bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium carbonate apatite deposition in the cervical spine with associated vertebral destruction
Authors: Ojemann Jeffrey G. , Grubb Robert L. , Kyriakos Michael , Baker Kim B.
Published: June 2009

✓ This 52-year-old woman developed crystal deposition disease involving the cervical vertebrae. She presented with symptomatic spinal cord compression secondary to extensive calcified lesions in the posterior elements of the cervical spine. Surgical decompression with posterior fusion was performed. Histological examination showed hardened deposits of calcium carbonate involving the soft tissue, and dissolution of the vertebral bone trabeculae. There was no inflammatory response to these deposits. One year postoperatively the patient developed severe pulmonary disease associated with the collagen-vascular disorder, scleroderma (calcinosis, Raynaud's phenomenon, esophageal hypomotility, sclerodactyly, and telangiectasia [CREST] syndrome). Calcium carbonate deposition disease represents an unusual clinical entity that is possibly associated with scleroderma or other collagen-vascular diseases, and it is distinct from ligamentum flavum calcification, calcium pyrophosphate deposition disease, and hydroxyapatite deposition disease.
Cerebral arteriovenous oxygen difference: a predictor of cerebral infarction and outcome in patients with severe head injury
Authors: Le Roux Peter D. , Newell David W. , Lam Arthur M. , Grady M. Sean , Winn H. Richard
Published: June 2009

✓ Jugular bulb oxygen monitoring can be used to estimate the adequacy of cerebral blood flow to support cerebral metabolism after severe head injury. In the present study, the authors studied the cerebral arteriovenous oxygen difference (AVDO2) before and after treatment in 32 head-injured patients (Glasgow Coma Scale scores ≤ 8) to examine the relationships among AVDO2 and cerebral perfusion pressure (CPP), delayed cerebral infarction, and outcome. Fifteen patients (Group A) underwent craniotomy for hematoma evacuation and 17 (Group B) received mannitol for sustained intracranial hypertension (intracranial pressure > 20 mm Hg, > 10 minutes). Radiographic evidence of delayed cerebral infarction was observed in 14 patients. Overall, 17 patients died or were severely disabled. Cerebral AVDO2 was elevated before craniotomy or mannitol administration; the mean AVDO2 for all patients before treatment was 8.6 ± 1.8 vol%. Following craniotomy or mannitol administration, the AVDO2 decreased in 27 patients and increased in five patients (mean AVDO2 6.2 ± 2.1 vol% in all patients; 6 ± 1.9 vol% in Group A; and 6.4 ± 2.4 vol% in Group B). The mean CPP was 75 ± 9.8 mm Hg and no relationship with AVDO2 was demonstrated. Before treatment, the AVDO2 was not associated with delayed cerebral infarction or outcome. By contrast, a limited improvement in elevated AVDO2 after craniotomy or mannitol administration was significantly associated with delayed cerebral infarction (Group A: p < 0.001; Group B: p < 0.01). Similarly, a limited improvement in elevated AVDO2 after treatment was significantly associated with an unfavorable outcome (Group A: p < 0.01; Group B: p < 0.001). In conclusion, these findings strongly indicate that, despite adequate cerebral perfusion, limited improvement in elevated cerebral AVDO2 after treatment consisting of either craniotomy or mannitol administration may be used to help predict delayed cerebral infarction and poor outcome after traumatic brain injury.
Validation of the optic nerve sheath response to changing cerebrospinal fluid pressure: ultrasound findings during intrathecal infusion tests
Authors: Hansen Hans-Christian , Helmke Knut
Published: June 2009

✓ Raised intracranial pressure leads to increased pressure around the optic nerve (ON), which underlies the formation of papilledema and the enlargement of the dural optic nerve sheath (ONS). In clinical practice, the presence of widened ONSs is demonstrable on neuroimaging, but their relationship to cerebrospinal fluid (CSF) pressure remains unknown. The authors investigated the ONS response to pressure during CSF absorption studies in 12 patients undergoing neurological testing. The ONS diameter was evaluated by serial B-mode ultrasound scans of the anterior ON near its entry into the globe.

All patients tested showed ONS diameter changes that exhibited covariance with the alteration of lumbar CSF pressure and were completely reversible during the infusion tests. The maximum difference in ONS diameter between baseline and peak pressure conditions was 1.8 mm on average (range 0.7–3.1 mm), corresponding to an average ONS diameter variation of 45% (range 15–89%). Regression analysis yielded a linear covariance between ONS diameter and CSF pressure with different slopes across subjects (0.019–0.071 mm/mm Hg, mean r = 0.78). However, this linear relationship was only present within a CSF pressure interval. This interval differed between patients: ONS dilation commenced at pressure thresholds between 15 mm Hg and 30 mm Hg and in some patients saturation of the response (constant ONS diameter) occurred between 30 mm Hg and 40 mm Hg. With a single exception, definitely enlarged ONS diameters (> 5 mm) were present when CSF pressure exceeded levels of 30 mm Hg. Retrospectively, discrimination between normal and elevated outflow resistance was possible on the basis of the ONS response to intrathecal infusion alone.

