Publications by authors named "W T Koos"

Myelosarcomas are rare, solid extramedullary tumors composed of granulocyte precursors in most cases associated with leukemia. A 38-year-old nonleukemic female presented with a myelosarcoma of the cavernous sinus. After surgical removal of the cavernous sinus tumor she was treated by chemotherapy and whole brain radiation therapy.

View Article and Find Full Text PDF

Although most visual pathway tumors are low-grade gliomas their biologic behavior is highly unpredictable. In order to determine whether assessment of proliferative activity can assist in predicting tumor behavior, we studied the MIB-1 labeling indices (MIB-1 LIs) in surgical specimens and monitored tumor growth in 31 consecutive children operated on between 1978 and 1997. The MIB-1 LIs at diagnosis varied from 0-10.

View Article and Find Full Text PDF

Image-guided surgery is currently considered to be of undisputed value in microsurgical and endoscopical neurosurgery, but one of its major drawbacks is the degradation of accuracy during frameless stereotactic neuronavigation due to brain and/or lesion shift. A computed tomography (CT) scanner system (Philips Tomoscan M) developed for the operating room was connected to a pointer device navigation system for image-guided surgery (Philips EasyGuide system) in order to provide an integrated solution to this problem, and the advantages of this combination were evaluated in 20 cases (15 microsurgical and 5 endoscopic). The integration of the scanner into the operating room setup was successful in all procedures.

View Article and Find Full Text PDF

Detection of anaplastic tumor foci for precise grading of gliomas is crucial for prognostic assessment and appropriate postoperative treatment planning. To avoided undergrading in large suspected low-grade gliomas, we employed frameless sterotaxy during open surgery for tissue sampling of radiologically suspected anaplastic foci. In nine patients (mean age 44 years, range 10-67) with large supratentorial suspected low-grade gliomas (32.

View Article and Find Full Text PDF

From Jan. 1993 to Sept. 1995 23 patients suffering from brain metastases from renal cell carcinoma were treated with the Leksell Gamma Knife at the University of Vienna.

View Article and Find Full Text PDF