Brachial plexus involvement

Introduction The 5-8th cervical anterior branch and the 1st thoracic anterior branch consist of 5 nerve roots. 5 parts divided into roots, stems, strands, bundles, and branches. There are 5 branches of sputum, sarcolemma, sputum, middle, and ruler. The brachial plexus consists of 5 stems, the C5-C6 nerve roots are in the outer edge of the anterior scalene muscle, and the composition is dry; the C7 is composed of the middle stem; the C8-T1 forms the lower stem. (Located on the surface of the first rib, about 1 cm per dry length). Each stem is divided into two groups (on the surface of the clavicle, about 1 cm each); each bundle consists of 3 bundles, the length of the bundle is about 3 cm, and each bundle is divided into nerve branches at the level corresponding to the condyle to form the terminal nerve. The brachial plexus is about 15 cm in length and has about 150 000 axons. The brachial plexus is located near the shoulder joint with a large range of motion, adjacent to the artery, which is easy to cause brachial plexus damage.

Cause

1, trauma: in the cause of brachial plexus damage, trauma is the most common, divided into closed and open damage. Closed injuries are seen in car accidents, sports injuries (such as skiing), birth injuries, neck traction, and anesthesia. When the limbs are fixed at a certain position for a long time, open injuries are mainly seen in gunshot wounds, instrument injuries, and radial angiography. , radial artery surgery, medial sternotomy, carotid artery bypass surgery, damage caused by jugular hemodialysis treatment has also been reported.

2, idiopathic brachial plexus neuropathy: also known as neuropathic muscular atrophy or painful brachial plexus neuritis, also known as Parsonage - Turner syndrome. This patient often has a history of viral infection, injection, trauma, or surgery. In addition, Lyme disease or rickettsial infection can occur occasionally. It has recently been reported that brachial plexus damage can also occur in a sputum-borne disease caused by Ebrlicbia bacteria.

3, thoracic outlet syndrome (TOS): a variety of different cervical deformities can damage the brachial plexus, plexus and blood vessels. It can be single-sided or double-sided. As the tight-fitting cervical annulus extends from the first rib to the residual cervical rib or the elongated seventh cervical transverse process, the nerve fibers in the anterior branch of the C8 and T1 or under the brachial plexus are damaged.

4, familial brachial plexus neuropathy: this disease is difficult to identify in the acute phase and painful brachial plexus neuritis. There is a family history, its genetic characteristics are single-gene autosomal dominant inheritance, and the age of onset is earlier. Sometimes cranial nerve damage (such as arrhythmia), as well as lumbosacral nerve and autonomic nerve damage. If there is a manifestation of familial invasive neuropathy, multiple peripheral nerve involvement can be found by neuroelectrophysiology. A sural nerve biopsy can reveal a slight loss of nerve fibers, a strange swelling, and a myelin-like thickening of the sausage.

5, radiation brachial plexus damage: brachial plexus neuropathy can occur slowly after radiotherapy, painless, often seen in the upper brachial plexus.

6, tumor: malignant tumor infiltration, common in the lungs, chest tumors, leading to progressive exacerbation of brachial plexus damage, more common in the following brachial plexus, more with Horner syndrome.

7. Others: It has been reported that in Behcet's disease, brachial plexus damage is caused by compression of non-traumatic subclavian aneurysms, accompanied by vascular ischemia. Other iliac aneurysms and subclavian hemangioma can also cause the disease.

an examination

Related inspection

Spinal muscle strength test

1 Among the five major nerves of the upper limbs (, musculocutaneous, median, temporal, ulnar nerve), there are any two groups of joint injuries (non-identical cutting injuries)

2 of the three major nerves of the hand (median, sacral, ulnar nerve), any one with scapular or elbow joint dysfunction (passive normal activity)

3 of the three major nerves (median, sacral, ulnar nerve) of the hand, combined with medial cutaneous nerve injury of the forearm (non-cutting injury).

