bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical usefulness of bedside intracranial morphological monitoring: mobile computerized tomography in the neurosurgery intensive care unit
Authors: Gunnarsson Thorsteinn , Hillman Jan
Published: January 2008

The practice of modern neurointensive care is based on the use of multimodality monitoring to respond rapidly to physiological, biochemical, or morphological changes and avoid secondary brain injury. Until recently, one important monitoring method, computerized tomography (CT), has not been available for bedside use. The authors have over 3 years of experience with the routine use of bedside CT scanning and have developed their own method of scanning the patients in their beds. In this report, they describe three illustrative cases in which the mobile CT scanner was of great value in the management of difficult neurosurgical intensive care problems. It is concluded that the availability of bedside morphological monitoring in the neurosurgery intensive care unit is of great help in management and clinical decision making.
Basic concepts of immunology and neuroimmunology
Authors: Sehgal Anil , Berger Mitchel S.
Published: January 2008

The immune system is a complex network of specialized cells and organs that defends the human body against attack from foreign pathogens. The major lymphocytes involved in protecting the body against potential infections are B and T cells, which also play an important role in combating tumor growth. The cells of the immune system patrol the tissues and organs through both blood and lymphatic vessels, but some organs—including cornea, testes, and brain—are usually not patrolled by these cells. The brain has been thought to be an immune-privileged site because of the tight blood–brain barrier (BBB) that protects it. Few cells migrate to the brain under normal circumstances, because the BBB permits only certain molecules to cross into brain tissue. Recently, however, studies have shown that activated T cells exposed to antigen can cross the intact BBB and migrate into brain. This finding opens the path to developing effective means of immunotherapy for lesions of the central nervous system. The authors discuss basic facets of the immune system, review the current knowledge about human neuroimmunology, and survey current strategies for developing immunotherapy-based treatments for human brain tumors.
Comparative analysis of paracrine immunotherapy in experimental brain tumors
Authors: Lesniak Maciej S. , Sampath Prakash , DiMeco Francesco , Viglione Michael P. , Tyler Betty M. , Pardoll Drew M. , Brem Henry
Published: January 2008

Object

Local delivery of cytokines has been shown to have a potent antitumor activity against a wide range of malignant brain tumors. In this study, the authors examined the efficacy of treating central nervous system (CNS) tumors by transfecting poorly immunogenic B16/F10 melanoma cells with interleukin (IL)-2, IL-4, or granulocyte-macrophage–colony stimulating factor (GM-CSF) gene, and using these cells to deliver the cytokine locally at the site of the CNS tumor. The object was to determine which cytokine would possess the greatest antitumor activity and to further elucidate its mechanism of action.

Methods

The transfected B16/F10 cells were irradiated to prevent replication and injected intracranially into C57BL/6 mice (10 mice per group) along with nonirradiated, nontransfected B16/F10 (wild-type) melanoma cells. Sixty percent of mice treated with IL-2 (p < 0.001 compared with control) and 10% treated with IL-4 (median survival = 31 days, p < 0.001 compared with control) were long term survivors (> 120 days). The median survival for animals treated with GM-CSF was 22 days with no long term survivors (p = 0.01 compared with control). Control animals that received only wild-type cells had a median survival of 18 days (range 15–20 days). Histopathological examination of brains from animals killed at different times showed minimal infiltration of tumor cells in the IL-2 group, moderate infiltration of tumor cells in the IL-4 group, and gross tumor invasion and tissue necrosis in the GM-CSF group. Animals treated with IL-2 showed a strong CD8 T cell–mediated response, whereas IL-4 evoked a prominent eosinophilic infiltrate in the area of the tumor.

Conclusions

High levels of locally expressed IL-2 rather than IL-4 or GM-CSF stimulate a strong immunological cytotoxic antitumor response that leads to significant prolongation of survival in mice challenged with B16/F10 intracranial melanoma tumor cells. Consequently, IL-2 may be a superior candidate for use in paracrine immunotherapy.
In vitro efficacy of recombinant diphtheria toxin–murine interleukin-4 immunoconjugate on mouse glioblastoma and neuroblastoma cell lines and the additive effect of radiation
Authors: Kim Ki-Uk , Vallera Daniel A. , Ni Hsaio-Tzu , Cho Kwan H. , Low Walter C. , Hall Walter A.
Published: January 2008

Object

The prognosis for patients with primary malignant brain tumors is poor despite aggressive treatment, and tumor recurrence is common regardless of the chosen therapy. Although multimodal treatment does not provide a cure, it is necessary to determine which treatment modalities have the greatest cytotoxic effect and can potentially prolong survival. Immunotoxin therapy is a novel approach for the treatment of tumors, and it has been successfully used in the central nervous system. Because the interleukin (IL)–4 receptor is commonly expressed on brain tumor cells, the purpose of this study was to evaluate the cytotoxic effect of using a modified diphtheria toxin–murine IL-4 (DT390-mIL4) immunoconjugate for the treatment of murine brain tumor cell lines and to determine whether the addition of radiation therapy could potentiate the effect of this agent.