It is concluded that the human ONS has sufficient elasticity to allow a detectable dilation in response to intracranial hypertension. Because of a variable pressure—diameter relationship, the subarachnoid pressure cannot be predicted exactly by single scans. Therefore, the clinical relevance of this method relies on the demonstration of pathologically enlarged sheaths or ongoing enlargement on serial ultrasonography studies.
Microelectrode-guided posteroventral medial radiofrequency pallidotomy for Parkinson's disease
Authors: Kopyov Oleg , Jacques Deane , Duma Christopher , Buckwalter Galen , Kopyov Alex , Lieberman Abraham , Copcutt Brian
Published: June 2009

✓ The outcome of radiofrequency-guided posteroventral medial pallidotomy was investigated in 29 patients with recalcitrant Parkinson's disease. Extracellular recordings were obtained in the target region to differentiate the internal from the external globus pallidus, and distinct waveforms were recorded in each region. Stimulation of the target site further verified the lesion location. Of the 29 patients treated during the course of 1 year, none showed any adverse side effects (such as hemianopsia or hemiparesis) from the procedure. Significant and immediate improvement in motor involvement (dyskinesia, rigidity, dystonia, freezing, and tremor) was observed as measured by the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr scale. Patients experienced improvements in their condition as measured on a self-rating scale, and their ability to perform the activities of daily living was also significantly improved. Although the onset and duration of the effect of a single dose of levodopa did not change, the number of hours in an “off” state of dyskinesia per day was significantly decreased. These results provide further evidence, in a large group of patients, that posteroventral medial pallidotomy results in significant control of the motor symptoms of Parkinson's disease with a minimum of undesirable side effects.
Seizures induced by intracerebral injection of thrombin: a model of intracerebral hemorrhage
Authors: Lee Kevin R. , Drury Ivo , Vitarbo Elizabeth , Hoff Julian T.
Published: June 2009

✓ The coagulation cascade plays an important role in brain edema formation caused by intracerebral blood. In particular, thrombin produces brain injury via direct brain cell toxicity. Seizures and increased cerebral electrical activity are commonly associated with intracerebral blood and are possible effects of thrombin leading to cell injury in the brain. In this study, artificial clots containing concentrations of thrombin found in hematomas were infused intracerebrally in rats. The animals were observed clinically for seizure activity, behavior, and neurological deficits. Several animals underwent video electroencephalographic (EEG) monitoring during intracerebral infusion and for 30 minutes postinfusion. All animals were killed 24 hours after injection, and brain water and ion contents were measured to determine the amount of brain edema. Clinically, thrombin produced focal motor seizures in all animals. None of the control animals or those receiving Nα-(2-Naphthalenesulfonyl-glycyl)-4-amidino-DL-phenylalanine-piperidide (α-NAPAP), a thrombin inhibitor added to the thrombin, showed clinical evidence of seizures. Of the rats undergoing EEG monitoring, all animals receiving thrombin showed electrical evidence of seizure activity, whereas none of the control animals exhibited seizure activity. There was no evidence of seizure activity on EEG monitoring when α-NAPAP was injected along with the thrombin. In addition, the artificial clots containing thrombin produced agitation and a circling tendency in the rats, along with brain edema. These results indicate that the coagulation cascade is involved in seizure production and increased brain electrical activity, which contribute to the neurological deficits and brain edema formation that are seen with intracerebral hemorrhage.
Selective motor hyperreinnervation using motor rootlet transfer: an experimental study in rat brachial plexus
Authors: Bertelli Jayme Augusto , Mira Jean Claude , Pecot-Dechavassine Monique , Sebille Alain
Published: June 2009

✓ Misdirection of sensory fibers into motor pathways is, in part, responsible for the poor results obtained after peripheral nerve repair. After avulsion of the C-5 root in rats, the authors connected a C-4 ventral rootlet to the musculocutaneous nerve by means of a sural nerve graft. In this way, they were able to increase the number of regenerating motor fibers and avoid growth of sensory fibers into the nerve grafts. Functional recovery was evaluated electrophysiologically and histologically. The origin of the axons that reinnervated the nerve graft was analyzed by means of morphological studies including retrograde labeling procedures. Motor neurons survived and regenerated after the rootlet transfer and there was no functional impairment. Many neurons were retrograde labeled in the ventral horn and widespread biceps muscle reinnervation was demonstrated with recovery of nearly normal electrophysiological properties. Motor hyperreinnervation of the musculocutaneous nerve was observed. This high degree of reinnervation in a long (40-mm) graft was attributed to the good chance that a muscle fiber can be reinnervated by a motor fiber when the number of regenerating motor neurons is increased and when competitive sensory fibers are excluded from reinnervation.
Regulated expression of the diphtheria toxin A gene in human glioma cells using prokaryotic transcriptional control elements
Authors: Paulus Werner , Baur Inge , Oberer Daniel M. , Breakefield Xandra O. , Reeves Steven A.
Published: June 2009

