Brachial plexus birth injury | Causes, types, and treatment

Brachial plexus birth injury happens when the brachial plexus nerves in the newborn get injured during labor. 

It occurs when nerves are stretched, compressed, or even torn apart in more critical cases.

So, let us delve deeper into the causes, symptoms, and treatment of brachial plexus birth injury.

What is the brachial nerve plexus?

It is a network of nerves that arise from the spinal cord in the cervical area to feed the upper limbs.

The nerve plexus comprises the nerve roots of the cervical vertebrae (C5-8) to the first thoracic vertebra (T1).

It then splits later into trunks, sections, and branches.

Plexus injury can occur due to an increase in stretching, compression, or as a result of road accidents. 

It also differs in severity according to the size and the number of damaged nerves.

Types of brachial plexus birth injury

There are different types and classes of brachial plexus birth injury depending on the injured nerves. 

Hence, they are classified as follows:

• Erb’s Palsy: Where cervical nerves (C5-6) are damaged.
• Klumpke’s Palsy: Where cervical nerve (C8) and the first thoracic nerve (T1) are damaged.
• Whole Arm Palsy: Includes the entire plexus (the cervical nerves C5-6-7-8, and the thoracic nerve T1).

Erb’s Palsy

Also known as brachial plexus birth injury, being the most common injury in children during labor.

It occurs in about one out of every 1000 babies. 

Moreover, the number of births that suffer from Erb’s palsy represents 50-60% of total Brachial plexus injuries in children.

It affects the stem nerves known as the upper brachial plexus, where the two cervical nerves (C5-C6) unite.

Furthermore, the injury appears at a point known as Erb’s point, located about 2-3 cm just above the middle of the collarbone. 

It might also spread to involve the cervical bone C7 in some cases.

Causes of brachial plexus birth injury

During natural delivery, the infant’s head goes out first from the birth canal then the shoulders. 

However, sometimes, the shoulder can become stuck behind the mother’s pelvic bone, a condition known as shoulder dystocia.

Therefore, the doctor resorts to pulling the head against the shoulder, which causes the brachial nerve plexus injury.

It can also cause paralysis or a broken collarbone.

However, a stuck shoulder is not the only reason for brachial plexus birth injury; there are a variety of other causes, including:

• Gestational diabetes.
• Dystocia.
• Increase in the fetus weight.
• Having twins.
• Increase in the mother’s weight during pregnancy.
• Breech birth.

Symptoms of brachial plexus birth injury

Symptoms differ depending on the type of plexus injury. 

Since each category has its own set of symptoms, the diagnosis will be straightforward.

Signs of Erb’s Palsy

When the upper part of the brachial plexus gets damaged, this will cause a deformation called the waiter’s tip deformity or the waiter’s tip posture.

The following characteristics distinguish this position:

1. The arm hangs by the side of the body with internal rotation due to weakness in both the deltoid muscle and the muscles responsible for the external rotation of the shoulder.
2. Forearm pronation with difficulty in folding the elbow due to biceps muscle weakness.
3. Flexion in the wrist joint due to a weakness in its extensor muscle.
4. The baby cannot raise his arm away from his body.
5. Loss of sensation in the outer side along the forearm because of the lateral musculocutaneous nerve injury.

Signs of Klumpke Palsy

In this type, the damage occurs in the cervical nerve C8 and the thoracic nerve T1 responsible for supporting hand muscles, causing a condition known as claw hand deformity.

Wrist and finger flexion, as well as a weak sensation on the inner side of the arm, distinguish this condition.

Klumpke Palsy is also known as lower brachial plexus injury but, when the second thoracic nerve root T2 gets injured, the child suffers from Horner syndrome.

Horner Syndrome is characterized by: 

1. Ptosis, a condition in which the upper eyelid droops.
2. Miosis, which is a constricted pupil.
3. Anhidrosis, which is the absence of sweating in the injured side of the face.

In case the entire brachial plexus (from C5 to T1) is injured, the child will suffer complete paralysis of the arm and loss of sensation in a condition called whole arm palsy.

Diagnosis of brachial plexus birth injury

The doctor diagnoses the brachial plexus injury through one of the following methods:

Ask about the child’s delivery method and if any complications occurred during the pregnancy.

Check if the mother had gestational diabetes, hypertension or used a vacuum extractor during delivery.

Neurological Examination

It includes evaluation of sensation, reflexes, and also muscle strength.

Physical Examination

It includes evaluating the motor function of the injured arm also, using the Toronto Scale, Active Movement Scale, and Mallet Scale.

Examination using one of the diagnostic tools

During the examination, the doctor depends on one of the following diagnostic tools:

1. X-rays to check if there is a broken collarbone.
2. CT scan and MRI to check if there is a shoulder dislocation.
3. Nerve conduction velocity and electromyography.

Types of Nerve Injuries

Based on the name of the scientist who discovered them, peripheral nerve injuries are classified into two types. 

Those two classes are Seddon classification and Sunderland classification.

Seddon Classification

Seddon classified the nerve injury into:

1. Neuropraxia: A blockage appears in a part of the nerve without any damage in the nerve continuity. However, it is a mild injury, and the nerve tends to recover rapidly.
2. Axonotmesis: A rupture in a part of the nerve axon with no damage to the nerve’s connective tissue and, it is considered more dangerous than the first type.
3. Neurotmesis: is the most dangerous type in which the nerve and the connective tissues are completely disrupted.

Sunderland Classification

In this class, the injury is divided into five categories:

1. First Degree: Neuropraxia
2. Second Degree: Disruption in the nerve axon with intact connective tissues.
3. Third Degree: Disruption in the axon and the interior connective layer while the middle and outer connective layers remain intact.
4. Fourth Degree: Disruption in the axon as well as the interior and middle connective layers while the outer layer remains intact.
5. Fifth Degree: A complete axonal and tissue disruption.

Treatment of brachial plexus birth injury

The occurrence and treatment of brachial plexus birth injury depend on the type of nerve injury. 

So, the treatment will be either natural or surgical according to the kind of damage.

Exercises for the treatment of brachial plexus birth injury

Natural therapy plays a vital role during the first six months of a baby’s life to prevent deformation.

It includes one of the following exercises:

1. Stretching exercises for short muscles.
2. Strengthening exercises for strengthing weakened muscles such as the deltoid muscle or biceps.
3. Electrical stimulation to enhance weak muscles.
4. Sensory stimulation.
5. Range of motion exercises to prevent joint stiffness and maintain the motion range.
6. Exercises that encourage the use of hands.
7. Occupational therapy.
8. Advising the mother to avoid pulling the baby from his arm, make him sleep on his uninjured arm, or start with the injured arm while dressing him.

Surgical Therapy

Includes the following:

1. Nerve transplantation
2. Tendon transfer

In conclusion, we tried to cover the different types of brachial plexus birth injury and treatment methods.

And we advise every mother to ensure that her baby is getting the appropriate treatment and to start it as soon as possible.

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