Endoscopic management of pediatric brain tumors.
ABSTRACT Primary endoscopic procedures for children with intraventricular brain tumors include endoscopic tumor biopsy and endoscopic tumor removal. The simultaneous treatment of hydrocephalus with endoscopic third ventriculostomy (ETV) or endoscopic septostomy increases the appeal of a minimally invasive endoscopic approach.
Eighty-five patients who underwent endoscopic management of an intraventricular brain tumor were identified from a prospective database. Of these patients, 26 were younger than 21 years of age at the time of diagnosis. The surgical technique, its success rate, and patient outcome were assessed. Illustrative cases are used in this study to detail the procedure of endoscopic tumor biopsy and resection. Endoscopic tumor procedures were successful in 96% of cases (23 of 24 endoscopic tumor biopsy samples and both endoscopic tumor removals). Fourteen simultaneous procedures were performed to treat hydrocephalus successfully. There was no recognized morbidity from the surgical procedures.
Endoscopic surgery in children with intraventricular brain tumors is an effective and safe method for sampling of the lesion and, in select cases, its resection. This minimally invasive technique should be considered in situations in which the patient might thereby avoid a more conventional procedure, given the high rate of success and low morbidity associated with endoscopic management.
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ABSTRACT: Low-rank estimators for higher order statistics are considered in this paper. The bias-variance tradeoff is analyzed for low-rank estimators of higher order statistics using a tensor product formulation for the moments and cumulants. In general, the low-rank estimators have a larger bias and smaller variance than the corresponding full-rank estimator, and the mean-squared error can be significantly smaller. This makes the low-rank estimators extremely useful for signal processing algorithms based on sample estimates of the higher order statistics. The low-rank estimators also offer considerable reductions in the computational complexity of such algorithms. The design of subspaces to optimize the tradeoffs between bias, variance, and computation is discussed, and a noisy input, noisy output system identification problem is used to illustrate the resultsIEEE Transactions on Signal Processing 04/1997; · 2.81 Impact Factor
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ABSTRACT: The successful treatment of children with a primary CNS germ cell tumor can be greatly influenced by the neurosurgeon involved in the diagnostic and therapeutic care of these children. Variability in surgical philosophies no doubt exists due to the relatively infrequent incidence of these tumors, a lack of consensus regarding diagnostic and therapeutic approaches, and the advent of recent surgical innovations. Many of these issues were discussed at the Second International Symposium on Central Nervous System Germ Cell Tumors through presented abstracts and invited presentations. The neurosurgical aspects of these proceedings are summarized here in an effort to present the agreed-upon and debated issues that may confront the pediatric neurosurgeon.Journal of Neurosurgery Pediatrics 08/2010; 6(2):125-30. · 1.63 Impact Factor
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ABSTRACT: In cases of non-communicating hydrocephalus, a combined endoscopic third ventriculostomy (ETV) and tumor biopsy might be necessary. We suggest a computer-assisted planning procedure to perform ETV and biopsy via a single burr hole. In 15 patients with non-communicating hydrocephalus with a mass obstructing the Sylvian aqueduct, an ETV in parallel to targeting the lesion was planned to be performed via a single burr hole. Prior to surgery, a 3D MRI data set was planned to be acquired for computer-assisted planning. The lesion target points were located in the third ventricle or in the lateral ventricle. By defining the optimal entry point as single burr hole, the trajectory was calculated to cause the least amount of tissue shift at the foramen of Monro (FM) or within the hemispheric tissue. The burr hole localization was measured relative to nasion and to midline. The diagnostic yield and the success rate of ETV were evaluated. The optimal entry point for third ventricular lesions was 111 ± 17 mm to the nasion and 16 ± 11 mm to the midline. Tissue shift at the level of FM was 2.4 ± 4 mm. For targeting the floor of the third ventricle in parallel to lesions of the lateral ventricle, the entry point was at 122 ± 11 mm to the nasion and 17 ± 9 mm to the midline. Rate of diagnostic yield was 86.7%. Success rate of ETV at follow-up of 34 ± 19 months was 86.7%. Performing ETV in parallel to target paraventricular lesions causing a hydrocephalus is feasible via a single burr hole by using computer-assisted planning and performing a navigated endoscopic procedure.Child s Nervous System 02/2011; 27(8):1233-41. · 1.24 Impact Factor