Brachial Plexus Injury
The nerve roots emerging from the spinal cord in the neck region travel in three major branches and join in the armpit area, forming a large network of nerves known as the brachial plexus. A brachial plexus injury occurs when there is damage to this nerve network.

The nerves that extend from the brachial plexus to the arm originate from the spinal cord. This nerve network consists of four major cervical nerve roots (C5–C8) and the first thoracic nerve root (T1). These roots combine and divide into three main branches: branches from the C5–C6 roots form the upper trunk, C7 forms the middle trunk, and branches from the C8–T1 roots form the lower trunk.

Each major trunk is further divided; some parts generally control muscles that bend and lift the arm (flexors), while other parts control muscles that extend and lower the arm (extensors).

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What is a Brachial Plexus Injury?
A brachial plexus injury is defined as the partial or complete paralysis of arm muscles that occurs when the nerve network (brachial plexus) traveling from the brain to the arm via the spinal cord is damaged for any reason. Depending on the affected nerve roots, the paralysis can begin in the arm muscles and extend to the fingers.

What Causes Brachial Plexus Injury?
Paralysis of varying degrees caused by a brachial plexus injury often begins in the newborn period and can persist throughout childhood and life, requiring long-term follow-up and rehabilitation. Most of these injuries occur during childbirth, although they have also been reported in cesarean deliveries. The most common risk factors include:

• High birth weight (especially above 4 kg),
• Difficult and prolonged labor,
• Use of instruments like vacuum or forceps during delivery,
• Shoulder or breech presentation,
• Structural narrowness in the mother’s pelvis.

Nerve trauma can present in several forms:

• Avulsion (the peripheral nerve is torn from the spinal cord),
• Neuropraxia (swelling around the nerve),
• Axonotmesis (the nerve sheath remains intact, but the axon is damaged).

Avulsion injuries are irreversible, while regeneration may occur in other types.

What Are the Symptoms of Brachial Plexus Injury?
Since the brachial plexus contains nerve fibers from C5 to T1, the resulting paralysis will vary depending on the level of the affected nerve. Although typically categorized under three main types, symptoms can overlap:

• Erb-Duchenne Palsy occurs with upper trunk involvement (C5-C6) and is the most common type. Infants with this type cannot move their shoulders and struggle to extend or rotate their arms. If C7 is involved, the fingers may curl into a “tip position.” If C4 is also affected, the phrenic nerve may be involved, causing additional symptoms.
• Klumpke’s Palsy involves the lower trunk (C8-T1) and is rare in isolation. In this type, shoulder and elbow movement is typically preserved, but a claw-like deformity of the hand is observed. Weakness in the hand and wrist occurs, although arm and shoulder movement is generally intact. Occasionally, sympathetic cervical chain involvement may result in Horner’s Syndrome.
• Total Plexus Involvement (Erb-Klumpke) affects the upper, middle, and lower trunks of the brachial plexus to varying degrees. These infants may exhibit complete motor and sensory loss depending on severity. Shoulder, arm, hand, and wrist movements are weakened. In fully developed cases, areflexia (loss of reflexes) and complete sensory loss can be seen. About 65% of these patients may present with Horner’s Syndrome (commonly seen in lower trunk injuries due to sympathetic chain damage, characterized by miosis, ptosis, enophthalmos, and loss of sweating on the affected side of the face).

Approximately 80% of cases show spontaneous recovery within the first 3 months. Clinical presentations may vary depending on the severity and extent of the injury.

How is Brachial Plexus Injury Diagnosed?
In addition to clinical symptoms, high-resolution MRI is one of the best diagnostic tools. This technique provides excellent visualization of soft tissues. Plain radiographs can help detect fractures in bony structures like the clavicle and humerus.

To assess nerve and muscle damage, electromyography (EMG) is a valuable diagnostic method and should be performed two to three weeks after injury. It provides information about the location and severity of the damage.

How is Brachial Plexus Injury Treated?
Once diagnosed, the patient should be evaluated using a team-based approach to achieve the best results. The treatment team should consist of the family, child, physical therapists, orthopedists, neurologists, and physiatrists, and treatment methods should be determined collaboratively.

A wide range of treatment approaches can be used, from conservative treatments to surgical interventions. Initially, conservative methods such as physiotherapy and occupational therapy should be tried. If successful, treatment should continue until full neurological function is restored or until progress reaches a plateau. In conservative treatment, the goals of rehabilitation are to:

• Preserve passive joint movement,
• Maintain joint flexibility and muscle strength,
• Prevent contractures during the expected recovery period.

Key aims also include:

• Reducing joint stiffness in the affected arm,
• Educating families on proper positioning of the affected arm,
• Promoting active use of the affected arm,
• Increasing and strengthening the baby’s arm movements.

Surgical indications and timing in brachial plexus injuries have always been a topic of debate. Opinions and practices vary widely among different centers and surgeons.