Cornelius H. Lam

Comparison between ventriculoatrial and ventriculoperitoneal shunting in the adult population

A comparison is made between ventriculoperitoneal (VP) and ventriculoatrial (VA) shunting in an adult population. Forty-nine patients with VA shunts and 73 with VP shunts, as well as six with a combination of the two, in total 128, were reviewed. Sixty-eight complications were encountered in 168 operations (40.5%). There were two deaths. The infection rate was 2.5%. Distal tube blockage occurred after five out of 109 VP shunt operations (79 patients), while four blockages occurred in 59 VA shunts (55 patients). In addition, six peritoneal catheters escaped from the peritoneal cavity requiring revision. We found the complication rate involving the distal end of the shunt to be similar between the two types, but favour the ventriculoperitoneal shunting because of the ease of placement and the lesser severity of potential complications.

Spinal leptomeningeal metastasis from cerebral glioblastoma. Appearance on magnetic resonance imaging

A case of circumferential leptomeningeal metastasis to the spinal cord from an intracranial glioblastoma multiforme (spinal meningeal gliomatosis) is presented. The clinical, radiographic, and pathological features are described. Spinal magnetic resonance imaging with gadolinium-diethylenetriaminepentaacetic acid accurately demonstrated the spread of disease when compared with autopsy findings. The value of spinal magnetic resonance imaging in patients with symptoms attributable to cerebrospinal fluid metastases is discussed.

Intra-Operative MRI-Guided Approaches to the Pediatric Posterior Fossa Tumors

Introduction: The posterior fossa in a child poses a considerable challenge to the neurosurgeon. MRI-guided surgery allows for real time interaction between imaging and the neurosurgeon, not permitted by frameless stereotaxy, and with higher resolution than ultrasound or CT. Materials and Methods: The University of Minnesota 1.5 T Phillips interventional MRI was used. From 1997 to 2000, nine posterior fossa intraoperative magnet cases out of eleven were pediatric. The mean age was 6.4 years and the median age 7. Seven midline craniotomies were performed, of which three were re-operations. Two were burr hole placements, one for cyst aspiration and P32 instillation, and the other for tumor biopsy. Results: Two tumors were predominantly in the fourth ventricle, four in the cerebellum, two in the brainstem, and one in the prepontine cystern. Four tumors were juvenile pilocytic astrocytomas, two were anaplastic astrocytomas, and one each was ependymoma, craniopharyngioma cyst, and medulloblastoma. Four patients had complete radiologic resection. Two had maximal resections limited by vital structures. P32 instillation and tumor biopsy were done in a single pass. Follow-up ranged from 3 months to 1.4 years. The cyst that was aspirated and had P32 instillation remains absent. The two mortalities were in the patients with medulloblastoma and anaplastic astrocytoma. There were no intra-operative mortalities. The other patient with anaplastic astrocytoma progressed. The remainder had stable imaging. Conclusion: MRI-guided surgery results in improved resection imaging and real-time needle guidance in tumor operations. Its value could lie in low-grade lesions, where maximal resection is most beneficial.

Traumatic aneurysm from shaken baby syndrome: Case report

OBJECTIVE AND IMPORTANCE We present a 6-week-old infant who developed a traumatic aneurysm from clearly documented shaken baby syndrome. Despite the theoretical similarity in the mechanism of such injuries, this is the first aneurysm reported that resulted from such a cause. The infant is also the youngest reported patient to have suffered from a traumatic aneurysm. CLINICAL PRESENTATION Police records documented shaking of the child as well as direct impact on the childs head. Three weeks later, the patient developed an intracerebral hemorrhage, which was revealed by angiography to have resulted from a pericallosal artery aneurysm. TECHNIQUE The aneurysm was totally resected through a porencephalic cyst, which had developed secondary to ischemic injury to the brain. CONCLUSION The temporal course, as well as the location of this traumatic aneurysm, is similar to that in older patients.

