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The Neuro Center's physician newsletter. Click here to go to Neurogram's home page. Neurosurgical Interventions in Pediatric DisordersAbnormal skull size or shapeThe two most common disorders causing abnormal skull size or shape and treated by our pediatric neurosurgeons are hydrocephalus and craniosynostosis. Although the diagnoses are often apparent on careful history and physical examination, head ultrasound, CT, and/or MRI are required for diagnosis and treatment. The majority of patients seen on referral for these possible diagnoses, however, do not require these tests, and pre-referral testing is not encouraged unless there is a clinical suspicion of an acute problem. HydrocephalusClinical FeaturesThere are a number of benign and pathologic etiologies for macrocephaly. Careful history and physical examination can often distinguish the pathologic from the normal variant. Of the more common normal variants, benign macrocephaly of infancy frequently is associated with a parental history of macrocephaly and is most often associated with enlargement of the subarachnoid spaces. Neurosurgical consultation often can reassure parents. The pathologic causes for macrocephaly and hydrocephalus include: aqueductal stenosis, Dandy-Walker malformation, Arnold-Chiari malformation, mass lesions, and perinatal meningitides. Key features of the history and physical examination in infants and children with macrocephaly include: Growth charts: Change in head circumference over time is a key development. A child whose head circumference is large but, nevertheless, following the normal curve causes less concern than one that is crossing percentiles. A single measurement can be alarming, but skull growth over time provides significantly more information. In addition, the parental head circumferences can be very revealing. Measurements are typically obtained of the parents at the time of evaluation. Developmental milestones: Children and infants who have not met developmental milestones flag medical attention. Developmental delay and macrocephaly often indicate more serious pathologies, including syndromic macrocephaly, hydrocephalus, and/or mass lesion. Signs of increased intracranial pressure: Symptoms and signs of increased intracranial pressure are well known. Symptoms depend on age but include projectile vomiting, headache--particularly in the early morning--and somnolence. Signs of increased ICP include a bulging anterior fontanelle in the erect infant, separation of the sutures, thinning of the scalp with the appearance of dilated scalp veins, and ocular signs. The ocular signs include papilledema and the setting-sun phenomena in which the globe is deviated downward and the upper lids are retracted. These patients deserve prompt neurosurgical intervention. ShuntingOver the last several years, the type of shunt used at the University of Virginia has changed significantly and improved the treatment of children with hydrocephalus. In the past, we have had essentially four valve pressures from which to choose for our shunts. If the initial valve pressure chosen was too high or too low for the particular patient, a new shunt would have to be placed, subjecting children to an additional operative procedure. We are now inserting shunts with programmable valves. Using a magnet, the pressure setting on the valve can be adjusted through the skin to meet a wide range of pressures. Pressure readjustments can occur in the outpatient setting within minutes. The University of Virginia remains at the forefront in the treatment of hydrocephalus, and a clinical trial is currently under way at UVa that compares various types of programmable valves. Skull MorphologyThe University of Virginia is among the premiere centers for the treatment of craniosynostosis and craniofacial malformations. The most common forms that demand neurosurgical intervention include sagittal and coronal synostosis. In the majority, repair of these disorders is cosmetic. Untreated craniosynostosis causes developmental delay and increased intracranial pressure in the minority. However, because the surgical treatment is so greatly facilitated by early intervention prior to closure of the normal sutures, early referral is encouraged. Generally, the neurosurgeon will attempt repair in the first year of life. Other forms of craniosynostosis do not require surgical intervention. Metopic synostosis often presents as a small ridge on the forehead. When not associated with hypotelorism, this condition generally resolves over time and is treated non-surgically. Another common presentation is over the question of lambdoid synostosis. True lambdoid synostosis requiring surgical repair presents with an ear that is displaced inferiorly and anteriorly. This syndrome is commonly confused with plagiocephaly, a benign molding of the skull secondary to prolonged resting of the child in the supine position. The ear may be displaced anteriorly, and the ipsilateral forehead may appear prominent. Plagiocephaly generally responds