Intramedullary glioependymal cyst and tethered cord in an infant.

INTRODUCTION: Intramedullary glioependymal cysts are rare congenital lesions of the spinal cord. Their association with another congenital lesion, i.e., tethered cord, is rarer still. RESULTS AND DISCUSSION: We present a case of intramedullary glioependymal cyst with a filar lipoma in an infant. The clinical features, terminology and pathogenesis are discussed. Many varieties of spinal cysts have been described. It is now believed that simple ciliated or goblet-containing intracranial and intraspinal cysts are endodermal rather than glioependymal in origin. The diagnostic criteria, too, have been defined. Although many of these lesions are developmental in origin their association with other congenital anomalies is rare.

A case of malignant tumour of the jugular foramen in a young infant.

Malignant tumours of jugular foramen are very rare in infants. To our knowledge there have been no earlier reports. The case of an infant who had a malignant schwannoma in the region of the jugular foramen is now reported. The difficulties of identifying a particular nerve as the origin of such a tumour are also indicated.

Simulation of cardiac conduction system in distributed computer environment.

A high resolution, three dimensional, computer model of the cardiac conduction system has been developed. Cardiac geometry was constructed from sectional images of VHP project of the National Library of Medicine. The heart was modeled as a matrix of cells that fill its anatomical structure. The intracellular distance was 1 mm and the total number of cells were 457,482. Electrophysiological parameters like action potential, absolute refractory period and conduction velocity were assigned to each of the cells. The pattern of the excitation sequence propagation as well as potentials on the body surface points were computed on a single processor. The working memory and the time for computation of the algorithms were minimized using efficient data structures. The time to compute an excitation sequence over one cardiac cycle was 4 hours. The algorithms were also implemented on a distributed network of personal computers running on a QNX operating system. The speed of computation of the excitation sequence algorithm was improved by a factor of 2.52 when the algorithm was implemented on a network of three Intel-66 MHz machines.

Intraoperative sonography in neurosurgery.

Intraoperative sonography is not employed as often as it should be. This report describes the techniques of intraoperative sonography during craniotomy. The authors have performed this in 15 cases. Details of three cases wherein the lesion was localised easily at operation are given. Surgical excision can be done after this procedure without producing any major deficit.

Mutism following posterior fossa surgery for medulloblastoma.

A case of child who developed mutism following surgery for medulloblastoma is described. Recovery was spontaneous.

Enterogenous cyst of spinal cord : a case report.

A case of spinal cord compression due to an enterogenous cyst is described.

Ventriculoatrial shunting via the azygos vein.

The treatment of hydrocephalus has evolved through many stages but the "cure" is still elusive. It is not unusual for the neurosurgeon to find that the commonly used routes for catheter placement or sites for drainage of cerebrospinal fluid (CSF) cannot be employed. The azygos vein was used to gain access to the right atrium when the CSF could not be drained into the peritoneal cavity, nor could the neck veins be used to place the catheter into the right atrium. The azygos vein is a convenient and safe route to reach the right atrium in selected patients.

Tethered-cord syndrome after repair of meningomyelocele.

The occurrence of tethered-cord syndrome is one of the delayed consequences of the repair of meningo-myelocele. The existing neurological deficit worsens, or a new deficit is superimposed on the existing one. In addition, urological and orthopedic symptoms are also frequently encountered. Although radiological studies may be suggestive of tethering of the cord, not all children are symptomatic. Magnetic resonance imaging is the best radiologic study available. Ultrasonography, although economical and easy to perform, does not yield an optimal image. It appears that a careful periodic clinical evaluation is the best way to evaluate the patients for surgery.

Early surgical management of coronal synostosis.

Craniofacial surgery aims to allow proper expansion of the brain and the creation of an acceptable appearance. Early surgery represents an important means to attain these goals, with the choice of surgical technique being as critical as timing.

Comparative study of suture and laser-assisted anastomoses in rat sciatic nerves.

Conventional suture repair of peripheral nerves results in a fibrotic reaction that is detrimental to nerve regeneration. As an alternative procedure known as "laser-assisted" repair, a laser can be used, along with a reduced number of sutures, to reanastomose served peripheral nerves. To explore the long-term implications of this technique, the right sciatic nerves of Sprague-Dawley rats were surgically cut and reanastomosed either by means of four epineurial sutures or two epineurial sutures and CO2 laser welds. Tensile strength, electrophysiology, histology, and functional studies were performed up to 11 months postoperatively. Tensile strength measurements indicate no long-term disadvantage with the laser-assisted technique, although the short-term tensile strength is lower than with conventional suture repair. The conduction velocities of the repaired nerves were similar for both techniques; however, laser-assisted repaired nerves were found to have lower stimulation thresholds and reduced branching compared to the suture repaired nerves. The measured functional recovery was similar for both repair techniques.

Postradiation meningioma in a child.

Tumors caused by radiation treatment are not unknown. They may be benign or malignant. Among these, postradiation meningiomas (PRM) are considered to be a distinct entity. A case of a child who developed a PRM is presented. She received radiation therapy for a presumed thalamic glioma 11 years earlier. An unusual and interesting aspect of this tumor was its attachment to the membrane of the old subdural hematoma, following a shunting procedure. There was no dural attachment. The pathology of PRMs and meningiomas in children are discussed in light of our recent experience.