Lumbosacral plexus injury
SOFT TISSUE INJURY
Soft tissue
injury is associated with fetal monitoring, particularly with fetal scalp blood
sampling for pH or fetal scalp electrode for fetal heart monitoring, which has a
low incidence of hemorrhage, infection, or abscess at the site of sampling.
Cephalhematoma
Cephalhematoma is a subperiosteal collection of blood secondary to rupture of
blood vessels between the skull and the periosteum; suture lines delineate its
extent. Most commonly parietal, cephalhematoma occasionally may be observed over
the occipital bone.
The extent of hemorrhage may be severe enough to present as anemia and
hypotension. Resolving hematoma will predispose to hyperbilirubinemia. Rarely,
cephalhematoma may be a focus of infection leading to meningitis or
osteomyelitis. Linear skull fractures may underlie a cephalhematoma (5-20% of
cephalhematomas). Resolution occurs over weeks, occasionally with residual
calcification.
No lab work usually is necessary. Skull x-ray/CT scan are used if neurologic
symptoms are present. Usually, management consists of observation only.
Transfusion and phototherapy are necessary if blood accumulation is significant.
Aspiration is more likely to increase the risk of infection. The presence of a
bleeding disorder should be considered. Skull X-ray/CT scan also are used if
concomitant depressed skull fracture a possibility.
Subgaleal hematoma
Subgaleal hematoma is bleeding in the potential space between the skull
periosteum and the scalp galea aponeurosis. Ninety percent result from vacuum
applied to the head at delivery. Subgaleal hematoma has a high frequency of
occurrence of associated head trauma (40%), such as intracranial hemorrhage or
skull fracture. The occurrence of these features does not correlate
significantly with the severity of subgaleal hemorrhage.
The diagnosis is generally a clinical one, with a fluctuant boggy mass
developing over the scalp (especially over the occiput). The swelling develops
gradually 12-72 hours after delivery, although it may be noted immediately after
delivery in severe cases. The hematoma spreads across the whole calvarium. Its
growth is insidious, and subgaleal hematoma may not be recognized for hours.
Subgaleal hematoma may present as hemorrhagic shock. The swelling may obscure
the fontanelle and cross suture lines (distinguishing it from cephalhematoma).
Watch for significant hyperbilirubinemia. The long-term prognosis generally is
good.
Lab work consists of a hematocrit evaluation. Management consists of vigilant
observation over days to detect progression. Transfusion and phototherapy may be
necessary. Investigation for coagulopathy may be indicated.
Caput succedaneum
Caput succedaneum is a serosanguinous, subcutaneous, extraperiosteal fluid
collection with poorly defined margins. It is caused by the pressure of the
presenting part against the dilating cervix. Caput succedaneum extends across
the mid line and over suture lines and is associated with head moulding. Caput
succedaneum usually does not cause complications. It usually resolves over the
first few days. Management consists of observation only.
Abrasions and lacerations
Abrasions and lacerations sometimes may occur as scalpel cuts during cesarean
section or during instrumental delivery (vacuum, forceps). Infection remains a
risk, but most will heal uneventfully.
Management consists of careful cleaning, application of antibiotic ointment,
and observation. Bring edges together using Steri-Strips. Lacerations
occasionally require suturing.
Subcutaneous fat necrosis
Subcutaneous fat necrosis usually is not detected at birth. Irregular hard,
nonpitting, subcutaneous plaques with overlying dusky, red-purple discoloration
on the extremities, face, trunk, or buttocks may be caused by pressure during
delivery. No treatment is necessary. Subcutaneous fat necrosis sometimes
calcifies.
PERIPHERAL NERVE INJURY
Brachial
plexus injury
Brachial plexus injury occurs most commonly in large babies, frequently with
shoulder dystocia or breech delivery. Incidence for brachial plexus injury is
0.5-2.0 per 1000 live births. The majority of cases are Erb palsy; entire
brachial plexus involvement occurs in 10% of cases.
