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Rocco A. Armonda, Jeffrey E. Thomas and Robert H. Rosenwasser

Endovascular surgical technology is in the early stages of evolution. A critical phase of this development has been microcatheter technology, which has permitted sufficiently precise intravascular navigation to safely engage the lumen of the aneurysm itself. Digital subtraction angiography, rapid filming techniques and image acquisition, and simultaneous multiplanar imaging capability are indispensable tools that are constantly being refined in the setting of ever-improving computer technology. The marriage of these different technologies has allowed effective endovascular treatment of difficult-to-access aneurysms in medically compromised patients for whom open microsurgery has inherently higher risks.

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Rocco A. Armonda, Jeffrey E. Thomas and Robert H. Rosenwasser

The authors present the unique experience of one neurovascular service under the direct supervision of the senior author, for which surgical, endovascular, and intensive care treatments were conducted in a select group of 32 patients with aneurysmal subarachnoid hemorrhage who had medically intractable symptomatic vasospasm.

A protocol of early and aggressive treatment was instituted using pentobarbital coma, cerebral angioplasty, and intracranial pressure (ICP) reduction. The patient population consisted of 25 women and seven men, whose ages ranged from 34 to 60 years (average 47 years). The patients' Hunt and Hess grades on presentation were as follows: Grade 0 (one); Grade I (three); Grade II (two); Grade III (nine); Grade IV (10); Grade V (seven). Microsurgical clipping alone was performed in 15 of 32 patients, endosaccular occlusion was performed in 17 of 20 patients, and two patients underwent combined treatment. Subsequent angioplasty was performed in 26 of 32 patients. Additionally, all 32 patients underwent treatment of increased ICP with ventriculostomy placement, removal of the bone flap (11), evacuation of associated intracranial hematoma (five), and decompressive obectomy (four).

Twenty-one patients survived and 11 died. Of the 21 survivors, seven have returned to work, live independently, and have no neurological deficits; eight require minimal assistance at home; four are in rehabilitation with moderate deficits at 3 months; and two remain in a persistent vegetative state.

In this group of aggressively treated patients who received pentobarbital cerebral protection, successful treatment of medically intractable cerebral vasospasm was related to time of treatment (< 2 hours), expeditious reduction of elevated ICP, and angioplasty.

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Robert H. Rosenwasser, Laurence I. Kleiner, Joseph P. Krzeminski and William A. Buchheit

✓ Direct therapeutic drainage and intracranial pressure monitoring from the posterior fossa has never been accepted in neurosurgical practice. Potential complications including cerebrospinal fluid leak, cranial nerve palsies, and brain-stem irritation have been a major deterrent. The authors placed a catheter for pressure monitoring in the posterior fossa of 20 patients in the course of posterior fossa surgery: 14 patients with acoustic schwannomas, four with posterior fossa meningiomas, one with cerebellar hemangioblastoma, and one with a solitary cerebellar metastatic lesion. A Richmond bolt was also placed in the frontal area.

Continuous monitoring of the supratentorial and infratentorial compartments was performed for 48 hours. During the first 12 hours the posterior fossa pressure was 50% greater than that of the supratentorial space in all patients (p < 0.01). Over the next 12 hours the supratentorial pressure was 10% to 15% higher than the posterior fossa pressures in all patients, and by 48 hours of monitoring the pressures had equilibrated. There was no mortality or morbidity referable to insertion of the posterior fossa catheter.

The conclusions drawn from this study are that: 1) direct monitoring and drainage of the posterior fossa is safe and effective; and 2) within the early postoperative period, the supratentorial pressures failed to reflect what is taking place within the posterior fossa. The implications and advantages of direct posterior fossa monitoring in the postoperative patient are discussed.

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Phillip E. Vinall, Michael S. Kramer, Lynn A. Heinel and Robert H. Rosenwasser

Object. Experimental rat models are often used to study cerebral ischemia, yet rats are nocturnal animals that have activity cycles that are the opposite of those of humans. In the following study the authors examined the circadian rhythm of sensitivity to an ischemic insult in rats by using an intraluminal thread technique to produce reversible middle cerebral artery occlusion.

Methods. Ischemia (2 hours of blockage followed by 22 hours of reperfusion) was induced in rats according to the 24-hour clock at either 100, 400, 700, 1000, 1300, 1600, 1900, or 2200 hours (11–14 rats per time period). The rat brains were removed, coronally sectioned, stained with 2,3,5-triphenyltetrazolium chloride and analyzed using commercially available software. Analysis of variance and cosinor-rhythmometry statistical tests were used for analysis of data. The time of day when the ischemic infarct was induced had a significant (p = 0.011) influence on the volume of the lesion. The volume of total brain infarct produced at 400 hours (7.65 ± 1.31%) was more than three times greater than the volume produced at 1600 hours (2.1 ± 0.34%). Cosinor-rhythm analysis indicated a peak occurrence of infarct volume at 6:02 (95% confidence interval 5:49–6:16). The size of the infarct correlated with core body temperature rhythms, which varied by 1.3 ± 0.62°C (mean ± standard deviation).

