Stephen K. Powers

Use of autogenous cranial bone grafts in maxillofacial surgery: a preliminary report.

In conventional reconstruction of the facial skeleton, bone grafts are usually harvested from distant sites such as the ilium or ribs. Because of the morbidity associated with the use of these sites, the calvarium was studied as an alternate donor site. Twenty-three patients underwent bone grafting using autogenous calvarial bone. Reconstructive procedures included alveolar cleft grafts, Le Fort I osteotomies, midface onlay grafts, and grafting of a mandibular continuity defect. Intraoperative and postoperative morbidity associated with the bone donor site was minimal, and there was good incorporation of all the grafts. Long-term follow up is necessary before definitive conclusions about the response of the grafted bone can be made, but short-term results were promising.

Differential retention of rhodamine 123 by avian sarcoma virus-induced glioma and normal brain tissue of the rat in vivo.

The time course of uptake, retention and clearance of the cationic lipophilic dye, rhodamine 123 (Rh123), within the central nervous system was qualitatively evaluated in rats. Weanling rats were injected intracerebrally with avian sarcoma virus, which induced malignant gliomas in situ before injection of Rh123. Comparison was made of the amount of fluorescence of Rh123 within the normal cerebral cortex, myelinated tracts of the brain, meninges, choroid plexus, and neoplastic foci at 1, 4, 8, 12 and 24 hours after intravenous injection. Fluorescence microscopy was utilized to identify tissues containing the dye. Normal neuropil did not contain Rh123 at any of the time periods studied. Gliomas retained the dye at 1, 4, 8 and 12 hours, with increasing uniformity of distribution and decreasing intensity of fluorescence over this time period. Fluorescence was not detected at 24 hours within the neoplastic tissues, but was evident at all time periods studied within the choroid plexus. The specific retention of Rh123 by malignant glioma and by the choroid plexus in vivo suggests that Rh123 may be useful for photochemotherapeutic treatment of brain neoplasms and disorders of the choroid plexus. Cancer 59:266–270, 1987.

Pseudotumor of the sellar and parasellar areas

A 54-year-old woman who had symptoms of intermittent meningeal irritation and hypopituitarism was found to have a sellar mass histologically consistent with pseudotumor. The lesion appears to have originated in the sphenoid sinus and subsequently to have spread intracranially, causing bony erosion. To our knowledge, this is the first description of pseudotumor occurring as a sellar mass.

Photosensitization of human glioma cells by chalcogenapyrylium dyes

Chalcogenapyrylium (CP) dyes which are specifically activated by red and near infrared light (600–900 nm) were examined as potential photosensitizers for photochemotherapy of malignant gliomas. Eleven CP dyes of varying chemical structure and redox potential were evaluated for selective toxicity against glioma and normal skin fibroblast cell cultures both before and after light activation. Eight of eleven CP dyes exhibited differential toxicity to tumor over fibroblast cells at dye concentrations of 1.0 µM. Dose dependent toxicity was seen both in the dark and after laser light activation. The toxicity of two of the CP dyes was significantly enhanced by photoactivation with 800 nm light.The CP dyes that absorb light maximally between 775 and 850 nm, in the range of excellent light penetration through brain, appear to be promising candidates as photosensitizers for treating malignant brain tumors.

Photodynamic Therapy of Prostate Cancer: An in Vitro Study

The photo-induced toxicity of hematoporphyrin derivative on Dunning R3327 rat prostate cancer cells was studied. Dunning R3327 cells in culture were incubated for two hours in hematoporphyrin derivative and then exposed to red light at 630 nanometers wavelength from an argon pumped dye laser. Cell survival was measured for varying laser power densities, variable concentrations of hematoporphyrin derivative and variable light exposure times. AT1 cells not incubated with hematoporphyrin derivative were directly killed by laser light exposure at power densities greater than 500 mw./cm.2, probably due to hyperthermia. Cells that retained hematoporphyrin derivative were effectively killed using non-thermal levels of red light exposure due to a photochemical effect. Decreasing cell survival of cells that retained hematoporphyrin was related to increasing time of exposure to red light. This form of therapy may be applicable to the treatment of locally invasive prostatic carcinoma in man.

