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Gene H. Barnett, David W. Miller and Joseph Weisenberger

Object. The goal of this study was to develop and assess the use and limitations of performing brain biopsy procedures by using image-guided surgical navigation systems (SNSs; that is, frameless stereotactic systems) with scalp-applied fiducial markers.

Methods. Two hundred eighteen percutaneous brain biopsies were performed in 213 patients by using a frameless stereotactic SNS that operated with either sonic or optical digitizer technology and scalp-applied fiducial markers for the purpose of registering image space with operating room space. Common neurosurgical and stereotactic instrumentation was adapted for use with a localizing wand, and recently developed target and trajectory guidance software was used.

Eight (3.7%) of the 218 biopsy specimens were nondiagnostic; five of these (2.4%) were obtained during procedures in 208 supratentorial lesions and three were obtained during procedures in 10 infratentorial lesions (30%; p < 0.001). Complications related to the biopsy procedure occurred in eight patients (seven of whom had supratentorial lesions and one of whom had an infratentorial lesion, p > 0.25). Five complications were intracerebral hemorrhages (two of which required craniotomy), two were infections, and one was wound breakdown after instillation of intratumoral carmustine following biopsy. There were only three cases of sustained morbidity, and there were two deaths and one delayed deterioration due to disease progression.

Two surgeons performed the majority of the procedures (193 cases). The three surgeons who performed more than 10 biopsies had complication rates lower than 5%, whereas two of the remaining four surgeons had complication rates greater than 10% (p = 0.15).

Twenty-three additional procedures were performed in conjunction with the biopsies: nine brachytherapies; five computer-assisted endoscopies; four cyst aspirations; two instillations of carmustine; two placements of Ommaya reservoirs; and one craniotomy.

Conclusions. Brain biopsy procedures in which guidance is provided by a frameless stereotactic SNS with scalp-applied fiducial markers represents a safe and effective alternative to frame-based stereotactic procedures for supratentorial lesions. There were comparable low rates of morbidity and a high degree of diagnostic success. Strategies for performing posterior fossa biopsies are suggested.

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Brandon A. Miller, Afshin Salehi, David D. Limbrick Jr. and Matthew D. Smyth

OBJECTIVE

The ROSA device is a robotic stereotactic arm that uses a laser system to register the patient’s head or spine with MR or CT images. In this study, the authors analyze their experience with this system in pediatric neurosurgical applications and present selected cases that exemplify the usefulness of this system.

METHODS

The authors reviewed all cases that utilized the ROSA system at their institution. Patient demographics, pathology, complications, electrode placement, laser ablation, and biopsy accuracy were analyzed. Patient disposition and condition at follow-up were also analyzed.

RESULTS

Seventeen patients underwent 23 procedures using the ROSA system. A total of 87 electroencephalography electrodes were placed, with 13% deviating more than 3 mm from target. Six patients underwent stereotactic needle biopsy, and 9 underwent laser interstitial thermotherapy (LITT). One patient who underwent LITT required a subsequent craniotomy for tumor resection. Another patient experienced an asymptomatic extraaxial hematoma that spontaneously resolved. No patient suffered neurological complications during follow-up. Follow-up from the last procedure averaged 180 days in epilepsy patients and 309 days in oncology patients.

CONCLUSIONS

The precision, ease of use, and versatility of the ROSA system make it well suited for pediatric neurosurgical practice. Further work, including long-term analysis of results and cost-effectiveness, will help determine the utility of this system and if its applications can be expanded.

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Nnenna Mbabuike, Kelly Gassie, Benjamin Brown, David A. Miller and Rabih G. Tawk

OBJECTIVE

Tandem occlusions continue to represent a major challenge in patients with acute ischemic stroke (AIS). The anterograde approach with proximal to distal revascularization as well as the retrograde approach with distal to proximal revascularization have been reported without clear consensus or standard guidelines.

METHODS

The authors performed a comprehensive search of the PubMed database for studies including patients with carotid occlusions and tandem distal occlusions treated with endovascular therapy. They reviewed the type of approach employed for endovascular intervention and clinical outcomes reported with emphasis on the revascularization technique. They also present an illustrative case of AIS and concurrent proximal cervical carotid occlusion and distal middle cerebral artery occlusion from their own experience in order to outline the management dilemma for similar cases.

