bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of cytological preparations for the intraoperative diagnosis of stereotactically obtained brain biopsies: a 19-year experience and survey of neuropathologists
Authors: Firlik Katrina S. , Martinez A. Julio , Lunsford L. Dade
Published: May 2009

Object. The goals of this study were to analyze the accuracy of cytological techniques, consisting of touch and smear preparations, for the intraoperative diagnosis of stereotactically obtained brain biopsy samples, and to determine the prevalence of the use of these methods among neuropathologists.

Methods. A survey regarding preferred methods for intraoperative diagnosis of stereotactically obtained brain biopsy samples was completed by 92 (62%) of 148 neuropathologists. Twenty-three percent of respondents chose frozen-section examination alone; 13% chose one or more cytological methods alone; and the remainder (64%) chose a combination of frozen-section examination and cytology.

At the University of Pittsburgh, the neuropathology records for all stereotactic brain biopsies performed from May 1979 through May 1998 were retrospectively reviewed. Of the 946 stereotactic brain biopsies, 316 cases were excluded because the intraoperative neuropathological consultation was not recorded. Thirty-five cases were excluded because frozen-section examinations were performed. Therefore, a total of 595 cases were suitable for analysis.

Intraoperative cytological investigation correlated with the final diagnosis in 90% of cases (52% complete correlation and 38% partial correlation). In 11% of cases there was no correlation between the intraoperative and final diagnoses. Intraoperative diagnoses were most accurate in cases of abscess, germinoma, lymphoma, metastasis, and malignant glioma.

Overall, 91% of biopsy specimens were diagnostic when examined using the paraffin-embedded section technique. The sensitivity of cytological preparations in detecting a diagnostic specimen was 96% and the specificity in detecting a nondiagnostic specimen was 75%.

Conclusions. Intraoperative cytological preparations correlated with the final diagnoses in 90% of stereotactic biopsies and had a 96% sensitivity in detecting diagnostic specimens. The highest rate of correlation was noted in cases of abscess, germinoma, lymphoma, metastasis, and malignant glial tumor.
Overexpression of bax in human glioma cell lines
Authors: Vogelbaum Michael A. , Tong Jianxin X. , Perugu Rajashri , Gutmann David H. , Rich Keith M.
Published: May 2009

Object. Cells that lose their ability to undergo apoptosis may promote the development of neoplasms and result in resistance to clinical treatment with DNA-damaging modalities such as radio- and chemotherapy. Four established human glioma cell lines that are resistant to apoptosis were transfected with the proapoptotic gene bax and assessed for their sensitivity to a proapoptotic stimulus.

Methods. Two cell lines had a wild-type p53 genotype (U87 and D247MG) and two had mutant p53 genotypes (U138 and U373). Constitutive overexpression of murine bax was achieved in U138 and U373 only, which resulted in an increased sensitivity of these lines to the apoptosis-inducing effect of cytosine arabinoside (ara-C). Multiple attempts to produce constitutive overexpression of bax in U87 and D247MG cells resulted in spontaneous, near-complete cell loss. Vector-only control transfections were successful in all four cell lines. Inducible overexpression of bax was achieved in the U87 cells and elevated levels of BAX were observed as early as 6 hours after gene induction. This overexpression of BAX resulted in the spontaneous induction of apoptosis in these cells.

Conclusions. Overexpression of BAX in four human glioma cell lines resulted in increased sensitivity to apoptosis. In the two lines that had a wild-type p53 genotype, overexpression of BAX produced spontaneous apoptosis. In contrast, the lines that had mutant, nonfunctional P53 did not undergo spontaneous apoptosis, but they were rendered more sensitive to the apoptosis-inducing effect of ara-C. Modulation of BAX expression may be a useful therapeutic modality for gliomas, regardless of p53 genotype.
Gangliocytoma masquerading as a prolactinoma
Authors: McCowen Karen C. , Glickman Jonathan N. , Black Peter McL. , Zervas Nicholas T. , Lidov Hart G. W. , Garber Jeffrey R.
Published: May 2009

✓ The authors describe the case of a 36-year-old man who presented with bitemporal hemianopsia and a serum prolactin concentration of 1440 ng/ml. Magnetic resonance imaging of the pituitary revealed a presumed macroadenoma with suprasellar and temporal lobe extension. Although the patient's prolactin level was lowered to 55 ng/ml by bromocriptine therapy, no tumor shrinkage occurred. Fourteen months later, progression of visual field defects necessitated transsphenoidal resection, which was incomplete. Immunocytochemical analysis of the biopsy tissue was positive for prolactin and, in view of the clinical picture, more detailed analysis was not performed.

External-beam radiotherapy was given 2 years later because of enlargement of residual tumor. Subsequently, despite a fall in the serum prolactin concentration to less than 20 ng/ml in response to the course of bromocriptine, the mass displayed further extension into the temporal lobe.

