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José L. Montes, David B. Clarke and Jean-Pierre Farmer

✓ The authors describe a technique of stereotactic transtentorial hiatus ventriculoperitoneal shunting for the treatment of the sequestered fourth ventricle, used successfully in the care of four patients. They recommend it as a safe, effective treatment of patients suffering from an isolated fourth ventricle.

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Meningeal melanocytoma of the planum sphenoidale

Case report and review of the literature

Michael Chow, David B. Clarke, William J. Maloney and Virgilio Sangalang

✓ Meningeal melanocytoma is a rare benign primary melanotic tumor of the meninges, most commonly found in the spinal canal and the posterior fossa. The authors report the 19th published case of a supratentorial meningeal melanocytoma and the first reported case in which the tumor arose from the planum sphenoidale. The patient's presenting symptoms were characteristic of a large bifrontal lesion and included headaches, personality change, lethargy, and urinary and fecal incontinence. Computerized tomography and magnetic resonance imaging studies revealed an extraaxial lesion arising from the planum sphenoidale. The patient underwent successful gross total removal of the tumor without neurological sequelae. Based on the findings shown in this case report, meningeal melanocytoma should be included in the differential diagnosis of extraaxial lesions arising from the area of the planum sphenoidale.

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Hiroaki Manabe, David O. Okonkwo, John L. Gainer, Ryon H. Clarke and Kevin S. Lee

Object

Ischemic injury is a potential complication in a variety of surgical procedures and is a particular impediment to the success of surgeries involving highly vulnerable neural tissue. One approach to limiting this form of injury is to enhance metabolic supply to the affected tissue. Trans-sodium crocetinate (TSC) is a carotenoid compound that has been shown to increase tissue oxygenation by facilitating the diffusivity of small molecules, such as oxygen and glucose. The present study examined the ability of TSC to modify oxygenation in ischemic neural tissue and tested the potential neuroprotective effects of TSC in permanent and temporary models of focal cerebral ischemia.

Methods

Adult male rats (330–370 g) were subjected to either permanent or temporary focal ischemia by simultaneous occlusion of both common carotid arteries and the left middle cerebral artery (3-vessel occlusion [3-VO]). Using the permanent ischemia paradigm, TSC was administered intravenously beginning 10 minutes after the onset of ischemia at 1 of 8 dosages, ranging from 0.023 to 4.580 mg/kg. Cerebral infarct volume was measured 24 hours after the onset of ischemia. The effect of TSC on infarct volume was also tested after temporary (2-hour) ischemia using a dosage of 0.092 mg/kg. In other animals undergoing temporary ischemia, tissue oxygenation was monitored in the ischemic penumbra using a Licox probe.

Results

Administration of TSC reduced infarct volume in a dose-dependent manner in the permanent ischemia model, achieving statistical significance at dosages ranging from 0.046 to 0.229 mg/kg. The most effective dosage of TSC in the permanent ischemia experiment (0.092 mg/kg) was further tested using a temporary (2-hour) ischemia paradigm. Infarct volume was reduced significantly by TSC in this ischemia-reperfusion model as well. Recordings of oxygen levels in the ischemic penumbra of the temporary ischemia model showed that TSC increased tissue oxygenation during vascular occlusion, but reduced the oxygen overshoot (hyperoxygenation) that occurs upon reperfusion.

Conclusions

The novel carotenoid compound TSC exerts a neuroprotective influence against permanent and temporary ischemic injury when administered soon after the onset of ischemia. The protective mechanism of TSC remains to be confirmed; however, the permissive effect of TSC on the diffusivity of small molecules is a plausible mechanism based on the observed increase in tissue oxygenation in the ischemic penumbra. This represents a form of protection based on “metabolic reflow” that can occur under conditions of partial vascular perfusion. It is particularly noteworthy that TSC could conceivably limit the progression of a wide variety of cellular injury mechanisms by blunting the ischemic challenge to the brain.

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Mark A. MacLean, Karim Mukhida, Jai J. S. Shankar, Matthias H. Schmidt and David B. Clarke

Transorbital penetration accounts for one-quarter of the penetrating head injuries (PHIs) in adults and half of those in children. Injuries that traverse (with complete penetration of) the brainstem are often fatal, with survivors rarely seen in clinical practice. Here, the authors describe the case of a 16-year-old male who suffered and recovered from an accidental transorbital PHI traversing the brainstem—the first case of complete neurological recovery following such injury. Neuroimaging captured the trajectory of the initial injury. A delayed-onset carotid cavernous fistula and the subsequent development of internal carotid artery pseudoaneurysms were managed by endovascular embolization.

