Christian W. Sikorski

Learner-Control Effects: A Review of Reviews and a Meta-Analysis

This article concerns the effects of learner control in computer-assisted instruction (CAI). After reviewing previous reviews of research on the topic, twenty-four studies of learner control were subjected to meta-analysis. The results of both the review and meta-analysis are equivocal. Several reviews indicate that learner control works less well with younger, less able students. Other reviews indicate that, given optimal conditions, learner control can work with any students. The meta-analysis, however, yielded an average effect size that was small and negative suggesting that the average student would be slightly better off without it. Although learner control has theoretical appeal, its effects on learning seem neither powerful nor consistent.

Lumbar CSF Shunting Preferentially Drains the Cerebral Subarachnoid over the Ventricular Spaces: Implications for the Treatment of Slit Ventricle Syndrome

Based on a proposed pathophysiology of slit ventricle syndrome (SVS), we have hypothesized that lumboperitoneal shunting exerts effects in SVS patients by increasing the buffering capacity for raised intracranial pressure (ICP) via an increase in cerebrospinal fluid drainage from the cerebral subarachnoid space (SAS). We describe 3 SVS patients with patent lumbar subarachnoid drainage but under-functioning ventriculoperitoneal shunts (VPS) who presented with ventriculomegaly (not SVS), and persistence of shunt malfunction like symptoms. Revision of the VPS resulted in complete resolution of symptoms despite a finding of low pressure in the ventricular space. This supports the hypothesis that lumboperitoneal shunting preferentially drains the SAS over the intraventricular space and in these cases allows the ‘SVS’ ventricles to enlarge by creating a pressure gradient from ventricles to SAS through the cortical mantle.

Immunotherapy for malignant glioma: current approaches and future directions

Abstract Traditional therapies for the treatment of malignant glioma have failed to make appreciable gains regarding patient outcome in the last decade. Therefore, immunotherapeutic approaches have become increasingly popular in the treatment of this cancer. This article reviews general immunology of the central nervous system and the immunobiology of malignant glioma to provide a foundation for understanding the rationale behind current glioma immunotherapies. A review of currently implemented immunological treatments is then provided with special attention paid to the use of vaccines, gene therapy, cytokines, dendritic cells and viruses. Insights into future and developing avenues of glioma immunotherapy, such as novel delivery systems, are also discussed.

Correction of Sagittal Craniosynostosis Using a Novel Parietal Bone Fixation Technique: Results over a 10-Year Period

Isolated sagittal synostosis is a common form of craniosynostosis affecting roughly 1 in 5,000 children at birth. This results in a scaphocephalic head shape with a characteristically elongated anterior-posterior dimension and narrowed biparietal diameter. We present our experience with the correction of scaphocephaly due to sagittal synostosis using cranial vault reconstruction with a novel form of parietal bone fixation in 21 patients over 10 years. The medial fixation results in a hinging effect whereby transverse brain growth at the squamoid suture is enhanced. This results in excellent cosmetic results that are immediate and durable without the need for postoperative molding helmets. Furthermore, the complications associated with this procedure are limited.

Endoscopic, Single-Catheter Treatment of Dandy-Walker Syndrome Hydrocephalus: Technical Case Report and Review of Treatment Options

Optimal treatment for hydrocephalus related to Dandy-Walker syndrome (DWS) remains elusive. Patients with DWS-related hydrocephalus often require combinations of shunting systems to effectively drain both the supratentorial ventricles and posterior fossa cyst. We describe an endoscopic technique, whereby a frontally placed, single-catheter shunting system effectively drained the supratentorial and infratentorial compartments. This reduces the complexity and potential risk associated with the combined shunting systems required by so many with DWS-related hydrocephalus.

Intradural spinal Wilm's tumor metastasis: case report.

OBJECTIVE:Wilms tumor metastasis to the central nervous system (especially the spine) is rare. We present a case of a lumbosacral intradural drop metastasis in a male child with a remote history of intracerebral Wilms tumor metastases. CLINICAL PRESENTATION:A 7-year-old boy with known metastatic Wilms tumor was discovered to have left frontal and parietal metastases. He subsequently underwent craniotomy and gross total resections of those lesions. Four years later, he developed low back pain and lower extremity weakness and was found to have an intradural lumbosacral lesion without intracranial recurrence. INTERVENTION:The patient underwent lumbar laminectomy for resection of the intradural lesion. The tumor was found to be in the subarachnoid space and displaced the nerve roots of the cauda equina to the periphery of the thecal sac. The nerve roots were matted and encased within tumor tissue, thereby limiting the surgery to biopsy only. Postoperatively, the patient received radiation to the lesion. Unfortunately, follow-up imaging 4 months later revealed little tumor regression, and the patients neurological condition did not improve significantly. CONCLUSION:Spinal intradural Wilms tumor metastases are rare. This is the only reported case in the literature of a probable drop metastasis from an intracerebral source. Although the optimal treatment for intra- or extradural Wilms tumor spine metastases is not known, our patient did not make significant neurological improvement with radiation therapy.

