Pathology of sciatica

2021-02-05 12:00 AM

Disc herniation is the most common cause of sciatica from root damage.


Sciatica is more common in men than women, and is usually between the ages of 30 and 50. Sciatica caused by root damage accounts for 90-95%, the rest is due to damage to the strings and tangles. There are 2 main groups of causes:

Systemic causes

Sciatica is caused by many different diseases such as stage III syphilis, gonorrhea, flu, rheumatism, typhoid, and malaria. This group is less common.

Group of causes in place

Disc herniation

Disc herniation is the most common cause of sciatica from root damage. In young people of working age, disc herniation is often acute after forceful movements in the wrong position of the spine (bent over lifting heavy objects in the wrong position, sudden body movements ...) Acute hip pain. In the elderly, disc degeneration is a common cause of recurrent and chronic low back pain. In obese people the risk is greater. There are times when a micro-traumatic disc injury persists in everyday life such as driving a long distance, bad posture (such as shifting to one side or leaning forward) for a long time. At this point, even slight exertion can cause disc herniation. Hernias are usually posterior lateral and in the intervertebral disc L4-L5 (roots L5) or mid-L5-S1 (roots S1).

Degenerative lumbar spine

Often chronic leads to degenerative spinal damage such as osteoporosis, osteomalacia, osteomalacia, deformation of the vertebral body, one or more vertebrae with ligament hypertrophy. Not only that, but also causes degenerative disc (mucous nucleus and fibrous ring), so it is easy to cause disc herniation.

Spondylolisthesis (spondylolisthesis)

The vertebrae slip forward or backward on another vertebra, congenital or traumatic. Women meet more than men. Spondylolisthesis or with spinal degeneration, nerve root damage (more common L5), lumbar spinal stenosis and severe may have horsetail syndrome.

Spondylitis (spondylitis)

 Common in the elderly, low back pain is characterized by increased exercise and often there is no correspondence between clinical and radiographs. Inflammatory lesions of the spine cause compression of nerve roots, narrowing of the lumbar spinal canal and in rare cases of clinical horsetail syndrome.

Ankylosing spondylitis (ankylosing spondylitis)

 Unlike spondylitis, which usually progresses silently with lower back pain and buttocks, spinal stiffness in the morning, seen in men before 40 years old, pain increases at night and does not relieve pain during rest. The test has increased blood sedimentation, antibodies against HLA-B27, X-ray shows that the vertebrae are stuck together and lose joint joints to create a typical "burning bamboo" image.


Directly to the sciatic nerve, fracture the lumbar spine, pelvic fracture, by direct injection into the sciatica or by injecting the oil-type drug in the buttocks spread to the sciatic nerve, the buttock abscess surgery.


Primary tumors: Myeloma, spinal tumors, nerve tumors.

Metastatic tumors: Metastasis from carcinoma (prostate, breast, lung, kidney, gastrointestinal tract), multiple myeloma, lymphoma (Hodgkin and non-Hodgkin). 

Spinal infection

Bacterial spondylitis:

Due to staphylococcus: Common after skin, urinary, lung and intravenous infections are not good sterile.

Tuberculous spondylitis (Pott's disease):

Usually secondary to pulmonary tuberculosis.

Epidural abscess.

Other causes

Lumbar spinal stenosis: Causes acquired (75%), congenital or a combination of both.

A facet joint hypertrophy: Usually on one side and compresses the corresponding nerve roots.

Lumbar thickened arachnoid inflammation - same: Inflammation, fibrosis that causes thickening of the arachnoid and compression of nerve roots, an unknown and common cause after lumbar surgery - together, after chronic infections calculation, trauma, subarachnoid bleeding, spinal anesthesia ...

Paget disease


The onset of sciatica varies greatly according to the cause. Post-exercise pain is common in disc herniation. Sometimes at first, back pain is first, then later pain follows the path of the sciatic nerve. There are many different causes, but generally have the following characteristics:

Natural pain

Starting from the waist and spreading down the legs is the most common, sometimes pointing down to the buttocks, to the thighs or down to the feet. If L5 lesions are spread from waist to buttocks, outer thighs, outer front of shins, front of ankle, instep and big toe. When S1, pain from the lower back spreads to the buttocks, the back of the thighs, the back of the legs, the heels, the soles of the feet outside the foot to the little toes. The pain is usually continuous sometimes flare-ups, but can also decrease or disappear while lying down ... Pain intensity varies from dull to unbearable pain. Sometimes the pain increases with coughing, sneezing, even when urinating. Sometimes there is paresthesia instead of pain.

After the examination

Pain point when pressed

Pain in the center or side of the spine, 2 cm from the midline to the L4, L5, and S1 regions.

