Prolonged continuous monitoring of intracranial pressure in severe Reye's syndrome.

Evidence from both clinical and pathological investigations suggests that increased intracranial pressure (ICP) is a significant factor in the mortality of patients with Reye's syndrome. This, coupled with a critical review of our previous 22 patients, which failed to document the efficacy of exchange transfusion, led us to include continous ventricular pressure monitoring in the supportive care of children with Reye's syndrome. To date, three children, ages 3 to 5 years, have been managed with continuous ICP monitoring. All had stage IV coma by both clinical and electroencephalographic criteria. Peak blood ammonia concentrations were 1,036, 316, and 56micronug/100 ml; all had elevations of serum glutamic oxaloacetic transaminase level, prothrombin time, and creatine phosphokinase level as well. Rapid, unprediatble increases in ICP occurred for many days in all children. Therapeutic measures most successful in controlling ICP were the intravenous administration of mannitol and hyperventilation. Elevations in ICP occurred despite serum osmolality as high as 418 mOsm and following oral administration of glycerol. Rapid increases in ICP also resulted from routine manipulation of the patients (e.g., postural drainage). Exchange transfusion, used in two of the three patients, increased ICP in one child and had no effect in the other. All three children have achieved complete recovery and are doing well 6 months after their illness. Our experience with these children suggests that vigorous supportive therapy, including careful monitoring of ICP, should be used as a basis of comparison when evaluating claims of specific treatment in Reye's syndrome.

Infections of CSF shunt and intracranial pressure monitoring devices.

Management of shunt infections varies, but externalization of shunt apparatus and the need for intraventricular antibiotics seem to have been rather uniformly adopted. No recent studies on EVD systems have been reported, largely because of the widespread use of alternatives such as the fiberoptic systems and the hollow subarachnoid bolt. Studies from the 1970s and personal experience with long-term monitoring in children with Reye's syndrome and head trauma indicate that it can be done safely with a low risk of infection. What the defining variable(s) for that low infection rate might be is not at all certain. Analysis of risk factors and the development of a study design that will provide statistically valid information must be accomplished before unbiased decisions can be made concerning the use of perioperative antibiotics in the management of CSF shunts. Until that is accomplished, the risks of such therapy must be carefully balanced against the possible (but unproven) benefit.

Spinal ultrasonography. Intraoperative and pediatric applications.

Ultrasonography has had limited usefulness in the diagnosis of diseases of the spine and spinal cord in older children and adults. However, its use intraoperatively in patients of all ages, and nonoperatively in infants and young children, is finding increased application. The authors, who perform and rely on spinal sonography in both clinical situations, present an overview of technique, normal anatomy, and selected pathologic entities based on their experience and the literature.

Arnold-Chiari malformation in an infant with Kleeblattschadel: an acquired malformation?

A case of Arnold-Chiari malformation in an infant with Kleeblattschadel is reported. The author suggests that the malformation may be acquired on the basis of cephalocranial disproportion and may be a contributing factor in the development of hydrocephalus.

Surgical considerations in the initial repair of meningomyelocele and the introduction of a technical modification.

Tethering of the spinal cord has been increasingly recognized as a cause of late deterioration in the child with repaired meningomyelocele. Findings at reoperation include dense arachnoiditis, dermal inclusion cysts, fibrolipoma of the filum terminale, and, on occasion, foreign body granulomas. This article reviews four key steps in meningomyelocele repair and the guidelines for detection of surgically remediable lesions associated with this disorder. In addition, it proposes a modification of the standard dural closure that may reduce the incidence of contributory adhesive arachnoiditis by the creation of a capacious cerebrospinal fluid space about the neural plaque.

Multiple intradural arachnoid diverticuli: the need for complete myelography.

