Object

Advances in endoscopic technology have afforded the neurosurgeon new avenues in the treatment of hydrocephalus, rendering many patients independent of shunts, thus averting shunt complications and failure. Cerebral aqueductoplasty has gained popularity as an effective treatment for membranous and short-segment stenoses of the sylvian aqueduct. Traditionally, this procedure has been performed via a coronal approach, passing through the lateral ventricle, foramen of Monro, and third ventricle into the aqueduct. The authors report on the success of a novel technique for this operation, in which they use a suboccipital foramen magnum trans—fourth ventricle approach.

开云体育世界杯赔率

A retrospective chart review was performed to document the success of cerebral aqueductoplasty procedures via the foramen magnum trans—fourth ventricle approach in patients who had membranous or short-segment stenosis of the cerebral aqueduct. Nine patients underwent 11 cerebral aqueductoplasty procedures. At a mean of 21 months of postoperative follow up, all patients demonstrated resolution of their preoperative symptoms. The only surgical complication was transient vertical diplopia or upgaze weakness in two patients. There was no permanent morbidity. Recurrent aqueductal stenosis developed in one patient twice, requiring the placement of an aqueductal stent via the same approach.

Conclusions

The authors state that in their experience, performing cerebral aqueductoplasty via the foramen magnum trans—fourth ventricle approach is both effective and safe. They advocate the use of this technique, if performed by an experienced neuroendoscopist, for select cases involving membranous or short-segment stenosis of the cerebral aqueduct, a trapped fourth ventricle, or aqueductal stent placement.

Object

Measurements of cerebrospinal fluid (CSF) velocities in the foramen magnum are used to determine the functional significance of Chiari malformation Type I (CM-I). Significantly higher peak velocities are found in adult patients with CM-I than in adult control participants. In addition, it appears that higher CSF velocities are found in pediatric patients with CM-I than in adult patients. Variations in CSF velocities across age groups in healthy individuals, however, have not been systematically studied.

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Phase-contrast magnetic resonance imaging was performed in 10 pediatric patients after induction of anesthesia to evaluate conditions thought not to affect CSF flow in the foramen magnum. The peak systolic and diastolic velocities were plotted with respect to age and compared with velocities obtained in a group of 10 healthy adult volunteers. Differences between the adult and pediatric groups were tested for significance by using the Student t-test.

Peak velocities ranged from 1.9 to 19.9 cm/second in the pediatric group and from 1.2 to 4.5 cm/second in the adults. A trend line fitted to the data showed a decrease in velocity with age in the first two decades of life, and little change thereafter. Differences in the pediatric and adult groups were significant at a level of 0.05.

Conclusions

Peak CSF velocities vary significantly with age. To determine the normalcy of a CSF flow measurement, it must be compared with age-appropriate normative data.

Object

The clinical diagnosis of cerebrospinal fluid (CSF) shunt malfunction can be challenging. In this prospective study, the authors evaluated a common method of interrogating shunts: the shunt tap; specifically, its ability to predict proximal malfunction.

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The authors performed standardized shunt taps in a consecutive series of cases involving children with suspected or proven shunt malfunction, assessing flow and, when possible, opening pressure. Data were collected prospectively, and results analyzed in light of surgical findings.

Results

A shunt tap was performed prior to 68 operative explorations in 51 patients. Of the 68 taps, 28 yielded poor or no CSF flow on aspiration. After 26 of these 28 procedures, proximal catheter obstruction was identified. After 28 taps with good CSF return and normal or low opening pressure, 18 shunts were found to have a proximal obstruction, 8 had no obstruction, and 2 had a distal obstruction. Another 12 taps with good CSF flow had high opening pressure; subsequent surgery showed distal obstruction in 11 of the shunts, and proximal obstruction in 1. The positive predictive value of poor flow was 93%, while good flow on shunt tap predicted adequate proximal catheter function in only 55% of cases.

Conclusions

Poor flow of CSF on shunt tap is highly predictive of obstruction of the proximal catheter. Because not all patients with good flow on shunt tap underwent surgical shunt exploration, the specificity of this test cannot be determined. Nonetheless, a shunt tap that reveals good flow with a normal opening pressure can be misleading, and management of such cases should be based on clinical judgment.