Traumatic lesions associated with brachial plexus injury are fractured
clavicle (10%), fractured humerus (10%), subluxation of cervical spine (5%),
cervical cord injury (5-10%), and facial palsy (10-20%). Erb palsy (C5-C6) is
most common and is associated with lack of shoulder motion. The involved
extremity lies adducted, prone, and internally rotated. Moro, biceps, and radial
reflexes are absent on the affected side. Grasp reflex usually is present. Five
percent of patients have an accompanying (ipsilateral) phrenic nerve paresis.
Klumpke paralysis (C7,8 T1) is rare, resulting in weakness of the intrinsic
muscles of the hand; grasp reflex is absent. If cervical sympathetic fibers of
the first thoracic spinal nerve are involved, Horner syndrome is present.
No uniformly accepted guidelines for determining prognosis exist. Narakas
developed a classification system (type I-V) based on the severity and extent of
lesion, providing clues to the prognosis in the first 2 months of life.
According to the collaborative perinatal study (59 infants), 88% of cases
resolved in the first 4 months, 92% by 12 months, and 93% by 48 months. In
another study of 28 patients with upper plexus involvement and 38 with total
plexus palsy, 92% recovered spontaneously.
Residual long-term deficits may include progressive bony deformities, muscle
atrophy, joint contractures, possible impaired growth of the limb, weakness of
the shoulder girdle, and/or "Erb engram" flexion of elbow accompanied by
adduction of shoulder.
Lab work consists of x-ray studies of the shoulder and upper arm to rule out
bony injury. The chest should be examined to rule out associated phrenic nerve
injury. Electromyogram (EMG) and nerve conduction studies occasionally are
useful. Fast spin-echo MRI can evaluate plexus injuries noninvasively in a
relatively short time, minimizing the need for general anesthesia. MRI can
define meningoceles and may distinguish between intact nerve roots and
pseudomeningoceles (indicative of complete avulsion). Carefully performed,
intrathecally enhanced CT scan myelography may show preganglionic disruption,
pseudomeningoceles, and partial nerve root avulsion. CT scan myelography is more
invasive and offers few advantages over MRI.
Management consists of prevention of contractures. Immobilize limb gently
across the abdomen for the first week and then start passive range of motion
exercises at all joints of the limb. Use supportive wrist splints. Best results
for surgical repair appear to be obtained in the first year of life. Several
investigators recommend surgical exploration and grafting if there is no
function in the upper roots at 3 months of age, though the recommendation for
early explorations far from universal. Complications of brachial plexus
exploration include infection, poor outcome, and burns from the operating
microscope. Patients with root avulsion do not do well. Palliative procedures
involving tendon transfers have been of some use. Latissimus dorsi and teres
major transfers to the rotator cuff have been advocated for improved shoulder
function in Erb palsy. One permanent and 3 transitory axillary nerve palsies
have been reported from the procedure.
CRANIAL NERVE AND SPINAL CORD INJURY
Cranial
nerve and spinal cord injuries result from hyperextension, traction, and
overstretching with simultaneous rotation. They may range from localized
neurapraxia to complete nerve or cord transection.
Cranial nerve injury
Unilateral branches of the facial nerve and vagus nerve, in the form of
recurrent laryngeal nerve, are most commonly involved in cranial nerve injuries
and result in temporary or permanent paralysis.
Compression by the forceps blade has been implicated in some facial nerve
injury, but most facial nerve palsy is unrelated to trauma.
Physical findings for central nerve injuries are asymmetric facies with
crying. The mouth is drawn towards the normal side, wrinkles are deeper on the
normal side, and movement of the forehead and eyelid is unaffected. The
paralyzed side is smooth with a swollen appearance; the nasolabial fold is
absent; and the corner of the mouth droops. There is no evidence of trauma on
the face.
Physical findings for peripheral nerve injuries are asymmetric facies with
crying. Sometimes evidence of forceps marks is present. With peripheral nerve
branch injury, the paralysis is limited to the forehead, eye, or mouth.
The differential diagnosis includes nuclear genesis (Möbius syndrome),
congenital absence of the facial muscles, unilateral absence of the orbicularis
oris muscle, and intracranial hemorrhage.