✓ Because accurate regulation of toxin gene expression is critical for safe and effective gene therapy applications, the authors have examined the regulation of diphtheria toxin A(DTA)fragment expression in human glioma cell lines using two transcriptional control systems derived fromEscherichia coli: the tetracycline (Tet) system and the lactose (Lac) system. The Tet system includes a tetracycline-controlled transactivator (tTA), a tTA-responsive minimum human cytomegalovirus (hCMV) promoter controlling the expression of theDTAgene, and tetracycline as an allosteric inhibitor. The Lac system includes the lac repressor (lacR), a lacR-regulated Rous sarcoma virus—long terminal repeat (RSV-LTR) promoter controlling the expression of theDTAgene, and isopropyl-thio-β-d-galactoside (IPTG) as an allosteric inducer. Expression plasmids encoding either tTA or lacR were transfected into U-87MG and U-343MG glioma cells along with the responsive DTA plasmid. Cell killing was monitored by the ability of the toxin to abolish protein synthesis and was quantitated using aluciferase reportergene. In the Tet system, tumor cell killing could be regulated by tetracycline up to 120-fold. In contrast, only a twofold IPTG-dependent regulation was obtained using the Lac system because of an incomplete repression ofDTAexpression in the uninduced state. Replacement of the RSV-LTR promoter with the heavy metal—inducible mouse metallothionein-1 promoter in the lacR-responsive unit, as well as the generation of a clonal glioma cell line expressing lacR, did not significantly enhance regulation ofDTAin the Lac system. In conclusion, this study demonstrates that the Tet system is of potential use in gene therapy applications in which regulated expression of a therapeutic gene is an important issue.
Triple anterior screw fixation of an acute combination atlas—axis fracture
Authors: Apostolides Paul J. , Theodore Nicholas , Karahalios Dean G. , Sonntag Volker K. H.
Published: June 2009

✓ The authors report the successful treatment of an acute combination atlas—axis fracture in an 85-year-old man using anterior odontoid and C1–2 transarticular facet screw fixation and a Philadelphia collar. Treatment with halo brace immobilization failed, and the patient experienced recurrent episodes of oxygen desaturation when placed partially prone for chest physiotherapy. If a posterior approach is not feasible, an anterior odontoid and C1–2 transarticular facet screw fixation can be considered as a salvage procedure for patients with acute combination atlas—axis fractures.
Cerebrospinal fluid interleukin-1 receptor antagonist and tumor necrosis factor—α following subarachnoid hemorrhage
Authors: Mathiesen Tiit , Edner Göran , Ulfarsson Elfar , Andersson Birger
Published: June 2009

✓ Subarachnoid hemorrhage (SAH) causes an inflammatory reaction and may lead to ischemic brain damage. Experimental ischemia has been shown to be connected with the alarm-reaction cytokines interleukin-1 receptor antagonist (IL-1Ra) and tumor necrosis factor—α (TNFα). Increased levels of these cytokines, however, have not been detected thus far in patients following an SAH event.

For this reason daily cerebrospinal fluid (CSF) samples were collected from 22 consecutively enrolled patients with SAH and from 10 non-SAH patients (controls). The CSF samples were studied using immunoassays for IL-1Ra and TNFα to investigate whether an SAH caused increased cytokine levels.

The mean IL-1Ra levels were significantly higher in patients with SAH who were in poor clinical condition on admission than in those who were in good condition (318 pg/ml vs. 82 pg/ml, p < 0.02). The IL-1Ra levels increased during delayed ischemic episodes and after surgery in patients who were in poor clinical condition. Significant increases in IL-1Ra and TNFα were detected during Days 4 through 10 in patients suffering from SAH who eventually had a poor outcome (p < 0.05). Patients with good outcomes and control patients had low levels of these cytokines.

The levels of IL-1Ra increased after surgery in patients with Hunt and Hess Grades III through V, but not in those with Grade I or II. This finding indicates that patients in poor clinical condition have a labile biochemical state in the brain that is reflected in increased cytokine levels following the surgical trauma.

Both IL-1Ra and TNFα are known to induce fever, malaise, leukocytosis, and nitric oxide synthesis and to mediate ischemic and traumatic brain injuries. The present study shows that levels of these cytokines increase after SAH occurs and that high cytokine levels correlate with brain damage. It is therefore likely that fever, leukocytosis, and nitric oxide synthesis are also mediated by IL-1 in patients suffering from SAH and it is probable that the inflammatory mediators contribute to brain damage.
Cerebellar astrocytoma: experience with 54 cases surgically treated at the Mayo Clinic, Rochester, Minnesota, from 1978 to 1990
Authors: Morreale Vittorio M. , Ebersold Michael J. , Quast Lynn M. , Parisi Joseph E.
Published: June 2009

✓ A comprehensive review of the literature has shown that the treatment of choice for cerebellar astrocytomas has primarily been gross-total resection of the mass and gross-total resection of the enhancing portion of pilocytic astrocytomas. Most large scale studies of postresection survival rates of patients with cerebellar astrocytomas were conducted when computerized tomography (CT) and magnetic resonance (MR) imaging were not readily available. It has been shown that postoperative CT scans or MR images are more reliable than the surgeon's estimate of the degree of tumor resection at the time of surgery. It is not possible, therefore, to make an accurate determination regarding a postresection prognosis based on the degree of suspected tumor resection without the availability of appropriate radiographic imaging. In this study, the authors retrospectively evaluated the treatment of 54 patients with cerebellar astrocytoma who underwent surgery at the Mayo Clinic in Rochester, Minnesota, from 1978 through 1990. Preoperative and postoperative CT scans or MR images were available in all 54 patients.
The complement membrane attack complex and the bystander effect in cerebral vasospasm
Authors: Park Charles C. , Shin Moon L. , Simard J. Marc
Published: June 2009