Methods

Spontaneous murine glioblastoma (SMA-560) and two neuroblastoma (Neuro-2a and NB41A3) cell lines were treated using DT390-mIL4 at different concentrations, and the anti–mouse IL-4 monoclonal antibody (11B11) was used for blocking its cytotoxicity. Other SMA-560 and Neuro-2a cell lines were treated using 500 cGy of radiation 3 hours before DT390-mIL4 treatment. Cytotoxity was evaluated using a trypan blue viability assay.

The immunoconjugate exhibited a dose-dependent cytotoxic effect with 50% inhibitory concentration values of 0.56 × 10−9 M in SMA-560, 1.28 × 10−9 M in Neuro-2a, and 0.95 × 10−10 M in NB41A3 cell lines. The cytotoxicity of DT390-mIL4 was specifically blocked by an excess of 11B11. Cytotoxicity was additive when the DT390-mIL4 at 10−9 M immunoconjugate administration was followed by radiation therapy.

Conclusions

These results indicate that the IL-4 receptor can be a target for diphtheria toxin fusion proteins and that radiation can potentiate the effects of DT390-mIL4. The development of multimodal approaches to treat malignant brain tumors with agents that have different mechanisms of action may be beneficial.
Induction of a therapeutic antitumor immunological response by intratumoral injection of genetically engineered Semliki Forest virus to produce interleukin-12
Authors: Yamanaka Ryuya , Zullo Susan A. , Tanaka Ryuichi , Ramsey Jay , Blaese Michael , Xanthopoulos Kleanthis G.
Published: January 2008

Object

The authors investigated immunogene therapy for malignant glioma to determine whether its therapeutic efficacy could be improved.

Methods

Four groups of 203-glioma–bearing mice were treated with injections of phosphate-buffered saline, Semliki Forest virus (SFV)–LacZ, retrovirus vector DFG–interleukin (IL)–12, and SFV-IL12, respectively.

The results indicated that therapeutic immunization with SFV-IL12 prolonged the survival of mice with established tumors. Semliki Forest virus induces apoptotic death to glioma cells, which facilitates the uptake of apoptotic cells by dendritic cells, providing a potential mechanism for enhanced immunogenicity.

Conclusions

Immunogene therapy with IL-12 via SFV may be an excellent candidate for the development of new cancer vaccines.
Dermal sinus tracts of the spine
Authors: Elton Scott , Oakes W. Jerry
Published: January 2008

Dermal sinus tracts in the spine range from asymptomatic pits to tracts with significant disease. These tracts may be associated with lesions that tether the spinal cord and can either become infected or produce neurological deficits. Over time the treatment of these lesions has varied little: complete resection and intradural exploration are the standard surgical interventions. The authors review their experience with 23 dermal sinus tracts treated in the last 19 years by the senior author. The clinical findings, radiographic appearance, treatment, and pathological findings of these lesions will be discussed. The authors will also provide a summary of the literature covering these lesions.
Cardiorespiratory fitness and the progression of carotid atherosclerosis in middle-aged men. Ann Intern Med 134:12–20, 2001
Authors: Couldwell William T.
Published: January 2008

Background

Good cardiorespiratory fitness has been associated with reduced risk for clinical events of atherosclerotic vascular diseases, but whether it is related to slower progression of early atherosclerosis is unclear. Objective: To study the association between cardiorespiratory fitness and the progression of early carotid atherosclerosis. Design: 4-year follow-up study. Setting: Eastern Finland. Participants: Population-based sample of 854 men 42 to 60 years of age. Measurements: Maximal oxygen uptake (VO2max [L/kg per minute]) was measured directly by using respiratory gas exchange in a cycle ergometer exercise test. Carotid atherosclerosis was assessed by using B-mode ultrasonography. Results: After adjustments for age, technical covariates, and cigarette smoking, VO2max had strong, inverse, and graded associations with 4-year increases i maximal intima-media thickness (IMT) (standard regression coefficient β = 0.120; P = 0.002); plaque height (β = 0.140; P < 0.001), surface roughness, and mean IMT (β = 0.080; P = 0.035). These associations weakened but remained statistically significant after additional adjustment for systole blood pressure, serum levels of apolipoprotein B, diabetes, and plasma fibrinogen levels. The increases in maximal IMT, surface roughness, and mean 26.1 mL/kg per IMT (23%, 32% and 100%, respectively) were larger among men in the lowest quartile of VO2max (< minute) than among those in the highest quartile (> 36.2 ML/kg per minute). Conclusions: Good cardiorespiratory fitness is associated with slower progression of early atherosclerosis in middle-aged men. These findings are important because they emphasize that middle-aged men can be evaluated for cardiorespiratory fitness to estimate their future risk for atherosclerotic vascular disease. Additional research is warranted to investigate a possible causal relationship between cardiorespiratory fitness and atherosclerosis.
Inactivation of the DNA-repair gene MGMT and the clinical response of gliomas to alkylating agents N Engl J Med 343:1350–1354, 2000
Authors: Stiefel Michael F. , Grady M. Sean
Published: January 2008