Nine years after the patient's initial presentation, he underwent transfrontal craniotomy for sudden deterioration in visual acuity caused by hemorrhage into the mass. No adenohypophyseal tissue was identified in the resected tissue. The mass was composed of dysplastic neurons that were strongly immunoreactive for synaptophysin and neurofilament (indicating neural differentiation) and prolactin. Review of the original biopsy specimen indicated that the prolactin-positive cells had striking neuronal morphological characteristics. The final diagnosis in this case is prolactin-secreting gangliocytoma. Although exceedingly rare, this disease must be added to the differential diagnosis in cases of “prolactinoma” when bromocriptine therapy is followed by a marked decline in serum prolactin that is not accompanied by significant tumor shrinkage. Furthermore, in such instances, consideration should be given to obtaining a biopsy sample prior to electing for radiotherapy.
Stereotactic radiosurgery for brainstem metastases
Authors: Huang Chuan-Fu , Kondziolka Douglas , Flickinger John C. , Lunsford L. Dade
Published: May 2009

Object. Brainstem metastases portend a dismal prognosis. Surgical resection is not part of routine management and radiation therapy has offered little clinical benefit. Radiosurgery provides a safe and effective treatment for many patients with brain metastasis, but its role in the brainstem has not been evaluated. In this study the authors examine the role of radiosurgery in the treatment of brainstem metastases.

Methods. The authors reviewed the outcomes after stereotactic radiosurgery in 26 patients with 27 brainstem metastases. Tumor locations included the pons (21 tumors) and midbrain (six tumors); 14 patients had additional tumors in other locations. Twenty patients presented with brainstem signs. The median dose to the tumor margin was 16 Gy (range 12–20 Gy). Twenty-four patients received fractionated whole-brain radiation therapy (WBRT) and 12 underwent additional chemotherapy or immunotherapy. The median follow-up time in these patients was 9.5 months (range 1–43 months).

After radiosurgery, the local control rate in brainstem tumors was 95%. In one patient in whom the tumor initially decreased in size, tumor enlargement was seen 7 months later. The median survival time was 11 months after diagnosis and 9 months after radiosurgery. Thirteen patients improved, 10 were stable, and three deteriorated. Eventually, 22 patients died, 18 of progression of their extracranial disease, three of new tumor growth (including one hemorrhage into a new brain metastasis), and one of extracranial disease plus new brain tumor growth.

Conclusions. Although they have slightly lower than the expected survival rates of patients with nonbrainstem tumors, patients with brainstem metastases may achieve effective palliation after stereotactic radiosurgery and WBRT.
Frameless stereotaxy with scalp-applied fiducial markers for brain biopsy procedures: experience in 218 cases
Authors: Barnett Gene H. , Miller David W. , Weisenberger Joseph
Published: May 2009

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.
Initial report on the limited value of hypoglossal nerve transfer to treat brachial plexus root avulsions
Authors: Malessy Martijn J. A. , Hoffmann Carel F. E. , Thomeer Ralph T. W. M.
Published: May 2009

Object. Hypoglossal nerve (12th cranial nerve) transfer was performed to treat the sequelae of brachial plexus root avulsion in 12 adults and two infants, and the patients were followed to assess the effectiveness of the surgery.

Methods. The 12th cranial nerve was transected at the base of the tongue, and a sural nerve graft was used to bridge the gap between the donor (12th) and recipient nerves: C-5 spinal, axillary, suprascapular, or musculocutaneous nerve. The mean graft length in adult patients was 15.75 ± 5.5 cm (± standard deviation, median 14.5 cm) and in the two infants the graft lengths were 7 and 8 cm, respectively. After a mean postoperative interval of 1138 ± 254 days, electromyographic examination of the target muscles showed tongue movement—related activity in all patients. Muscle force strength measured according to the Medical Research Council's guidelines, was Grade 3 or higher in 21% of patients. Contraction, however, could only be attained by tongue movements, and volitional control was not achieved.

Conclusions. Although recovery of muscle strength was obtained by 12th cranial nerve transfer, the functional gain remained virtually nonexistent because central control was missing.
A positron emission tomography study of cerebrovascular reserve before and after shunt surgery in patients with idiopathic chronic hydrocephalus
Authors: Klinge Petra M. , Berding Georg , Brinker Thomas , Knapp Wolfram H. , Samii Madjid
Published: May 2009

Object. In this study the authors use positron emission tomography (PET) to investigate cerebral blood flow (CBF) and cerebrovascular reserve (CVR) in chronic hydrocephalus.

Methods. Ten patients whose mean age was 67 ± 10 years (mean ± standard deviation [SD]) were compared with 10 healthy volunteers who were 25 ± 3 years of age. Global CBF and CVR were determined using 15O—H2O and PET prior to shunt placement and 7 days and 7 months thereafter. The CVR was measured using 1 g acetazolamide. Neurological status was assessed based on a score assigned according to the methods of Stein and Langfitt.

