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Cardiac performance indices during hypervolemic therapy for cerebral vasospasm

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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Reoperative management of intracranial aneurysms

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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Retrolabyrinthine transsigmoid approach to basilar trunk and vertebrobasilar artery junction aneurysms

Technical note

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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Cavernous malformations

Steven L. Giannotta and DanieL L. Barrow

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A review of ocular manifestations in intracranial hypotension

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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Angiographic Occult Vascular Malformations

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Temporary occlusion of the middle cerebral artery in intracranial aneurysm surgery: time limitation and advantage of brain protection

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.

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Cardiac performance enhancement from dobutamine in patients refractory to hypervolemic therapy for cerebral vasospasm

Michael L. Levy, Craig H. Rabb, Vladimir Zelman, and Steven L. Giannotta

✓ The use of the beta-agonist dobutamine in combination with hypervolemic preload enhancement of cardiac performance was analyzed in 23 patients who failed to respond to traditional preload enhancement following aneurysmal subarachnoid hemorrhage. The patients ranged in age from 13 to 82 years, and three had a history of cardiac disease. Each patient underwent placement of a flow-directed balloon-tipped catheter and the following measurements were obtained during hyperdynamic therapy: pulmonary artery wedge pressure, central venous pressure, cardiac index, stroke volume index, total peripheral resistance, and left ventricular stroke work index (LVSWI). Mean baseline cardiac function was found to be within normal limits (LVSWI = 47.6 ± 4.2 gm/min/sq m and cardiac index = 3.30 ± 0.22 liter/min/sq m). After baseline measurements were recorded, 5% albumin was infused at 300 cc/hr and dobutamine was initiated at a rate of 5 to 10 µg/kg/hr. This hyperdynamic therapy with dobutamine in the presence of volume loading resulted in a 52% increase in cardiac index, a 15% increase in LVSWI, and a 21% decrease in total peripheral resistance. The clinical reversal of ischemic symptoms due to subarachnoid hemorrhage was evident in 18 (78%) of the 23 patients.

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Temporary occlusion of the middle cerebral artery in intracranial aneurysm surgery: time limitation and advantage of brain protection

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 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, 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 isoflurane (ISO) group. In the ISO 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 in the ISO group who underwent occlusion lasting 10 minutes or longer suffered an infarction versus five of 23 patients in the IVBP group. 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 a 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 ISO 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 patients with multiple aneurysms need further evaluation before specific recommendations can be made.

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Cranial base approaches to posterior circulation aneurysms

J. Diaz Day, Takanori Fukushima, and Steven L. Giannotta

✓ Aneurysms arising from the posterior circulation, especially when they are large and complex, continue to present a technical challenge. The development of cranial base strategies and principles has added to surgical management options. The authors used one of four cranial base approaches for the treatment of 30 patients with large and/or complex aneurysms arising from the vertebrobasilar circulation. These approaches included the extradural temporopolar, combined petrosal, retrolabyrinthine—transsigmoid, and the extreme-lateral inferior transtubercular exposure. The indications, technique, and results of each approach in this series are discussed, and a management paradigm is suggested for such aneurysms.