Most infants begin to recover in the first week, but full resolution may take
several months. Palsy that is due to trauma usually will resolve or improve,
whereas palsy that persists often is due to absence of the nerve.
Management consists of protecting the open eye with patches and synthetic
tears (methylcellulose drops) every 4 hours. Neurologic and surgical
consultation should be sought if no improvement is observed in 7-10 days.
Diaphragmatic paralysis secondary to traumatic injury to the cervical nerve
roots supplying the phrenic nerve can occur as an isolated finding or in
association with brachial plexus injury. The clinical syndrome is variable. The
course is biphasic; initially the infant experiences respiratory distress with
tachypnea and blood gases suggestive of hypoventilation (hypoxemia, hypercapnia,
acidosis). Over the next several days, the infant may improve with oxygen and
varying degrees of ventilatory support. Elevated hemi-diaphragm may not be
observed in the early stages. Approximately 80% of lesions involve the right
side and about 10% are bilateral.
The diagnosis is established by ultrasound or fluoroscopy of the chest, which
reveals the elevated hemi-diaphragm with paradoxical movement of the affected
side with breathing.
The mortality for unilateral lesions is approx. 10-15%. The majority of
patients recover in the first 6-12 months. An outcome for bilateral lesions is
poorer. Mortality approaches 50% and prolonged ventilatory support may be
necessary.
Management consists of careful surveillance of respiratory status, and
intervention, when appropriate, is critical.
Laryngeal nerve injury
Disturbance of laryngeal nerve function may affect swallowing and breathing.
Laryngeal nerve injury appears to result from an intrauterine posture in which
the head is rotated and flexed laterally. During delivery, similar head
movement, when marked, may injure the laryngeal nerve, accounting for
approximately 10% of vocal cord paralysis attributed to birth trauma. The infant
presents with a hoarse cry or respiratory stridor, most often caused by
unilateral laryngeal nerve paralysis. Swallowing may be affected if the superior
branch is involved. Bilateral paralysis may be caused by trauma to both
laryngeal nerves or, more commonly, by a CNS injury such as hypoxia or
hemorrhage involving the brain stem. Bilateral paralysis often presents with
severe respiratory distress or asphyxia.
Direct laryngoscopic examination is necessary to make the diagnosis and to
distinguish vocal cord paralysis from other causes of respiratory distress and
stridor in the newborn. Differentiate from other rare etiologies, such as
cardiovascular or CNS malformations or a mediastinal tumor.
Paralysis often resolves in 4-6 weeks, though recovery may take as long as
6-12 months in severe cases. Treatment is symptomatic. Small frequent feeds,
once the neonate is stable, minimize the risk of aspiration. Infants with
bilateral involvement may require gavage feeding and tracheotomy.
Spinal cord injury
Spinal cord injury incurred during delivery results from excessive traction
or rotation. Traction is more important in breech deliveries (minority of
cases), and torsion in vertex deliveries. True incidence is difficult to
determine. The lower cervical and upper thoracic region for breech delivery and
upper and midcervical region for vertex delivery are the major sites of injury.
Major neuropathological changes consist of acute lesions, which are
hemorrhage, especially epidural, intraspinal, and edema. Hemorrhagic lesions are
associated with varying degrees of stretching, laceration, and disruption or
total transaction. Occasionally the dura may be torn, and rarely the vertebral
fractures or dislocations may be observed.
The clinical presentation is stillbirth or rapid neonatal death with failure
to establish adequate respiratory function, especially in cases involving the
upper cervical cord or lower brain stem. Severe respiratory failure may be
obscured by mechanical ventilation and may cause ethical issues later. The
infant may survive with weakness and hypotonia, and the true etiology may not be
recognized. A neuromuscular disorder or transient hypoxic ischemic
encephalopathy may be considered. Most infants will later develop spasticity
that may be mistaken for cerebral palsy.
Prevention is the most important aspect of medical care. Obstetrical
management of breech deliveries, instrumental deliveries, and pharmacological
augmentation of labor must be appropriate. Occasionally, injury may be sustained
in utero.