The DNA-repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) inhibits the killing of tumor cells by alkylating agents. MGMT activity is controlled by a promoter; methylation of the promoter silences the gene in cancer, and the cells no longer produce MGMT. We examined gliomas to determine whether methylation of the MGMT promoter is related to the responsiveness of the tumor to alkylating agents. METHODS: We analyzed the MGMT promoter in tumor DNA by a methylation-specific polymerase-chain-reaction assay. The gliomas were obtained from patients who had been treated with carmustine (1,3-bis(2-chloroethyl)-1-nitrosourea, or BCNU). The molecular data were correlated with the clinical outcome. RESULTS: The MGMT promoter was methylated in gliomas from 19 of 47 patients (40 percent). This finding was associated with regression of the tumor and prolonged overall and disease-free survival. It was an independent and stronger prognostic factor than age, stage, tumor grade, or performance status. CONCLUSIONS: Methylation of the MGMT promoter in gliomas is a useful predictor of the responsiveness of the tumors to alkylating agents.
Transmandibular, circumglossal, retropharyngeal approach for chordomas of the clivus and upper cervical spine
Authors: DeMonte Franco , Diaz Eduardo , Callender David , Suk Ian
Published: January 2008

Extensive clival tumors that involve both the midline and lateral skull base compartments, or those that extend inferiorly to the anterior cervical spine, are difficult to expose in a wide fashion using any of the transmaxillary, transoral, or transcervical routes. In the transmandibular, circumglossal, retropharyngeal (TCR) approach wide access of this region can be obtained, thus allowing for a more complete resection of tumor and infiltrated bone. It also provides for an improved ability to perform dural reconstruction, should it be necessary. Over the past 4 years four patients with extensive clival chordomas underwent resection via the TCR approach. Gross-total resection was achieved in two patients, a greater than 98% resection in one patient, and a greater than 95% resection in the fourth patient. The surgical technique, all approach-related complications and morbidity, and patient outcome are discussed. If an expanded exposure of the clivus is necessary, the TCR approach is a good choice as well as a useful surgical technique to have available.
Skull base chordomas: overview of disease, management options, and outcome
Authors: Lanzino Giuseppe , Dumont Aaron S. , Lopes M. Beatriz S. , Laws Edward R.
Published: January 2008

Cranial base chordomas are locally invasive tumors that, from a midline, clival location, extend in different directions and display various patterns of skull base invasion. Although histologically benign, their invasive nature makes true “oncological” resection virtually impossible to achieve in most cases, despite modern skull base surgical techniques. Moreover, because of the tumor's location and proximity to critical neural and vascular structures, surgery-related morbidity can be significant when an aggressive resection is undertaken. Cytoreductive surgery assumes a critical role in the management of these lesions. The choice of surgical approach and the extent of resection are dependent on several factors: location and extension of the tumor, the surgeon's philosophy and familiarity with a specific approach, and the patient's preexisting clinical status. Proton-beam radiotherapy seems to be effective as an adjunct to surgery in achieving local tumor control. The timing of radiation therapy, however, remains controversial. Gamma knife surgery has been proposed as an adjunctive therapy, but the limited experience and short follow-up periods do not permit formulation of meaningful conclusions at this time. Recurrences are common, although in a subset of patients prolonged disease-free survival is demonstrated.
Chordomas of the skull base: follow-up review and prognostic factors
Authors: Colli Benedicto O. , Al-Mefty Ossama
Published: January 2008

Object

Chordomas are rare tumors that arise from the remnants of the notochord. Because of their deep location, local infiltrative nature, and involvement of surrounding bone, treatment of chordoma is a challenge. The authors analyze the data and prognostic factors obtained during the follow-up period (range 1–150 months, median 38 months) in 53 patients with craniocervical junction chordoma and 10 patients with chondrosarcoma.

Methods

Several surgical approaches were used, and some tumor excisions required staged procedures. Survival was calculated according the Kaplan–Meier method. Statistical analysis was performed using the Fisher exact and Kruskal–Wallis tests. Radical/subtotal resection was achieved in 77.8% of the patients. The mortality rate during the follow-up period was 14.3%. In patients harboring chondrosarcoma better 5-year recurrence-free survival (RFS) rates were demonstrated than in those with chordoma (100% and 50.7%, respectively). Histological patterns (typical or chondroid chordoma) and patient age at onset of symptoms had no effect on the RFS rates. Radical/subtotal resections were associated with better RFS rates than partial resection. Adjuvant proton-beam radiotherapy was shown to increase the RFS rates compared with conventional radiotherapy (90.9% and 19.4%, respectively at 4 years posttreatment). Karyotypically abnormal tumors were associated with worst RFS rates as compared with karyotypically normal lesions (44.5% and 90.3%, respectively at 3 years). Cases of cranial nerve palsy, followed by CSF leakages were the most frequent postoperative complication. Permanent postoperative neurological deficit was observed in 28.6% of the patients.