Differential diagnosis

Brachial plexus involvement needs to be identified as follows:

I brachial plexus injury

Theoretically, we can only see clinical symptoms and signs when only two adjacent nerve roots are damaged at the same time. We call this phenomenon a single-compensation phenomenon and a double-root combination phenomenon. For the convenience of description, the brachial plexus root is divided into an upper brachial plexus and a lower brachial plexus. The upper brachial plexus includes the C5-7 nerve root; the lower brachial plexus includes the C8 nerve root and the T1 nerve root.

1 Upper brachial plexus injury: the shoulder joint can not be abducted and lifted, the elbow joint can not flex and can stretch, although the wrist joint can flex and stretch but the muscle strength is weakened. The upper part of the upper extremity is mostly missing, and the thumb feels diminished. The 2-5 fingers, the inner part of the hand and the forearm feel completely normal. When the examination, the shoulder muscles are atrophied with the deltoid muscle, and the upper arm muscles are atrophied with the biceps. With. In addition, there are obstacles to the rotation of the forearm, and finger movements are normal.

The above symptoms are similar to the dry (C5, C6) injury on the brachial plexus. Whether the C7 injury is combined or not, the latissimus dorsi and the finger-extension muscle are mainly examined for paralysis. If there is atrophy of the trapezius muscle, limited shrub activity, and paralysis of the levator scapula and rhomboid muscle, it means that the upper brachial plexus root is injured at the proximal intervertebral foramen or avulsion before the knot.

2 lower brachial plexus injury: loss of function or serious obstacles in the hand, shoulder, elbow, wrist joint activity is still good, the Horner sign often appears on the affected side. During the examination, all the internal muscles of the hand can be found to be atrophy. Among them, there are interosseous muscles, claw-type hands and flat hand deformities, fingers can not be bent or have serious obstacles, but the metacarpophalangeal joints have a straightening action (the function of the extension and extension muscles) ), the thumb can not be abducted on the palm side. The skin of the forearm and hand ulnar side is missing, and the skin inside the arm may also be missing.

The above symptoms are similar to those of the brachial plexus and the medial bundle injury. If the Horner's sign appears, it proves that the T1 sympathetic nerve has been injured. This often indicates C8, T1 near the intervertebral foramen injury or preganglionic injury. Clinically, in addition to C8, T1 nerve combined with broken injury, sometimes combined with C7 nerve root and simultaneous injury, the clinical symptoms and signs at this time are similar to simple C8, T1 nerve root injury, but careful examination can be found latissimus dorsi There is paralysis, or muscle weakness, refers to the extension of the total muscle also has the performance of muscle weakness, the plane of the sensory disorder can be enlarged to the temporal side.

3 total brachial plexus injury: in the early stage, the entire upper limb showed slow paralysis, each joint can not actively move, but passive movement is normal. The shrug movement still exists due to the trapezius function. The upper limbs felt that there were still some areas on the inside of the arm, and all others were lost. The inner skin of the upper arm is shared by the medial cutaneous nerve of the arm and the intercostal brachial nerve. The latter comes from the second intercostal nerve, so the inner skin of the arm remains in the brachial plexus. The upper extremity tendon reflexes disappeared, the temperature was slightly lower, the distal part of the limb was swollen, and the Horner sign appeared. In the advanced stage, the upper limb muscles are significantly atrophied, and the joints are often restricted by passive movement due to contracture of the joint capsule, especially in the shoulder and knuckles.

Differential diagnosis of preganglionic and postganglionic injuries in brachial plexus root injury Brachial plexus root injury is divided into two major categories, one is preganglionic injury in the vertebral foramen; the other is postganglionic injury outside the vertebral foramen. The nature of post-ganglous injury should be differentiated from neurological concussion, nerve compression, nerve partial injury and complete injury. The method of differentiation is determined by the nature of the injury, the date, the extent of major functional loss, and the different changes in myoelectricity and nerve conduction velocity. The treatment method depends on different pathological conditions, and can be conservatively observed or treated (including decompression stitching and transplantation). Pre-segmental injury is broken in the anterior and posterior filamentous structures in the spinal canal. It has not only the ability to heal itself or the possibility of surgical repair. Therefore, once the diagnosis is confirmed, nerve transposition should be performed early, so it is clinically Before the holiday, the differential diagnosis after the festival has a great significance.

