Etiology
1.Stretching injury
Such as upper limb injury caused by belt entrapment.
2.Collision injury
If the shoulder is hit by a fast car or the shoulder is hit by a flying stone.
3.Cutting injury or gunshot wound
4.Crush injury
Such as clavicle fracture or shoulder lock is crushed.
5.Birth injury
Injuries caused by abnormal fetal position during childbirth or straining during labor.
Classification
Generally divided into upper brachial plexus injury, lower brachial plexus injury and full brachial plexus injury. According to the mechanism of brachial plexus injury and injury site to make the following classification.
1, open brachial plexus injury
2, closed (pulling) brachial plexus injury
(1) supraclavicular brachial plexus injury ① above the ganglion brachial plexus injury (preganglionic injury); ② below the ganglion brachial plexus injury (postganglionic injury)
(2) subclavian brachial plexus injury
3.Radiation brachial plexus injury
4.Labor palsy
Clinical manifestations
1.Brachial plexus nerve root injury
(1) Upper brachial plexus nerve root (cervical 5-7) injury axillary, musculocutaneous, suprascapular and dorsal scapular nerve paralysis, radial and median nerve partial paralysis. The shoulder joint cannot be abducted and lifted, the elbow joint cannot be flexed, the wrist joint can be flexed and extended but the muscle strength is weakened, forearm rotation is also impaired, finger movement is still normal, and most of the sensation in the upper extremity is missing. The deltoid, supraspinatus, scapularis, rhomboid, radial wrist flexor, pronator teres, brachioradialis, and posterior rotator muscles are paralyzed or partially paralyzed.
(2) Lower brachial plexus nerve root (cervical 8 thoracic 1) injury ulnar nerve paralysis, damage to medial brachial cutaneous nerve, medial forearm cutaneous nerve, and partial paralysis of median and radial nerves. The hand function is lost or severely impaired, the shoulder, elbow and wrist joints are still moving well, and Horner’s sign is often present on the affected side. All the muscles in the hand are atrophied, especially the interosseous muscles, and the fingers cannot be flexed and extended or are severely impaired. The ulnar carpal flexors, superficial and deep finger flexors, interosseous muscles, and all interosseous muscles were paralyzed. The triceps brachii and forearm extensor muscles were partially paralyzed.
(3) The whole upper limb of the whole brachial plexus is paralyzed in the early stage of injury, and the joints cannot move actively, but the passive movement is normal. Because the trapezius muscle is partially innervated, the shrugging movement can exist. The sensation of the upper extremity was lost except for the medial arm because the intercostal brachial nerve from the second intercostal nerve was still present. All tendon reflexes of the upper limbs were absent, the temperature was slightly low, and the distal limbs were swollen. In the late stage, the muscles of the upper limbs were significantly atrophied, and the joints were often restricted in passive activities due to contracture of the joint capsule, especially the shoulder and finger joints.
2.Brachial plexus nerve trunk injury
(1) The clinical symptoms and signs of upper trunk injury are similar to those of upper brachial plexus nerve root injury.
(2) middle trunk injury independent injury is rare, but can be seen in the healthy side of the cervical 7 nerve root transposition repair surgery cut cervical 7 nerve root or middle trunk. There is only numbness in the finger belly of the index and middle finger, and the muscle strength of the extensor group is reduced, which can gradually recover after 2 weeks.
(3) lower trunk injury its clinical symptoms and signs and lower brachial plexus nerve root injury is similar.
3, brachial plexus nerve bundle injury
(1) lateral bundle injury myocutaneous, lateral root of median nerve and anterior lateral thoracic nerve paralysis. The elbow joint can not be flexed, or can be flexed (brachioradialis compensated) but biceps paralysis; forearm can be rotated forward but rotated forward round muscle paralysis, wrist can be flexed but radial wrist flexor paralysis, other joint activities of the upper limb is still normal. Sensory loss of the radial margin of the forearm. The biceps, radial wrist flexors, pronator teres and pectoralis major clavicularis were paralyzed, and the movements of the shoulder and hand joints were normal.
(2) Medial bundle injury ulnar, medial root of median nerve and anterior medial thoracic nerve palsy. The internal muscles of the hand and forearm flexors are paralyzed, the fingers cannot be flexed and extended (the metacarpophalangeal joints can be straightened), the thumb cannot be palmarly abducted, the palm and fingers cannot be opposed, and the hand is not functional. The medial forearm and ulnar sensation of the hand are lost. The hand is flattened and claw-shaped hand deformity. The shoulder and elbow joints functioned normally. Medial bundle injury and cervical 8 thoracic 1 nerve root injury manifest similarly, but the latter often has pectoralis major (thoracic rib), triceps, forearm extensor group paralysis, while the former does not have this phenomenon.