Pain Control with Laser-Produced Dorsal Root Entry Zone Lesions

Pain relief was evaluated in 40 patients with various types of deafferentation pain that were treated with dorsal root entry zone (DREZ) lesions produced with microsurgical lasers. Good long-term pain relief was evident in some paraplegics and in all patients with brachial plexus avulsion. Several other small subgroups of patients benefited from laser DREZ lesions as well. Pain associated with arachnoiditis and peripheral nerve injury or neuropathy did not respond to laser DREZ lesioning. Based upon the smaller lesion dimensions produced with the lasers, it is proposed that interruption of impulses in the tract of Lissauer may be a mechanism of pain control in patients that responded to laser DREZ lesions.

Improved survival from intracavitary photodynamic therapy of rat glioma.

The effectiveness of intratumoral photoradiation in photodynamic therapy (PDT) using a polyporphyrin photosensitizer was studied in the RT‐2 rat glioma model. One week after intracerebral implantation of RT‐2 cells, experimental rats received a single i.p. injection of 2 mg/kg of PhotofrinTM. After administration of the photosensitizer (48 h), the tumors were partially resected and the exposed cavity was irradiated with 15 J of laser light at a wavelength of 630 nm. Further treatment with a large craniectomy significantly enhanced rat survival. Control rats which received no photosensitizer but were treated with surgery, alone or in combination with laser irradiation, succumbed from early tumor recurrence. Photodynamic therapy without decompressive surgery resulted in hemorrhagic infarction of residual tumor and adjacent brain with focal cerebral edema which resulted in cerebral herniation and early death. Our results indicate that photodynamic therapy is effective in treating residual brain tumor but at the expense of brain tissue surrounding the tumor. Unless relieved, intracranial pressure from photodynamic therapy‐associated cerebral edema in this animal model resulted in shortened survival.

THE EFFECT OF A CHALCOGENAPYRYLIUM DYE WITH AND WITHOUT PHOTOLYSIS ON MITOCHONDRIAL FUNCTION IN NORMAL AND TUMOR CELLS

Abstract A chalcogenapyrylium dye 8b, which is under investigation for the photodynamic therapy of malignant gliomas (brain tumors), was evaluated for inhibition of mitochondrial function both before and after exposure to laser light of 800 nm. Neoplastic and normal cells forced to use mitochondrial substrates were killed by the light‐activation of intracellular 8b as well as exposure to classic mitochondrial inhibitors, rotenone and sodium azide. Correspondingly, cells in glucose‐rich media showed little decrease in viability due to the photolysis of intracellular 8b or the presence of mitochondrial toxins. The toxicity of 8b without light activation was found to be the same regardless of the cells energy source. Measurement of cellular ATP generated during treatment also showed the photolysis of intracellular 8b to be more inhibitory towards mitochondrial function than the unactivated parent compound. We conclude that the chalcogenapyrylium dyes localize to the mitochondrion and that photoactivation results in mitochondrial injury.

Successful use of a vascularized intercostal muscle flap to seal a persistent intrapleural cerebrospinal fluid leak in a child

The diagnosis and management of a persistent intrapleural-dural cerebrospinal fluid fistula following excision of a large mediastinal ganglioneuroma with intraspinal extension is reported. Use of a vascularized intercostal muscle flap to close the dural fistula was curative in this 4-year-old patient.

Traumatic laceration of pericallosal artery resulting in interhemispheric subdural hematoma: A case report

Interhemispheric subdural hematoma (IHSDH) usually manifests itself in a delayed fashion after trauma as a slow neurological deterioration with signs of the falx syndrome (paresis or seizures of the lower extremity contralateral to the hematoma). Several etiologies of IHSDH have been described, with tearing of bridging veins being especially associated with trauma. We present the second reported case of IHSDH due to traumatic arterial laceration. This lesion demonstrates a benign and delayed initial presentation. Conservative observation has been employed in the past with mixed results. Patients receiving early definitive surgical treatment have a lower mortality rate then those treated similarly having convexity SDHs. This review of 31 cases discusses the salient aspects of this clinical entity, emphasizing the need for prompt diagnosis and treatment, despite the patients seemingly stable neurological status.