Conclusions

A better prognosis was observed in patients with chondrosarcoma compared with those harboring chordoma. Histological pattern and the patient's age at symptom onset were not factors that influenced prognosis in cases of chordoma. Extensive resection and possibly adjuvant proton-beam radiotherapy provided better prognosis for these patients.
Identification of isochromosome 1q as a recurring chromosome aberration in skull base chordomas: a new marker for aggressive tumors?
Authors: Sawyer Jeffrey R. , Husain Muhammad , Al-Mefty Ossama
Published: January 2008

Object

The authors conducted a study of 22 skull base chordomas.

Methods

A series of 22 skull base chordomas was analyzed with G banding. Subsequently, metaphase cells obtained from three tumors were reexamined using multicolor spectral karyotyping. Clonal chromosome aberrations were identified in 11 cases, all of which were recurrent tumors. Three tumors showed a remarkable similarity in cytogenetic features, and these features appear to characterize a recurring combination of nonrandom chromosome aberrations, including isochromosome 1q, gain of chromosome 7, and monosomy for chromosomes 3, 4, 10,13, and 18. Isochromosome 1q was identified as the sole recurring structural chromosome rearrangement in these tumors. The pattern of chromosome loss reported in the progression of lumbosacral chordoma also appears to be true of skull base chordomas with the additional findings of isochromosome 1q, gain of chromosome 7, and loss of chromosome 18.

Conclusions

Skull base chordomas characterized by isochromosome 1q and monosomy 13 provide support for the concept of the loss of putative tumor suppressor loci on 1p and 13q and aggressive tumor behavior.
Osteoporotic vertebral fractures
Authors: Watts Nelson B.
Published: January 2008

Osteoporosis is a significant public health problem. Vertebral fractures are the most common fracture in patients with osteoporosis, occurring in approximately 750,000 cases each year. The fractures may cause acute or chronic pain, reduce the quality of life, and shorten life expectancy. Several medications are available that reduce the risk of fracture. Vertebroplasty and kyphoplasty (balloon-inflated expansion of collapsed vertebrae followed by injection of bone cement) may reduce or relieve pain in selected patients. Although surgery is rarely necessary for the management of osteoporotic vertebral fractures, it may be indicated for other reasons. No studies have been conducted to determine if the outcome of spinal fusion is different in patients with osteoporosis and, if it is, whether management of the patient's osteoporosis will improve the outcome.
Principles of bone healing
Authors: Kalfas Iain H.
Published: January 2008

Our contemporary understanding of bone healing has evolved due to knowledge gleaned from a continuous interaction between basic laboratory investigations and clinical observations following procedures to augment healing of fractures, osseous defects, and unstable joints. The stages of bone healing parallel the early stages of bone development. The bone healing process is greatly influenced by a variety of systemic and local factors. A thorough understanding of the basic science of bone healing as well as the many factors that can affect it is critical to the management of a variety of musculoskeletal disorders. In particular, the evolving management of spinal disorders can greatly benefit from the advancement of our understanding of the principles of bone healing.
Bone morphogenetic protein in spinal fusion: overview and clinical update
Authors: Subach Brian R. , Haid Regis W. , Rodts Gerald E. , Kaiser Michael G.
Published: January 2008

The widespread use of fusion procedures in the management of spinal disorders has led investigators to explore the use of growth and differentiation factors in such procedures. As an adjuvant to allograft bone or as a replacement for harvested autograft, bone morphogenetic proteins (BMPs) appear to improve fusion rates after spinal arthrodesis in both animal models and humans, while reducing the donor-site morbidity previously associated with such procedures. The use of recombinant genetic technology in the production of BMP has improved the efficiency, cost effectiveness, and safety of producing and using such materials. Recombinant human BMP-2 (rhBMP-2), as one of the first factors identified in the process of endochondral bone formation, has been extensively researched over the past decade. The efficacy and dose profile of this differentiation factor in the context of various carrier substrates has been investigated. Based on the encouraging results of preliminary studies, the future role of rhBMP-2 may lie in its replacement of autologous bone grafting and, consequently, the reduced need for instrumented fixation, while concurrently improving overall fusion rates. The authors provide an overview of BMP and review its use in clinical and laboratory settings.
Gene-based therapies for the induction of spinal fusion
Authors: Helm Gregory A. , Dayoub Hayan , Jane John A.
Published: January 2008

Numerous mesenchymal growth factors with osteogenic properties have now been identified. Although many of these proteins can induce bone formation when delivered on a carrier matrix, these approaches have not been fully developed in the laboratory or clinic. The expression of osteogenic proteins via direct or ex vivo gene therapy techniques is also compelling because high-level, long-term gene expression can now be achieved using novel viral and nonviral vectors. In this brief review the authors will highlight recent advances in genetic therapies for the induction of osteogenesis, as well as their potential use for the promotion of spinal arthrodesis.
Posterior fusion of the subaxial cervical spine: indications and techniques
Authors: Liu James K. , Das Kaushik
Published: January 2008

