The term “obstetrical brachial plexus injury” was coined by Duchenne in the 1800’s. Since then, experts have learned a great deal about the causes and dangers associated with harm to the brachial plexus, yet it still remains one of the most common types of birth injuries today, affecting thousands of infants each year.
Brachial Plexus Injury Causes
The brachial plexus a group of nerve fibers that run from the spinal cord and through the neck into the arms. When an infant experiences a brachial plexus injury, it can happen to any part of the nerve fibers, and can range in severity depending upon the location of the injury and how it happened. One of the most common causes of infant brachial plexus include excessive stretching and force during labor and delivery. In most instances, the delivery is stressful and difficult, often marked by the use of birth-assistance tools such as forceps or a vacuum extraction tool. Other causes include:
- A breech delivery
- Large infant weight and size (fetal macrosomia)
- The infant’s shoulders lodged in the mother’s pelvic area
- Maternal diabetes
- Underdeveloped muscles in the neck
- Maternal obesity
Even if birth-assisting tools are not used, brachial plexus injuries can occur if a doctor applies improper pressure and force on the baby while delivery by hand. For instance, infant shoulder dystocia occurs when the baby’s head is delivered but the shoulders remain lodged in the mother’s pelvic area. In an attempt to delivery the infant before asphyxia or any other dangerous medical complication occurs, a physician may pull the baby’s shoulders with excessive force. This can lead to tearing and stretching the brachial plexus nerves.
In some instances, contractions may cause brachial plexus injuries. If the labor is prolonged and the baby is stuck in the birth canal, the mother’s contractions can place stress on the infant’s shoulders, head, and upper arms, leading to bruising, tearing, and in some rare cases, fractures.
Types of Brachial Plexus Injuries
There are several types of brachial plexus injuries, some more common than others, and as previously stated, some more severe and serious than others.
Neuropraxia, the most common and least severe type of brachial plexus injury, is marked by minor strains or tears in the brachial plexus nerves. Since it’s the the mildest brachial plexus injury, it usually clears up on its own within a few months. Neurapraxia injuries affect the protective lining and covering of the nerve, yet the actual nerve is usually unharmed. Regardless, this type of injury can bring on pain and difficulties until it clears up. Symptoms of neurapraxia can include:
- Muscle weakness in the affected area
- Burning, tingling, and/or numbness in the affected area
- Extreme sensitivity in the affected area
- Sensation disturbances
Erb’s palsy is often referred to as another name for brachial plexus birth palsy. It occurs when the brachial plexus nerves in the upper arm are damaged. Erb’s palsy will range in severity depending upon how the injury happened. Some of the dangers of Erb’s palsy include:
- Full or partial paralysis in the affected arm
- Loss of sensory and/or motor function in the affected arm
- Decreased grip and arm numbness in the affected arm
- The affected arm may be bent towards the body or hang limp
Depending on how serious the injury is, Erb’s palsy treatment options include:
- Physical therapy
- Massaging the affected arm regularly
Klumpke’s Palsy is a brachial plexus injury caused by damage to the lower nerve roots (c8-T1). Klumpke’s palsy can cause numbness, loss of feeling, miosis, and a claw-like appearance in the hand of the affected arm. Klumpke’s palsy affects the hand, wrist, and arm of the affected area, and is typically caused by shoulder dystocia. Shoulder dystocia occurs when an infant becomes lodged in the mother’s pelvic bone, leading to excessive pulling and stretching during delivery.
Sometimes, Klumpke’s palsy will heal on its own without treatment, but for severe cases, such as partial or full paralysis, medication and surgery may be required.
Symptoms of Brachial Plexus Injuries
The symptoms of a brachial plexus injury usually surfaces shortly after birth. As mentioned earlier, the symptoms may include:
- No Moro Reflex on the affected side
- Limited or no movement on the affected side
- Claw-like hand appearance
- Abnormal muscle contractions, which may become permanent, even after treatment options
How is a Brachial Plexus Injury Determined?
In order to diagnose a brachial plexus injury, physicians may go through a series of tests and evaluations. For example, a motor evaluation determines how the muscles function via a five-point grading system that assesses an infant’s ability or inability to use certain muscles.
A Moro Reflex test is also usually administered to test for absent reflexes in the affected area. In addition, physicians will perform a physical examination, sometimes including X-rays, to look for any fractures to the clavicle bone.
Brachial Plexus Treatment Options
As aformentioned, treatment will depend upon how severe the injury is and what type of injury occurred. While some infants will go on the heal naturally or with the help of physical therapy, others my require surgery and medication.
Surgery for brachial plexus injuries may include a medical procedure known as a “nerve transfer.” A nerve transfer allows doctors to take a healthy, functioning nerve from a muscle that is used less often, known as nerve grafting, and transfer it to the damaged nerve. Although it may not completely treat a brachial plexus injury, studies suggests that many infants who underwent nerve transfer surgery were able to recover and use the damaged area.
It’s important to note that surgery is usually reserved until three months after the injury occurred. Since the majority of babies who experience brachial plexus injuries recover within the first three months or so, doctors usually wait to see if the injury heals on its own. During this time period, however, physical therapy and daily massaging of the damaged area may be recommended.
The goal of physical therapy is help infants develop the muscles in the affected area and eventually go on to have full use of the damaged arm, hand, and/or wrist. Massaging, range-of-motion activities, stretching, and exercises are all typical physical therapy activities. Although physical therapy may start without surgery, it is almost always recommended after an infant undergoes any surgical procedures.
Medication is primarily used for pain and to help relax muscles for those who have tight, painful contractions. If surgery is required, the baby will be given a light anesthesia medication for pain.
Brachial Plexus Injury Prognosis and Outlook
Most infants fully heal from their brachial plexus injuries. However, the outlook for those who don’t heal within three to six months still remains unclear. Although studies have shown that many people go on to have better use of their damaged areas after surgery and treatment, there are still not enough studies and research performed to indicate a clear prognosis.
In addition, the more serious the injury is, the less chance of a full recovery. According to the NYU Langone Medical Center, the success rate for severe injuries are at 50%, meaning that the patients have a 50% chance of recovering and having full use of the affected area. For less severe brachial plexus injuries that still require surgery, there may be a success rate as high as 90%.
It’s important to note, however, that each injury and each situation is unique. Physicians will work with the parents and explain the chances of recovery according to the baby’s specific injuries. Wound infections, although uncommon, may develop after surgery.
Additionally, difficulties with breathing, artery and vein damage, and paralysis are all risks of surgery. Fortunately, all of these risks are extremely rare and most infants heal without additional trauma. The area may be swollen and infants may be experience numbness in the affected area for a while after surgery, but this typically diminishes within a few weeks after the procedure.