Press along the sciatica over the Valleix 3 cm system from the center of the spine to the horizontal line with the L5 S1, between the buttocks, the back of the thighs, the hock, the ankle point, the calf point and the ankle point out.

Pain caused by nerve tension

Lasègue Mark: In the supine position, lift patient's legs sideways if they are less than 70 (patient complains of pain in the back of thigh or lower leg as positive.

Bonnet Mark: In supine position, lift the patient's legs and close the patient's thigh one by one if the pain along the sciatic nerve is positive.

Chavany's Mark: While lifting and causing pain, is positive.

Néri's Mark: Patient is upright, knees straightened and then bent over if the painful side leg contracts (knee flexion) are positive.

Mark Naffriger - Jonnes: Infection of the bilateral neck vein if lumbar pain spreads down the back of the leg is positive. Common in hernias is still in and out.

Spine mark - hip when patient stands

The spine was slightly crooked and lost its physiological curve, protruding in the lumbar region. The body and pelvis are tilted to the opposite side of the painful leg, the body is slightly bent forward to reduce pressure on the sciatica.

Her buttocks sagged down. Muscle spinal spondylosis.

Heel reflex

Decreased or lost in root damage S1.

Movement sign

I cannot walk with my fingers when S1 is damaged, while L5 cannot walk on my heels. When walking, the leg pain slightly shrinks.

Muscle nutritional disorders

Marx in L5 lesions, while S1 is atrophy of calf muscles.

Neurological disorders plant

There may be abnormalities of vasomotor reflex, skin temperature, sweat excretion reflex, hair-erecting reflex in the sore leg.


Standard film and lumbar dynamic film

Mainly exclude the bone cause. Disc disease implies that when the disc is narrowed, in a straight film, the disc is narrow on the healthy side and the disc is tilted, the disc is open back.

CT scan or resonance from the lumbar spine

Identify multiple lesions and locate hernias.

Nerve root staining

Determine a lateral and medial disc herniation. It also identifies other causes such as nerve tumors, horsetail tumors ...


Electromyography for detecting and evaluating nerve root damage in lumbar pain. However, the method of electro-electromyography with a needle electrode is more commonly used than measuring the neurotransmitter rate in lesion mapping and prognosis.

Biochemical tests - cells

Tests for blood count, sedimentation blood, biochemistry of blood and urine ... are rarely indicated for acute low back pain unless there is suspicion of association with inflammatory disease or systemic disease.

Clinical form

Rapid muscle atrophy is also called paralysis

Horsetail syndrome form

Usually, central disc herniation ruptures all ligaments, causing soft paralysis of the legs, disturbances of the feeling of the legs and saddle area, and round muscle disorders such as urinary retention, constipation, impotence.

Sciatica pain form 2 sides

Pain in both legs but no round muscle disorder and no feeling disturbance in the saddle. Sometimes it hurts from one side and then to the other.

Differential diagnosis

Pain in the nerves of the lower extremities

Femur: Pain in the anterior thigh and decrease or loss of knee tendon reflex.

Femur nerve: Pain on the outer surface of the upper thighs.

Squeezing nerve: Pain in the inner thigh.


Joints in pots

Pain may spread downwards, but when the crest is pressed down, it hurts, taking the pelvis to see that the joint and pot on the side are blurred.

Hip joints

Limited joint movement, painful movement, even with leg contraction. Distinguish by the Patrick method. If the patient complains that the pain is damage to the hip joint during Patrick's test.

Pelvic dermatitis

Pain in the back of thighs, the affected leg is always contracted and tends to rotate inward. Leg stretching is painful. An unprepared abdominal film showed blurred lateral perineal muscle pain. Abdominal ultrasound during gastrointestinal lavage can detect perineal peripheral blurred vision.



Absolute rest in severe cases, should lie on a hard bed, avoid hammock or sit on the swing. Avoid strong movements such as sudden turns, running, jumping, bending ...

Physical therapy

Mechanical impact by spinal stretching, chiropractic, gymnastics, infrared, shortwave, candle wax ...

Drug treatment

Analgesic: Aspirin, non-steroid anti-inflammatory, blocking epidural or epidural roots by corticosteroids or Novocain in combination with vitamin B12.

Muscle relaxants like Myola stan, sedatives like seduxen, Xanax ...

Vitamin group B high dose combined with folic acid.

Depending on the cause, treat as in infection with antibiotics ...

Surgical treatment

Nuclear (nucleolus) by iniprol or hexatrione.

Surgery in such cases as dyspepsia, paralysis, horsetail syndrome, lumbar spinal stenosis, pain that cannot be tolerated despite the use of analgesics or relapses. Can open surgery or laser.