✓ Activation of complement results in formation of membrane attack complexes (MACs) that can insert themselves either into cells that initiate complement activation or into nearby (“innocent bystander”) cells. The MACs form large-conductance, nonspecific ion channels that can cause lytic or sublytic cell damage. The authors used a highly sensitive patch clamp technique to assess the contribution of the bystander effect to the pathophysiology of cerebral vasospasm. They compared the effect of complement activation by autologous aged versus fresh erythrocytes on the membrane conductance of freshly isolated rat cerebral artery smooth-muscle cells. In the presence of autologous serum aged, but not fresh, erythrocytes caused a large increase in membrane conductance, an effect that was prevented by heat-inactivating the serum. Ethyleneglycol tetraacetic acid in the presence of Mg++attenuated the effect, indicating that complement activation was taking place via the classic pathway. The effect was reproduced by zymosan-activated autologous serum, suggesting that such changes in conductance could result from insertion of MACs secondary to a bystander effect. Both C8- and C9-depleted heterologous sera produced minimal effects that were converted to full effect by addition of the missing complement component. Superoxide dismutase plus catalase did not attenuate the conductance changes produced by autologous serum plus aged erythrocytes. Autologous serum plus aged erythrocyte membrane ghosts that were free of lysate caused a typical increase in conductance. This study demonstrates that complement activation by aged erythrocytes can result in MAC insertion into innocent bystander smooth-muscle cell membranes and that this mechanism, heretofore undescribed, may contribute to development of vasospasm after subarachnoid hemorrhage.
Microcirculation after cerebral venous occlusions as assessed by laser Doppler scanning
Authors: Nakase Hiroyuki , Kempski Oliver S. , Heimann Axel , Takeshima Toshikazu , Tintera Jaroslav
Published: June 2009

✓ Research on cerebral venous circulation disturbances (CVCDs) has been limited partly by the paucity of animal models that produce consistent venous infarction. Occlusion of two adjacent cortical veins in rats by means of a photochemical thrombotic technique provides a minimally invasive, clinically relevant, and reproducible model suited to study the pathophysiology of CVCDs. In this study, the effects of venous occlusion on regional cortical blood flow and the brain damage that ensues were evaluated.

Cortical vein occlusion was induced by photoactivation of rose bengal via 100-µm fiberoptic illumination. The cerebral venous flow pattern was examined using fluorescence angiography until 90 minutes after venous occlusion, and regional cerebral blood flow (rCBF) was determined at 48 locations by using laser Doppler scanning. Histological damage was assessed 48 hours after vein occlusion. Occlusion of two cortical veins (Group T; seven animals) was compared with single-vein occlusion and its ensuing brain damage (Group S; five animals) and with sham-operated control (five animals). An rCBF reduction occurred 30 minutes after occlusion in Group T and was more extensive than the decrease in Group S after 60 minutes. Observation frequency histograms based on local CBF data obtained in Group T demonstrated that local CBF at some sites decreased to a level below the ischemic threshold within 90 minutes. Six of the seven rats in Group T had a growing venous thrombus with extravasation of fluorescein. The resulting infarction was significantly larger in Group T (9.8 ± 4.5% of the hemispheric area) than in Group S (only 3 ± 1.5% of the hemispheric area).

In conclusion, microcirculation perturbations occur early after venous occlusion and result in the formation of a venous thrombus accompanied by local ischemia and severe venous infarction. The extent of vein occlusion determines the resulting brain damage. Based on the results of this study, the authors conclude that CVCDs may be attenuated by prevention of venous thrombus progression together with the use of protective measures against the consequences of ischemia.
Follow-up evaluation of dissecting aneurysms of the vertebrobasilar circulation by using gadolinium-enhanced magnetic resonance imaging
Authors: Nagahiro Shinji , Hamada Jun-ichiro , Sakamoto Yuji , Ushio Yukitaka
Published: June 2009

✓ The authors assessed the reliability of magnetic resonance (MR) imaging contrast enhancement for the detection and follow-up evaluation of dissecting aneurysms of the vertebrobasilar circulation. Twenty consecutively admitted patients who underwent both gadolinium-enhanced MR imaging and conventional angiography were reviewed. Enhancement of the dissecting aneurysm was seen in all but one of the 20 patients, including 10 (71%) of 14 patients examined in the chronic phases, when the T1-hyperintensity signal that corresponded to the intramural hematoma was unrecognizable. The enhanced area corresponded to the “pearl sign” or aneurysm dilation noted on the comparable angiogram. On follow-up MR studies enhancement had spontaneously disappeared in four patients at a time when comparable vertebral angiograms revealed disappearance of the aneurysm dilation. The enhancement persisted in five of nine patients examined more than 24 weeks after symptom onset; in all five patients the aneurysm dilation remained on comparable angiograms. Dynamic MR studies showed rapid and remarkable enhancements with their peaks during the immediate dynamic phase after injection of the contrast material. The authors conclude that gadolinium-enhanced MR imaging is useful for the detection and follow-up evaluation of dissecting aneurysms of the vertebrobasilar circulation.
Charles Labbé (1851–1889)
Authors: Bartels Ronald H. M. A. , Van Overbeeke Jacobus J.
Published: June 2009

