Search

Reports from our laboratory have shown that regional brain tissue pressure (RBTP) gradients develop in response to supratentorial but not posterior fossa extradural masses. We undertook this experiment to discover the mechanism of this differing response. RBTP was measured in the right and left frontal lobes (RF, LF), temporal lobes (RT, LT), midbrain (MB), and cerebellum (CB) of ten pigs. Balloons were expanded in the epidural space at C2 to occlude the subarachnoid space. A temporal extradural mass was expanded incrementally. The C2 balloon was deflated after temporal mass expansion. Expansion of the cervical balloon resulted in a homogeneous rise in RBTP. Expansion of the temporal mass resulted in the development of small RBTP gradients with the following relationship: RT > LT = LF > RF = CB > MB. In comparison with a previous series of animals without cervical balloons, animals in this series demonstrated higher global ICP in response to equal size masses and smaller RBTP gradients. Cervical balloon deflation resulted in decreased global ICP and increased RBTP gradients. The development of RBTP gradients in response to expanding supratentorial masses therefore appears to be at least partially dependent upon the presence of a normal communication between the supratentorial space and the spinal subarachnoid space.

One of the most frequently occurring questions in the neurological critical care of children involves the indications for measurement of intracranial pressure (ICP) and the appropriate therapies for abnormally elevated ICP. Advances in monitoring technology have improved the safety and accuracy of ICP measurement. Clinical and basic research into the mechanisms of brain swelling and the efficacy of various therapies, especially in the realm of traumatic brain injury, has allowed the development of rational and specific treatment strategies for elevated ICP. For several diseases, the ability to measure and manage ICP has resulted in marked improvements in outcomes. This article reviews the indications for, and recommended methods of, measuring ICP in children and discusses the status of therapies commonly used to control elevated ICP.

✓ A porcine model was used to study the regional intracranial pressure (ICP) differences caused by a frontal mass lesion. Intraparenchymal ICP monitors were placed in the right and left frontal lobes, right and left temporal lobes, midbrain, and cerebellum. A frontal epidural mass lesion was created by placing a balloon catheter through a burr hole into the right frontal epidural space. A computer was used to acquire data from all monitors at 50-msec intervals. The balloon was expanded by 1 cc over a period of 1 second every 5 minutes and maximum pressure immediately before and during expansion was determined for each balloon volume at each site. Prior to expansion of the mass, the morphology of the cerebellum pressure tracing was different from that seen in all supratentorial regions. Also, pressures in the midbrain, at baseline, were slightly but significantly lower than pressures in the frontal and temporal regions. During expansion of the mass, a pressure differential that increased as the size of the mass increased developed between intracranial regions. Furthermore, the regional pressures were found to vary in a consistent fashion expressed by the formula RF = LF > RT = LT > MB > CB, in which RF and LF are the right and left frontal lobes, RT and LT are the right and left temporal lobes, MR is the midbrain, and CB is the cerebellum. The study shows that an expanding epidural mass reproducibly results in a gradient of brain parenchymal pressure. This gradient results in parenchymal pressures that are significantly different in each region of the brain depending on the proximity of that region to the epidural mass. The results of this study have implications for clinical ICP monitoring and therapy.

Introduction Aqueductal stenosis may be caused by a number of etiologies including congenital stenosis, tumor, inflammation, and, very rarely, vascular malformation. However, aqueductal stenosis caused by a developmental venous anomaly presenting as congenital hydrocephalus is even more rare, and, to the best of our knowledge, has not yet been reported in the literature. In this study, we review the literature and report the first case of congenital hydrocephalus associated with aqueductal stenosis from a developmental venous anomaly. Case presentation The patient is a three-day-old, African-American baby girl with a prenatal diagnosis of hydrocephalus. She presented with a full fontanelle, splayed sutures, and macrocephaly. Postnatal magnetic resonance imaging showed triventricular hydrocephalus, suggesting aqueductal stenosis. Examination of the T1-weighted sagittal magnetic resonance imaging enhanced with gadolinium revealed a developmental venous anomaly passing through the orifice of the aqueduct. We treated the patient with a ventriculoperitoneal shunt. Conclusions Ten cases of aqueductal stenosis due to venous lesions have been reported and, although these venous angiomas and developmental venous anomalies are usually considered congenital lesions, all 10 cases became symptomatic as older children and adults. Our case is the first in which aqueductal stenosis caused by a developmental venous anomaly presents as congenital hydrocephalus. We hope adding to the literature will improve understanding of this very uncommon cause of hydrocephalus and, therefore, will aid in treatment.

