Roberto Spiegelmann and William A. Friedman
✓ Previously reported suboccipital transcerebellar stereotactic biopsy methods, performed with the patient in the prone position, have required general endotracheal anesthesia. A technique is described for performing such biopsies with the patient in the lateral decubitus position, under local anesthesia. Phantom planning and routine computerized tomography graphics allow the selection of a safe entry point and intra-axial trajectory to the lesion. The time required for data acquisition and the operative procedure itself compares well with that of more routine biopsy techniques.
Roberto Spiegelmann, Edgardo Schinder, Mordejai Mintz and Alexander Blakstein
✓ Thirty-three cases of true human tails have been reported in the modern English literature. A new case is described and its radiological and pathological features are presented. A review of the literature and analysis of the pathological characteristics of this interesting lumbosacral stigma indicate that the true human tail is a benign condition not associated with any underlying cord malformation.
Roberto Spiegelmann, Zvi Harry Rappaport and Abraham Sahar
✓ A case is reported of spastic paraparesis due to a thoracic spinal arachnoid cyst. Symptoms occurred about 10 years after craniospinal injury. The histological examination revealed hemosiderin-containing macrophages trapped in the cyst wall. This finding and its possible pathogenetic implications are discussed, and the pertinent literature is reviewed.
Roberto Spiegelmann, Zvi Lidar, Jana Gofman, Dror Alezra, Moshe Hadani and Raphael Pfeffer
Object. The use of radiosurgery in the treatment of acoustic neuromas has increased substantially during the last decade. Most published experience relates to the use of the gamma knife. In this report, the authors review the methods and results of linear accelerator (LINAC) radiosurgery in 44 patients with acoustic neuromas who were treated between 1993 and 1997.
Methods. Computerized tomography scanning was selected as the stereotactic imaging modality for target definition. A single, conformally shaped isocenter was used in the treatment of 40 patients; two or three isocenters were used in four patients who harbored very irregular tumors. The radiation dose directed to the tumor border was the only parameter that changed during the study period: in the first 24 patients who were treated the dose was 15 to 20 Gy, whereas in the last 20 patients the dose was reduced to 11 to 14 Gy. After a mean follow-up period of 32 months (range 12–60 months), 98% of the tumors were controlled. The actuarial hearing preservation rate was 71%. New transient facial neuropathy developed in 24% of the patients and persisted to a mild degree in 8%. Radiation dose correlated significantly with the incidence of cranial neuropathy, particularly in large tumors (≥ 4 cm3).
Conclusions. Single-isocenter LINAC radiosurgery proved to be an effective treatment for acoustic neuromas in this series, with results that were comparable with those reported for gamma knife radiosurgery and multiple isocenters.
Roberto Spiegelmann, William A. Friedman, Frank J. Bova, Daniel P. Theele and J. Parker Mickle
✓ Fifteen cats were irradiated with an animal LINAC (linear accelerator) radiosurgery device. After 6 months, they were studied with gadolinium-enhanced magnetic resonance (MR) imaging, gross pathology after Evans blue perfusion, and histopathology. The lesion size was relatively constant in the cats receiving a dose of 7500, 10,000, 12,500, or 15,000 cGy to the 84% isodose line of a 1-cm collimator. The composition of the lesion correlated with dose: the lower-dose lesions were found histologically to contain areas of edema, demyelination, reactive gliosis, and vascular proliferation; the higher-dose lesions contained increasing amounts of hemorrhage and coagulative necrosis. The borders of the lesions were sharply demarcated from surrounding normal brain. Gadolinium-enhanced MR studies correlated well with areas of blood-brain barrier breakdown, as confirmed by areas of Evans blue staining. This model could serve as the basis for further studies of the biological effects of LINAC radiosurgery.