✓ The vein of Labbé is a very important structure and every neurosurgeon is acquainted with its anatomy. Because of the recent increasing interest and experience in skull base surgery, the vein of Labbé has received a great deal of attention. Intraoperative damage to this vein should be avoided and several methods to prevent this have been described. Despite these developments, nothing is written in the neurosurgical literature about the man who described this vein for the first time: Charles Labbé. The authors therefore conducted an extensive search of the literature and uncovered several public records in France to learn more about Charles Labbé.
Chronic interstitial infusion of protein to primate brain: determination of drug distribution and clearance with singlephoton emission computerized tomography imaging
Authors: Laske Douglas W. , Morrison Paul F. , Lieberman Daniel M. , Corthesy Mark E. , Reynolds James C. , Stewart-Henney Patricia A. , Koong Sung-Soo , Cummins Alex , Paik Chang H. , Oldfield Edward H.
Published: June 2009

✓ High-flow interstitial infusion into the brain, which uses bulk fluid flow to achieve a relatively homogeneous drug distribution in the extracellular space of the brain, has the potential to perfuse large volumes of brain. The authors report reproducible long-term delivery of 111In—diethylenetriamine pentaacetic acid—apotransferrin (111In-DTPA-Tf) (molecular mass 81 kD) to Macaca mulatta brain and monitoring with single-photon emission computerized tomography (SPECT). The 111In-DTPA-Tf was infused at 1.9 µl/minute over 87 hours into the frontal portion of the centrum semiovale using a telemetry-controlled, fully implanted pump. On Days 1, 3, 4, 8, 11, and 15 after beginning the infusion, planar and SPECT scans of 111In-DTPA-Tf were obtained. Spread of protein in the brain ranged from 2 to 3 cm and infusion volumes ranged from 3.9 to 6.7 cm3. Perfusion of over one-third of the white matter of the infused hemisphere was achieved. From brain SPECT images of 99mTc—hexamethylpropyleneamine oxime, which was administered intravenously before each 111In scan, the authors also found that blood perfusion in the infused region was reduced by less than 5% relative to corresponding noninfused regions. Histological examination at 30 days revealed only mild gliosis limited to the area immediately surrounding the needle tract. These findings indicate that long-term interstitial brain infusion is effective for the delivery of drugs on a multicentimeter scale in the primate brain. The results also indicate that it should be possible to perfuse targeted regions of the brain for extended intervals to investigate the potential utility of neurotrophic factors, antitumor agents, and other materials for the treatment of central nervous system disorders.
Proliferation potential and histological features in neurofibromatosis 2-associated and sporadic meningiomas
Authors: Antinheimo Jussi , Haapasalo Hannu , Haltia Matti , Tatagiba Marcos , Thomas Sebastian , Brandis Almuth , Sainio Markku , Carpen Olli , Samii Madjid , Jääskeläinen Juha
Published: June 2009

✓ The authors compared the histological appearance and proliferation potential of 35 meningiomas in patients with neurofibromatosis 2 (NF2) and 30 sporadic meningiomas in age- and gender-matched patients without NF2. The NF2 meningiomas showed more mitotic figures (p < 0.001) and nuclear pleomorphism (p = 0.003) than the sporadic meningiomas; however, the incidence of meningothelial, fibroblastic, and transitional subtypes occurred equally in both groups. The proliferation potential was significantly higher in the 35 meningiomas removed from 23 patients with NF2 than in the 30 sporadic meningiomas removed in the 30 patients without NF2 (mean MIB-1 labeling indices: 2.5 vs. 1.75, p = 0.0147). The higher proliferation potential of the NF2 meningiomas may reflect differences in molecular biology between sporadic and NF2 meningiomas and may be related to an earlier onset, multiplicity, and more aggressive behavior of NF2 tumors.
In times of change learners inherit the earth
Authors: Rich J. Charles
Published: June 2009