well to conservative treatment, however, and does not require neurosurgical intervention. Neurosurgical consultation for these often non-surgical conditions is appropriate and provides parents with the reassurance and information that they need. The University of Virginia has a long history of treating craniosynostosis and craniofacial abnormalities. Our staff are authors of the current texts describing its surgical management and continue to perform the basic science research that improves our understanding of the pathology. Dr. John Jane works closely with Dr. Kant Lin, associate professor of plastic surgery, and both participate in a multidisciplinary approach for these children. Remaining at the forefront of craniofacial surgery, Drs. Jane and Lin continue to develop innovative reconstructive techniques and currently employ absorbable plates and fixation devices to prevent overly rigid fixation. Sacral Dimple Versus MyelomeningoceleAlthough the incidence of myelomeningocele is declining, management of these often physically challenged children remains a significant part of pediatric neurosurgery. Infants born with open myelomeningoceles are repaired acutely and later present with spasticity. It is the children in whom there is a suspicion of an occult myelomeningocele that will be discussed here. Infants and toddlers are often referred for evaluation of pits or dimples in the lumbo-sacral region. The primary concern, of course, is that these represent stigmata of an underlying spinal dysraphism. Pits and indentations in the lumbar region, particularly when associated with a hairy patch, are often harbingers of an occult spinal dysraphism. Despite a normal neurological examination, these children deserve neurosurgical consultation and MRI is the radiographic study of choice. Although plain films and ultrasound can be valuable screening tools, we have found that MRI is inevitably required for diagnosis and treatment. True sacrococcygeal dimples are low-lying indentations or pits located at the level of the coccyx. Although classical teaching tells us that these are not associated with dysraphisms, children who have the condition deserve neurosurgical evaluation as we have diagnosed occult spinal disorders in some of them. Even though early surgery is most often not indicated in children with occult spinal dysraphism or tethered spinal cords, early neurosurgical evaluation does provide children with the close follow-up that is required. Cerebral Palsy-Spastic Diplegia and QuadriplegiaSpastic diplegia and quadriplegia are disabling conditions affecting children with cerebral palsy, traumatic brain injury, and myelomeningoceles. Although the degree of spasticity and neurological impairment varies, treatment of spasticity can improve ambulation, decrease pain associated with spasms, and facilitate activities of daily living such as wheelchair positioning and transfers. Although medical therapy using dantrolene, diazepam, and baclofen can be effective, neurosurgical intervention is often required. Without effective treatment of spasticity, many children develop contractures and hip dislocations and require repeated orthopedic interventions for tendon release, osteotomies, and internal femoral rotation. The hope is that early neurosurgical intervention may reduce the need for orthopedic intervention. The two primary neurosurgical interventions are selective dorsal rhizotomy and baclofen pump insertion. Selective dorsal rhizotomy has changed significantly since the 1980s. Currently, a laminectomy of only one or two levels is required and patients generally stay in house for four to five days. With the selective sectioning of the lumbar nerve roots, most children experience a significant improvement in their spasticity as well as in their gait and strength. Using a multidisciplinary approach, children are evaluated initially at the Kluge Children's Rehabilitation Center, where quantitative gait testing is performed. Their referrals are made for both orthopedic and/or neurosurgical evaluation as needed. Postoperatively, an experienced physical therapy team works closely with the children while they are in house or are outpatients. Since the mid-1980s, intrathecal baclofen has been known to improve spasticity. Often children who improve with oral baclofen but who are intolerant of its side effects can experience significant relief with intrathecal administration. Preoperative evaluation requires a two-day hospitalization during which time a lumbar puncture is performed with installation of a bolus of baclofen. Patients are then closely monitored, and objective data are obtained to discern clinical benefit. If appropriate, patients are then scheduled for surgery. The catheter is inserted by lumbar puncture, and the pump--currently the size of a hockey puck--is placed in the subcutaneous tissues in the lateral quadrant of the abdomen. The limiting factor is currently the size of the pump, but children as young as five years old have been treated successfully.
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