed while getting out of bed or sitting up, which can lead to better effects. After 3 weeks of bed rest, one can get up and move around with a lumbar brace, and avoid bending over to hold objects for 3 months. This method is simple and effective, but it is difficult to persist. After relief, it is important to strengthen the lumbar and back muscle exercises to reduce the chance of recurrence.

　　(2) Traction therapy: Using pelvic traction can increase the intervertebral space width, reduce the intradiscal pressure, reposition the protruding disc part, alleviate the stimulation and compression on the nerve root, and should be performed under the guidance of a professional doctor.

　　(3) Physical Therapy and Massage: Can relieve muscle spasm, reduce intradiscal pressure, but note that violent massage can worsen the condition, and caution should be exercised.

　　(4) Epidural Corticosteroid Injection: Corticosteroids are long-acting anti-inflammatory agents that can reduce inflammation and adhesions around the nerve roots. Generally, a long-acting corticosteroid preparation + 2% lidocaine is used for epidural injection, once a week, 3 times as a course, and another course can be used after 2-4 weeks.

　　(5) Nucleus Pulposus Chemical Dissolution Method: Use collagenase or papain, inject it into the intervertebral disc or between the protruding nucleus pulposus and the dura mater, selectively dissolve the nucleus pulposus and annulus fibrosus without damaging the nerve roots, to reduce intradiscal pressure or make the protruding nucleus pulposus smaller to alleviate symptoms. However, this method has the risk of allergic reactions.

　　2. Percutaneous Nucleus Pulposus Discectomy/Laser Nucleoplasty

　　Enter the intervertebral space under X-ray monitoring with special instruments, grind and aspirate part of the nucleus pulposus or laser gasify it, thereby reducing the intradiscal pressure to alleviate symptoms, suitable for patients with prolapse or mild herniation, not suitable for patients with concurrent lateral recess stenosis or those with obvious herniation, or for those with nucleus pulposus prolapse into the spinal canal.

　　3. Surgical Treatment

　　(1) Indications for Surgery: ① History over three months, strict conservative treatment is ineffective, or conservative treatment is effective but frequently recurs with severe pain; ② First attack, but with severe pain, especially with obvious lower limb symptoms, patients find it difficult to move and sleep, and are in an强迫 position; ③ With symptoms of cauda equina compression; ④ Single nerve root paralysis, accompanied by muscle atrophy and muscle strength decline; ⑤ With spinal canal stenosis.

　　(2) Surgical Methods: Perform a posterior lumbar and thoracic incision, resect part of the lamina and articular processes, or excise the intervertebral disc through the lamina interspace. For central disc herniation, excise the lamina after resection and perform extradural or intradural disc excision. For patients with lumbar instability and lumbar spinal stenosis, simultaneous spinal fusion surgery is required.

　　In recent years, minimally invasive surgical techniques such as microdiscectomy, microendoscopic discectomy, and percutaneous transforaminal endoscopic discectomy have reduced surgical trauma and achieved good results by minimizing the damage.