✓ Neurosurgery, as traditionally practiced, is changing. Eric Hoffer observed, “In times of change learners inherit the earth; while the learned find themselves beautifully equipped to deal with a world that no longer exists.” Historically, learners have possessed certain attributes. They anticipate rather than react to change. They become essential facilitators within their altered environment. They are effective advocates for principled behavior and ethical practices. They skillfully communicate the new and technically arcane with a common touch. Learners also understand the lessons of history. The potential of process technology, illustrated by Morton's 1846 application of already well-understood science, in essence, to transform the profession of surgery by making painless operations possible, is one example. Voluntary professional associations such as organized neurosurgery can also learn from the contrasting experiences of the Donner Party and the Utah Pioneers as they made their way down the same canyon of the Wasatch mountain range during the summers of 1846 and 1847, respectively. Group dynamics during those two episodes differed strikingly. It was the vanguard party of Utah Pioneers who exemplified the characters of learners. They acted with unity, common purpose, and careful preparation designed to benefit those who followed them. Years from now, how will the current individual and institutional behavior of neurosurgeons and their associations be judged? An interval assessment is suggested at the April, 2012 American Association of Neurological Surgeons Annual Scientific Meeting. From that perspective, will it be determined that the neurosurgical discipline acted presciently, as would those Hoffer describes as learners? Will neurosurgery be said to have understood and thereby profited from the lessons of history? These are pertinent questions. The answers, considered as a proposed progress report 15 short years from now, could accurately predict the scientific and professional position that neurological surgery will occupy in the future. Deserved long-term success based on the effective, far-sighted behavior exhibited by learners is my confident expectation.
Upper cervical spine fusion in the pediatric population
Authors: Lowry David W. , Pollack Ian F. , Clyde Brent , Albright A. Leland , Adelson P. David
Published: June 2009

✓ The outcomes of 25 pediatric patients who underwent upper cervical or occipitocervical fusion at the authors' institution since 1983 were reviewed. At a mean age of 9 years, the patients presented with spinal instability that was associated with os odontoideum in 11 cases, rotatory subluxation in five cases, odontoid fracture in two cases, atlantooccipital dislocation in two cases, and congenital atlantoaxial instability in five patients, four of whom had Down's syndrome (trisomy 21). Ten children had abnormal findings on neurological examination preoperatively; however, nine experienced improvement or resolution of deficits as of their latest follow-up evaluation (mean 17 months). Fusion was achieved with the first operation in 21 of 25 patients; eventually it was attained in all but one. Four patients exhibited persistent spinal instability after an initial procedure. This was caused by erosion of a multistranded cable through the intact arch of C-2 in two cases, by pin site infection necessitating early halo removal in one case, and by slippage in a halo following a Gallie procedure, which was revised with a Brooks fusion in one case. This series, the largest yet published, shows that with appropriate surgical management, posterior upper cervical fusion in the pediatric population is highly successful. Careful attention to halo pin site care and caution in using multistranded cable in young patients may improve results.
Transpalatal approach for the extracranial surgical repair of transsphenoidal cephaloceles in children
Authors: Kennedy Erin M. , Gruber David P. , Billmire David A. , Crone Kerry R.
Published: June 2009

✓ The surgical treatment of transsphenoidal cephaloceles in children is controversial. Reduction and repair via a transcranial approach are associated with high postoperative rates of morbidity, mortality, and hypothalamic dysfunction. In this study, four patients, aged 3 to 35 months at surgery, underwent successful transpalatal repair of two encephaloceles and two meningoceles. Two patients presented with nasal obstruction in infancy, one presented with unexplained meningitis, and in one patient the lesion was found incidentally during evaluation for seizures. Two children had median cleft face syndrome, another had an associated Arnold—Chiari type I malformation, and the fourth had no other cranial abnormalities. All patients underwent preoperative evaluation including magnetic resonance (MR) imaging. Auditory, ophthalmological, genetic, endocrinological, or other evaluation was undertaken as indicated. Lesions were approached through the median raphe of the hard and soft palates. All cephaloceles were easily visualized and dissected after division of the nasal palatal mucosa. The dural sac and its contents were reduced by surface coagulation after division and dissection of the overlying mucosa. Once reduced, the bone defect was obliterated in three of four patients. The dura was not opened and anomalous neural elements were not resected. At follow-up evaluation, all patients demonstrated resolution of preoperative symptoms without evidence of infection or lasting morbidity. Follow-up MR imaging showed reduction in all cases. The authors conclude that this transpalatal approach is safe and reliable for the treatment of transsphenoidal cephaloceles in young children.
The transcallosal—transforaminal approach to the third ventricle with regard to the venous variations in this region
Authors: Türe Uğur , Yaşargil M. Gazi , Al-Mefty Ossama
Published: June 2009

✓ Surgical approaches to lesions located in the anterior and middle portions of the third ventricle are challenging, even for experienced neurosurgeons. Various exposures involving the foramen of Monro, the choroidal fissure, the fornices, and the lamina terminalis have been advocated in numerous publications. The authors conducted a microsurgical anatomical study in 20 cadaveric brain specimens (40 hemispheres) to identify an exposure of the third ventricle that would avoid compromising vital structures.

An investigation of the variations in the subependymal veins of the lateral ventricle in the region of the foramen of Monro was performed, as these structures are intimately associated with the surgical exposure of the third ventricle. In 16 (80%) of the brain specimens studied, 19 (47.5%) of the hemispheres displayed a posterior location of the anterior septal vein—internal cerebral vein (ASV—ICV) junction, 3 to 13 mm (average 6 mm) beyond the foramen of Monro within the velum interpositum, not adjacent to the posterior margin of the foramen of Monro (the classic description). Based on this finding, the authors advocate opening the choroidal fissure as far as the ASV—ICV junction to enlarge the foramen of Monro posteriorly. This technique achieves adequate access to the anterior and middle portions of the third ventricle without causing injury to vital neural or vascular structures.