The authors also review the relevant literature. Sixteen cases of imaging-confirmed PHI traversing the brainstem have been reported, 14 involving the pons and 12 penetrating via the transorbital route. Management and outcome of PHI are informed by object velocity, material, entry point, trajectory, relationship to neurovascular structures, and the presence of a retained foreign body. Trauma resuscitation is followed by a careful neurological examination and appropriate neuroimaging. Ophthalmological examination is performed if transorbital penetration is suspected, as injuries may be occult; the potential for neurovascular complications highlights the value of angiography. The featured case shows that complete recovery is possible following injury that traverses the brainstem.

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Meningeal melanocytoma

Report of a case and a historical comparison

David B. Clarke, Richard Leblanc, Gilles Bertrand, Gilbert R. C. Quartey and G. Jackson Snipes

✓ Meningeal melanocytomas are rare tumors of the central nervous system that are found almost exclusively in the posterior fossa and spinal cord and whose natural history is poorly defined. In this report, the authors review the clinical presentation, radiological appearance, operative findings, and histological features in two cases of meningeal melanocytoma: one cranial and one spinal.

Two women, aged 21 and 30 years, were admitted to the hospital 60 years apart: the first because of progressive paraplegia and the second because of slowly progressive hearing loss. The first patient had an extradural tumor that was treated by laminectomy, subtotal resection, and postoperative radiotherapy in 1936. Her symptoms recurred 16 years later and she underwent reoperation of the residual tumor, which was found to have an intradural component. The authors' patient, who presented 60 years later, underwent plain and enhanced computerized tomography and magnetic resonance imaging that demonstrated a large posterior fossa lesion indicative of either an acoustic neuroma or a meningioma. She underwent posterior fossa decompression but only partial excision of the tumor could be accomplished because vigorous bleeding limited the extent of the resection. Surgery was followed by radiotherapy. The residual tumor enlarged despite these measures and required repeated resection 6 months later. At the second operation the tumor was much less vascular, perhaps reflecting the effects of radiotherapy, and was removed almost entirely. The patient died 6 months later from an anticoagulant-related cerebellar hemorrhage. In both cases the lesions were jet black, and histological examination revealed melanin-containing hypercellular tumors with rare mitotic figures.

Meningeal melanocytomas are being diagnosed with increased frequency in parallel with improvements in neuroimaging and clarification of histological features. Clinical presentation of patients with these tumors typically occurs in their fifth decade and women are affected twice as often as men. The posterior fossa lesions can mimic acoustic neuromas and meningiomas in location and radiological appearance; however, the internal auditory canal is normal. In the spine, meningeal melanocytomas present with the clinical features of myeloradiculopathy. Diagnosis is made intraoperatively from the gross, jet-black appearance of the tumor and from histological examination. Vascularity, size, and location may render complete resection unfeasible. Because of the tumor's propensity to recur, radiotherapy has been recommended but its role remains to be elucidated.

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Ravi Kumar, Ramesh Kumar, Grant W. Mallory, Jeffrey T. Jacob, David J. Daniels, Nicholas M. Wetjen, Andrew B. Foy, Brent R. O’Neill and Michelle J. Clarke

OBJECT

Nonpowder guns, defined as spring- or gas-powered BB or pellet guns, can be dangerous weapons that are often marketed to children. In recent decades, advances in compressed-gas technology have led to a significant increase in the power and muzzle velocity of these weapons. The risk of intracranial injury in children due to nonpowder weapons is poorly documented.

METHODS

A retrospective review was conducted at 3 institutions studying children 16 years or younger who had intracranial injuries secondary to nonpowder guns.

RESULTS

The authors reviewed 14 cases of intracranial injury in children from 3 institutions. Eleven (79%) of the 14 children were injured by BB guns, while 3 (21%) were injured by pellet guns. In 10 (71%) children, the injury was accidental. There was 1 recognized assault, but there were no suicide attempts; in the remaining 3 patients, the intention was indeterminate. There were no mortalities among the patients in this series. Ten (71%) of the children required operative intervention, and 6 (43%) were left with permanent neurological injuries, including epilepsy, cognitive deficits, hydrocephalus, diplopia, visual field cut, and blindness.

CONCLUSIONS

Nonpowder guns are weapons with the ability to penetrate a child’s skull and brain. Awareness should be raised among parents, children, and policy makers as to the risk posed by these weapons.