The biomechanical stability of the subaxial cervical spine (C3–7) can be compromised by numerous pathological processes, and the restoration of stability may ultimately require fusion and placement of rigid internal fixation devices. A posterior fusion and stabilization procedure is often used to treat cervical instability secondary to traumatic injury, rheumatoid arthritis, ankylosing spondylitis, neoplastic disease, infections, and previous laminectomy. Numerous techniques and advances in spinal instrumentation have evolved over the last 30 years. The authors review the indications and the various methods for stabilizing and fusing the subaxial cervical spine via posterior approaches.
Anterior cervical interbody fusion with hydroxyapatite graft and plate system
Authors: Bruneau Michael , Nisolle Jean-Francois , Gilliard Claude , Gustin Thierry
Published: January 2008

Object

In cases of spondylosis or spine trauma, cervical interbody grafts are sometimes required after anterior discectomy. To avoid morbidity related to the harvesting of iliac crest bone, numerous materials have been developed such as allografts, methylmethacrylate, biocompatible osteoconductive polymer, and coralline grafts or cages. Some of these materials, however, are inefficient for fusion or are associated with specific complications. Conversely, hydroxyapatite (HA) grafts have numerous advantages. For example, their mechanical properties provide adequate load resistance and their porosity allows infiltration by newly formed bone, leading to complete fusion. The authors studied the results of using HA grafts combined with plating in patients who underwent anterior cervical discectomy.

Methods

Fifty-four patients underwent 68 cervical interbody fusion procedures in which an HA graft and plating were used. Indications for surgery were radiculopathy (caused by soft-disc herniation or spondylosis) in 46 cases, spondylotic myelopathy in two cases, and spinal trauma in six cases. Postoperatively the patients were followed for a mean of 24.6 months. Patients underwent radiography to evaluate fusion, intervertebral disc height, and the degree of lordosis.

Clinically, excellent or good results (based on the Odon classification) were demonstrated in 91% of patients who presented with radiculopathy. Complete interbody fusion was achieved in 99% of all cases. Preoperative kyphotic deformities were corrected in all cases after surgery. Intervertebral disc height was maintained throughout follow up. Surgery-related morbidity was low; only one patient suffered from a permanent dysphagia. Graft deterioration was observed in 13 cases and two graft fractures occurred but without adversely affecting fusion. There were no cases of graft extrusion.

Conclusions

Hydroxyapatite grafts are very efficient in achieving cervical fusion, maintaining intervertebral disc height, and restoring lordosis. When combined with the placement of a cervical plate, immediate stability is achieved and graft displacement is prevented.
An introductory overview of orbital tumors
Authors: Darsaut Tim E. , Lanzino Giuseppe , Lopes M. Beatriz , Newman Steven
Published: January 2008

The term “orbital tumors” comprises a wide variety of lesions that often share the same cardinal clinical finding (exophthalmos) and clinical history. Age at presentation, associated ophthalmological findings, and radiological features, however, provide invaluable information as to the possible histological type of tumor. The present article serves as an introductory overview regarding the pathological characteristics, clinical features, radiological characteristics, and principles of treatment of orbital tumors.
Transcortical surgery for lateral ventricular tumors
Authors: Ellenbogen Richard G.
Published: January 2008

Object

Tumors of the lateral ventricle can be removed via two major approaches: the transcallosal or the transcortical route. The purpose of this study is to discuss the techniques and outcomes in transcortical surgery of tumors located in the lateral ventricle.

Methods

An experience with 29 consecutive lateral ventricular tumors resected via the transcortical route, over a 5-year period, is presented. The risks, complications, and outcomes of this surgical series, as well as those reported in the literature, are discussed. Surgical approaches to all five regions of the lateral ventricle are described. Neuropsychological, functional, and neurological outcomes are evaluated.

Conclusions

The transcortical technique makes it possible to resect lesions in each of the five regions of the lateral ventricle. It provides superior microsurgical working space and flexibility for maneuvering within the lateral ventricle. The key to a successful transcortical approach is an understanding of the functional anatomy of eloquent cortex to be broached, the location of the lesion, and its vascular supply. A clear understanding of the advantages and limitations of the transcortical approach makes performing this procedure for resection of large lesions in the ventricle both safe and effective. The majority of the patients in this series (86%) had a good outcome, returning to baseline functional status and suffering minimal morbidity. In the microsurgical era, transcortical surgery–related postoperative morbidity and outcome are dependent more on tumor histological type and site of origin than on approach.
Pediatric supratentorial intraventricular tumors
Authors: Suh Daniel Y. , Mapstone Timothy
Published: January 2008

A variety of mass lesions can arise within or in proximity to the ventricular system in children. These lesions are relatively uncommon, and they present a unique diagnostic and surgical challenge. The differential diagnosis is determined by tumor location in the ventricular system, clinical presentation, age of the patient, and the imaging characteristics of the lesion. In this report the authors provide an introduction to and an overview of the most common pediatric supratentorial intraventricular tumors. The typical radiographic features of each tumor and location preference within the ventricular system are reviewed. Management and treatment considerations are discussed. Examination of tissue samples to obtain diagnosis is usually required for accurate treatment planning, and resection without adjuvant therapies is often curative. The critical management decision frequently involves determining which lesions are appropriate for surgical therapy. Care ful preoperative neuroimaging is extremely useful in planning surgery. Knowledge of the typical imaging characteristics of these tumors can help to determine the diagnosis with relative certainty when a tissue sample has not been obtained, because a small subset of these lesions can be managed expectantly.
Definition of the adult Chiari malformation: a brief historical overview
Authors: Bejjani Ghassan K.
Published: January 2008

