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Maciej Wozniak, David G. McLone and Anthony J. Raimondi

✓ Microangiotomography was used to identify the normal and pathological pattern of cerebral vessels in the hy-3 murine mutant mouse (normal and hydrocephalic) at various developmental stages from birth through 21 days of life. The technique employed allows resolution, in the range of 7 to 10 µ of the surface and in-traparenchymal (perforating) microvasculature. Ventricular enlargement causes displacement of primary cerebral arteries, followed by both stretching and a decrease in the caliber of primary, secondary, and tertiary vessels (arterial and venous). Ultimately, there is a reduction in the number and caliber of the microvasculature, resulting in diminished cerebral blood flow and cerebral edema. Tissue destruction leading to ependymal rupture, parenchymal cavitation, and the formation of porencephalic cysts within the edematous parenchyma ensues.

External ventricular drainage, by decompressing the ventricles, resulted in rapid restoration of the filling of the primary and secondary vessels, thereby suggesting the primary role of vascular changes in the production of brain damage. This study offers experimental evidence that early diversion of the cerebrospinal fluid interrupts this chain of events in congenital murine hydrocephalus.

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Anthony J. Raimondi, Sandra J. Clark and David G. McLone

✓ In a study of congenital hydrocephalus in the murine mutant (hy-3/hy-3), the authors found that aqueductal stenosis develops during the progression of hydrocephalus. In Stage 1 hydrocephalus (ventricular dilation and open aqueduct), a block in the subarachnoid space over the cerebral convexities causes the lateral and third ventricles to enlarge. The ependyma becomes stretched and a collection of edematous fluid forms in the subependymal layer. In Stage 2 hydrocephalus (edema in white matter around lateral ventricles and compression of quadrigeminal plate), edema develops peripheral to ependyma in the aqueduct and compresses the lateral surfaces of the aqueductal wall to obstruct the lumen. While periaqueductal edema is spreading, the forces of the expanding midline structures and the cystic occipital horns alter the relationship of brain structures. There is no proliferation of glia, but, rather, a “simple stenosis” which results from a combination of ventricular dilation, cerebral edema, brain shift, brain-stem compression, and brain-stem edema. In this study, normal ependymal specializations were observed that indicate a more active functional role for aqueductal ependyma than previously recognized.

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David G. McLone

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Tadanori Tomita and David G. McLone

✓ This review concerns 22 children who were treated from 1980 through 1983 for medulloblastoma in the posterior fossa. Treatment included attempts at radical resection of the tumor and postoperative craniospinal radiation therapy, with 5000 to 5500 rads directed to the posterior fossa and 2500 rads to the remaining craniospinal axis. This lower radiation dose to the neuraxis was used to avoid late adverse effects upon the growing central nervous system of the children. Gross confirmation of total resection was obtained in 13 patients (the “total resection group”); however, nine patients had a subtotal resection leaving a small portion of the tumor extending into the cerebellar peduncles or the cerebellopontine angle, or else encasing the posterior inferior cerebellar artery (the “subtotal resection group”). Six patients in the total resection group demonstrated tumor extension into the cerebellar peduncles, which was removed by means of a surgical carbon dioxide laser without neurological sequelae. Biopsy of the arachnoid membrane from the cisterna magna and cytological examination of the cerebrospinal fluid (CSF) prior to manipulation of the tumor werecarried out in 12 patients. All but one showed dissemination of medulloblastoma cells. Myelography and CSF cytological study were undertaken 2 months after radiation therapy in 12 patients and were positive in two. There were no case mortalities in the total resection group during the 24- to 67-month follow-up period, whereas the 1-year survival rate in the “subtotal resection group” was only 44.4%. This study suggests that medulloblastoma can be controlled with a low radiation dose to the neuraxis, should a grossly confirmed total resection be achieved at craniotomy.

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Tadanori Tomita, David G. McLone and Thomas P. Naidich

✓ A mycotic aneurysm of the intracavernous portion of the carotid artery produced total ophthalmoplegia in a 2-year-old boy. Serial angiography displayed progressive enlargement of the aneurysm which was successfully treated by carotid ligation. Angiography is mandatory to rule out carotid artery complications secondary to cavernous sinus thrombophlebitis.

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David G. McLone

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Theodore W. Eller, Lawrence P. Bernstein, Richard S. Rosenberg and David G. McLone

✓ A case of congenital tethered cervical spinal cord is presented in a young adult. Metrizamide computerized tomography was the most useful imaging technique for identifying the tethered spinal cord. Intraoperative somatosensory evoked potentials correlated well with clinical improvement following surgery.

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John R. Ruge, Leonard J. Cerullo and David G. McLone

✓ The authors present two cases of pneumocephalus occurring in patients with permanent shunts and review nine previously reported cases. Mental status changes and headache are the most common presenting symptoms. Six of the 11 cases of pneumocephalus occurred in patients with shunt placement for hydrocephalus secondary to aqueductal stenosis. In these patients, thinned cerebrospinal fluid barriers secondary to longstanding increased intracranial pressure may predispose them to pneumocephalus. Temporary extraventricular drainage is an effective method of treatment in this group of patients. Two other etiologies are identified with significance to treatment, and the role of craniotomy is discussed.

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John R. Ruge, Grant P. Sinson, David G. McLone and Leonard J. Cerullo

✓ Maturity of the spine and spine-supporting structures is an important variable distinguishing spinal cord injuries in children from those in adults. Cinical data are presented from 71 children aged 12 years or younger who constituted 2.7% of 2598 spinal cord-injured patients admitted to the authors' institutions from June, 1972, to June, 1986. The 47 children with traumatic spinal cord injury averaged 6.9 years of age and included 20 girls (43%). The etiology of the pediatric injuries differed from that of adult injuries in that falls were the most common causative factor (38%) followed by automobile-related injuries (20%). Ten children (21.3%) had spinal cord injury without radiographic abnormality (SCIWORA), whereas 27 (57%) had evidence of neurological injury. Complete neurological injury was seen in 19% of all traumatic pediatric spinal cord injuries and in 40% of those with SCIWORA. The most frequent level of spinal injury was C-2 (27%, 15 cases) followed by T-10 (13%, seven cases). Upon statistical examination of the data, a subpopulation of children aged 3 years or younger emerged. These very young children had a significant difference in level of injury, requirement for surgical stability, and sex distribution compared to 4- to 12-year-old children.

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Concezio Di Rocco, David G. McLone, Takeyoshi Shimoji and Anthony J. Raimondi

✓ Continuous 24-hour recordings of intracranial pressure and electroencephalographic activity were made on five hydrocephalic children in whom, in the resting wakefulness state, the intracranial pressure (ICP) was considered normal. An increase in both the mean ICP and its oscillations related to cardiac systole was recorded during slow-wave sleep. Further episodic increases, up to a factor of 7 compared to wakefulness values, occurred during sleep. In three patients it was possible to correlate such episodic increases to the rapid eye movement phases of sleep. The authors discuss these phenomena and their possible implication in the progression of hydrocephalus.