Transcranial Doppler analysis of cerebral hemodynamics in primary craniosynostosis: study in progress.

BACKGROUND: Regional elevations in intracranial pressure (ICP) have been monitored adjacent to areas of cranial stenosis by some authors [9,19,20]; however, noninvasive techniques such as transcranial Doppler (TCD) would be preferable if increased ICP could be detected just as reliably. METHODS: TCD examinations of basal cerebral arteries were performed in 31 children with skull deformities. Skull X rays and computed tomography (CT) scans or magnetic resonance imaging (MRI) were analyzed for degree of cranial vault abnormality, as well as for presence or absence of intracranial pathology. Neurodevelopmental examination and clinical signs of increased ICP, if any, were recorded. RESULTS: The overall incidence of increased resistivity indices (RI) was 70%. Patients with asymmetric skull deformities (plagiocephaly) or sagittal synostosis (scaphocephaly) were statistically more prone to exhibit increased RI compared to previously reported prevalences. CONCLUSIONS: Because TCD is a convenient, rapid, accurate, and noninvasive method by which to gauge ICP, it should be considered in the preliminary work-up of a patient with craniosynostosis.

Correlation of intracranial pressure and transcranial Doppler resistive index after head trauma.

PURPOSE: To investigate the usefulness of transcranial Doppler ultrasonography in the evaluation of intracranial pressure changes after head injury. METHODS: Transcranial Doppler examinations and intracranial pressure measurements using intraparenchymal monitors were performed in 12 cases of closed head injury. Twenty-four sets of data, including the Glasgow Coma Scale, intracranial pressure, transcranial Doppler, and carbon dioxide pressure were compared. The side-to-side difference in the resistivity index was also assessed. RESULTS: There was a significant correlation between increased pressure values and resistivity index when comparing measurements from the same side. There was no correlation between carbon dioxide pressure and any transcranial Doppler parameter or intracranial pressure measurement. No significant correlation was found between the resistivity index and the Glasgow Coma Scale. End diastolic velocity was a stronger determinant of resistivity index than peak systolic velocity. CONCLUSION: The relationship of ipsilateral measurements of intracranial pressure to resistivity index is valid. The resistivity index must be analyzed within the context of the particular disease studied, especially with respect to the hemodynamic alterations. Initial findings suggest that intracranial pressure monitoring cannot be replaced by serial transcranial Doppler measurements in the treatment of the patient with acute head injury.

Variation of the magnetic relaxation rate 1/T1 of water protons with magnetic field strength (NMRD profile) of untreated, non-calcified, human astrocytomas: correlation with histology and solids content.

The magnetic relaxation rate 1/T1 of tissue water protons was measured over a wide range of magnetic field strengths (NMRD profile) for 92 fresh surgical specimens of astrocytomas to search for correlations of 1/T1 with tumor histology, as determined by light microscopy, and to assess the diagnostic potential of NMRD profiles for grading astrocytomas. A third goal was to elucidate the molecular determinants of 1/T1. Each specimen was histologically graded and inspected for evidence of mineral deposits (Ca, Fe); its dry weight was determined and expressed in % of original wet weight. To minimize variability not directly related to tumor grade, this initial report is limited to NMRD profiles of 47 non-calcified, non-hemorrhagic, untreated astrocytomas. For these, the mean value of 1/T1 at very low magnetic field strengths was found to increase with increasing grade of malignancy; no clear correlation could be demonstrated at high fields where most imaging is done. The spread of 1/T1 for different grades of malignancy is large, however, and the overlap significant, even at the lowest field, so that astrocytomas can not be graded by NMRD profiles alone. Average 1/T1 and average dry weight increase with grade of malignancy; but the variability of 1/T1 among specimens of the same dry weight is large, indicating that at least one other cellular parameter, not variable in normal tissue, influences 1/T1 strongly. We hypothesize that this parameter reflects changes at the molecular level in size distribution, mobility, or intermolecular interaction of cytoplasmic proteins. Which specific changes are induced by malignant transformation in astrocytomas remains to be investigated.

Cerebral blood flow velocity after head injury: transcranial Doppler evaluation. Work in progress.

To study blood flow velocity (BFV) changes, serial transcranial Doppler ultrasound (US) examinations of basal cerebral arteries were performed in 47 patients with head injury. Computed tomographic (CT) scans obtained at admission were analyzed for the presence of intracranial hemorrhages. Glasgow Coma Scale scores were obtained at admission in 46 patients. The prevalence of posttraumatic increased BFV was 77% (n = 36). Two groups of patients were identified according to the time of onset of increased BFV. They differed with respect to duration and severity of changes, Glasgow Coma Scale score, and evidence of intracranial hemorrhagic lesions. Low Glasgow Coma Scale scores were predictive of increased BFV within 72 hours after injury (P < .001). Patients with hemorrhages were significantly more prone to experience increased BFV within 72 hours (P < .05); 34% of patients who did not have hemorrhage, however, developed increased BFV. Increased BFV after head trauma is not uniformly found and cannot be explained by one pathologic mechanism.

Genitourinary malformations associated with agenesis of the corpus callosum.