Of the variety of complications associated with ICP monitoring, CSF infection is the most common. Multiple factors have been associated with an increased rate of infection, including increased age, prolonged duration of monitoring, concomitant use of steroids, multiple changes of monitors, and the presence of a concurrent infection [1, 6]. Although numerous studies have indicated that the ventricular catheter (VC) has the highest reported infection rate of all currently used ICP monitors, the advantages afforded by CSF drainage for the management of elevated ICP justify the use of VC assuming that the complication rate is acceptably low.

Post-traumatic ventricular enlargement (PTVE) is a known consequence of head injury. However, its incidence and factors associated with its occurrence have not been well delineated in the severely head injured patient. We have investigated PTVE int the Traumatic Coma Data Bank (TCDB) to define its incidence, risk factors, and impact on outcome in severely head injured patients.

✓ In this study, data were prospectively collected from 753 patients (111 children and 642 adults) with severe head injury and examined for evidence of diffuse brain swelling and its association with outcome. Diffuse brain swelling occurred approximately twice as often in children (aged 16 years or younger) as in adults. A high mortality rate (53%) was found in these children, which was three times that of the children without diffuse brain swelling (16%). Adults with diffuse brain swelling had a mortality rate (46%) similar to that of children, but only slightly higher than that for adults without diffuse brain swelling (39%). When the diagnosis of diffuse brain swelling was expanded to include patients with diffuse brain swelling plus small parenchymal hemorrhages (< 15 cu cm), these mortality rates were virtually unchanged.

A 10-year retrospective review of 15 children with cerebral tumors and seizures was conducted to study the factors responsible for delay in the diagnosis of tumors and to assess outcome following surgery. Mean duration of seizures prior to surgery was 37 months. Ninety-three percent had no focal neurologic deficits. Head computed tomography was abnormal in 64%, whereas magnetic resonance imaging was abnormal in all patients. Electroencephalography showed focal abnormalities ipsilateral to the tumor in 73%. There was no surgical mortality. Eighty percent were seizure free or had rare seizures following surgery. Factors contributing to a delayed diagnosis of the brain tumor included a nonfocal neurologic examination and delay in obtaining an appropriate neuroimaging study. We believe that head magnetic resonance imaging should be the investigation of choice in partial epilepsies. (J Child Neurol 2000;15: 141-145).

✓ A No. 4 French fiberoptic catheter initially developed as an intravascular pressure sensor was incorporated into a system to be used as an intracranial pressure (ICP) monitor. Initially, a series of acute and chronic animal experiments carried out in the rabbit and pig, respectively, demonstrated the reliability and safety of the device. Subsequently, this new monitor was compared to a concurrently functioning ICP monitor in 15 adult and five pediatric patients. This clinical experience also confirmed the safety, accuracy, and reliability of the device. Since these initial studies, this monitor has been used to routinely measure ICP in a large number of adult and pediatric patients. The monitor has functioned well, and there have been no complications related to its use except for an occasional problem with breakage of the optic fiber as a result of patient movement or nursing maneuvers, which has been easily corrected by replacement of the probe. As nursing personnel and ancillary services have become familiar with this new monitor, breakage has not been a problem. This new device can be placed into the ventricular system, the brain parenchyma, or the subdural space, and appears to offer substantial advantages over other monitors presently in use.

We present two cases that demonstrate the occurrence of symptomatic arachnoid cysts after craniotomy. Both patients presented 1 year postoperatively with generalized seizures as the only symptom. Focal or localizing neurological signs were not present. Both patients responded well to shunting procedures.

