Brachial plexus palsy
caused by childbirth
By Prof. Zhuang Chui Qing,
Head physician of the Department of Orthopedic Surgery, Chang Geng Hospital, Taiwan
This is an award winning research paper. The government of Republic of China commended this article based on national medical research as a prominent contribution to citizen health. The paper has been widely published in Mainland China.
Translated by: Joe Hing Kwok Chu
The brachial plexus consists of five strands of nerves: C5, C6, C7, C8, and T1. These nerves start from the spinal column and thread through, above, and below the collarbones and under the armpits to the arms. They control the movements of the muscles of the chest, back, upper arms, and lower arms, as well as the sensation of the skin of the upper limbs. If the brachial plexus is paralyzed, the upper limb(s) will show obvious functional obstruction, with varying degrees of dysfunction.
Because there are differences between brachial plexus palsy in adults and in babies caused by childbirth-- causes, clinical characteristics, and controversies-- it is best to address each type separately.
CAUSES OF BRACHIAL PLEXUS PALSY IN CHILDREN
The most common causes of brachial plexus palsy result from shoulder dystocia in childbirth and are as follows:
(1) The head of the baby is down, and the body is too heavy. Eighty per cent of the victims weigh over 4 kilograms. Usually they are delivered with forceps or vacuum suction equipment.
(2) The mother's pelvis is too small, or the baby's shoulders are too wide. This usually results in brachial plexus palsy plus a broken collarbone.
(3) The body weight of the baby is not very heavy, but the baby is in breech position.
(4) Though C-section births have a much smaller risk of brachial plexus palsy, it does occur.
(5) Firstborns rarely suffer from brachial plexus palsy. About two-thirds of the cases happen during the second birth or subsequent births.
Brachial plexus palsy appears with different symptoms depending on the extent of birth trauma. The injury first appears at the age of one month. There are mainly two kinds: Erb's palsy and the complete palsy. Erb's palsy refers to the injury of nerves C5 and C6 together. The baby has difficulty lifting the shoulder, bending the elbow, rotating the lower arm outward (palm facing up). Sometimes the wrist may droop if C7 gets injured. With Erb's palsy the baby is able to curl and straighten the fingers.
The complete paralysis refers to C5 through T1 injuries. Not only the shoulder and the elbows are impaired, but also the wrist and the hands are difficult to bend and straighten. The eye on the affected side becomes smaller. (This condition of the eye may be temporary or permanent. )
If the nerves are allowed to heal naturally and are not repaired early, the children suffer greater disabilities than the ones who are treated early with surgery.
The most important factors
1. The degree of injury. Detachment of the nerves is worse than breakage. Detachment always causes the complete paralysis of the nerve. Fortunately most of the injuries are breakage, not detachment.
2. When the nerve grows back by itself, it results in different degrees of interwoven conditions. When the nerves break, it may be a partial break, and then they grow back naturally and regain the function. However, as they grow back, they become interwoven and the signal becomes confused. For example, nerve signals for lifting the shoulder and contracting the shoulder can happen at the same time, or for lifting the shoulder and bending the elbow, or for bending and straightening the elbow. The result is paralysis or near paralysis. Confused signals ask opposing muscles to contract at the same time. When the children grow up, they may not know how to lift the shoulder, bend the elbow or rotate the lower arm. So they have difficulty putting their hands on their waist ("at ease" position) or putting on their trousers.
3. If the detachment is from C7 to T1, the arm and the hand can become seriously atrophied, the sensation disappears, the bone becomes abnormal, and the joint becomes contracted. Then the reconstruction surgery can be difficult, and the result is a lifelong dysfunction.
The main diagnosis depends primarily upon clinical observation and the history of the childbirth. Mechanical and electronic instruments for testing (Nerve Conduction Velocity tests, CT, MRI) are of limited help.
The treatment of choice is early nerve reconstruction. Many obstetricians suggest that the injury can be healed naturally without surgery. But in fact it is not so. Most of the children are more or less disabled, and have loss of functions. The less serious ones have the affected arm shorter (4-6 cm). The serious ones have bones that become abnormal; the joint becomes contracted. They become difficult to reconstruct later. The only way to prevent that is to do early nerve reconstruction. If after three months the child still cannot bend the elbow, it shows that the injury is serious and the prognosis is poor. Nerve reconstruction surgery at this time (3 months of age) can prevent serious sequelae.
If it is more serious, (not only the elbow cannot be bent, but the hands and wrists become paralyzed), then the surgery must be performed early, at two months of age. Or if, after three months after the birth, the baby cannot bend its elbow, but the wrists and hands can open and extend, then the surgery can be postponed to the fifth month. If the elbow cannot be bent, then surgery is required.
The method is to use general anesthesia, and then use the nerve from the lower leg, which as a feeling/sensation nerve is not important, for transplant. If the nerves are detached, then it is necessary to perform nerve transfer, taking the minor nerve or the nerve of the ribs for transplant.
After surgery the neck must be stabilized for three weeks. Then rehabilitation therapy may begin and continue for two years. After the child is four years old, according to the condition of the recovery, then it may be determined that additional reconstructive surgery is necessary.
RECONSTRUCTION FROM THE SEQUELAE OF THE FUNCTIONAL DEFICIENCY
This refers to cases without early reconstruction. After the child is four years old, the residuals of the functional deficiency (of the shoulder, elbow, wrist, hand, muscles, and tendons) need more than two separate surgeries.
According to Narakas incidence of this problem is one per thousand to four per thousand depending on the medical advancement of the societies. In Taiwan there are more than 320,000 babies born every year; then the incidence of brachial plexus palsy would be 300 - 1200 infants out of the 320,000. In other words in Taiwan there should be at least 300 incidents.
According to our hospital's Labor and Delivery Department physician, twelve babies out of 12,481 births (1 per 1,000) had shoulder dystocia deliveries. Half of these twelve had brachial plexus palsy. The incidence for our hospital is 0.4/1,000. Many of the cases have some kind of legal controversy.
Within the ten-year period 1985-1994, there were 242 children with functional deficiencies who came to the hospital clinic for treatment. Every year there are 15 occurrences of reconstructive surgery and 30 occurrences of muscle tendon transplants.
The best solution to this problem is prevention.
The microsurgery was pioneered in China by the Second Medical School and Hospital of Shanghai. In the early 70's there were 27 American surgeons who went there to study microsurgery.
The number of incidences in the author's hospital is much smaller than the statistics of Narakas on advanced nations would suggest.
國內醫藥研究成果對國民健康有傑出貢獻獎, 得獎人: 長庚醫院教授整形外科主治醫師莊垂慶
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