Seven months after shunt placement, five patients showed clinical improvement (Group A) and five did not (Group B). The average global CBF before shunt deployment was significantly reduced in comparison with the control group (40 ± 8 compared with 61 ± 7 ml/100 ml/minute; mean ± SD, p < 0.01). In Group A the CBF values were significantly lower than in Group B (36 ± 7 compared with 44 ± 8 ml/100 ml/minute; p < 0.05). The CVR before surgery, however, was not significantly different between groups (Group A = 43 ± 21%, Group B = 37 ± 29%). After shunt placement, there was an increase in the CVR in Group A to 52 ± 37% after 7 days and to 68 ± 47% after 7 months (p < 0.05), whereas in Group B the CVR decreased to 14 ± 18% (p < 0.05) after 7 days and returned to the preoperative level (39 ± 6%) 7 months after shunt placement.

Conclusions. The preliminary results indicate that a reduced baseline CBF before surgery does not indicate a poor prognosis. Baseline CBF before shunt placement and preoperative CVR are not predictive of clinical outcome. A decrease in the CVR early after shunt placement, however, is related to poor late clinical outcome, whereas early improvement in the CVR after shunt placement indicates a good prognosis.
Correlation between histopathological findings in C-5 and C-6 nerve stumps and motor recovery following nerve grafting for repair of brachial plexus injury
Authors: Malessy Martijn J. A. , van Duinen Sjoerd G. , Feirabend Hans K. P. , Thomeer Ralph T. W. M.
Published: May 2009

Object. Proximal spinal nerve stumps were used as donor sites for grafts to repair brachial plexus traction lesions. The quality of the stumps was assessed histologically, and its correlation with the strength attained in the target muscle was studied.

Methods. Four histopathological parameters in frozen tissue sections of 31 C-5 or C-6 nerve stumps were examined by a neuropathologist. The total quantity of myelin was compared with normal values. Also, thick myelinated fibers, fibrosis, and misdirected axons were assessed. Stumps embedded in plastic were used in a morphometric study of myelinated fiber profiles. The fiber density, mean size, and size distribution in five donor stumps were determined; three normal C-5 spinal nerves obtained at autopsy served as controls. Finally, the relative area occupied by fiber profiles and interspace was computed. Linear regression was used as a multivariate analysis, adjusting the outcome of surgical repair for effects of age, interval between trauma and surgery, and graft length.

Histopathological examination showed that the total quantity of myelin in donor stumps used for biceps muscle reinnervation was considerably reduced. On morphometric examination the fiber density did not differ significantly between stumps obtained in patients and control stumps obtained at autopsy. However, a significant reduction of the area occupied by myelinated fibers was measured: from 46% in controls to 13% in patients (p < 0.0001). Likewise, a significant reduction was found in the mean fiber size: from 7.4 µm in controls to 3.7 µm in patients (p < 0.0001).

The relationship between the myelin quantity in the proximal stump and the grade of biceps muscle recovery was statistically significant (p = 0.02). From the 95% confidence interval it was concluded that the estimated effect of a mean increase of myelinated fibers by 25% almost equals an increase in recovery of one point on the Medical Research Council scale (grade range 0–5).

Conclusions. Both histopathological and morphometric examination showed a reduction of the quantity of myelin in C-5 or C-6 stumps used as donor sites for grafts. The amount of myelin is significantly correlated with biceps muscle function after nerve grafting. Because it is possible to assess the quantity of myelin by intraoperative examination of frozen sections, this correlation is potentially useful in the decision-making process of whether to use stumps for grafting or to use nerve transfer procedures to restore biceps muscle function.
Microsurgical anatomy of the extracranial—extradural origin of the posterior inferior cerebellar artery
Authors: Fine Andrew D. , Cardoso Alberto , Rhoton Albert L.
Published: May 2009

Object. The authors describe the microsurgical anatomy of the posterior inferior cerebellar artery (PICA) with an extradural origin and discuss its importance as a common variation.

Methods. The microsurgical anatomy of paired PICAs with an extradural origin were examined.

Conclusions. Five to 20% of PICAs have an extradural origin. In the case described, both PICAs arose extradurally from the third segment of the vertebral artery (VA). Both origins were less than 1 cm proximal to the site at which the VA penetrated the dura, and neither PICA gave rise to extradural branches. Extradurally, the PICAs coursed parallel to the VA and the C-1 nerve and the three structures penetrated the dura together. Intradurally, the PICAs remained lateral and posterior to the brainstem, whereas, in the common PICA configuration, the first segment of the PICA courses anterior to the medulla. Neither PICA sent branches to the anterior brainstem, which is commonly found in PICAs with an intradural origin. There were no soft-tissue or bone anomalies.
Cerebral metabolism in experimental hydrocephalus: an in vivo 1H and 31P magnetic resonance spectroscopy study
Authors: Braun Kees P. J. , van Eijsden Pieter , Vandertop W. Peter , de Graaf Robin A. , Gooskens Rob H. J. M. , Tulleken Kees A. F. , Nicolay Klaas
Published: May 2009

Object. Brain damage in patients with hydrocephalus is caused by mechanical forces and cerebral ischemia. The severity and localization of impaired cerebral blood flow and metabolism are still largely unknown. Magnetic resonance (MR) spectroscopy offers the opportunity to investigate cerebral energy metabolism and neuronal damage noninvasively and longitudinally. Previous 1H MR spectroscopy studies have shown an increased lactate resonance that is suggestive of anaerobic glycolysis. The aim of this study was to assess cerebral damage and energy metabolism in kaolin-induced hydrocephalus in adult rats by using in vivo 1H and 31P MR spectroscopy. The presence of lactate was correlated with high-energy phosphate metabolism and intracellular pH. The measurement of relative concentrations of N-acetyl aspartate (NAA), choline (Cho), and total creatine (tCr) served to assess neuronal damage.