Endoscopic Cyst Fenestration Outcomes in Children One Year of Age or Less

The use of endoscopic fenestration (EF) is becoming an increasingly common treatment for symptomatic intracranial cysts. Very little data exist regarding outcomes for this procedure in children 1 year of age or younger. We retrospectively reviewed the clinical outcomes of 8 children 1 year of age or less treated at our institution with endoscopic cyst fenestration. The mean follow-up was roughly 2.5 years. These data were combined with 17 other cases obtained from the published literature. EF was successful in rendering patients shunt-free or minimizing the number of ventricular catheters in 18 of 26 operations. There were 8 outright failures – two in 1 patient. Given the risks and complications of cerebrospinal fluid shunting in children less than 1 year of age, we advocate the consideration of EF as initial treatment of symptomatic intracranial cysts.

Adjustable shunt valve reprogramming at home: safety and feasibility.

OBJECTIVEShunt valve resistance changes using a specialized magnetic programming device permit noninvasive changes to cerebrospinal fluid drainage. In selected cases between 2001 and 2005, patients and families used shunt valve programming devices at home. This study examines the safety and efficacy of this practice. METHODSWe conducted a retrospective review of the medical records of patients who had been given a shunt valve-programming device for home use. A survey was mailed to patients or family members requesting information regarding their experiences with the shunt valve programming device. Patient and family responses were tabulated and a statistical analysis was performed. RESULTSTwenty patients or families returned the survey. The median patient age was 19.6 years (range, 6–48 yr); 25% were male. Seventeen patients had pseudotumor cerebri, one had an arachnoid cyst, and two had slit ventricle syndrome. Fifteen patients had lumboperitoneal shunts, one had a ventriculoperitoneal shunt, three had cisterna magna shunts, and one had an arachnoid cyst-to-peritoneal shunt. No adverse events were attributable to the use of the home shunt valve programmer. Thirty-five percent of respondents used the programmer at least once every week, 40% used the programmer between once a week and once a month, and 25% used the programmer less frequently than once per month. Overall, 85% of respondents reported that they benefited “very much” from the use of a home shunt valve programmer and 15% of respondents benefited “somewhat.” CONCLUSIONProviding shunt valve programming devices to selected patients for home use is a safe practice associated with high patient satisfaction. However, the selection of appropriate patients, comprehensive patient education, and close patient-physician communication are crucial to the success of this practice.

Role of barbiturate coma in the management of focally induced, severe cerebral edema in children

Barbiturates are widely used in the management of high intracranial pressure (ICP) caused by diffuse brain swelling. The cardiovascular, renal, and immunological side effects of these drugs limit them to last-line therapy. There are few published data regarding the role of barbiturates in focal brain lesions causing refractory elevated ICP and intraoperative brain swelling in the pediatric population. The authors here present 3 cases of nontraumatic, focally induced, refractory intracranial hypertension due to 2 tumors and 1 arteriovenous malformation, in which barbiturate therapy was used successfully to control elevated ICP. They focus on cardiovascular, renal, and immune function during the course of pentobarbital therapy. They also discuss the role of pentobarbital-induced hypothermia. From this short case series, they demonstrate that barbiturates in conjunction with standard medical therapy can be used to safely reduce postoperative refractory intracranial hypertension and intraoperative brain swelling in children with focal brain lesions.

Surgery for low-grade gliomas: current evidence and controversies

Despite decades of studies, the surgical management of cerebral low-grade gliomas remains quite controversial. Recommendations range from observation with biopsy to radical resection. This controversy arises from several factors, chief of which is the lack of prospective, randomized studies specifically addressing the issue of resection. Nevertheless, the available data, with its inherent inadequacies, must be used to help guide the care of these patients. This article reviews the current literature on the role of surgery for these tumors and attempts to put forward reasonable treatment options in an area where even the American Association of Neurological Surgeons can find no standard management to recommend aside from biopsy prior to the onset of therapy.