What is Sciatica?

Sciatica is a syndrome based on pain in the sciatic nerve pathway and distribution areas. The vast majority of cases of sciatica are secondary to sciatic nerve stimulation and damage caused by lesions in the sciatic nerve and surrounding structures, which are called secondary sciatica; a few are primary, that is, sciatic neuritis.

Basic Information

English name: sciatica
Visiting department: orthopedics

Common locations: Hip, back of thigh, back of calf, and outside of foot
Common causes: Lumbar disc herniation
Common symptoms: The symptoms of this disease are mainly pain in the sciatic nerve pathway and distribution area

Causes of sciatica

There are many causes. The sciatica of most patients is secondary to the sciatic nerve stimulation and damage caused by lesions in the sciatic nerve and its surrounding structures. It is called secondary sciatica; a few are primary, that is, sciatic neuritis.

Clinical manifestations of sciatica

General symptoms

(1) The pain is mainly limited to the sciatic nerve distribution area, the back of the thigh, the back of the calf, and the foot. Patients with severe pain can take a unique posture; waist flexion, knee flexion, and toes landing. If the lesion is located at the nerve root, the pain in the spinal canal increases (cough, force).

(2) The degree of muscle weakness can vary widely depending on the etiology, location of the lesion, and the degree of damage. There may be weakness or paralysis of all or part of the sciatic innervation muscle.

(3) Tenderness of the sciatic nerve with or without sciatic notch.

(4) There is a sciatic nerve traction sign, a positive Lasgue sign and its allelic sign. The presence of this sign is often parallel to the severity of pain. The sign of local anesthesia sciatic nerve root or neural trunk can disappear.

(5) Achilles tendon reflexes disappear or disappear, and knee reflexes may increase due to stimulation.

(6) Various sensations in the innervation area of the sciatic nerve may be reduced or disappeared, including the vibration of the lateral malleolus, and there may be extremely light sensory disturbances.

2. sciatic neuritis

Often accompanied by various types of infections and systemic diseases, such as upper respiratory infections. Because the sciatic nerve is relatively superficial, sciatic neuritis is prone to occur when wet and cold, and it is necessary to pay attention to the complications of collagen and diabetes when sciatic neuritis occurs in systemic diseases.

Most of the sciatica is unilateral, without back and back pain. The pain is usually persistent or episodic. Symptoms worsen when the spinal canal pressure increases, and can also radiate along the sciatic nerve path. Sciatic nerve tenderness is obvious, and gastrocnemius tenderness exists. Pain and muscle weakness are usually not parallel. Generally, the pain is heavier, and muscle weakness is not obvious. In the acute stage, it is difficult to judge motor function due to pain. Sagging of the foot, gastrocnemius, and tibialis anterior Atrophy; Achilles tendon reflexes are reduced or disappeared, but Achilles tendon reflexes are normal, knee reflexes are normal, and superficial sensory disturbances are obvious.

3. Secondary sciatica

(1) Prolapse of lumbar intervertebral disc is the most common cause of sciatica. It occurs in waist 4-5 and waist 5 1. About 1/3 cases have a history of acute lumbar trauma. Most patients occur between 20-40 years old. It is characterized by back pain for weeks and months, and sciatica on the lower leg of the back. In addition to the general symptoms of sciatica, physical examination also has tense lumbar back muscles, limited waist movement, scoliosis, and spinous process tenderness at the lesion.

(2) Lumbar osteoarthritis is more common in people over 40 years of age, with subacute chronic onset, long history of low back pain, difficulty standing up for a long time, and difficulty sitting down for a long time. It can be clinically manifested as one or both sides. Sciatica and waist symptoms.

(3) Congenital malformation of lumbar and sacral vertebrae Lumbar vertebrae, lumbosacral vertebralization , and hidden spina bifida. The latter, in addition to showing sciatica, often has a history of enuresis, physical examination often has foot deformities, and lumbosacral skin abnormalities such as A small depression in the back of the anus, a small hemangioma on the midline of the palate, this often objectively and accurately indicates the unhealed part of the lamina.

(4) Sacral arthritis is commonly rheumatoid and tuberculous lesions, which stimulate the waist 4 to 5 nerve trunks when there is exudation of the joint capsule, and some patients may have symptoms of sciatica.

Sciatica examination

Imaging examination

It has important positions, including lumbar and sacral vertebrae, sacroiliac joint X-rays, spinal MRI, myelography and CT, and can be used for pelvic CT or MRI in addition to clinical pelvic physical diagnosis.

2. Electrophysiological examination

The EMG of the paraspinal muscle can help identify root sciatica and distal lesions. EMG with short head of the biceps femoris can help distinguish the lateral sciatic nerve and common peroneal neuropathy. Patients with pelvic or femoral fractures are difficult to perform routine physical examinations, and EMG can help evaluate nerve function. The femoral nerve and common peroneal nerve motor nerve conduction velocity and F wave may be abnormal, and the sciatic nerve conduction velocity is difficult to stimulate the proximal end of the lesion.

3. Other

Applying corticosteroids or local anesthetics to the piriformis muscle can help diagnose piriformis syndrome if pain is relieved.

Differential diagnosis of sciatica

Should be distinguished from lumbar muscle strain, buttock fibritis, and other diseases of the hip and back of the thigh pain, these are local pain, no sensory disturbance, loss of muscle strength, hyporeflexia and other neurological signs.

Sciatica Treatment

First of all, due to treatment, and pay attention to symptomatic treatment, all sciatica should rest in bed and sleep on a hard bed. Application of vitamin B drugs, analgesic treatment, no treatment until the cause is unknown.