Methods. Hydrocephalus was induced in adult rats by surgical injection of kaolin into the cisterna magna. Magnetic resonance studies, using a 4.7-tesla magnet, were performed longitudinally in hydrocephalic animals at 1 (10 rats), 8 (six rats), and 16 weeks (six rats) thereafter, as well as in eight control animals. To evaluate ventricular size and white matter edema T2-weighted MR imaging was performed. The 1H MR spectra were acquired from a 240-µl voxel, positioned centrally in the brain, followed by localized 31P MR spectroscopy on a two-dimensional column that contained the entire brain but virtually no extracranial muscles. The 1H and 31P MR spectroscopy peak ratios were calculated after fitting the spectra in the time domain, intracellular pH was estimated from the inorganic phosphate (Pi) chemical shift, and T2 relaxation times of 1H metabolites were determined from the signal decay at increasing echo times.

Conclusions. In hydrocephalic rats, ventricular expansion stabilized after 8 weeks. White matter edema was most pronounced during acute hydrocephalus. Lactate peaks were increased at all time points, without a decrease in phosphocreatine (PCr)/Pi and PCr/adenosine triphosphate (ATP) peak ratios, or pH. Possibly lactate production is restricted to periventricular brain tissue, followed by its accumulation in cerebrospinal fluid, which is supported by the long lactate T2 relaxation time. Alternatively, lactate production may precede impairment of ATP homeostasis. The NAA/Cho and tCr/Cho ratios significantly decreased during the acute and chronic stages of hydrocephalus. These changes were not caused by alterations in metabolite T2 relaxation time. The decreases in the NAA/Cho and tCr/Cho ratios implicate neuronal loss/dysfunction or changes in membrane phospholipid metabolism, as in myelin damage or gliosis. It is suggested that 1H MR spectroscopy can be of additional value in the assessment of energy metabolism and cerebral damage in clinical hydrocephalus.
Growing blood clot mimicking an aneurysm on postoperative computerized tomography and magnetic resonance imaging studies
Authors: Bertalanffy Alexander , Dietrich Wolfgang , Aichholzer Martin , Hittmair Karl , Czech Thomas
Published: May 2009

✓ The authors describe the case of a 15-year-old boy who underwent resection of a large left temporal tumor. During a normal postoperative course, computerized tomography (CT) scanning demonstrated a spherically hyperdense structure near the internal carotid artery, enlarging on a control CT scan. A suspected false aneurysm was confirmed on magnetic resonance imaging; angiographic studies were negative. The authors believed they were dealing with a thrombosed false aneurysm and they performed operative revision. Intraoperatively the “aneurysm” could be dissected off the internal carotid artery and no lesion of the arterial wall was obvious. Histological findings showed a fresh blood clot. This case demonstrates that a blood clot may mimic an aneurysm on CT and magnetic resonance studies, which has not been described earlier. The origin of the blood clot remains unclear.
Serial angiography and endovascular treatment of dissecting aneurysms of the anterior cerebral and vertebral arteries
Authors: Amagasaki Kenichi , Yagishita Tsutomu , Yagi Shinichi , Kuroda Katsuhiro , Nishigaya Kazuyuki , Nukui Hideaki
Published: May 2009

✓ This 47-year-old man was admitted to the hospital with disturbance of consciousness due to subarachnoid hemorrhage caused by a ruptured dissecting aneurysm of the left anterior cerebral artery (ACA). Conservative treatment resulted in improvement in the patient's consciousness; however, repeated rupture occurred during the chronic stage. Endovascular coil embolization of the parent artery was successful. Serial angiography demonstrated all stages in the development of the aneurysm. Follow-up angiography demonstrated an incidental dissecting aneurysm of the right vertebral artery. This aneurysm was also treated by endovascular embolization. No new neurological deficit appeared during or after the treatment.

Multiple dissecting aneurysms are rare, especially those involving both supra- and infratentorial regions. A ruptured dissecting aneurysm of the ACA is also an uncommon vascular disorder. This case shows that rebleeding may occur, even during the chronic stage, and thus appropriate treatment for the prevention of subsequent bleeding is essential. Incidental dissecting aneurysms can be treated using the endovascular technique, but further study is necessary.
Adenosine-induced transient asystole for management of a basilar artery aneurysm
Authors: Groff Michael W. , Adams David C. , Kahn Ronald A. , Kumbar Uday M. , Yang Bo-Yi , Bederson Joshua B.
Published: May 2009

