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Michael L. Levy and Steven L. Giannotta

✓ The effect of hypervolemic preload enhancement on cardiac performance was systematically analyzed in nine patients following aneurysmal subarachnoid hemorrhage. The patients ranged in age from 34 to 63 years, and none had a history of cardiac disease. Each patient underwent placement of a flow-directed balloon-tipped catheter and the following measurements were taken during hypervolemic therapy: pulmonary artery wedge pressure (PAWP), central venous pressure (CVP), cardiac index (CI), stroke volume index (SVI), and left ventricular stroke work index (LVSWI). After baseline measurements were recorded, hetastarch or plasmanate was infused intravenously at 300 cc/hr. Thermal output determination and pressures were measured every 15 minutes. The PAWP did not correlate in a statistically significant fashion with the CVP in the ranges recorded; however, a statistically significant correlation did exist between PAWP increases and increases in CI, SVI, and LVSWI (p < 0.01). There was no statistical correlation between PAWP increases above 14 mm Hg and improvement in cardiac performance as evidenced by CI, SVI, and LVSWI measurements. It is concluded that CVP is an unreliable index of cardiac performance during hypervolemic therapy and that, in previously healthy individuals, a PAWP of 14 mm Hg is associated with maximum cardiac performance.

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Steven L. Giannotta and Dennis R. Maceri

✓ A retrolabyrinthine transsigmoid approach was employed successfully in three patients with vertebrobasilar aneurysms. The major benefits of this technique include a relatively shallow depth of exposure, lack of brain stem retraction, and simplicity as compared to traditional and some recently proposed methods. All three patients have returned to their previous activities.

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Steven L. Giannotta and N. Scott Litofsky

✓ Nineteen patients underwent 20 operative procedures for the treatment of recurrent or residual aneurysms. There were 13 small, three large, and four giant lesions; with one exception, all were in the anterior circulation. Five individuals presented with recurrent subarachnoid hemorrhage, six were referred for symptoms of mass effect, and nine were known to have had inadequate treatment at the time of the initial operative procedure. The average time interval from initial treatment to either recurrent subarachnoid hemorrhage or compressive effects was 10.5 and 9.75 years, respectively.

No deaths resulted from the reoperative procedures. Two patients suffered moderate disability and one had severe disability. Malpositioned or slipped clips, intraoperative rupture, and inadequate exposure were responsible for 75% of the initial operative failures. The technical difficulty of the reoperative procedure correlated with the length of time between initial and reoperative treatment, the presence of clips and coating agents, and the complexity of the lesion. A classification scheme for preoperative planning and case selection is proposed based on the technical adjuncts required for reoperative aneurysm procedures.

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Steven L. Giannotta and DanieL L. Barrow

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Gabriel Zada, Thomas C. Solomon and Steven L. Giannotta

Object

Intracranial hypotension (ICH) can present with a wide variety of visual symptoms and findings. Deficits in visual acuity and visual fields as well as ophthalmoplegia due to cranial nerve dysfunction have been frequently described. The aim of this review was to identify the most commonly reported ocular manifestations associated with ICH.

Methods

The authors conducted a review of the literature to date to identify all studies of patients with ICH and ocular manifestations.

Results

The most commonly encountered cranial nerve deficit resulting from ICH (> 80% of reported cases) is an abducens nerve paresis, which may occur unilaterally or bilaterally. Although less common, oculomotor and trochlear nerve palsies have been reported as well. The optic nerve complex is frequently involved in ICH and may manifest as deficits in visual acuity and field cuts. Visual deficits and ophthalmoplegia improved following appropriate management in 97% of reported cases.

Conclusions

Intracranial hypotension can present with a wide spectrum of visual deficits, the causes of which are multifactorial. Cranial nerve paresis, especially of the abducens nerve, is frequently reported. The majority of symptoms and cranial nerve deficits reviewed respond favorably to conservative management, epidural blood patch administration, or in a minority of cases, surgical intervention.

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John G. Frazee, Steven L. Giannotta and W. Eugene Stern

✓ A primate model of chronic cerebral vasoconstriction is presented which closely approximates the human experience following subarachnoid hemorrhage. Treatment of the vasoconstriction with intravenous nitroglycerin produces a modest, but statistically significant, increase in the size of the most constricted vessels (11%, p < 0.02) when compared with a control infusion of normal saline. The significance of these experiments is discussed.

