CP is the most common movement disorder in children. Cerebral palsy is caused by abnormal development or damage to the parts of the brain that control movement, balance, and posture. Most often the problems occur during pregnancy. These include difficult birth or poor prenatal and/or neonatal treatment. They may also occur during childbirth, or shortly after birth.
A Number of sub-types are classified based on the specific problems present. For example, those with stiff muscles have spastic cerebral palsy, those with poor coordination have ataxic cerebral palsy and those with writhing movements have athetoid cerebral palsy. Diagnosis is based on the child’s development over time. Often babies with cerebral palsy do not roll over, sit, crawl, or walk as early as other children their age. No cure exists presently for cerebral palsy, however, some children have near normal adult lives with appropriate treatment.
Intrauterine hypoxia occurs when the fetus is deprived of an adequate supply of oxygen. Intrauterine hypoxia can cause cellular damage that occurs within the brain and spinal cord. This results in an increased mortality rate, including an increased risk of sudden infant death syndrome (SIDS). Oxygen deprivation in the fetus and neonate have been implicated as either a primary or as a contributing risk factor in numerous neurological and neuropsychiatric disorders such as epilepsy, attention deficit disorders ADHD, eating disorders and cerebral palsy.
To determine whether an insufficient supply of oxygen and blood during labor and delivery was the likely cause of brain injury, several factors are considered together. These include a low Apgar score at 5 and 10 minutes after birth. A doctor evaluates a newborn on five criteria to arrive at the Apgar score, as a way to gauge the baby’s well-being. High acid level (called acidemia) in the umbilical artery; major organ failure; and an MRI scan showing a particular pattern of cerebral injury.
An abnormal MRI on Day 3, accompanied by certain labor and delivery problems, suggests that oxygen deprivation around the time of birth caused the brain injury. An MRI done 10 days after birth can indicate the extent of a baby’s brain injury. Brain injuries evolve, and it may take more than a week before the extent is evident on an MRI.
There are few effective remedies for those problems, but if certain abnormalities in the fetal heart rate are present when a woman goes into labor, the doctor may be able to prevent a serious brain injury by doing a cesarean delivery. If doctors were to be more forthcoming in reporting problems encountered during the care of pregnant women, especially at the time of labor and delivery, such honesty could well identify preventable causes of brain injuries in newborns and enable corrective action.
Shoulder Dystocia and Brachial Plexus Injuries
Depending on the location of the injury, the signs and symptoms can range from complete paralysis to anesthesia.
Brachial plexus injuries are frequent in newborns when excessive stretching of the neck occurs during delivery and/or when the baby’s upper limb is pulled excessively during delivery. For the upper brachial plexus injuries, paralysis occurs in those muscles supplied by C5 and C6 like the deltoid, biceps, brachialis, and brachioradialis.
Brachial plexus injuries are injuries that affect the nerves that carry signals from the spine to the shoulder. This can be caused by the shoulder being pushed down and the head being pulled up, which result in a stretching or tearing the nerves. Injuries associated with mal-positioning commonly affect the brachial plexus nerves. Because the brachial plexus nerves are very sensitive to position, there are very limited ways of preventing such injuries. The most common victims of brachial plexus injuries consist of newborns. There is an incident of approximately 1–3 brachial plexus injuries per 1000 vaginal birth deliveries.
Nerve damage occurring during delivery has been connected to birth weight. Larger newborns being more susceptible to this injury and that may well have to do with the delivery methods. A cesarian section ( C-Section) will avoid the risk of brachial plexus injury in large birth weight pregnancy and in those instances wherein the cervix does not dilate. Whether or not a cesarian can be performed depends upon risk v. benefit considerations.
Shoulder dystocia is a specific case whereby after the delivery of the head, and the shoulder of the infant cannot pass below, or requires significant manipulation to pass below, the pubic symphysis. It is diagnosed when the shoulders fail to deliver shortly after the fetal head. Shoulder dystocia is an obstetric emergency, and fetal demise can occur if the infant is not delivered, due to compression of the umbilical cord within the birth canal.
About 16% of deliveries where shoulder dystocia occurs will have conventional risk factors. These maternal risk factors consist of an age greater than 35 years; short in stature; small/abnormal pelvis; term plus (more than 42 weeks gestation); a high maternal birth weight; and diabetes.
Factors that increase the risk are:
- The need for oxytocics (drugs used to induce labor)
- Prolonged first or second stage of labor
- Turtle sign (when the infants head recedes back, ‘much like a turtle in a shell’)
- Head bobbing in the second stage of labor
- Failure to restitute (external rotation)
- No shoulder rotation or descent
- Instrumental delivery
Recurrence rates are relatively high (if the patient had shoulder dystocia in a previous delivery, the risk is now 10% higher than in the general population).
Management of shoulder dystocia has become a focus point for many obstetrical nursing units in North America. These encourage nursing units to do routine drills to prevent delays in delivery that adversely affect both mother and fetus. A common treatment mnemonic is ALARMER:
- Ask for help. This involves preparing for the help of an obstetrician, for anesthesia, and for pediatrics for subsequent resuscitation of the infant that may be needed if the methods below fail.
- Leg hyperflexion (McRoberts’ maneuver)
- Anterior shoulder disimpaction (pressure)
- Rubin maneuver
- Manual delivery of posterior arm
- Roll over on all fours
The advantage of proceeding in the order of ALARMER is that it goes from least to most invasive, thereby reducing harm to the mother in the event that the infant delivers with one of the earlier maneuvers. In the event that these maneuvers are unsuccessful, a skilled obstetrician may attempt some of the additional procedures such as, intentional clavicular fracture as a final attempt at nonoperative vaginal delivery.
The major concern of shoulder dystocia is damage to the upper brachial plexus nerves. These supply the sensory and motor components of the shoulder, arm and hands. The probable mechanism is manual stretching of the nerves, which in itself can cause injury. Furthermore, excess tension may physically tear the nerve roots out from the neonatal spinal column, resulting in total dysfunction. The ventral roots (motor pathway) are most prone to injury, as they are in the plane of greatest tension. The anterior, sensory nerves are somewhat protected due to the usual inward movement of the shoulder.
An excellent resource for more information regarding birth injury and the preventive steps to be take during pregnancy and delivery is the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics.
For more information, contact us.