✓ Advances in anesthetic and surgical management, such as induced deep hypothermic circulatory arrest and application of temporary clips, have improved outcome for patients with basilar artery aneurysms. Nonetheless, these techniques are associated with significant risks. The authors report a case in which three transient periods of cardiac asystole were induced during basilar artery aneurysm surgery. Adenosine-induced asystole facilitated the safe clipping of the aneurysm by producing consistent periods of profound hypotension and collapse of the aneurysm without the need for temporary clipping. This technique provided unencumbered identification of perforating arteries, precise definition of the local anatomy, and an ideal environment for the safe placement of the aneurysm clip.
Greater superficial petrosal nerve neurinoma
Authors: Kumon Yoshiaki , Sakaki Saburo , Ohta Shinsuke , Ohue Shiro , Nakagawa Koh , Tanaka Kazunori
Published: May 2009

✓ The authors report a case of middle cranial fossa neurinoma arising from the left greater superficial petrosal nerve in a 21-year-old woman who presented with a left-sided otitis media that chronically recurred over a period of 5 years. On examination, the patient had a left-sided mild conductive hearing impairment and a slight disturbance in tear secretion on the left side, with sensory disturbance in the left palate. Three-dimensional computerized tomography scans clearly demonstrated the enlargement of the foramen lacerum and foramen ovale, and heavily T2-weighted magnetic resonance images revealed the tumor's location along with the course of the greater superficial petrosal nerve and its extension into the tympanic cavity. Following complete surgical excision of the tumor and tympanoplasty via a middle cranial fossa approach, the patient retained useful hearing without facial palsy.
Changes in ankle spasticity and strength following selective dorsal rhizotomy and physical therapy for spastic cerebral palsy
Authors: Engsberg Jack R. , Ross Sandy A. , Park Tae Sung
Published: May 2009

Object. In this investigation the authors quantified changes in ankle plantarflexor spasticity and strength following selective dorsal rhizotomy (SDR) and intensive physical therapy in patients with cerebral palsy (CP).

Methods. Twenty-five patients with cerebral palsy (CP group) and 12 able-bodied volunteers (AB controls) were tested with a dynamometer. For the spasticity measure, the dynamometer was used to measure the resistive torque of the plantarflexors during passive ankle dorsiflexion at five different speeds. Data were processed to yield a single value that simultaneously encompassed the three key elements associated with spasticity: velocity, resistance, and stretch. For the strength test, the dynamometer rotated the ankle from full dorsiflexion to full plantarflexion while a maximum concentric contraction of the plantarflexors was performed. Torque angle data were processed to include the work done by the patient or volunteer on the machine. Plantarflexor spasticity values for the CP group were significantly greater than similar values for the AB control group prior to surgery but not significantly different after surgery. Plantarflexor strength values of the CP group were significantly less than those of the AB control group pre- and postsurgery. Postsurgery strength values did not change relative to presurgery values.

Conclusions. The spasticity results of the present investigation agreed with those of previous studies indicating a reduction in spasticity for the CP group. The strength results did not agree with the findings of most previous related literature, which indicated that a decrease in strength should have occurred. The strength results agreed with a previous investigation in which knee flexor strength was objectively examined, indicating that strength did not decrease as a consequence of an SDR. The methods of this investigation could be used to improve SDR patient selection.
Increased incidence and impact of nonconvulsive and convulsive seizures after traumatic brain injury as detected by continuous electroencephalographic monitoring
Authors: Vespa Paul M. , Nuwer Marc R. , Nenov Valeriy , Ronne-Engstrom Elisabeth , Hovda David A. , Bergsneider Marvin , Kelly Daniel F. , Martin Neil A. , Becker Donald P.
Published: May 2009

Object. The early pathophysiological features of traumatic brain injury observed in the intensive care unit (ICU) have been described in terms of altered cerebral blood flow, altered brain metabolism, and neurochemical excitotoxicity. Seizures occur in animal models of brain injury and in human brain injury. Previous studies of posttraumatic seizures in humans have been based principally on clinical observations without a systematic approach to electroencephalographic (EEG) recording of seizures. The purpose of this study was to determine prospectively the incidence of convulsive and nonconvulsive seizures by using continuous EEG monitoring in patients in the ICU during the initial 14 days postinjury.

Methods. Ninety-four patients with moderate-to-severe brain injuries underwent continuous EEG monitoring beginning at admission to the ICU (mean delay 9.6 ± 5.4 hours) and extending up to 14 days postinjury. Convulsive and nonconvulsive seizures occurred in 21 (22%) of the 94 patients, with six of them displaying status epilepticus. In more than half of the patients (52%) the seizures were nonconvulsive and were diagnosed on the basis of EEG studies alone. All six patients with status epilepticus died, compared with a mortality rate of 24% (18 of 73) in the nonseizure group (p < 0.001). The patients with status epilepticus had a shorter mean length of stay (9.14 ± 5.9 days compared with 14 ± 9 days [t-test, p < 0.03]). Seizures occurred despite initiation of prophylactic phenytoin on admission to the emergency room, with maintenance at mean levels of 16.6 ± 2.8 mg/dl. No differences in key prognostic factors (such as the Glasgow Coma Scale score, early hypoxemia, early hypotension, or 1-month Glasgow Outcome Scale score) were found between the patients with seizures and those without.