With the widespread use of newer neuroimaging techniques and modalities, significant tonsillar herniation is being diagnosed in more than 0.5% of patients, some of whom are asymptomatic. This puts the definition of the adult Chiari malformation to the test. The author provides a historical review of the evolution of the definition of the adult Chiari malformation in the neurosurgery, radiology, and pathology literature.
Treatment of Chiari type I malformation in patients with and without syringomyelia: a consecutive series of 66 cases
Authors: Alzate Juan C. , Kothbauer Karl F. , Jallo George I. , Epstein Fred J.
Published: January 2008

Object

The authors describe the results of performing a standard posterior craniovertebral decompression and placement, if indicated, of a syringosubarachnoid shunt for the treatment of patients with Chiari I malformation with and without syringomyelia.

Methods

This is a retrospectively analyzed consecutive series of 66 patients (mean patient age 15 years, range 1–53 years). The uniform posterior craniovertebral decompression consisted of a small suboccipital craniectomy, a C-1 laminectomy, microsurgical reduction of the cerebellar tonsils, and dural closure with a synthetic dural graft to increase the cerebrospinal fluid space at the craniocervical junction. The presence of a large syrinx, with significant thinning of the spinal cord tissue and obliteration of the spinal subarachnoid space, particularly when combined with syrinx-related symptoms, was an indication for the placement of a syringosubarachnoid shunt.

In 32 patients Chiari I malformation alone was present, and 34 in patients it was present in combination with syringomyelia. Clinical findings included pain, neurological deficits, and spinal deformity. The presence of syringomyelia was significantly associated with the presence of scoliosis (odds ratio 74.4 [95% confidence interval 8.894–622.4]).

All patients underwent a posterior craniovertebral decompression procedure. In 22 of the 34 patients with syringomyelia a syringosubarachnoid shunt was also placed. The mean follow-up period was 24 months (range 3–95 months). Excellent outcome was achieved in 54 patients (82%) and good outcome in 12 (18%). In no patient were symptoms unchanged or worse at follow-up examination, including four patients who initially required a second operation for persistent syringomyelia. Pain was more likely to resolve than sensory and motor deficits after decompressive surgery.

Radiological examination revealed normalization of tonsillar position in all patients. The syrinx had disappeared in 15 cases, was decreased in size in 17, and remained unchanged in two.

Conclusions

Posterior craniovertebral decompression and selective placement of a syringosubarachnoid shunt in patients with Chiari I malformation and syringomyelia is an effective and safe treatment. Primary placement of a shunt in the presence of a sufficiently large syrinx appears to be beneficial. The question of if and when to place a shunt, however, requires further, preferably prospective, investigation.
Cerebellar fits in children with Chiari I malformation
Authors: Pandey Aditya , Robinson Shenandoah , Cohen Alan R.
Published: January 2008

Object

The authors describe a series of children with Chiari I malformation who presented with fulminating symptoms of “cerebellar fits” characterized by drop attacks with or without deterioration of consciousness, opisthotonic posturing, and varying degrees of respiratory compromise.

Methods

A retrospective analysis was undertaken of the medical records of 47 consecutive patients undergoing surgery for symptomatic Chiari I malformations at Rainbow Babies and Children's Hospital.

Thirteen (28%) of the 47 patients presented with complaints consistent with cerebellar fits. Before the correct diagnosis was made, nine (69%) of the 13 children had previously undergone evaluation with electroencephalography and/or electrocardicography and Holter monitoring because of suspected cortical epilepsy or cardiogenic syncope. In each of the 13 children magnetic resonance imaging demonstrated pegged cerebellar tonsils herniated below the foramen magnum. A deep indentation or blanched discoloration of the cerebellar tonsils was noted in five (38%) of these 13 patients at the time of surgery. Of patients with symptomatic Chiari I malformations, the mean degree of tonsillar herniation was significantly less for those in whom cerebellar fits occurred than those in whom they were absent (8.8 mm and 13.9 mm, respectively; p = 0.007). In only one of the patients with cerebellar fits was a syrinx present, and this was a small focal lower thoracic collection. Spells resolved after surgery in all patients who presented with cerebellar fits.

Conclusions

Cerebellar fits may mimic other disorders such as cardiogenic syncope and epileptic seizures. The correct diagnosis may be delayed or the conditions may be misdiagnosed by those who fail to consider Chiari I malformation as a cause of drop attacks, abnormal extensor posturing, and apneic spells in children. The response to decompressive surgery in these patients is gratifying.
Phase-contrast magnetic resonance imaging of cerebrospinal fluid flow in the evaluation of patients with Chiari I malformation
Authors: Menick Barry J.
Published: January 2008

The author describes the methods used for obtaining and interpreting qualitative and quantitative data regarding cerebrospinal fluid flow (CSF) and cerebellar tonsillar motion at the craniocervical junction during the cardiac cycle in patients with Chiari I malformations.
Syringosubarachnoid shunt for syringomyelia associated with Chiari I malformation
Authors: Hida Kazutoshi , Iwasaki Yoshinobu
Published: January 2008

Object

The authors describe the surgical procedures for placing syringosubarachnoid shunts and the results of surgery, as well as the prevention of shunt malfunction.