Agenesis of the corpus callosum is an infrequent congenital anomaly that occurs in partial or complete forms, and is frequently associated with other craniofacial and skeletal abnormalities. An increased association with genitourinary abnormalities has not been previously defined. We reviewed the records of 22 boys and 11 girls with agenesis of the corpus callosum. Of the patients 18 had complete radiological or necroscopic evaluation and 15 had physical examinations as the sole means of evaluation. Renal anomalies were the most frequent genitourinary abnormalities identified in these children, although ureteral, genital and bladder abnormalities were also encountered. There was an exceptionally high incidence of undescended testes (23%), approximately 20-fold greater than the frequency in the normal population, possibly resulting from hypothalamic insufficiency associated with midline cranial defects. We suggest, therefore, that all patients with agenesis of the corpus callosum should be thoroughly evaluated with bladder and renal ultrasound studies to rule out any genitourinary abnormalities. Male patients with agenesis of the corpus callosum and undescended testes should undergo hypothalamic/pituitary axis testing.

Shunt nephritis. Case report.

The incidence of shunt nephritis has decreased over the past several years due to the increased use of ventriculoperitoneal (VP) shunts rather than the ventriculovascular systems for which this complication was originally reported in 1965. Despite this trend, the syndrome has been reported in cases of VP shunting and, for this reason, merit a renewed look. Shunt nephritis is thought to be secondary to immune complex formation and deposition in the kidney in response to Staphylococcus epidermidis. The diagnostic workup and management of this disease is discussed.

The association of hydrocephalus with intramedullary spinal cord tumors: a series of 25 patients.

171 patients with intramedullary spinal cord tumors were operated on, of which 25 patients (15%), mostly children, developed symptomatic hydrocephalus. Twenty patients (12%) had malignant tumors, with 13 of the 20 cases (63%) complicated by increased intracranial pressure and ventriculomegaly. Of the remaining 151 patients with benign tumors (89%), only 12 (8%) developed symptomatic hydrocephalus. In an effort to understand the relationship between hydrocephalus and intramedullary spinal cord tumor, the authors analyze the level and histology of the neoplasm, as well as its association with spinal cysts. A review of the neurosurgical literature reveals that 34 similar cases of hydrocephalus associated with intramedullary spinal cord tumors have been reported to date. The authors note that the presence of hydrocephalus in patients with malignant intramedullary astrocytomas is associated with a shorter rate of survival than in those patients with high-grade lesions but without hydrocephalus, apparently due to rapid tumor progression. The ventriculomegaly seen with benign spinal cord gliomas has no statistically significant effect upon long-term prognosis.

Cranial surgery in ancient Peru.

Trephination is the oldest known surgical technique. Peru has been recognized as a major source of ancient trephined skulls, many of which date back 2300 years. This presentation reviews from a neurosurgical perspective many of the archaeological studies performed on these skulls. Comparative osteology has shown that almost 70% of patients survived the procedure. The various instruments, hemostatic agents, anesthetics, surgical techniques, and cranioplasties used are reconstructed from the anthropological literature. The possible reasons for the use of trephination are discussed. Analysis of the data leads to the conclusion that, despite their rudimentary knowledge of disease, the ancient Incas must have had some knowledge of anatomy and proper surgical procedure.

Planning ventriculoperitoneal shunts in infants and small children.

A neurosurgeon planning a ventriculoperitoneal shunt in an infant or child must consider the question of how long a shunt to use in order to compensate for linear growth. Ideally, the system should be just long enough to accommodate the child's further development without being any longer than necessary. To approach the problem systematically, we used established criteria for prediction of growth to determining the catheter length required in adulthood. Our aim was to devise a simple 'rule of thumb' method for determining the catheter length necessary for maximal survival of a functioning shunt system.

Hemodynamic analysis of associated extracranial atraumatic vertebral artery aneurysm and arteriovenous fistula. Case report.

A case of atraumatic arteriovenous (AV) fistula of the extracranial vertebral artery associated with an atraumatic aneurysm of the contralateral extracranial vertebral artery is reported. The fistulous lesion was excised after distal and proximal ligation of the vessel. Subsequently, the contralateral aneurysm underwent spontaneous dissolution. Seven cases of extracranial vertebral AV fistulae associated with ipsilateral vertebral artery aneurysms (four traumatic and three as part of vascular dysplastic syndromes) have been reported previously.

Congenital fourth ventricular midline outlet obstruction. Report of two cases.

Obstruction of the foramen of Magendie unrelated to illness or trauma is rare in adults. Two cases of congenital membranous occlusion of the foramen of Magendie in adults are presented. Analysis of the reported cases of fourth ventricular outlet obstruction disclosed only three similar cases.

Subacute cervical spine instability.

A case of delayed onset of C5-6 subluxation after a motor vehicle accident, with normal initial cervical spine roentgenograms and neurological findings consistent with concomitant cerebral trauma, is presented. Damage to the cervical spine was due to fractures of the C-6 body and superior articular facet undetected by routine radiologic studies.

Atraumatic extracranial vertebral artery aneurysm: case report and review of the literature.

A case of atherosclerotic aneurysm of the extracranial vertebral artery in a 31-year-old woman is reported. The lesion was excised after distal and proximal ligation of the vessel. Review of the literature showed that atraumatic extracranial vertebral artery aneurysm unrelated to systemic illness is rare. Analysis of the reported cases of such lesions disclosed only one comparable case in a 73-year-old man.