Erb's palsy is a condition involving total or partial paralysis of the arm and hand due to nerve damage. Erb's palsy is one of the more common birth injuries and it occurs when the brachial plexus nerves are damaged during childbirth due to excessive stretching or force as the baby goes through the birth canal.What is Erb's Palsy?
Erb's palsy (also known as Erb-Duchenne palsy) is a common birth injury which results in paralysis of the arm due to nerve damage. It is a type of brachial plexus injury that was named after Dr. Wilhem Erb who first classified the condition in 1874. The hallmark symptom of Erb's palsy is partial or complete paralysis of one arm which is accompanied by atrophy of the adjacent chest and shoulder muscles. In a child with Erb's palsy, the affected arm will appear to hang limp and rotated inward with the forearm pronated. The child is usually unable to raise the arm from their side or flex the elbow. The result is that children with Erb's palsy have what is sometimes referred to as a "waiter's tip" arm. Erb's palsy injuries occur in about 2 out of every 1,000 live births in the U.S.Causes of Erb's Palsy
Erb's palsy occurs when certain nerves within the brachial plexus nerve junction are damaged during childbirth. The brachial plexus is a key network of nerves running from the spine through the shoulders and down into the arms. This nerve channel serves to transmit brain signals to the arms and hands. Injury to certain nerves within the brachial plexus disrupts the signals from the brain to the arm resulting in the paralysis classified as Erb's palsy.
The injury to the brachial plexus nerves that causes Erb's palsy is something that occurs as a result of trauma during childbirth. The most common cause of Erb's palsy is excessive stretching or lateral traction of the baby's head and neck as the child passes through the birth canal. During a vaginal delivery, the baby will often become stuck in the birth canal.
Shoulder dystocia is the most common type of obstetric complication in which the baby becomes stuck in the birth canal. With shoulder dystocia, the shoulders fail to rotate out of the short, anterior-posterior to the longer, oblique diameter of the pelvic inlet. The head and body of the fetus descends while the shoulder or shoulders remain stuck at the pelvic inlet. The force for this descent can result from normal maternal contractions and pushing but is often the result of lateral traction applied by the clinician. This can result in stretching of the nerves resulting in Erb's palsy.
The medical literature confirms that multiple force-related factors can contribute to brachial plexus deformation and possible injury. These include those endogenously generated by uterine contractions and reflex maternal pushing efforts against an obstructed delivery.
When this occurs doctors must use various techniques to dislodge the baby and maneuver them through the birth canal. This process frequently results in excessive lateral traction and stretching of the baby's neck and head in opposite directions causing damage to the nerves in the brachial plexus. Erb's palsy can also be caused by compression or pinching of the brachial plexus nerves during birth.Different Types of Erb's Palsy
Erb's palsy is categorized into 4 different types depending on the specific type and extent of injury to the nerve tissue within the brachial plexus:
- Neuropraxia: this is most common and least severe type of Erb's palsy. It occurs when the nerves in the brachial plexus are overstretched during birth but the nerves do not actually tear. This type of Erb's palsy usually only causes limited paralysis in the arm accompanied by so-called "stingers" in the shoulder and neck area.
- Neuroma: a more serious type of Erb's palsy results when the nerve injury is classified as a neuroma. With this type of injury, the nerves are still not torn but they get stretched so severely that scar tissue forms as they heal. The scar tissue creates pressure and pinching within the nerves. This type of Erb's palsy is much more difficult to treat and usually results in some level of permanent paralysis.
- Rupture: when the nerves within the brachial plexus are stretched so much that the nerve tissue actually tears apart, the injury is classified as a rupture. Cases of Erb's palsy involving a rupture can be very serious because ruptured tissue will not heal on its own. Complex reconstructive surgery is therefore required to treat this type of Erb's palsy.