Methods

The series consisted of 59 patients with syringomyelia associated with Chiari I malformation in whom syringosubarachnoid shunts were placed. Their ages ranged from 4 to 62 years (median 28 years). The follow-up period ranged from 13 to 219 months. The authors principally implanted the shunts in patients with large-sized syringes. Neurological improvement was satisfactory, and postoperative magnetic resonance imaging demonstrated that the syringes had resolved or decreased in size in all patients. Reoperation was necessary in 10 patients who were treated before 1993.

Conclusions

To prevent shunt malfunction, both dorsal root entry zone myelotomy and placement of the syringo-subarachnoid shunt tube into the ventral subarachnoid space are useful.
History of hydrocephalus and its treatments
Authors: Lifshutz Jason I. , Johnson Walter D.
Published: January 2008

Hydrocephalus has amazed and challenged clinicians throughout the history of medicine. In reviewing the treatment of hydrocephalus, the integral relationship between basic science and therapy is reaffirmed. As we embark into a new millennium, it is appropriate to reflect on the past studies of this disorder, review various attempted and currently used, and finally speculate on possible future directions in its treatment.
Irving S. Cooper and the early surgical management of movement disorders
Authors: Hornyak Mark , Rovit Richard L. , Simon Arlene Stolper , Couldwell William T.
Published: January 2008

Irving S. Cooper was a pioneer in the field of functional neurosurgery. During his very productive and controversial career, he proposed the surgical treatment of Parkinson disease (PD) by ligating the anterior choroidal artery to control tremor and rigidity. Subsequently, he developed seminal techniques for chemopallidectomy and cryothalamectomy for PD. He also attempted to use electrical stimulation of the cerebellum or the thalamus to treat spasticity. Cooper continued his work on brain stimulation until his death in 1985. He made video recordings of nearly all of his patients during his tenure (1977–1985) at New York Medical College.

Cooper's clinical video recordings were reviewed, and selected footage was compiled into a video history of Cooper's surgical management of various movement disorders. Included are pre-, post-, and some intraoperative recordings that Cooper made to document his treatment of patients with PD, tremor, Wilson disease, cerebral palsy, chorea, dystonia musculorum deformans, and some rarer entities.
Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis. N Engl J Med 344(19):1434-1441, 2001
Authors: Couldwell William T.
Published: January 2008

Background

Once-daily injections of parathyroid hormone or its amino-terminal fragments increase bone formation and bone mass without causing hypercalcemia, but their effects on fractures are unknown. Methods: We randomly assigned 1637 postmenopausal women with prior vertebral fractures to receive 20 or 40 microg of parathyroid hormone (1-34) or placebo, administered subcutaneously by the women daily. We obtained vertebral radiographs at base line and at the end of the study (median duration of observation, 21 months) and performed serial measurements of bone mass by dual-energy x-ray absorptiometry. Results: New vertebral fractures occurred in 14 percent of the women in the placebo group and in 5 percent and 4 percent, respectively, of the women in the 20-microg and 40-microg parathyroid hormone groups; the respective relative risks of fracture in the 20-microg and 40-microg groups, as compared with the placebo group, were 0.35 and 0.31 (95 percent confidence intervals, 0.22 to 0.55 and 0.19 to 0.50). New nonvertebral fragility fractures occurred in 6 percent of the women in the placebo group and in 3 percent of those in each parathyroid hormone group (relative risk, 0.47 and 0.46, respectively [95 percent confidence intervals, 0.25 to 0.88 and 0.25 to 0.861). As compared with placebo, the 20-microg and 40-microg doses of parathyroid hormone increased bone mineral density by 9 and 13 more percentage points in the lumbar spine and by 3 and 6 more percentage points in the femoral neck; the 40-microg dose decreased bone mineral density at the shaft of the radius by 2 more percentage points. Both doses increased total-body bone mineral by 2 to 4 more percentage points than did placebo. Parathyroid hormone had only minor side effects (occasional nausea and headache). Conclusions: Treatment of postmenopausal osteoporosis with parathyroid hormone (1-34) decreases the risk of vertebral and nonvertebral fractures; increases vertebral, femoral, and total-body bone mineral density; and is well tolerated. The 40-microg dose increased bone mineral density more than the 20-microg dose but had similar effects on the risk of fracture and was more likely to have side effects.
Motor cortex stimulation for deafferentation pain
Authors: Saitoh Youichi , Hirano Shun-ichiro , Kato Amami , Kishima Haruhiko , Hirata Masayuki , Yamamoto Kazumi , Yoshimine Toshiki
Published: January 2008

Object

The authors tested a modified motor cortex stimulation (MCS) protocol for the treatment of deafferentation pain in 15 patients: eight patients with poststroke pain, four with brachial plexus injury, two with phantom limb pain, and one with spinal cord injury.