A theory on the embryogenesis of oculo-auriculo-vertebral (Goldenhar) syndrome.

Oculo-auriculo-vertebral (OAV) syndrome is made up of anomalies, mainly of first and second branchial arch derivatives. Characteristic features include structural malformations of the external and middle ears, face, and jaw. It has been previously suggested that hemorrhage involving the first and second branchial arches causes hypoplasia and malformation of the face and auricle, but this theory cannot explain the multisystemic and protean manifestations of this disease. The theory set forth describes the cutaneous, facial, vertebral, and systemic anomalies in the OAV spectrum as a result of ectodermal nondisjunction early in development with subsequent mesodermal tethering. A subgroup of OAV may therefore be a disorder of ectodermal nondisjunction involving the otic placode similar to the spectrum of diseases such as occult spinal dysraphism that is associated with the same mechanism in the embryonic neuraxis. This would imply a molecular mechanism involving cell adhesion molecules that unify the two disease processes and explain the multisystem anomalies of the OAV syndrome.

Apolipoprotein E exerts selective and differential control over vitamin E concentrations in different areas of mammalian brain

Apolipoprotein E (apoE) is known to be a risk factor for the incidence of Alzheimers disease (AD). In addition, vitamin E has been reported to have a role in the treatment of AD. We examined the potential interrelationship between vitamin E and apoE in brain. As the first step, we determined the concentrations of α‐tocopherol in selected brain regions of apoE‐deficient mice at different ages. The mice were fed normal rodent chow. All regions of the brain in apoE‐deficient mice contained less α‐tocopherol than control samples at 2.5 months of age, the initial time of study. This trend continued for 9.5 months for most regions except the spinal cord and cerebellum. Tocopherol levels in these latter regions of apoE‐deficient animals increased to control levels during the study. Serum α‐tocopherol and cholesterol levels were high in the apoE‐deficient animals; however, the CNS cholesterol levels were the same in apoE‐deficient and control mice. This suggests that 1) the decline in brain α‐tocopherol in apoE deficiency is not due to overall alterations in lipid metabolism; and 2) the processing of α‐tocopherol in brain follows a separate pathway than that of cholesterol. Subcellular concentrations of α‐tocopherol were unaltered by apoE deficiency indicating that intracellular handling of tocopherol is not affected by apoE. ApoE may be an important protein controlling vitamin E levels in specific brain regions. Further understanding of the interactions between apoE and vitamin E could be important in the appropriate use of vitamin E in AD.

Immortalization and functional characterization of rat arachnoid cell lines

Modeling the behavior of mammalian arachnoid cells is critical to understand hydrocephalus and other brain disorders involving abnormal flow of cerebrospinal fluid, yet relatively little is known about the physiology of arachnoid cells due to lack of a robust three-dimensional model system. Explanted primary cultures have been the only option to study transport across arachnoid cell membranes, but practical limitations of primary culture include slow growth, early senescence, and poor reproducibility. The purpose of this study was to create immortalized rat arachnoid cell lines to permit in vitro study of arachnoid granulations and properties of cerebrospinal fluid (CSF) flow. We established and partially characterized two immortalized cell lines generated from primary rat arachnoid cells, using retroviral gene transfer of SV40 large T antigen (SV40 LTAg) either with or without human telomerase (hTERT). The established cell lines stably express either SV40 LTAg alone, or SV40 LTAg and hTERT, and demonstrate high proliferative rate, contact inhibition at confluence, and stable expression of protein markers characteristic of native arachnoid cells over more than 160 passages.

Nonteratomatous tumors in the pediatric sacral region.

