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Anthony C. Wang, Joseph J. Gemmete, Catherine E. Keegan, Cordelie E. Witt, Karin M. Muraszko, Khoi D. Than and Cormac O. Maher

Roberts/SC phocomelia syndrome (RBS) is a rare but distinct genetic disorder with an autosomal recessive inheritance pattern. It has been associated with microcephaly, craniofacial malformation, cavernous hemangioma, encephalocele, and hydrocephalus. There are no previously reported cases of RBS with intracranial aneurysms. The authors report on a patient with a history of RBS who presented with a spontaneous posterior fossa hemorrhage. Multiple small intracranial aneurysms were noted on a preoperative CT angiogram. The patient underwent emergency craniotomy for evacuation of the hemorrhage. A postoperative angiogram confirmed the presence of multiple, distal small intracranial aneurysms.

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Cordelie E. Witt, Anthony C. Wang, Cormac O. Maher, Khoi D. Than, Hugh J. L. Garton and Karin M. Muraszko

In this report, the authors describe the first known case of inducible hemifacial weakness in a patient with Chiari malformation Type I (CM-I). The patient was a 14-year-old girl with a 1-year history of right facial paresis induced by sustained leftward head rotation. These episodes were characterized by weak activation of her right facial muscles with preserved eye opening and closure. Additionally, she had hypernasal speech, persistent headaches, and intermittent left arm twitching. Magnetic resonance imaging demonstrated a CM-I. A suboccipital craniectomy and C-1 laminectomy were performed for decompression of the CM-I, with duraplasty and coagulation of the pial surface of the cerebellar tonsils. At the 9-month follow-up, the patient's inducible hemifacial weakness had completely resolved. Her symptoms were thought to have resulted from the CM-I, perhaps due to traction on the right facial nerve by the ectopic tonsils with head rotation.

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Ik-Seong Park, Joseph R. Meno, Cordelie E. Witt, Abhineet Chowdhary, Thien-Son Nguyen, H. Richard Winn, Al C. Ngai and Gavin W. Britz

Object

Cerebrovascular dysfunction after subarachnoid hemorrhage (SAH) may contribute to ischemia, but little is known about the contribution of intracerebral arterioles. In this study, the authors tested the hypothesis that SAH inhibits the vascular reactivity of intracerebral arterioles and documented the time course of this dysfunction.

Methods

Subarachnoid hemorrhage was induced using an endovascular filament model in halothane-anesthetized male Sprague-Dawley rats. Penetrating intracerebral arterioles were harvested 2, 4, 7, or 14 days postinsult, cannulated using a micropipette system that allowed luminal perfusion and control of luminal pressure, and evaluated for reactivity to vasodilator agents.

Results

Spontaneous tone developed in all pressurized (60 mm Hg) intracerebral arterioles harvested in this study (from 66 rats), with similar results in the sham and SAH groups. Subarachnoid hemorrhage did not affect dilation responses to acidic pH (6.8) but led to a persistent impairment of endothelium-dependent dilation responses to adenosine triphosphate (p < 0.01), as well as a transient attenuation (p < 0.05) of vascular smooth muscle–dependent dilation responses to adenosine, sodium nitroprusside, and 8-Br-cyclic guanosine monophosphate (cGMP). Impairment of NO-mediated dilation was more sustained than adenosine- and 8-Br-cGMP–induced responses (up to 7 days postinsult compared with 2 days). All smooth muscle–dependent responses returned to sham levels by 14 days after SAH.

Conclusions

Subarachnoid hemorrhage led to a persistent impairment of endothelium-dependent dilation and a transient attenuation of vascular smooth muscle–dependent dilation responses to adenosine. Impairment of NOmediated dilation occurred when the response to cGMP was intact, suggesting a change in cGMP levels rather than an alteration in intracellular mechanisms downstream from cGMP.