Acute subdural hematoma following halo pin tightening in a patient with bilateral vertebral artery dissection.

We report the first case of acute subdural hematoma (SDH) developing after tightening the halo of an osteoporotic 61-year-old woman on warfarin therapy for bilateral traumatic vertebral artery dissection. We discuss literature relevant to this case with an emphasis on identifying warning signs, including recurrent pin loosening, especially in patients with compromised bone structure and high risk of bleeding. Our 61-year-old patient presented to neurosurgery clinic for a 2-month follow-up of a type-III odontoid fracture sustained in a motor vehicle accident. The patient had repeatedly loosened halo pins, and shortly after the pins were tightened, the patient had a syncopal event and struck her head. An emergent computed tomography scan revealed acute SDH requiring emergent craniotomy and evacuation. SDH following pin penetration in a patient with bilateral vertebral artery dissection, osteoporosis, and anticoagulation has not been reported as a complication of the use of the halo vest for stabilization of the cervical spine. The risk of this serious complication can be minimized by giving special consideration to patients with comorbidities and by repositioning problematic pins. This case demonstrates the importance of special attention to bone strength, bleeding risk, and recurrent minor complaints with use of the halo vest.

Growth of human schwannomas in the subrenal capsule of the nude mouse.

To develop a reproducible in vivo model for the growth of human schwannomas we implanted tumor specimens from 14 different patients (13 acoustic neurinomas; 1 trigeminal schwannoma) into the subrenal capsule of 108 nude mice. In 11 experiments, the animals were implanted with only solid tumor from the surgical specimens. In two experiments, the tumor implants were made from solid tumors and cell clusters. In one experiment, the tumor implants were made from cell clusters alone. The size and neovascularization of these tumors were serially determined during a 1.5- to 3-month period. The percentages of tumors that survived or grew were 77.3% from solid tumors and 70% from cell clusters. Maximum tumor volume varied as did the time span to reach that volume. Tumor enlargement and stability correlated well with neovascularity; regressing tumor showed minimal or no neovascularity. Histological analysis of the implanted tumors showed spindle cells that are similar to the original tumor. Immunohistochemical staining for S100 demonstrated the Schwann cell nature of the implants. Analysis of genomic DNA from an acoustic neurinoma that had been implanted for 3 weeks was consistent with its human origin. There were no significant microscopic differences among groups receiving solid tumor implants or cell clusters. These studies suggest that implantation of human schwannomas into the subrenal capsule of the nude mouse is a reproducible method to study tumor growth that may be useful in testing potential therapeutic regimens or genetic modulation of schwannomas.

Implantation of human meningiomas into the subrenal capsule of the nude mouse. A model for studies of tumor growth.

To develop a reproducible in vivo model for the growth of human meningiomas, meningiomas from 16 patients were implanted into the subrenal capsule of the nude mouse. In eight experiments solid tumor implants taken directly from surgical specimens were used, in four experiments the implants were made from early-passage monolayer cell cultures, and in four experiments both techniques were used. Successful tumor growth was observed in 10 (83%) of the 12 solid tumor implants and in six (75%) of the eight implants from cell cultures. The size and neovascularization of these tumors were serially determined over a 3-month period. Tumor doubling occurred in 1 to 3 weeks in all of the solid tumor implant group. In the group of six tumors successfully implanted from cell cultures, three doubled in 1 to 3 weeks and three grew more rapidly, reaching 10 to 20 times their original volume. Neovascularity occurred in the tumors within 3 weeks of implantation. Each of the solid tumor implants had a histological pattern similar to that of the corresponding original specimen. Only three of those implanted from cell cultures were similar to the original tumor; the other three displayed features characteristic of malignant meningioma. These studies suggest that implantation of human meningiomas in the subrenal capsule of the nude mouse is a feasible model that may be useful for evaluating hormonal or genetic modulation of tumor growth and for testing potential treatment regimens.

[Early surgery of intracranial aneurysms]. / Chirurgie précoce des anévrysmes intracraniens.

In spite of scientific progress during the last two decades, microsurgery, neuroanesthesiology, and a better knowledge of the pathophysiology of cerebral vasospasm, the outcome of subarachnoid hemorrhage (S.A.H.) patients remains very poor. Each year, 28,000 North Americans are afflicted. Eighteen thousand of these patients will either die or become severely debilitated, a mortality morbidity of 64%. Only one patient out of five may return to the premorbid state. International cooperative studies report that the highest rate of rebleeding occurs during the first 24 hours post S.A.H. There is no rebound phenomenon during the 7th-8th day post S.A.H. Cerebral vasospasm begins during the 2d-4th day post S.A.H. and reaches its peak around the 8th day post bleed. Antifibrinolytics like AMICAR (aminocaproic acid) do not reduce significantly the rebleeding rate. In most of the cases the therapeutic level of these drugs is reached only on the third or fourth day of treatment. Hence antifibrinolytics are inactive during the first crucial seventy two hours. Antifibrinolytics increase the incidence of vasospasm, hydrocephalus, and thromboembolic phenomenon. At Infant Jesus Hospital, Quebec City, S.A.H. patients are operated on early since more than two years. Patients included in this study were admitted between January 1983 and December 1984. One hundred and thirty six patients were operated upon, 22 patients operated on acutely, less than 72 hours post S.A.H. Evaluation of these patients included the Glasgow Coma Scale (G.C.S.), the grade according to Botterell classification, a CT Scan, and angiography. A preoperative evaluation included Botterell classification and G.C.S., a post operative evaluation was performed during the first and seventh post operative days.(ABSTRACT TRUNCATED AT 250 WORDS)