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Brian Lee, Yvette D. Marquez and Steven L. Giannotta

Lesions of the brainstem pose a technical challenge due to their close proximity to critical vascular structures, neural pathways, and nuclei. Hemangioblastomas are rare lesions of the central nervous system and can cause significant neurological dysfunction, primarily due to enlargement of the cystic component. This is especially relevant when hemangioblastomas occur in eloquent brainstem regions. However, the outcomes after hemangioblastoma resection are good if complete surgical resection of the tumor of the mural nodule, can be achieved. This video demonstrates the excision of a brainstem hemangioblastoma via a left retrosigmoid craniotomy under Stealth guidance.

The video can be found here: http://youtu.be/bCkuaPwMV20.

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Ian A. Buchanan, Brian Lee, Arun P. Amar and Steven L. Giannotta

Abciximab is a glycoprotein IIb/IIIa receptor antagonist that functions to prevent platelet aggregation, thus reducing thrombus initiation and propagation. It has been widely used during percutaneous endovascular interventions, such as aneurysm coil embolization, angioplasty, atherectomy, and stent placement, as both a preventative and a salvage therapy. The use of abciximab in cardiac and neurosurgical procedures has been associated with a reduced incidence of ischemic complications and a decreased need for repeated intervention. In these settings, abciximab has been delivered transarterially via a microcatheter or infused intravenously for systemic administration. The authors describe novel in situ delivery of abciximab as an agent to dissolve “white clots,” which are composed primarily of platelets, during an intracranial superficial temporal artery to middle cerebral artery bypass in a 28-year-old woman with severe intracranial occlusive disease. Abciximab was able to resolve multiple platelet-based clots after unsuccessful attempts with conventional clot dispersal techniques, such as heparinized saline, tissue plasminogen activator, mechanical passage of a wire through the vessel lumen, and multiple takedowns and re-anastomosis. After abciximab was administered, patency was demonstrated intraoperatively using indocyanine green dye and confirmed postoperatively at 1 and 10 months via CT angiography. The in situ use of abciximab as an agent to disperse a thrombus during intracranial bypass surgery is novel and has not previously been described in the literature, and serves as an additional tool during intracranial vessel bypass surgery.

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Sean D. Lavine, Lena S. Masri, Michael L. Levy and Steven L. Giannotta

✓ The risk of focal infarction secondary to the induced reversible arrest of local arterial flow during microsurgical dissection of middle cerebral artery (MCA) aneurysms was evaluated further to define the optimal approach to temporary arterial occlusion. To compare the effectiveness of potential brain-protection anesthetics, a group of patients treated with the intravenous agents propofol, etomidate, and pentobarbital, administered individually or in combination, was compared to a group treated with the inhalational agent isoflurane.

Forty-nine consecutive MCA aneurysm surgeries involving the temporary clipping of the parent vessel were retrospectively reviewed. Thirty-eight patients received intravenous brain-protection (IVBP) anesthesia. Groups of patients with and without infarctions, and receiving and not receiving IVBP anesthesia, were compared based on the duration and nature of temporary arterial occlusion. Postoperative radiographic evidence of new infarction was used as the threshold for failure of occlusion tolerance. The overall infarction rate was 22.4% (11 of 49 patients), including 15.8% (six of 38 patients) in the IVBP group versus 45.5% (five of 11 patients) in the group that did not receive brain protection (NBP). In the NBP group, the mean duration of temporary occlusion was 3.9 ± 2.2 minutes for patients without infarction versus 12.2 ± 4.3 minutes for patients with focal infarction (p < 0.01). In contrast, the mean duration was 13.6 ± 10.6 minutes for patients without infarction and 18.5 ± 9.9 minutes for patients with infarction in the IVBP group. All patients (four of four) in the NBP group who underwent occlusion lasting 10 minutes or longer suffered an infarction versus five of 23 patients in the IVBP group (p < 0.0001). Patients with multiple aneurysms were found to be at increased risk of developing focal infarction, whereas those treated with intermittent temporary clip application were at decreased risk.

It is concluded that patients in whom focal iatrogenic ischemia is induced during MCA aneurysm clip ligation have a significant advantage compared with those receiving isoflurane when they are given pentobarbital as the primary neuroprotective agent or when they receive propofol or etomidate titrated to achieve electroencephalographic burst suppression, particularly if more than 10 minutes of occlusion time is required. It is also concluded that 10 minutes is a general guideline for safe, temporary occlusion of the MCA. The use of intermittent temporary arterial occlusion and its use in patients with multiple aneurysms need further evaluation before specific recommendations can be made.