1 history: pre-holiday injury is more serious, often combined with a history of coma, multiple fractures of the neck, shoulders and upper limbs, often persistent severe pain after injury.

2 signs: C5, C6 root avulsion injury, trapezius muscle atrophy, shrugging limited. C8T1 root avulsion injury, often appear Horner's sign (upper eyelid drooping, pupil diminution, eyeball subsidence, no sweat on the side of the side).

3 Neurophysiological examination: Somatosensory evoked potential (SEP) and sensory nerve activity potential (SNAP) electrophysiological examination are helpful for the differential diagnosis of brachial plexus ganglia posterior segmental injury. Preganglionic injury SNAP is normal (post-root sensory nerve cells are located) Outside the spinal cord, the injury occurs in the proximal side of the node, the sensory nerve has no Waller degeneration, can induce SNAP), SEP disappears; SNAP and SEP disappear after the post-segment injury.

4 imaging examination: pre- and post-segmental injury on the CTM with the filling defect of the anterior and posterior branches of the corresponding nerve root in the spinal canal as the standard, and compared with the healthy nerve root. Normal imaging nerve roots are filling defects, such as root injury, there is contrast agent filling in the corresponding area.

II brachial plexus injury

1 Upper dry injury: Symptoms and signs are similar to upper brachial plexus root injury.

2 medium dry injury: independent injury is rare in clinical practice. In addition to the short-term period (usually 2 weeks), the injury of the middle finger refers to the abdominal numbness and muscle strength of the extensor muscle group, and there are no obvious clinical symptoms and signs. Can be seen in the contralateral C7 nerve root displacement repair.

3 dry injury: symptoms and signs are similar to the lower brachial plexus injury. The function of the hand (flexion and extension and adduction and abduction) is completely lost, and no object can be pinched.

III brachial plexus injury: (completed by categorical diagnosis of five major nerve injuries)

1 Outer beam damage.

2 Medial bundle injury.

3 After the bundle damage.

Diagnosis of the five major nerve injuries (the most important classification diagnosis)

1 nerve injury: deltoid muscle atrophy, shoulder abduction is limited.

In the case of simple sacral nerve injury, the plane of injury is below the branch; combined with sacral nerve injury, the lesion plane is in the posterior bundle; the musculocutaneous nerve injury is in the upper plane of injury; combined with the median nerve injury, the lesion plane is at the root of C5.

2 musculocutaneous nerve injury: biceps atrophy, elbow flexion limited.

Simple musculocutaneous nerve injury, the plane of injury is below the branch; combined with radial nerve injury, the lesion plane is in the upper trunk; combined with the median nerve injury, the lesion plane is in the lateral bundle; combined with radial nerve injury, the lesion plane is in the C6 nerve root.

3 nerve injury: triceps, diaphragm and wrist extension, thumb extension, finger extensor muscle atrophy and limited function.

Simple sacral nerve injury has a lesion plane below the branch; combined with radial nerve injury, the injury plane is in the posterior bundle; combined with musculocutaneous nerve injury, the lesion plane is at the C6 nerve root; combined with median nerve injury, the lesion plane is at the C8 nerve root .

4 median nerve injury: flexor and flexor digitorum, atrophy of large fish muscle atrophy, thumb and finger flexion and thumb-to-palm function limited, 1-3 finger sensory disorder simple median nerve injury, lesion plane below the branch; Cervical nerve injury, lesion plane in the lateral bundle; combined with radial nerve injury, lesion plane in C8 nerve root; combined with ulnar nerve injury, lesion plane in the lower trunk or medial bundle.

5-foot nerve injury: ulnar wrist flexor muscle atrophy, small fish muscle, internal muscles including interosseous muscle and sacral muscle, and adductor muscle atrophy, finger adduction, limited abduction, interphalangeal joint straightening Restricted, hand fine function is limited, 4-5 refers to sensory disorder simple ulnar nerve injury, lesion plane below the branch; combined with median nerve injury, injury plane in the lower trunk or medial bundle; combined with radial nerve injury, lesion plane in chest 1 Nerve root.

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