The high incidence of posteriorly located ASV—ICV junctions is a significant factor influencing the successful course of surgery. Precise planning of the surgical approach is possible, because the location of the junction is revealed on preoperative neuroradiological studies, in particular on magnetic resonance venography. It can therefore be determined in advance which foramen of Monro qualifies for posterior enlargement to gain the widest possible access to the third ventricle. This technique was applied in three patients with a third ventricular tumor, and knowledge of the venous variations in this region was an important resource in guiding the operative exposure.
Noninvasive optical imaging of the subarachnoid space and cerebrospinal fluid pathways based on near-infrared fluorescence
Authors: Sakatani Kaoru , Kashiwasake-Jibu Masaki , Taka Yoshinori , Wang Shijie , Zuo Huancong , Yamamoto Katsuyuki , Shimizu Koichi
Published: June 2009

✓ The authors have developed a noninvasive optical method to image the subarachnoid space and cerebrospinal fluid pathways in vivo based on the near-infrared fluorescence of indocyanine green (ICG).

The ICG was bound to purified lipoproteins (ICG—lipoprotein) and injected into the subarachnoid space of neonatal and adult rats. The ICG fluorescence was detected by a cooled charge-coupled device camera. After injection of ICG—lipoprotein into the cerebral subarachnoid space of the neonatal rat, ICG fluorescence was clearly detected at the injection site through the skull and skin. The ICG fluorescence was observed in the cerebellum and the lumbar spinal cord 1 and 8 hours postinjection, respectively. After injection of ICG—lipoprotein into the lumbar spinal subarachnoid space of an adult rat, ICG fluorescence was observed from the injection site to the thoracic levels along the spinal subarachnoid space. In addition, with the rat's head tilted downward, ICG fluorescence had extended to the cerebral subarachnoid space by 1 hour postinjection. The ICG fluorescence imaging of the cerebral subarachnoid space demonstrated an increase in fluorescence intensity around the lambdoid suture and the forebrain. On dissection of the rat brain the former location was identified as the supracerebellar cistern and the latter as the olfactory cistern.

The results of this study are the first to demonstrate that an optical technique is applicable to imaging of the subarachnoid space and cerebrospinal fluid pathways in vivo. In addition, ICG—lipoprotein provides a sensitive optical tracer for imaging extravascular biological structures. Finally, ICG fluorescence imaging does not require an intricate imaging system because ICG is localized near the surface of the body.
Pheochromocytoma and multiple intracranial aneurysms: is it a coincidence?
Authors: Erbengi Aykut , Inci Servet
Published: June 2009

✓ The authors present a case of multiple intracranial aneurysms associated with a pheochromocytoma. The aneurysms were successfully clipped, and a suprarenal tumor located on the left side was totally removed. To the authors' knowledge this is the fourth reported case of these combined entities in the literature. The authors speculate on the possible etiopathogenesis of the relationship between intracranial aneurysms and attacks of hypertension caused by the presence of neoplasms that discharge acute and irregular levels of catecholamines, especially pheochromocytomas. Perioperative management designed to avoid undesired complications in this rare association is also discussed.
Aneurysm clips: magnetic quantification and magnetic resonance imaging safety
Authors: Dujovny Manuel , Alp M. Serdar , Dujovny Nadav , Zhao Y. J. , Gundamraj N. Rao , Misra Mukesh , Dobben Glen
Published: June 2009

✓ Knowledge of the magnetic properties of cerebral aneurysm clips in patients undergoing magnetic resonance (MR) imaging is imperative. The authors quantified in electromagnetic units the magnetic properties of 13 different types of aneurysm clips by using a vibrating sample magnetometer. Their results showed that the magnetic moment of these clips ranged from 0.15 EMU/g to as high as 152.7 EMU/g. Based on these results and tests of the movement of the clips during MR imaging, they conclude that aneurysm clips with a magnetic moment less than 1 EMU/g may be safely used during MR imaging. The quantification of magnetic properties into electromagnetic units by using a vibrating sample magnetometer is a reliable method applicable to any testing field gradient. This method can be used as a standard to measure and label the magnetic properties of aneurysm clips.
Temporary occlusion of the middle cerebral artery in intracranial aneurysm surgery: time limitation and advantage of brain protection
Authors: Lavine Sean D. , Masri Lena S. , Levy Michael L. , Giannotta Steven L.
Published: June 2009

✓ 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.
Incidence of cerebral vasospasm after endovascular treatment of acutely ruptured aneurysms: report on 69 cases
Authors: Murayama Yuichi , Malisch Tim , Guglielmi Guido , Mawad Michel E. , Viñuela Fernando , Duckwiler Gary R. , Gobin Y. Pierre , Klucznick Richard P. , Martin Neil A. , Frazee John
Published: June 2009

✓ Cerebral vasospasm is the most common cause of morbidity and mortality in patients admitted to the hospital after suffering aneurysmal subarachnoid hemorrhage (SAH). The early surgical removal of subarachnoid clots and irrigation of the basal cisterns have been reported to reduce the incidence of vasospasm. In contrast to surgery, the endovascular treatment of aneurysms does not allow removal of subarachnoid clots. In this study the authors measured the incidence of symptomatic vasospasm after early endovascular treatment of acutely ruptured aneurysms with Guglielmi detachable coils (GDCs).