Conclusions. Circadian rhythms, as well as the reversed natural body rhythms of the rat compared with humans, should be considered when extrapolating data to human or other animal studies. Temporal rhythms may also provide information concerning the cascading disease processes associated with cerebral ischemia.

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Edison P. Valle-Giler, Elias Atallah, Stavropoula Tjoumakaris, Robert H. Rosenwasser and Pascal Jabbour

The Pipeline embolization device (PED) has become a very important tool in the treatment of nonruptured cerebral aneurysms. However, a patient’s difficult anatomy or vascular stenosis may affect the device delivery. The purpose of this article was to describe an alternate technique for PED deployment when ipsilateral anatomy is not amenable for catheter navigation.

A 44-year-old woman with a symptomatic 6-mm right superior hypophyseal artery aneurysm and a known history of right internal carotid artery dissection presented for PED treatment of her aneurysm. An angiogram showed persistence of the arterial dissection with luminal stenosis after 6 months of dual antiplatelet treatment. The contralateral internal carotid artery was catheterized and the PED was deployed via a transcirculation approach, using the anterior communicating artery. Transcirculation deployment of a PED is a viable option when ipsilateral anatomy is difficult or contraindicated for this treatment.

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Badih Daou, Petra Klinge, Stavropoula Tjoumakaris, Robert H. Rosenwasser and Pascal Jabbour

OBJECTIVE

There are several etiologies that can lead to the development of secondary normal pressure hydrocephalus (sNPH). The aim of this study was to evaluate the etiology, diagnosis, treatment, and outcome in patients with sNPH and to highlight important differences between the separate etiologies.

METHODS

A comprehensive review of the literature was performed to identify studies conducted between 1965 and 2015 that included data regarding the etiology, treatment, diagnosis, and outcome in patients with sNPH. Sixty-four studies with a total of 1309 patients were included. The inclusion criteria of this study were articles that were written in English, included more than 2 patients with the diagnosis of sNPH, and contained data regarding the etiology, diagnosis, treatment, or outcome of NPH. The most common assessment of clinical improvement was based on the Stein and Langfitt grading scale or equivalent improvement on other alternative ordinal grading scales.

RESULTS

The main etiologies of sNPH were subarachnoid hemorrhage (SAH) in 46.5%, head trauma in 29%, intracranial malignancies in 6.2%, meningoencephalitis in 5%, and cerebrovascular disease in 4.5% of patients. In 71.9% of patients the sNPH was treated with ventriculoperitoneal shunt placement, and 24.4% had placement of a ventriculoatrial shunt. Clinical improvement after shunt placement was reported in 74.4% and excellent clinical improvement in 58% of patients with sNPH. The mean follow-up period after shunt placement was 13 months. Improvement was seen in 84.2% of patients with SAH, 83% of patients with head trauma, 86.4% of patients with brain tumors, 75% of patients with meningoencephalitis, and 64.7% of patients with NPH secondary to stroke.

CONCLUSIONS

Secondary NPH encompasses a diverse group of clinical manifestations associated with a subset of patients with acquired hydrocephalus. The most common etiologies of sNPH include SAH and traumatic brain injury. Secondary NPH does indeed exist, and should be differentiated from idiopathic NPH based on outcome and on clinical, pathophysiological, and epidemiological characteristics, but should not be considered as a separate entity.

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Ronald P. Benitez, Rocco A. Armonda, James Harrop, Jeffrey E. Thomas and Robert H. Rosenwasser

Carotid endarterectomy for atherosclerotic occlusive disease has become the standard of care for the treatment of symptomatic and asymptomatic occlusive disease of the carotid bifurcation, based on the results of the North American Symptomatic Carotid Endarterectomy Trial, as well as the Asymptomatic Carotid Atherosclerosis Study. For surgical treatment to be of benefit, the perioperative complication rate for neurological events should be 6% or less in the symptomatic population and 3% or less in the asymptomatic group. The performance of carotid endarterectomy for recurrent stenosis and radiation-induced stenosis has reported neurological events ranging from 4 to 10%. It is in this particular population that carotid angioplasty and stent placement may play a role.

The authors performed a retrospective analysis of 11 patients who underwent carotid angioplasty and stent placement for recurrent or radiation-induced stenosis. One patient in whom endarterectomy was performed by the vascular surgery service had a critical stenosis distal to the endarterectomy site and awoke with a neurological deficit. This patient underwent reexploration and placement of a stent in the artery distal to the arteriotomy site.

The follow-up period ranged from 7 to 12 months. Patient age ranged from 65 to 77 years (mean 75 years). Five of eight patients underwent angioplasty and stent placement for recurrent atherosclerotic disease. Two patients had radiation-induced stenosis, and one patient had a stent placed intraoperatively. All patients, with the exception of the one who underwent intraoperative stent placement, had posttreatment stenoses of less than 15%. The surgical patient had a 30% residual stenosis distally. There were no intra- or postoperative transient ischemic attacks, major or minor strokes, or deaths.

Patients who have recurrent or radiation-induced stenosis are potential candidates for angioplasty and stent placement. Before this can be recommended as an alternative to surgical correction, a longer follow-up period is required.

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Robert H. Rosenwasser

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Adam S. Arthur, Philipp Taussky, Min S. Park, Michael F. Stiefel and Robert H. Rosenwasser