Six patients representing seven cases of spontaneous (nontraumatic) saphenous neuralgia secondary to entrapment of the nerve in the subsartorial canal are presented. All patients complained of medial knee and leg pain. Clinical findings included tenderness over the subsartorial canal and sensory changes in the cutaneous distribution of one or both terminal branches of the saphenous nerve. The diagnosis was confirmed by saphenous nerve block in all cases. All patients were treated operatively, which resulted in symptomatic improvement. All six patients initially underwent external neurolysis; however, three patients required saphenous neurectomy for recurrent symptoms. Saphenous neuralgia should be considered in the differential diagnosis of medial lower extremity pain.

It is now recognized that integrative central nervous system function involves not only electrophysiological phenomena and chemical neurotransmission, but also interaction between brain and endocrine hormones. With the recent upsurge in interest in “peptidergic” neurons, it has become evident that many hypothalamic and pituitary peptides occur in brain outside the boundaries of the hypothalamo-pituitary axis. Anterior and posterior pituitary peptides, hitherto characterized as “peripheral hormones,” have now been identified in cerebrospinal fluid (CSF). This Chapter reviews our current knowledge about the occurrence of the antidiuretic hormone, arginine vasopressin (AVP), and the closely related nonapeptide hormone, arginine vasotocin (AVT), in human CSF.

Data were obtained prospectively for 7,912 head-injured patients admitted from 1980 to 1981 to 41 hospitals in 3 U.S. metropolitan areas. Highly significant independent predictors of mortality were motor score, number of reactive eyes, systolic blood pressure, abdominal injury, chest injury, age, and hospital unit (hospital or group of hospitals). The difference between the number of deaths observed and the number expected, by hospital unit, ranged from 43% below expectation to 52% above expectation. The 2 hospital units with the lowest mortality had only 1 death, where 9.4 would be expected, in patients whose risk of death was estimated to be less than 10%. In the single hospital with clearly excess mortality, however, the standardized mortality ratios were 208, 135, and 144% for the risk groups whose probabilities of death were 0 to 50, 50 to 80, and 80 to 100%, respectively. The lack of deaths in those hospitals with the best mortality experience and the excess mortality in the hospital with the worst mortality experience appear to be explained largely by differences in patients who, by clinical criteria, seem to be at low risk for death, and not by severely injured patients.

The identification of absent or compressed basal cisterns on CT scans obtained after closed head injury has been shown to be related both to mortality and to the subequent development of elevated intracranial pressure (Murphy et al. 1983, van Dongen et al. 1983, Toutant et al. 1984). One of these studies (Toutant et al. 1984) was performed using data acquired from the pilot phase of the Traumatic Coma Data Bank. Recently, the main phase of this study has been completed and the data is undergoing initial analyses. We felt it would be of interest to compare the relationship of the findings of absent or compressed cisterns on initial CT scans to outcome in this larger group of patients and hypothesized that the information gained from the pilot study suggesting that recognition and aggressive management of patients with this radiographic finding would result in improved outcome.

Ninety-eight brain contusions in 17 patients served as a data base for a comparative study of MR and CT for defining brain contusions. MR was the more sensitive technique, detecting 98% of the brain contusions compared with only 56% by CT. CT was slightly better for showing hemorrhagic components, documenting 77% of hemorrhages compared with 71% for MR. The appearance of the contusions on MR was variable, depending on the T1- and T2-weighting of the images and the constituents of the contusions, such as edema, hemorrhage, and encephalomalacia. On MR, hemorrhagic components appeared as high signal on T1-weighted images and as either low or high signal on T2-weighted images, depending on the age of the hemorrhage. The approximate ages of hemorrhagic contusions were often suggested by their appearance on T1- and T2-weighted images. CT is very effective for evaluating acute head trauma, but MR is recommended for documenting brain contusions during the subacute and chronic stages of head injuries.

✓ A series of 8814 head-injured patients admitted to 41 hospitals in three separate metropolitan areas were prospectively studied. Of these, 1906 patients (21.6%) were 14 years of age or less. This “pediatric population” was compared to the remaining “adult population” for mechanism of injury, admission Glasgow Coma Scale score, motor score, blood pressure, pupillary reactivity, the presence of associated injuries, and the presence of subdural or epidural hematoma. The relationship of each of these factors was then correlated with posttraumatic mortality. Except for patients found to have subdural hematoma and those who were profoundly hypotensive, the pediatric patients exhibited a significantly lower mortality rate compared to the adults, thus confirming this generally held view. This study indicates that age itself, even within the pediatric age range, is a major independent factor affecting the mortality rate in head-injured patients.

