How does a brachial plexus injury occur?
The brachial plexus is formed from the roots of the lower cervical and first thoracic segments of the spinal cord and controls the entire arm. During childbirth, when the shoulder gets stuck behind the pubic symphysis, the distance between the neck and shoulder increases sharply, and the upper roots are overstretched. The degree of damage varies: from a slight stretching of the membranes, which disappears in a few weeks, to rupture of the trunk or separation of the root from the spinal cord. The timing and completeness of recovery depend on the depth of the damage, so the child is monitored over time.
- Roots C5–C6 are most often affected - upper type, Erb's palsy
- The lower type (Dejerine-Klumpke palsy) affects the hand
- Total type - the whole hand is motionless
- Mild sprains go away in weeks
- Spine rupture and avulsion require surgery
Causes and risk factors
The main mechanism is the difficult birth of shoulders in a large child. The risk is higher with diabetes mellitus in the mother, large weight gain during pregnancy, a narrow pelvis, rapid or, conversely, protracted labor, as well as when using a vacuum extractor and forceps. With a breech presentation, injury occurs differently - with traction on the torso. It is important to understand: some cases develop even during normal labor without any errors, so parents should not blame themselves.
- Large fetus, birth weight more than 4 kg
- Shoulder dystocia
- Maternal diabetes mellitus
- Breech presentation
- Vacuum extraction and obstetric forceps
- Prolonged second stage of labor
Symptoms
The classic picture is already noticeable in the delivery room: the hand is brought to the body, the palm is turned back and extended at the elbow - this position is figuratively called the pose of the asking hand. The child does not raise his arm or bend it at the elbow, and the Moro reflex on this side is incomplete or absent. At the same time, the grasping reflex is preserved, because the hand is innervated by the lower trunks. Often accompanied by a fracture of the collarbone. Over time, in the absence of exercise, contracture of the shoulder joint and shortening of the arm may develop.
- The hand lies motionless along the body
- Shoulder rotated inward, elbow extended
- Asymmetric Moro reflex
- The grasp reflex of the hand is preserved
- Sometimes - crepitus and pain in the clavicle area
- Later - limited external rotation of the shoulder
Survey
The diagnosis is made by the doctor based on the characteristic posture and range of movements, assessing them repeatedly during the first months. An X-ray is needed to rule out a fracture of the collarbone or humerus. Ultrasound of the soft tissues and joint helps to see effusion and changes in the shoulder area. Electroneuromyography shows which muscles have retained connection with the nerve, and is usually informative no earlier than the third or fourth week. If by three months there is no active flexion at the elbow, the pediatric neurologist will refer the child to a neurosurgeon and order an MRI of the brachial plexus.
- Dynamic assessment of movements and reflexes
- X-ray of the clavicle and humerus
- Ultrasound of soft tissues and shoulder joint
- ENMG after the third or fourth week
- MRI of the brachial plexus with poor dynamics
- Examination by an ophthalmologist for drooping eyelids
Treatment and rehabilitation
In the first one to two weeks, the hand is left at rest and in a gentle position so as not to increase the stretching of the nerves; Rigid long-term fixation is not necessary. Then they begin daily passive movements in all joints of the hand, so that contractures do not form, massage and physical therapy are added as prescribed by the doctor. Parents are taught techniques that are performed at home several times a day - this is more important than any procedures. If elbow flexion is not restored by three to six months, microsurgical surgery on the plexus is discussed, and later tendon and muscle interventions for persistent restrictions.
- Rest and gentle handling in the first days
- Daily passive gymnastics to prevent contractures
- Massage of the arm and shoulder girdle in courses
- Physiotherapy as prescribed by a doctor
- Correct positioning when feeding and changing clothes
- Microsurgical reconstruction in the absence of recovery
- Regular examinations by a neurologist and orthopedist before school age