Conclusions. Seizures occur in more than one in five patients during the 1st week after moderate-to-severe brain injury and may play a role in the pathobiological conditions associated with brain injury.
Endoscopy of the posterior fossa and dissection of acoustic neuroma
Authors: Göksu Nebil , Bayazıt Yıldırım , Kemaloğlu Yusuf
Published: May 2009

Object. The authors evaluated the importance of endoscopes in eliminating the disadvantages of the posterior fossa approach, such as the lack of adequate visualization of the lateral aspect of the internal acoustic canal (IAC).

Methods. Between 1989 and 1998, 32 patients underwent removal of acoustic neuroma (AN) via a combined retrosigmoid—retrolabyrinthine approach. Endoscopes were used at different stages of the operation, and their use was evaluated with regard to elimination of the disadvantages of the posterior fossa approach. All patients in whom AN had been diagnosed underwent surgery in which a standard retrosigmoid—retrolabyrinthine approach was used. Standard sinus endoscopes of 0°, 30°, and 70° were introduced into the cerebellopontine angle before debulking the tumor, and the IAC was inspected at the end of the operation. Neurovascular integrity as well as the relationship between the AN and surrounding structures were evaluated. The IAC was inspected for residual tumor, and if any was found, endoscopically guided tumor dissection was performed.

Conclusions. Endoscopes have facilitated an understanding of the anatomy between an AN and neighboring neurovascular structures. For surgery in which the posterior fossa approach is used, endoscopes can make operations safer by eliminating the disadvantages of the approach. In addition to allowing inspection of the fundus, it is possible to perform endoscopically guided tumor dissection within the IAC.
A mobile high-field magnetic resonance system for neurosurgery
Authors: Sutherland Garnette R. , Kaibara Taro , Louw Deon , Hoult David I. , Tomanek Boguslaw , Saunders John
Published: May 2009

Object. The authors' goal was to place a mobile, 1.5-tesla magnetic resonance (MR) imaging system into a neurosurgical operating room without adversely affecting established neurosurgical management. The system would help to plan accurate surgical corridors, confirm the accomplishment of operative objectives, and detect acute complications such as hemorrhage or ischemia.

Methods. The authors used an actively shielded 1.5-tesla magnet, together with 15 mtesla/m gradients, MR console computers, gradient amplifiers, a titanium, hydraulic-controlled operating table, and a radiofrequency coil that can be disassembled. The magnet is moved to and from the surgical field by using overhead crane technology. To date, the system has provided unfettered access in 46 neurosurgical patients.

In all patients, high-definition T1- and/or T2-weighted images were rapidly and reproducibly acquired at various stages of the surgical procedures. Eleven patients underwent craniotomy that was optimized after preincision imaging. In four patients who harbored subtotally resected tumor, intraoperative MR imaging aided the surgeon in removing the remaining tumor. Interestingly, the intraoperative administration of gadolinium demonstrated a dynamic expansion of enhancement beyond the preoperative contrast contour in patients with malignant glioma. These zones of new enhancement proved, on examination of biopsy samples, to be tumor.

Conclusions. The authors have demonstrated that high-quality MR images can be obtained in the operating room within reasonable time constraints. Procedures can be conducted without compromising or altering traditional neurosurgical, nursing, or anesthetic techniques. It is feasible that within the next decade intraoperative MR imaging may become the standard of care in neurosurgery.
Gliomas in rodent whisker barrel cortex: a new tumor model
Authors: Sherburn Eric W. , Wanebo John E. , Kim Paul , Song Sheng-Kwei , Chicoine Michael R. , Woolsey Thomas A.
Published: May 2009

Object. Surgical treatment of gliomas is difficult because they are invasive. Invasion of essential cortex often limits or precludes surgical resection. A tumor model was developed in which the rodent whisker barrel cortex was used to examine how gliomas affect cortical function and structure.

Methods. Both DBT (mouse) and C6 (rat) glioma cell lines were grown in culture and labeled with the fluorescent marker Dil in vitro. Labeled tumor cells were then injected into the whisker barrel cortex of adult mice and rats. Neurological assessments were made daily and magnetic resonance (MR) images were obtained. Animals were killed by perfusion 6 to 14 days after injection, and histological sections were prepared and studied.

Tumors were found in all 20 rats and 10 mice that had been injected with the C6 and DBT cell lines, respectively. The animal cells had been labeled with Dil in vitro, and all in vivo tumors proved to be Dil positive. The MR images revealed the tumor locations and serial MR images demonstrated tumor growth. Histological evaluation confirmed the location of the tumor and the disruption of barrel cortex architecture.

Conclusions. Both DBT and C6 glioma cell lines can be used to generate malignant glial tumors reproducibly in the whisker barrel cortex. Fluorescent labeling and cytochrome oxidase staining permit visualization of tumor growth patterns, which disrupt the barrel cortex by microscopic invasion and by gross tissue deformation. Magnetic resonance imaging demonstrates the anatomical extension of these tumors in live rodents. Using this model for further studies on the effects of malignant glioma growth on functional cerebral cortex should advance our understanding of the neurological issues and management of patients with these tumors.
Expression of vascular permeability factor in craniopharyngioma
Authors: Vaquero Jesús , Zurita Mercedes , de Oya Santiago , Coca Santiago , Morales Carmen , Salas Clara
Published: May 2009

Object. The expression of vascular endothelial growth/permeability factor (VEG/PF) has recently been correlated with the presence of tumor-associated cysts in some intracranial tumors. The purpose of this study was to evaluate a possible relationship between the presence of VEG/PF and the formation of cysts in craniopharyngiomas.