The diagnosis is made by MRI or CT myelography. Little evidence indicates
that laminectomy or decompression has anything to offer. A potential role for
methylprednisolone exists. Supportive therapy is important.
BONE INJURY
Fractures most
often are observed following breech delivery and/or shoulder dystopia in
macrosomia infants.
Clavicular fracture
The clavicle is the most frequently fractured bone in the neonate during
birth and most often is an unpredictable, unavoidable complication of normal
birth. Some correlation with birth weight, midforceps delivery, and shoulder
dystocia exists. The infant may present with pseudoparalysis. Examination may
reveal crepitus, palpable bony irregularity, and sternocleidomastoid muscle
spasm. X-ray will confirm the fracture.
Healing usually occurs in 7-10 days. Arm motion may be limited by pinning the
infant's sleeve to the shirt. Assess other associated injury to spine, brachial
plexus, or humerus.
Long bone fracture
Loss of spontaneous arm or leg movement is an early sign of long bone
fracture, followed by swelling and pain on passive movement. The obstetrician
may feel or hear a snap of fracture at the time of delivery. X-ray of the limb
will confirm the diagnosis.
Femoral and humeral shaft fractures are treated with splinting. Closed
reduction and casting is necessary only when displaced. Watch for evidence of
radial nerve injury with humeral fracture. Callus formation occurs, and complete
recovery is expected in 2-4 weeks. In 8-10 days, the callus formation is
sufficient to discontinue immobilization. Orthopedic consultation is
recommended.
X-ray will distinguish this condition from septic arthritis.
Epiphysial displacement
Separation of humeral or femoral epiphysis occurs through the hypertrophied
layer of cartilage cells in the epiphysis. The diagnosis is made clinically
based on the finding of swelling around the shoulder, crepitus, and pain when
the shoulder is moved. Motion is painful and the arm lies limp by the side. As
the proximal humeral epiphysis is not ossified at birth, it is not visible on
x-ray. Callus appears in 8-10 days and is visible on x-ray.
Management consists of immobilizing the arm for 8-10 days. Fracture of the
distal epiphysis is more likely to have a significant residual deformity than is
fracture of the proximal humeral epiphysis.
INTRA-ABDOMINAL INJURY
Intra-abdominal
injury is relatively uncommon and sometimes can be overlooked as a cause of
death in the newborn. Hemorrhage is the most serious acute complication, and the
liver is the most commonly damaged internal organ.
Signs and symptoms of intraperitoneal bleed
Bleeding may be fulminant or insidious but ultimately will present with
circulatory collapse. Intra-abdominal bleed should be considered for every
infant presenting with shock, pallor, unexplained anemia, and abdominal
distension. Overlying abdominal skin may have bluish discoloration. X-ray is not
diagnostic but may suggest free peritoneal fluid. Paracentesis is the procedure
of choice.
Hepatic rupture
The most common lesion is subcapsular hematoma, which increases to 4-5 cm
before rupturing. Symptoms of shock may be delayed. Lacerations are less common,
often caused by abnormal pull on peritoneal support ligaments or effect of
excessive pressure by the costal margin. Infants with hepatomegaly may be at
higher risk. Other predisposing factors include prematurity, postmaturity,
coagulation disorders, and asphyxia. In cases associated with asphyxia, vigorous
resuscitative effort (often by unusual methods) is the culprit. Splenic rupture
is at least a fifth as common as liver laceration. Predisposing factors and
mechanisms of injury are similar.
Rapid identification and stabilization of the infant are the keys to
management, along with assessment of coagulation defect. Blood transfusion is
the most urgent initial step. Persistent coagulopathy may be treated with fresh
frozen plasma, transfusion of platelets, etc.
Hepatic rupture has no specific predilection for any race and has equal sex
distribution. It usually presents immediately following birth or becomes obvious
within the first few hours or days.
Recognition of
trauma necessitates a careful physical and neurological evaluation of the infant
to establish whether additional injuries exist. Occasionally, injury may result
from resuscitation. Symmetry of structure and function should be assessed as
well as specifics such as cranial nerve examination, individual joint range of
motion, and scalp/skull integrity.
REFERENCES