A 12-year-old boy presented with enuresis, leg weakness, and lower extremity spasticity. An initial lumbar water-soluble contrast myelogram disclosed an arachnoid diverticulum. After the insertion of a cystopleural shunt, the patient improved and was dry. However, 2 months later the patient became enuretic and developed weakness. Repeat myelography showed a second arachnoid diverticulum located in the midthoracic region. This second diverticulum was treated by marsupialization of the cyst wall to the subfascial space. The authors stress the need for complete myelography in patients with intradural spinal arachnoid diverticuli and present a brief review of the literature.

Childhood cerebellopontine angle teratoma associated with congenital hydrocephalus.

A case of childhood teratoma in the cerebellopontine angle associated with shunted congenital hydrocephalus is presented. The need for detailed computed axial scanning with and without contrast in congenital hydrocephalus not associated with intraventricular hemorrhage or myelodysplasia is emphasized.

Postoperative regression of opticochiasmatic astrocytoma: a case for expectant therapy.

After incisional biopsy, an opticochiasmatic astrocytoma in a 2-year-old child with neurofibromatosis was seen to regress by computed tomographic scanning. This case illustrates the need for expectant therapy in this entity.

Magnetic resonance imaging in the evaluation of low attenuation lesions on computed tomography.

Computed tomography has proven invaluable in the assessment of intracranial mass lesions. Low attenuation lesions can, however, present diagnostic difficulties. We report three cases where magnetic resonance imaging was beneficial in clarifying solid versus cystic intracranial lesions.

Control of shunt infection. Report of 150 consecutive cases.

The author analyzes 150 consecutive ventriculovenous, ventriculoperitoneal, and lumboperitoneal shunt procedures with particular attention to shunt colonization by Staphylococcus epidermidis. There was one primary infection with Staphylococcus epidermidis early in the series, and in two other cases, the organism was felt to be a secondary invader. In those procedures involving either primary placement or revision of a ventriculovenous shunt, there was not a single infection. The operative protocol that has virtually eliminated Staphylococcus epidermidis is outlined.

The use of intravenous fluorescein in the repair of large myelomeningoceles. Technical note.

Intravenous fluorescein has been found a valuable guide in the identification of necrotic skin, which can then be debrided before wound closure. Fluorescein was used in four infants undergoing repair of large myelomeningoceles with no deleterious effects.

Loss of autoregulation and posttraumatic ischemia following experimental spinal cord trauma.

Blood flow in the dorsolateral funiculus of the cat thoracic spinal cord was studied after severe experimental cord injury, using a modification of the hydrogen clearance technique. Autoregulation was intact during the initial 60 to 90 minutes after cord injury, but was then lost coincident with the onset of ischemia. The data suggest that the ischemic response to spinal cord injury is mediated both by the loss of autoregulation and by relative vasoconstriction of the resistance vessels. Therapeutic intervention aimed at maintaining perfusion during the early posttraumatic period may prove of value in reversing or limiting some elements of dysfunction due to the secondary injury of ischemia.

Bifrontal decompressive craniectomy in the management of head trauma.

Retrospective analysis of 13 patients who had bifrontal decompressive craniectomy for the management of posttraumatic cerebral edema shows a significant decrease in expected mortality, but severe morbidity in the survivors. Only one patient returned to the pretrauma level of neurological function. No correlation could be found between the quality of survival and the neurological or operative findings. The need for more accurate prognostic criteria in the evaluation of severely head-injured patients is discussed.

Sagittal synostectomy. Technical note.

A procedure for correction of scaphocephaly is described. It differs from strip craniectomy in that it provides early correction of the deformity by removing the protuberances at the bregma and at the occiput. The morbidity and mortality of this procedure is no greater than with the more standard linear craniectomy.

Altered blood flow and secondary injury in experimental spinal cord trauma.

A modification of the hydrogen clearance technique was used to study blood flow in the dorsolateral funiculus of traumatized thoracic spinal cord in cats. The result of this study show that ischemia occurred in all animals both at the level of trauma, and 1 cm below the site of trauma. There was, however, a period of over 1 hour after trauma during which blood flow was maintained at both sites. This investigation not only confirms the presence of ischemia in the lateral funiculus of the injured spinal cord but suggests that a period of time exists in the posttraumatic period during which pharmacological intervention may alter the ischemic response and possibly prevent secondary injury resulting from the ischemia.

