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; 45(3-45):673 - 685. DOI:10.1109/78.558484
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ABSTRACT: Endoscopic fenestration has been recognized as an accepted treatment choice for patients with symptomatic arachnoid cysts. The success of this procedure, however, is greatly influenced by individual cyst anatomy and location as well as the endoscopic technique used. This review was conducted to assess what variables influence the treatment success for different categories of arachnoid cysts. Thirty-three consecutive patients who underwent endoscopic fenestration for treatment of an intracranial arachnoid cyst were identified from a prospective database. The surgical indications and techniques were reviewed, and surgical success rates and patient outcomes were assessed. Specific examples of each cyst category are included to illustrate the technical aspects of endoscopic cyst fenestration. Endoscopic fenestration of arachnoid cysts was successful when judged by cyst decompression, and symptom resolution was noted in 32 (97%) of 33 cases. The one patient with short-term treatment failure underwent a successful repetition of the operation. There were no surgery-related morbidities or deaths. Arachnoid cysts are a relatively benign pathological entity that can be managed by performing endoscopically guided cyst wall fenestrations into the ventricular system or cerebrospinal fluid-containing cisterns. Proper patient selection, preoperative planning of endoscope trajectory, use of frameless navigation, and advances in endoscope lens technology and light intensity combine to make this a safe procedure with excellent outcomes.Neurosurgical FOCUS 01/2006; 19(6):E7. DOI:10.3171/foc.2005.19.6.8
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ABSTRACT: Endoscopy is a useful technique for obtaining biopsy samples of intraventricular tumors, and it offers the advantage of simultaneous treatment of obstructive hydrocephalus through endoscopic third ventriculostomy (ETV). Figures in the literature on the diagnostic yield of endoscopic biopsy, its complication rate, and the success rate of ETV in this context vary significantly. The authors performed a retrospective analysis of biopsy accuracy, complication rate, and success rate of ETV in a series of 31 endoscopic biopsy procedures. All data regarding tissue and cerebrospinal fluid sampling, endoscopy-related complications, procedures performed for hydrocephalus treatment, tissue diagnosis, and further management were reviewed. The accuracy of the biopsy findings was graded on a four-level scale: Level I, fully diagnostic; Level II, diagnostic with some reservation; Level III, pathological categorization problematic; and Level IV, not interpretable. Failure of ETV was defined as the need for any further operation for the treatment of hydrocephalus. Tissue diagnosis was graded as Level I or II in 23 cases. One Level I diagnosis differed from the diagnosis made following craniotomy. During the study period one patient underwent endoscopy without biopsy because the tumor could not be visualized. Consequently, the percentage of successful biopsies was 69% (22 of 32 endoscopic procedures). Complications occurred in six cases (19%), of which two (6%) were significant. Three patients (10%) suffered hemorrhagic complications. When combined with biopsy, the ETV procedure was successful in nine (64%) of 14 patients. Endoscopic biopsy of intraventricular tumors is a useful technique for establishing a tissue diagnosis and is associated with an acceptable complication rate. The biopsy does not affect the success rate of simultaneous ETV.Journal of Neurosurgery 06/2007; 106(5 Suppl):340-6. DOI:10.3171/ped.2007.106.5.340