RESULTS

A total of 22 studies were identified, with a total of 790 patients with tandem occlusions in AIS. Eleven studies used the anterograde approach, 3 studies used the retrograde approach, 4 studies used both, and in 4 studies the approach was not specified. In the studies that reported Thrombolysis in Cerebral Infarction (TICI) grades, an average of 79% of patients with tandem occlusions were reported to have an outcome of TICI 2b or better. One study found good clinical outcome in 52.5% of the thrombectomy-first group versus 33.3% in the stent-first group, as measured by the modified Rankin Scale (mRS). No study evaluated the difference in time to reperfusion for the anterograde and retrograde approach and its association with clinical outcome. The patient in the illustrative case had AIS and tandem occlusion of the internal carotid and middle cerebral arteries and underwent distal revascularization using a Solitaire stent retrieval device followed by angioplasty and stent treatment of the proximal cervical carotid occlusion. The revascularization was graded as TICI 2b; the postintervention National Institutes of Health Stroke Scale (NIHSS) score was 17, and the discharge NIHSS score was 7. The admitting, postoperative, and 30-day mRS scores were 5, 1, and 1, respectively.

CONCLUSIONS

In stroke patients with tandem occlusions, distal to proximal revascularization represents a reasonable treatment approach and may offer the advantage of decreased time to reperfusion, which is associated with better functional outcome. Further studies are warranted to determine the best techniques in endovascular therapy to use in this subset of patients in order to improve clinical outcome.

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Robert L. Martuza, Douglas C. Miller and David T. MacLaughlin

✓ Frozen tissue samples were obtained from meningiomas in 42 patients. Both cytosolic and nuclear fractions were tested for estradiol and progestin binding using equilibrium binding assays. The results were correlated with the age of the patient and the histological type and cellular density of the tumor.

Cytosolic estradiol binding was noted in 25 (60%) of 42 tumors, with eight (19%) of the 42 having levels over 10 femtomoles (fM)/mg protein. Nuclear estradiol binding was detected in 16 (57%) of 28 tumors, with six (21%) of the 28 having levels over 10 fM/mg protein. Cytosolic progestin binding was noted in 16 (73%) of 22 samples, with levels in nine (41%) of 22 being greater than 10 fM/mg protein. There was no correlation between the level of cytoplasmic progestin binding and either the level of cytoplasmic estradiol binding or the level of nuclear estradiol binding. In several specimens, levels of cytoplasmic progestin binding in excess of 100 fM/mg protein were found in tissues demonstrating little or no estradiol binding by either the nucleus or the cytosol. This discrepancy differs from the situation found in other hormonally responsive tissues such as breast or uterus, and suggests either a possible derangement of the normal cellular hormonal control mechanism or that the measured hormone binder is a molecule other than a classical hormone receptor.

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Neeraj Kumar, Gary M. Miller, David G. Piepgras and Bahram Mokri

A source of bleeding is often not evident during the evaluation of patients with superficial siderosis of the CNS despite extensive imaging. An intraspinal fluid-filled collection of variable dimensions is frequently observed on spine MR imaging in patients with idiopathic superficial siderosis. A similar finding has also been reported in patients with idiopathic intracranial hypotension. The authors report on a patient with superficial siderosis and a longitudinally extensive intraspinal fluid-filled collection secondary to a dural tear. The patient had a history of low-pressure headaches. His spine MR imaging and spine CT suggested the possibility of an underlying vascular malformation, but none was found on angiography. Repair of the dural tear resulted in resolution of the intraspinal fluid collection and CSF abnormalities. The significance of the association between superficial siderosis and idiopathic intracranial hypotension, and potential therapeutic and pathophysiological implications, are the subject of this report.