Methods. The expression of VEG/PF was studied in histological specimens from a series of 12 craniopharyngiomas. In this series, the tumors were classified as presenting a mainly solid pattern with small macroscopic cysts (four patients) or a mainly cystic pattern (eight patients). The mainly solid tumors containing small macroscopic cysts showed little or no VEG/PF positivity, which was mainly present in tumor cells surrounding cysts. Nevertheless, mainly cystic craniopharyngiomas showed a moderate or high degree of VEG/PF positivity in tumor cells.

Conclusions. These findings indicate that the predominance of a cystic or solid macroscopic appearance of craniopharyngiomas may be influenced by the degree of VEG/PF expression within the tumor cells.
Neuronal damage in gerbils caused by intermittent forebrain ischemia
Authors: Sorimachi Takatoshi , Abe Hiroshi , Takeuchi Shigekazu , Tanaka Ryuichi
Published: May 2009

Object. The purpose of this study was to investigate the possibility of preventing cumulative neuronal damage after repetitive severe ischemia.

Methods. The authors monitored ischemic depolarization in the gerbil hippocampus, which has recently been shown to be a good experimental model of the effects of brief ischemia on the brain, and evaluated neuronal damage in the CA1 subregion 7 days after the ischemic insult. In a single-ischemia paradigm, the results indicate that induction of ischemia-induced neuronal damage depended on the duration of ischemic depolarization. Neuronal damage can be detected in the CA1 subregion after a period of depolarization lasting 210 seconds. Using a double-ischemia paradigm in which the animals were subjected to two periods of ischemia, there was apparently no accumulation of neuronal damage from the first ischemic episode to the second, provided the duration of the first period of ischemic depolarization did not exceed 90 seconds. Neuronal damage accumulated when the duration of the first ischemia episode exceeded 90 seconds, regardless of the duration of the reperfusion interval between the two ischemic insults. Finally, when the ischemic insult was spread over four separate episodes, each lasting 90 seconds (with a reperfusion interval of 5 minutes), neuronal damage was not found when the total depolarization period was less than 420 seconds.

Conclusions. The authors conclude that cumulative neuronal damage may be avoided by adopting an intermittent ischemia approach. The implications of these results for human surgery requiring temporary occlusion of the cerebral arteries are discussed.
Partial myotomy/myectomy of the trapezius muscle with an asleep-awake-asleep anesthetic technique for treatment of cervical dystonia
Authors: Krauss Joachim K. , Koller Remo , Burgunder Jean-Marc
Published: May 2009

✓ The authors describe a technique for performing partial sectioning and myectomy of the trapezius muscle in patients with severe cervical dystonia that is unresponsive to conservative treatment. Asleep-awake-asleep anesthesia allows intraoperative control of the sectioning procedure to avoid causing postoperative weakness of arm elevation above the horizontal plane. The procedure has been performed successfully in three patients. In all cases the dystonic posture of the shoulder and local pain were improved postoperatively. There were no new deficits. This technique can be used as an adjunct to other peripheral surgical procedures in patients with marked laterocollis and dystonic elevation and anteversion of the shoulder.
Identification of motor pathways during tumor surgery facilitated by multichannel electromyographic recording
Authors: Yingling Charles D. , Ojemann Steven , Dodson Barbara , Harrington Margaret J. , Berger Mitchel S.
Published: May 2009

Object. The goal of this study was to determine the usefulness of electromyographic (EMG) recording in locating motor pathways near the central sulcus or internal capsule during surgery.

Methods. Multichannel EMG recordings were compared with visual observation of contralateral body movement that was elicited by direct cortical or subcortical stimulation used to identify motor pathways before and during tumor resection.

The EMG recordings were more sensitive than visual observation alone in identifying motor responses: in 30% of cases, responses were identified by EMG recording alone at some point during the operation and, in 9% of cases, EMG responses were the only responses observed. Additionally, EMG recordings often detected seizure activity resulting from electrical stimulation of the cortex that could not be appreciated on visual inspection. No new motor deficits were seen postoperatively in 88% of the patients in this series.

Conclusions. Using EMG recording in addition to motor pathway mapping results in greater sensitivity, allowing the use of lower stimulation levels and facilitating detection of stimulation-induced seizure activity.
Ventricular pressure monitoring during bilateral decompression with dural expansion
Authors: Yoo Do-Sung , Kim Dal-Soo , Cho Kyung-Suck , Huh Pil-Woo , Park Chun-Kun , Kang Joon-Ki
Published: May 2009

Object. The management of massive brain swelling remains an unsolved problem in neurosurgery. Despite newly developed medical and pharmacological therapy, the rates of mortality and morbidity caused by massive brain swelling remain high. According to many recent reports, surgical decompression with dural expansion is superior to medical management in patients with massive brain swelling. To show the quantitative effect of decompressive surgery on intracranial pressure (ICP), the authors performed a ventricular puncture and measured the ventricular ICP continuously during decompressive surgery and the postoperative period.

