Two concurrent spinal dural arteriovenous fistulae in a patient with rapidly progressive myelopathy. A case report.

A rare case of two separate spinal dural arteriovenous fistulae (DAVFs) occurring concurrently in a patient with a rapidly progressive myelopathy is reported. Although concurrent spinal DAVFs may be "well known," their occurrence has been only anecdotally reported. To the authors' knowledge, this well documented case of a presumably rare variant of spinal DAVFs is the first to appear in the literature and is instructive for reconsidering approaches to optimal diagnosis and evaluation of posttherapeutic efficacy of these lesions.

Enhanced in vitro uptake and retention of 3H-tetraphenylphosphonium by nervous system tumor cells.

Photodynamic therapy is a promising treatment for human brain tumors because of the selective retention of certain compounds by tumor cells. Certain lipophilic cationic compounds, such as tetraphenylphosphonium (TPP), are selectively taken up by a variety of carcinomas. Although preferential retention of TPP has been demonstrated for the breast carcinoma cell line MCF-7, this compound had not been tested previously on cells derived from nervous system tumors. In the present study, tritiated-TPP (3H-TPP) uptake and retention for eight different cell cultures of three histologically different types of nervous system tumors was measured and the data were compared to a positive control (MCF-7) and negative controls (normal African Green monkey kidney epithelium (CV-1) and the normal human fibroblast (WI-38) cell lines). Uptake and retention characteristics could be grouped by specific pathological tumor types, but individual tumor variability was notable. Malignant astrocytoma (grade III/III glioblastoma) and malignant neurofibrosarcoma cells showed preferential uptake and retention of 3H-TPP relative to meningioma cells and normal controls. A clonogenic assay utilizing the cytotoxic lipophilic cationic compound dequalinium showed strong retainers of 3H-TPP to be more susceptible to the effects of dequalinium than weak retainers. These data demonstrate that certain human and experimental animal nervous system tumor cell lines retain lipophilic compounds possessing a delocalized positive charge. Lipophilic cationic compounds may be useful in the intraoperative delineation of tumor margins and in the photodynamic therapy of certain nervous system tumors.

A new 1.9-mu wavelength laser for neurosurgery.

The 1.9-mu wavelength component of a 1.9/1.06-mu two-wavelength laser with near-continuous wave properties was tested for its potential use in neurosurgery. The 1.9-mu wavelength has tissue-ablative capabilities, while the 1.06-mu wavelength (Nd:YAG) is suitable for achieving hemostasis. The advantages of the 1.9-mu wavelength over the CO2 laser include its ability to transmit through silica fiberoptic delivery systems and its deeper penetration in water (approximately 100 mu, a depth 10 times greater than for the CO2 laser), which is compatible with irrigation during ablation. To test the effectiveness of the laser, bilateral craniotomies were performed in anesthetized rats immobilized in a stereotactic frame. Under an operating microscope, lesions were made on the cortex by delivering the 1.9-mu laser beam through a 400-mu fiber at an average power of 1 W over a range of fluences. Subjective intraoperative observations were notable for minimal bleeding, absence of charring when the tissue was irrigated with a thin stream of saline, and uniform lesion formation. For comparison, lesions were generated with a commercially available continuous-wave CO2 laser at equivalent power and fluences. Histological specimens were divided into three groups based on the study after laser application: acute (30 minutes), subacute (48 hours), and chronic (14 days). The extent of thermal injury for the 1.9-mu laser in the acute lesions was quantitatively and histologically similar to that generated by the CO2 laser. Regions of injury extended approximately from the apex of the lesion, and crater depths generated by both lasers were similar (250 to 750 mu) in the range of fluences investigated (1.25 to 10 kJ/sq cm). Subacute and chronic histological specimens demonstrated inflammatory and repair responses that correlated with the acute injury regions in both the 1.9-mu and CO2 laser-treated specimens. This study demonstrates a neurosurgical potential for a new two-wavelength laser that ablates tissue effectively with limited thermal injury. The 1.9-mu laser is comparable to the widely used CO2 laser but offers several unique advantages, including the ability for delivery through a fiberoptic system and to irrigate tissue during use.

Distribution of hematoporphyrin derivative in canine glioma following intraneoplastic and intraperitoneal injection.

Hematoporphyrin derivative (HPD) is a photosensitizing agent that has been used to locate and kill tumors. The distribution of tritiated (3H)-HPD was studied in a transplantable canine glioma model following intraperitoneal or direct intraneoplastic injection. Compared to intraperitoneal administration of 3H-HPD, direct injection resulted in levels that were more than 2.5 times higher in tumor tissue and approximately 10 times lower in skin. Dose-corrected analysis of the data indicated that outside the central nervous system (CNS) the distribution of 3H-HPD is dose-related, regardless of route of injection. Within the CNS, direct injection leads to more efficient uptake of 3H-HPD, especially at the tumor periphery. Fluorescence microscopy confirmed the selective biodistribution of HPD fluorescence within the cytoplasm of tumor cells.