Sixty-nine patients classified as Hunt and Hess Grades I to III underwent occlusion of intracranial aneurysms via GDCs within 72 hours of rupture. The amount of blood on the initial computerized tomography (CT) scan was classified by means of Fisher's scale. Symptomatic vasospasm was defined as the onset of neurological deterioration verified with angiographic or transcranial Doppler studies. Hypertensive, hypervolemic, hemodilution therapy, with or without intracranial angioplasty, was used to treat vasospasm after GDC placement.

Symptomatic vasospasm occurred in 16 (23%) of 69 patients. The clinical grade at admission and the amount of blood on the initial CT were both associated with the incidence of subsequent vasospasm. At 6-month clinical follow-up examination, 12 of these 16 patients experienced a good recovery, two were moderately disabled, and two patients had died of vasospasm.

In conclusion, the 23% incidence of symptomatic vasospasm in this series compares favorably with that found in conventional surgical series of patients with acute aneurysmal SAH. These results indicate that endovascular therapy does not have an unfavorable impact on cerebral vasospasm.
Cervical cord neurapraxia: classification, pathomechanics, morbidity, and management guidelines
Authors: Torg Joseph S. , Corcoran Thomas A. , Thibault Lawrence E. , Pavlov Helene , Sennett Brian J. , Naranja R. John , Priano Steven
Published: June 2009

✓ One hundred ten cases of the transient neurological phenomenon, cervical cord neurapraxia (CCN), are presented. The authors established a classification system for CCN, developed a new computerized measurement technique for magnetic resonance (MR) imaging, investigated the relationship of the cervical cord to the canal, and analyzed clinical, x-ray, and MR data. One hundred nine males and one female were included in the study; the average age of the participants was 21 years (range 13–33 years). All episodes occurred during sports participation; 87% occurred while the patient was playing football. Follow-up review lasting an average of 3.3 years was available for 105 patients (95%).

Narrowing of the sagittal diameter of the cervical canal in the adult spine was confirmed to be a causative factor. Cervical cord neurapraxia was not associated with permanent neurological injury and no permanent morbidity occurred in patients who returned to contact activities. Of the patients returning to contact activities, 35 (56%) experienced a recurrent episode. The risk of recurrence was increased with smaller spinal canal/vertebral body ratio (p < 0.05), smaller disc-level canal diameter (p < 0.05), and less space available for the cord (p < 0.05). There was no correlation between either the classification of the CCN episode or the disease noted on MR imaging and x-ray films and the risk of recurrence.

The authors conclude that: 1) CCN is a transient neurological phenomenon and individuals with uncomplicated CCN may be permitted to return to their previous activity without an increased risk of permanent neurological injury; 2) congenital or degenerative narrowing of the sagittal diameter of the cervical canal is a causative factor; 3) the overall recurrence rate after return to play is 56%; and 4) the risk of recurrence is strongly and inversely correlated with sagittal canal diameter and it is useful in the prediction of future episodes of CCN (p < 0.001). These data will enable the physician to counsel individuals regarding a predicted risk of recurrence based on canal measurements.
Pericollicular surgical approaches to the rhomboid fossa. Part I. Anatomical basis
Authors: Strauss Christian , Lütjen-Drecoll Elke , Fahlbusch Rudolf
Published: June 2009

✓ A safe paramedian approach to the rhomboid fossa for surgical treatment of intrinsic brainstem lesions is based on detailed knowledge of the morphometric anatomy of superficially located motor structures. The morphometry of the rhomboid fossa is described in this report on the basis of histological studies conducted in six human brainstem specimens, with special emphasis on the colliculus facialis and the trigona nervi hypoglossi and vagi. Morphometric data include analysis of shrinkage factors in each specimen. The colliculus is a landmark for the nervus facialis, oculomotor nuclei, and the paramedian pontine reticular formation. In the surgeon's view from the posterior approach, the colliculus covers an area of 5.7 mm in the mediolateral and 6.8 mm in the craniocaudal direction and is located 0.6 mm lateral to the median sulcus. The fibers of the nervus facialis come as close as 0.2 mm to the surface of the fourth ventricle. The colliculus is located 15.7 mm above the obex. The trigona nervi hypoglossi and vagi cover a rectangular area measuring 3.1 by 6.5 mm and serve as a landmark for lower cranial nerve nuclei. These nuclei are located 0.3 mm lateral to the midline. An area with a maximum extension of 0.9 cm between the colliculus and trigona can be used for an infracollicular paramedian approach. The same applies to a supracollicular approach cranial to the colliculus and caudal to the fibers of the nervus trochlearis within the medullary velum, with a craniocaudal extension of 4 mm. Superficial motor nuclei and fibers can be identified by neurophysiological mapping, which helps to define safe surgical corridors into the rhomboid fossa, thus reducing functional morbidity caused by the operative approach in intrinsic pontine and pontomedullary lesions.