Methods. Twenty patients with massive brain swelling who underwent bilateral decompressive craniectomy with dural expansion were included in this study. In all patients, ventricular puncture was performed at Kocher's point on the side opposite the massive brain swelling. The ventricular puncture tube was connected to the continuous monitor via a transducer device. The ventricular pressure was monitored continuously, during the bilateral decompressive procedures and postoperative period.

The initial ventricular ICP was variable, ranging from 16 to 65.8 mm Hg. Immediately after the bilateral craniectomy, the mean ventricular ICP decreased to 50.2 ± 16.6% of the initial ICP (range 5–51.5 mm Hg). Additional opening of the dura decreased the mean ICP by an additional 34.5% and reduced the ventricular pressure to 15.7 ± 10.7% of the initial pressure (range 0–15 mm Hg). Ventricular pressure measured postoperatively in the neurosurgical intensive care unit was lowered to 15.1 ± 16.5% of the initial ICP. The ventricular ICP trend in the first 24 hours after decompressive surgery was an important prognostic factor; if it was greater than 35 mm Hg, the mortality rate was 100%.

Conclusions. Bilateral decompression with dural expansion is an effective therapeutic modality in the control of ICP. To obtain favorable clinical outcomes in patients with massive brain swelling, early decision making and proper patient selection are very important.
Empty sella syndrome: does it exist in children?
Authors: Ammar Ahmed , Al-Sultan Ali , Mulhim Fatma Al , Hassan Abdulla Yousef Al
Published: May 2009

Object. The empty sella syndrome (ESS) is well documented in adults, and although the same phenomenon of herniation of the arachnoid space into the enlarged sella turcica has been noted in children, it is not widely known that children suffer from this syndrome. Therefore, the aims of this paper are to increase neurosurgeons' awareness of the existence of this phenomenon in children and to add to the scant body of literature on the subject.

Methods. The authors treated 12 children, ranging in age between 2 and 8 years, in whom neuroradiological studies demonstrated an enlarged sella turcica filled with cerebrospinal fluid and herniation of suprasellar and arachnoid spaces. The causes of ESS in these children were high intracranial pressure, neglected or improperly treated hydrocephalus, and suprasellar arachnoid cyst. Primary ESS was found as well. Most of the children presented with headache, abnormal body weight (the majority being underweight), and short stature. The results of hormone assays were normal in all children.

Conclusions. If undiagnosed and untreated, ESS in children may lead to serious consequences, including impairment of pituitary and hypothalamic function and damage to the optic chiasm. It is important to raise awareness in the neurosurgical community about the existence of ESS in children so that it can be diagnosed and treated at an early stage. A classification system for the diaphragma sellae is recapitulated.
Neuroendoscopic approach to tectal tumors: a consecutive series
Authors: Oka Kazunari , Kin Yoshiaki , Go Yoshinori , Ueno Yushi , Hirakawa Katsuyuki , Tomonaga Masamichi , Inoue Tohru , Yoshioka Susumu
Published: May 2009

Object. The authors report a consecutive series of 10 patients who presented with signs and symptoms caused by tectal tumors. Clinical findings, radiographic features, neuroendoscopic management strategies, and histological findings are reported and discussed.

Methods. Since January 1990, 11 neuroendoscopic procedures were performed in 10 patients who harbored tectal tumors. The patients were followed for an average of 5 years (range 2 months-11 years), and a retrospective study was conducted in which case notes, radiological findings, operative notes, and histopathological findings were assessed. Magnetic resonance (MR) imaging was performed, and the images were used to classify patients into three groups: those with hypertrophy of the tectum in whom isointensity appeared on T1-weighted images (Group 1); those with a tectal tumor occupying the cerebral aqueduct in whom decreased signal intensity appeared on T1-weighted images, as well as no enhancement after gadolinium administration (Group 2); and those with a tectal tumor in whom mixed signal intensity and conspicuous evidence of contrast enhancement appeared on T1-weighted images (Group 3). The results of histological examination were consistent with MR imaging features: in Group 1, glial tissue or gliosis; in Group 2, benign astrocytoma; and in Group 3, malignant astrocytoma. Cerebrospinal fluid diversion was the only surgical treatment that provided relief from obstructive hydrocephalus. One patient in Group 3 underwent radiotherapy and subsequent partial tumor removal under neuroendoscopic guidance. Thereafter, the tumor remained in decline. All patients had normal intellectual status after undergoing surgery in which a neuroendoscope was used.

Conclusions. Neuroendoscopic procedures can provide histological diagnosis, define the tumor—midbrain interrelationship, and be highly effective in treating obstructive hydrocephalus and in removing tectal tumors. This procedure may receive clinical application as a new management strategy for tectal glioma.