Study Design. Two institutional experiences in nonteratomatous sacral tumors of the child were analyzed retrospectively. Objectives. To examine noncongenital nonteratomatous sacral tumors, which are more common in older infants and, as a group, are rare. Summary of Background Data. Pediatric sacral tumors usually occur in the newborn period, with most of these tumors being sacrococcygeal teratomas. Other common benign congenital tumors of the sacrum include lipomas, dermoids, and epidermoids. Methods. Six patients were found in a 6-year period. Four patients underwent posterior resection of their tumors. One underwent a combined anterior and posterior approach. One patient underwent a posterior resection and will undergo a second stage anterior approach later to allow for chemotherapy and radiation to shrink the intrapelvic portion of the tumor. Results. Ages ranged from 8 to 11 years. Three were males, and three were females. Five of six presented with back pain, three had constipation, and two had gait difficulties. Pathologies were diverse. They included ganglioneuroma (n = 1), myxopapillary ependymoma (n = 2), primitive neuroectodermal tumor (n = 1), aneurysmal bone cyst (n = 1), and Ewing’s sarcoma (n = 1). No progression of disease has occurred in the follow-up period of 1.5 to 7 years (average, 5 years). Radical resection did not result in instability. Conclusions. In contradistinction to adults, in whom chordomas and metastases are the most common primary and secondary tumors, the pediatric group does not have a predominant pathology. Tumors may attain extremely large sizes and may be very vascular. Multiple therapeutic methods may be required, including adjuvant chemotherapy and, possibly, embolization. Because of the wide range of pathologies, prognosis is varied.

Congenital Tumors of the Central Nervous System: The MCH Experience

Introduction: Congenital brain tumors in the younger pediatric population are rare lesions that are histologically distinct from those in the older pediatric population. Malignant histology is common, with persistently poor outcomes despite accessible neuroimaging and evolving adjuvant therapy. There remains scant literature about the natural history of these patients because of rarity and varied institutional experiences. Methods: A retrospective review was performed of congenital brain tumor patients surgically treated at the Montreal Children’s Hospital (MCH) over a 22-year period. Patients presenting in the first year of life were evaluated for demographic information, presenting symptoms, lesion location, and management. Analysis was by median rank test and χ2 statistics. Results: 13 cases of congenital brain tumors were identified: 5 supratentorial and 8 infratentorial. Median age (p = 0.93) and gender (p = 0.57) did not differ by location, and predominant histologies were choroid plexus papilloma and primitive neuroectodermal tumor. Seizure activity was exclusive to supratentorial lesions (40%, p = 0.03), with hypotonia observed only among infratentorial lesions (50%, p = 0.02). There was equal incidence of hydrocephalus (69%, p = 0.57) and increasing head circumference (38%, p = 0.27) by lesion location. Supratentorial lesions were treated by total resection (n = 3), subtotal resection (n = 1), and biopsy (n = 1). Infratentorial lesions were treated by total resection (n = 1), subtotal resection (n = 2), biopsy (n = 1), no operation (n = 2), and decompressive laminectomy for two spinal lesions. Conclusions: Congenital brain tumor patients represent fewer than 2% of patients treated at MCH. An evolving understanding of management objectives for these lesions requires understanding institutional experiences. Patients with supratentorial lesions frequently present with seizures, hydrocephalus, and macrocrania, and more frequently underwent total resection at surgery.

Conservative therapy of atlantoaxial osteomyelitis: A case report

Study Design A rare case of C1‐C2 vertebral osteomyelitis treated conservatively is described. The radiologic findings as well as the follow‐up evaluation are reported. Objective To increase knowledge about the pathogenesis and treatment of vertebral osteomyelitis in the high cervical region. Summary of Background Data This is one of the first cases reported of successful conservative treatment of osteomyelitis at this level. Methods In a 58‐year‐old man with lumbar staphylococcal infection, a subsequent cervical infection developed. Because the lumbar spondylitis was treated promptly, the cervical osteomyelitis was treated at a very early stage of development. Results Operative decompression is the treatment most often used in osteomyelitis at the C1‐C2 level. This is an extremely unusual circumstance in which early treatment of the infection negated the need for surgery. Conclusion Conservative treatment of osteomyelitis at the C1‐C2 level can be efficacious in the correct setting.