Preoperative evaluation and surgical management of the Arnold-Chiari II malformation.

The authors report their recent experience with 14 meningomyelocele patients with the Arnold-Chiari II malformation. Three major types of fourth ventricle anomalies seen in the Arnold-Chiari II malformation are defined, based on preoperative magnetic resonance imaging and intraoperative ultrasound studies. The Type A deformity is defined as no cystic dilatation of the fourth ventricle. In the Type B anomaly, there is intracranial dilatation of the fourth ventricle. The Type C deformity involves intraspinal dilatation of the fourth ventricle, either dorsal to the cord or within the substance of the cord. The Type A deformity was most common in infants, and in two cases progression from a Type A to Type B deformity was documented. Recognition of the type of Arnold-Chiari II malformation aids in designing an operative approach more specific to that structural abnormality. Intraoperative ultrasound is a valuable adjunct in localization of the underlying anomalies and permits safe decompression of the fourth ventricle. The authors' indications for surgery now include failure to thrive due to either early respiratory and swallowing dysfunction, progressive spasticity, or upper-extremity weakness. Nine patients significantly improved following surgery and three patients with a progressively deteriorating course were stabilized by surgery. Decompression of the fourth ventricle by fenestration and internal shunting appears to be well tolerated, even in young infants, and is recommended in the treatment of the Arnold-Chiari II deformity.

Alteration of posttraumatic ischemia in experimental spinal cord trauma by a central nervous system depressant.

Blood flow after severe experimental injury to the thoracic spinal cord was studied in cats, using a modification of the hydrogen clearance technique. Gamma hydroxybutyrate, a central nervous system depressant, was shown to markedly alter the ischemic response to injury if given during the early posttraumatic period. Other vasoactive drugs investigated had no effect on posttraumatic ischemia. Therapeutic intervention during the early posttraumatic period aimed at increasing blood flow while decreasing the metabolic requirements of the injured cord may prove of value in reversing or limiting some elements of long-tract dysfunction due to the secondary ischemic insult.

Management of severe cerebral edema in the metabolic encephalopathy of Reye-Johnson syndrome.

Fifteen critically ill children with the diagnosis of Reye-Johnson syndrome were treated with techniques developed to maintain adequate cerebral perfusion pressure and levels of circulating blood glucose. One child died, three sustained neurological deficit, and nine children (70%) recovered without significant neurological dysfunction. The technique developed during the period these children were treated, the indications for their use, and factors that can interfere with maintaining adequate cerebral perfusion in patients with increased intracranial pressure from metabolic encephalopathy are described. The results suggest that neurological damage in this syndrome results from neuronal injury secondary to inadequate cerebral perfusion and/or hypoglycemia, and that neurological dysfunction like hepatic dysfunction should produce minimal mortality and morbidity if cerebral perfusion and adequate levels of circulating blood glucose are sustained during the period of increased intracranial pressure and liver failure.

Stereotaxic biopsy of intrinsic lesions of the brain stem.

Despite improved brain-stem imaging by magnetic resonance and high-resolution x-ray computerized tomography, definitive diagnosis and therapy of intrinsic lesions of the brain stem require histological verification. A stereotaxic approach to brain-stem lesions provides a high yield of positive histological diagnosis with a low incidence of morbidity. A series of 14 stereotaxic procedures performed on 12 patients with intrinsic lesions of the mesencephalon, pons, and medulla is reviewed. A detailed description of the transfrontal approach used by the authors is presented. Definitive pathological diagnosis was obtained in all patients. There was no operative mortality and only one case of permanent neurological deficit. The significance of accurate histological diagnosis in the therapy of brain-stem lesions is discussed.