(3) Injury to the posterior fasciculus paralyzes the subscapularis and vastus lateralis muscles innervated by the subscapularis nerve; the latissimus dorsi muscle innervated by the thoracodorsal nerve; the deltoid and vastus minor muscles innervated by the axillary nerve; and the upper arm and forearm extensor groups innervated by the radial nerve. The shoulder joint cannot be abducted, the upper arm cannot be rotated inward, the elbow and wrist cannot be dorsally extended, the metacarpophalangeal joint cannot be straightened, the thumb cannot be straightened and radially abducted, and there is sensory deficit or loss in the lateral shoulder, the dorsal forearm and the radial half of the dorsal hand.
Examination
1.Neurophysiological examination
Electromyography (EMG) and nerve conduction velocity (NCV) have important reference values for the presence or absence of nerve injury and the degree of injury, and are generally examined 3 weeks after the injury.
2.Imaging
In brachial plexus radicular avulsion injury, myelography plus computed tomography (CTM) may show extravasation of contrast into the surrounding tissue spaces, tear of the dural sac, spinal bulge, and spinal cord displacement. Generally, most of the spinal bulges imply a tear of the nerve root, or although some continuity of the nerve root exists, the internal damage has been severe and has continued to a very close plane, often suggesting a sufficiently large force Similarly, magnetic resonance imaging (MRI) can show not only nerve root tears, but also coexisting spinal membrane bulges, cerebrospinal fluid leaks, spinal cord hemorrhage, and edema, etc. Hematomas are high signal on T1WI and T2WI, and cerebrospinal fluid and edema are high signal on T2WI and low signal on T1WI. MRI water imaging is more clear in showing leakage of subarachnoid space and cerebrospinal fluid, when the water (cerebrospinal fluid) is high signal, while all other tissue structures are low signal.
Diagnosis
The diagnosis of brachial plexus injury includes clinical, electrophysiological, and imaging diagnoses, and for brachial plexus injuries that require surgical exploration, an intraoperative diagnosis is also made. According to the symptoms and signs specific to different nerve branch injuries, combined with the history of trauma, anatomical relationships and special examinations, the injured nerve and its plane of injury and the degree of injury can be identified. The steps for the diagnosis of brachial plexus injury are as follows.
1, determine whether there is a brachial plexus nerve injury
The presence of brachial plexus injury should be considered when the following conditions are present.
① upper extremity 5 nerves (axillary, musculocutaneous, median, radial, ulnar) in any 2 branches of the joint injury (not the same plane of cutting injury).
(ii) combined shoulder or elbow joint dysfunction (normal passive motion) in any 1 of the 3 nerves of the hand (median, radial, ulnar).
③any 1 of the 3 nerves of the hand (median, radial, ulnar) combined with medial forearm cutaneous nerve injury (non-cutting injury).
2.Determine the site of brachial plexus injury
Treatment
1.General treatment
For common pulling brachial plexus injury, early conservative treatment is the main treatment, that is, the application of neurotrophic drugs (vitamin B1, vitamin B6, vitamin B12, etc.), physical therapy for the injured part, such as electrical stimulation therapy, infrared, magnetic therapy, etc., functional exercises for the affected limb, prevention and control of joint capsule contracture, and can be combined with acupuncture, massage, massage, conducive to the elimination of nerve shock, release of nerve adhesions and joint relaxation. The observation period is usually about 3 months.
2.Surgical treatment
(1) Surgical indications
(1) Open injury of brachial plexus nerve, cutting injury, gunshot injury, surgical injury and drug injury should be explored early and repaired surgically.
② Brachial plexus nerve collision injury, strain injury, pressure smash injury, such as an absent preganglionic injury should be operated early, for closed postganglionic injury, can be first conservative treatment for 3 months. In the following cases, surgical exploration can be considered: those who do not recover significantly after conservative treatment; those who have a jump in functional recovery, such as those who have not recovered the function of the shoulder joint, but the function of the elbow joint is recovered first; those who have interrupted the process of functional recovery for 3 months without any progress.
(3) In cases of birth injury, if there is no obvious functional recovery six months after birth or the function is only partially recovered, surgical exploration can be performed.
(2) Surgical methods brachial plexus exploration: supraclavicular brachial plexus exploration; infraclavicular brachial plexus exploration; brachial plexus exploration at the clavicle.
(3) Surgical principles According to the findings during surgery, the principles of management are as follows: nerve release; nerve grafting; nerve transposition.