- Avulsion: the most serious cases of Erb's palsy occur when the damage to the nerves is classified as an avulsion. This type of nerve injury occurs when the nerve fibers are actually torn away and detached from the spinal cord or surrounding structure. Detached nerves cannot be surgically reattached so the only option is to surgically splice the detached nerves to nearby nerves.
The symptoms of Erb's palsy are usually very distinctive and can be noticed very early on in the baby's development. The focal point of Erb's palsy symptoms is obviously the arm:
- Baby does not move one arm or arm appears weaker than the other
- Weaker arm is always held against the body with a bent elbow
- Baby is not able to grip or has very weak grasping ability in affected hand
- Numbness in affected hand
With the more severe cases of Erb's palsy, the symptoms are clear and unmistakable. If a 4-month-old baby has total paralysis in one arm a diagnosis of Erb's palsy is fairly obvious. Diagnosing less serious cases of Erb's palsy may require more extensive physical examination by your pediatrician over a period of time. Diagnostic imaging tests such as MRIs or CT scans are also utilized to help identify and asses the nerve damage causing Erb's palsy.Treatment for Erb's Palsy
There are basically 2 treatment options for Erb's palsy: therapy & surgery. The appropriate course of treatment for Erb's palsy will vary depending on the extent or severity of the nerve injury involved. In about 80% of Erb's palsy cases, the nerve damage actually resolves on its own (with some physical therapy) within the first year of life. When the nerve damage is more severe and therapy is not effective; surgical restoration will also be necessary to achieve the best possible results. There are 2 different surgical procedures used for the treatment of Erb's palsy: grafting & decompression. With nerve grafting surgery, nerve tissue is taken from another part of the body and surgically implanted in the damaged so that new nerve tissue can grow on to it. Decompression surgery is a less invasive procedure in which a small incision is made through which the surgeon attempts to alleviate compression on the nerve.Financial Support for Erb's Palsy
Caring for a child with a birth injury like Erb's palsy can have both emotional and financial costs. Medical treatment and rehabilitative support for a child with Erb's palsy can be very expensive and may not be covered by insurance. Fortunately, there are a number of private and public sources of financial assistance for families with Erb's palsy. Government sponsored financial assistance is available in the form of Supplemental Security Income (SSI) and Supplemental Nutrition Assistance Program (SNAP). There are also private sources of financial assistance in the form of legal settlements.Supporting Literature on Erbs Palsy
- Ouzounian JG, Korst LM, Phelan JP. Permanent Erb's palsy: a lack of a relationship with obstetrical risk factors. Am J Perinatal 1998 Apr. 15(4):221-223.
- Jennett RJ, Tarby TJ, Kreinick CJ. Brachial plexus palsy: an old problem revisited. Am J. Obstet Gynecol 1992;166(6):1673-1676.
- Phelan JP, Ouzounian JG, Gherman RB, Korst LM, Goodwin TM. Shoulder dystocia and permanent Erb palsy: the role of fundal pressure. Am J Obstet Gynecol 1997;176: S138.
- Jennett RJ, Tarby TJ. Brachial plexus palsy: an old problem revisited again. H. Cases in point. Am J Obstet Gynecol 1997;176(6):1354-1357
- Brown B. Karmin I. Lapinski R. Lescale K. Dual mechanism responsible for brachial plexus injuries. Am J Obstet Gynecol 1997;176: S137.
- Gherman RB, Ouzounian JG, Miller DA, Kwok L. Goodwin TM. Spontaneous vaginal delivery: a risk factor for Erb's palsy? Am J Obstet Gynecol 1998:178:423-427.
- Hamilton EF, Ciampi A, Dyachenko A, Lerner HM, Miner L, Sandmire HF. Is shoulder dystocia with brachial plexus injury preventable? Fetal Matern Med Rev 2008;19:293-310.
- Kreitzer MS. O'Leary JA. Brachial plexus injury at cesarean section. Pp. 249-255 in: O'Leary JA. Shoulder Dystocia and Birth Injury: Prevention and Treatment, 3rd ed. Totawa, NJ: Humana Press, 2009.