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Evaluation of brain function in severe human head trauma with multimodality evoked potentials

Part 1: Evoked brain-injury potentials, methods, and analysis

Richard P. Greenberg, David J. Mayer, Donald P. Becker and J. Douglas Miller

✓ Methods for obtaining multimodality evoked potentials, somatosensory, visual, auditory, and auditory brain-stem potentials in patients with severe head trauma are described. A method of analyzing abnormal multimodality evoked potentials (graded evoked brain-injury potentials) is proposed that defines the degree of abnormality of the electrophysiological data and expresses it simply in four grades per modality. Data from 20 normal subjects are given for comparison with the abnormal data obtained from 51 patients with head trauma.

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John L. D. Atkinson, Brian G. Weinshenker, Gary M. Miller, David G. Piepgras and Bahram Mokri

Object. Spontaneous spinal cerebrospinal fluid (CSF) leakage with development of the intracranial hypotension syndrome and acquired Chiari I malformation due to lumbar spinal CSF diversion procedures have both been well described. However, concomitant presentation of both syndromes has rarely been reported. The object of this paper is to present data in seven cases in which both syndromes were present. Three illustrative cases are reported in detail.

Methods. The authors describe seven symptomatic cases of spontaneous spinal CSF leakage with chronic intracranial hypotension syndrome in which magnetic resonance (MR) images depicted dural enhancement, brain sagging, loss of CSF cisterns, and acquired Chiari I malformation.

Conclusions. This subtype of intracranial hypotension syndrome probably results from chronic spinal drainage of CSF or high-flow CSF shunting and subsequent loss of brain buoyancy that results in brain settling and herniation of hindbrain structures through the foramen magnum. Of 35 cases of spontaneous spinal CSF leakage identified in the authors' practice over the last decade, MR imaging evidence of acquired Chiari I malformation has been shown in seven. Not to be confused with idiopathic Chiari I malformation, ideal therapy requires recognition of the syndrome and treatment directed to the site of the spinal CSF leak.

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Bryce Weir, Ramon Erasmo, Jack Miller, John McIntyre, David Secord and Bruce Mielke

✓ This study investigates the relationship between vasospasm and repeated subarachnoid hemorrhages in 18 monkeys. Sixteen received weekly 4 cc injections of autogenous blood into the subfrontal subarachnoid space. The weekly mortality rate for 4 weeks was 6%, 33%, 20%, and 37% respectively. The over-all mortality was 75%. The degree of vasospasm did not correlate with the morbidity and mortality. Vasospasm was limited to the intradural cerebral vessels and was diffuse. It never lasted longer than a few hours, late vasospasm did not occur, and the degree of vasospasm did not alter with repeated occasions of “subarachnoid hemorrhage.” Immediate electrocardiogram abnormalities were related to the height of the cerebrospinal fluid pressure rise following the subarachnoid hemorrhage (injected blood). Pathological examination of the vessels shown to be in spasm was normal. The study suggests that the increased mortality associated with repeated subarachnoid hemorrhage is due to cumulative structural damage rather than a heightened vasospastic response to repeated hemorrhages.

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Brandon A. Miller, David I. Bass and Joshua J. Chern

Arteriovenous malformations (AVMs) are typically considered congenital lesions, although there is growing evidence for de novo formation of these lesions as well. The authors present the case of an AVM in the same cerebral cortex that had been affected by a severe traumatic brain injury (TBI) more than 6 years earlier. To the best of the authors' knowledge, this is the first report attributing the formation of an AVM directly to TBI.

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David R. Guyer, Neil R. Miller, Donlin M. Long and George S. Allen

✓ Visual function was assessed in 15 eyes of 11 patients who underwent unilateral (seven patients) or bilateral (four patients) optic canal decompression for presumed compressive optic neuropathies. Both immediate and long-term postoperative vision was evaluated in all eyes. Over 90% of the eyes that had undergone nerve decompression had either the same or improved visual acuity and visual field immediately following surgery. In this group of patients there were no deaths and there was only one postoperative complication, a transient dysphasia caused by an epidural hematoma that was evacuated. Long-term follow-up evaluations revealed that most of the eyes retained their immediate postoperative visual function or showed gradual visual improvement with time. The results of this series as well as a review of the available literature indicate that optic canal decompression via craniotomy can be a safe procedure and that it appears to have lasting visual benefit in many patients.