This chapter presents a review of the diagnosis and management of posttraumatic ventricular enlargement in the very young child. Although it is well known that ventricular enlargement can occur after head trauma, the etiology of this phenomenon, its therapy, and its prognosis are quite variable. A discussion of this type of hydrocephalus should consider those processes which cause a permanent or transient disruption of normal cerebrospinal fluid (CSF) dynamics as well as those which cause secondary ventricular enlargement as a result of cortical (neuronal) loss. The management of the very young child who develops ventricular enlargement after a head injury must be individualized, giving consideration to the mechanism of the initial injury, the initial clinical findings and radiographic studies, the subsequent clinical course, and the results of follow-up radiographic studies and ancillary tests.

IntroductionGiant invasive spinal schwannoma is defined as a tumor that extends over two or more vertebral levels, erodes vertebral bodies, and extends into the extraspinal space disrupting myofascial planes. Because of its rarity, there have been few published reports describing clinical features and surgical outcomes, especially in the pediatric patient population.Case presentationWe analyzed the medical record, pathologic findings, and radiographic studies of a 14-year-old Hispanic boy who presented to Texas Children’s Hospital with a three-month history of progressive spastic paraparesis. Preoperative computed tomography and magnetic resonance imaging reports showed a large mass lesion centered at the left T7-8 neural foramen with intra- and extraspinal extension, resulting in severe spinal cord compression and vertebral body erosion, and protrusion into the retropleural space and descending aorta. Our patient underwent a single-stage posterior approach for complete resection of the tumor with reconstruction and stabilization of the vertebral column. The pathological examination was consistent with schwannoma. At the six-month follow-up, our patient had resolution of preoperative symptoms and remains neurologically intact without any radiographic evidence of recurrent tumor.ConclusionTo the best of our knowledge, our case represents the fourth child with giant invasive spinal schwannoma reported in the literature. We describe our case and review the literature to discuss the aggregate clinical features, surgical strategies, and operative outcomes for giant invasive spinal schwannoma in the pediatric age group.

Introduction The solid variant of aneurysmal bone cyst is rare, and only 13 cases involving the spine have been reported to date, including seven in the thoracic vertebrae. The diagnosis is difficult to secure radiographically before biopsy or surgery. Case report An 18-year-old Hispanic man presented to our facility with a one-year history of left chest pain without any significant neurological deficits. An MRI scan demonstrated a 6 cm diameter enhancing multi-cystic mass centered at the T6 vertebral body with involvement of the left proximal sixth rib and extension into the pleural cavity; the spinal cord was severely compressed with evidence of abnormal T2 signal changes. Our patient was taken to the operating room for a total spondylectomy of T6 with resection of the left sixth rib from a single-stage posterior-only approach. The vertebral column was reconstructed in a 360° manner with an expandable titanium cage and pedicle screw fixation. Histologically, the resected specimen showed predominant solid fibroblastic proliferation, with minor foci of reactive osteoid formation, an area of osteoclastic-like giant cells, and cyst-like areas filled with erythrocytes and focal hemorrhage, consistent with a predominantly solid variant of aneurysmal bone cyst. At 16 months after surgery, our patient remains neurologically intact with resolution of his chest and back pain. Conclusions Because of its rarity, location, and radical treatment approach, we considered this case worthy of reporting. The solid variant of aneurysmal bone cyst is difficult to diagnose radiologically before biopsy or surgery, and we hope to remind other physicians that it should be included in the differential diagnosis of any lytic expansile destructive lesion of the spine.

We compared magnetic resonance imaging (MRI) and CT on 16 children with brainstem gliomas. MRI demonstrated masses of decreased signal intensity, which enlarged and distorted brainstems in all patients with active disease and showed brainstem abnormalities in 21 of 23 studies (91%). In one-half of the patients, MRI showed more extensive disease than did CT. Exophytic portions of tumors were shown well on MRI. MRI was more sensitive than CT in demonstrating disease relapse.