Methods

Preoperative pharmacological tests were performed with phentolamine, lidocaine, ketamine, thiopental, morphine, and a placebo. In 12 patients we placed a 20– or 40–grid electrode in the subdural space to determine the best stimulation point for pain relief over a few weeks and therefore the optimum position for a permanent internal device. In four patients, the MCS devices were implanted in the interhemispheric fissure to reduce lower-extremity pain. In one patient, the MCS device was placed within the central sulcus, and a 20-grid electrode was placed on the brain surface. In two patients with pain extending from the upper extremity to the hyperbody, dual-electrode devices were implanted to drive two electrodes. In 10 of the 15 patients MCS-induced pain reduction was achieved (four with excellent, two with good, and four with fair alleviation of pain). The result of pharmacological testing indicated that patients with ketamine sensitivity seem to be good candidates for MCS.

Conclusions

Test stimulation with a subdural multigrid electrode was helpful in locating the best stimulation point for pain relief.
Motor cortex stimulation for neuropathic pain
Authors: Smith Helen , Joint Carlolf , Schlugman David , Nandi Dipankar , Stein John F. , Aziz Tipu Z.
Published: January 2008

Motor cortex stimulation is increasingly reported in the literature as a surgical option for the alleviation of neuropathic pain. The authors review the published literature and present their results including those demonstrated in a randomized controlled trial that confirmed the efficacy of the procedure. Patient selection and prediction of outcomes, however, remain difficult issues.
Epidural motor cortex stimulation with functional imaging guidance
Authors: Mogilner Alon Y. , Rezai Ali R.
Published: January 2008

Chronic epidural motor cortex stimulation (MCS) has been shown to have promise in the treatment of patients with refractory deafferentation pain. Precise placement of the electrode over the motor cortex region corresponding to the area of pain is essential for the success of this procedure. Whereas standard anatomical landmarks have been used in the past in conjunction with image guidance, the use of functional brain imaging can be beneficial in the precise surgical planning. The authors report the use of functional imaging–guided frameless stereotactic surgery for epidural MCS. Five patients underwent MCS in which functional imaging guidance was used. Prior to surgery, patients underwent magnetic resonance (MR) imaging with skin fiducial markers placed on standard anatomical reference prints, followed by magnetoencephalography (MEG) mapping of the sensory and motor cortices. In two patients, functional MR imaging was also performed using a motor task paradigm. The functional imaging data were integrated into a frameless stereotactic database by using a three-dimensional coregistration algorithm. Subsequently, a frameless stereotactic craniotomy was performed using the integrated anatomical and functional imaging data for surgical planning. Intraoperative somatosensory evoked potentials (SSEPs) and direct stimulation were used to confirm the target and final placement of the electrode.

Direct stimulation and SSEPs performed intraoperatively confirmed the accuracy of the functional imaging data. Trial periods of stimulation successfully reduced pain in three of the five patients who then underwent permanent internal placement of the system. At a mean 6-month follow up, these patients reported an average reduction in pain of 55% on a visual analog scale. The integration of functional and anatomical imaging data allows for precise and efficient surgical planning and may reduce the time necessary for intraoperative physiological verification.
Elevated jugular venous oxygen saturation after severe head injury
Authors: Cormio Manuela , Valadka Alex B. , Robertson Claudia S.
Published: January 2008

Object

The aim of this study was to investigate the incidence of elevated (≥ 75%) jugular venous oxygen saturation (SjvO2) and its relationship to cerebral hemodynamic and metabolic parameters and to outcome after severe head injury.

Methods

Data from 450 severely head injured patients admitted to the Neurosurgical Intensive Care Unit of Ben Taub General Hospital were analyzed retrospectively. The SjvO2 was measured in blood obtained from indwelling jugular bulb catheters. Patients were classified into the following categories: high (Group I), normal (Group II), or low SjvO2 (Group III) if their mean SjvO2 over the duration of monitoring was 75% or higher, 74 to 56%, or 55% or lower, respectively.

A high SjvO2 occurred in 19.1% of patients. There was no consistent relationship between SjvO2 and simultaneous cerebral blood flow (CBF) or cerebral perfusion pressure measurements. Compared with Groups II and III, the patients in Group I had a significantly higher CBF and lower cerebral metabolic rate of oxygen (CMRO2). In Group I, the out- comes were death or persistent vegetative state in 48.8% of patients and severe disability in 25.6%. These outcomes were significantly worse than for patients in Group II. Within Group I, the patients with a poor neurological outcome were older and more likely to have suffered a focal head injury; they demonstrated a lower CMRO2 and a greater rate of cerebral lactate production than the patients who attained a favorable outcome.

Conclusions

Posttraumatic elevation of SjvO2 is common but cannot be automatically equated with hyperemia. Instead, elevated SjvO2 is a heterogeneous condition that is associated with poor outcome after head injury and may carry important implications for the management of comatose patients.