bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility of frameless single-fraction stereotactic radiosurgery for spinal lesions
Authors: Gerszten Peter C. , Ozhasoglu Cihat , Burton Steven A. , Kalnicki Shalom , Welch William C.
Published: January 2008

Object

The role of stereotactic radiosurgery for the treatment of intracranial lesions is well established. Its use for the treatment of spinal lesions has been limited by the availability of effective target-immobilizing devices. In this study the authors evaluated the CyberKnife Real-Time Image-Guided Radiosurgery System for spinal lesion treatment involving a single-fraction radiosurgical technique.

Methods

This frameless image-guided radiosurgery system uses the coupling of an orthogonal pair of x-ray cameras to a dynamically manipulated robot-mounted linear accelerator possessing six degrees of freedom, which guides the therapy beam to the target without the use of frame-based fixation. Cervical lesions were located and tracked relative to osseous skull landmarks; lower spinal lesions were tracked relative to percutaneously placed gold fiducial bone markers. Fifty-six spinal lesions in 46 consecutive patients were treated using single-fraction radiosurgery (26 cervical, 15 thoracic, and 11 lumbar, and four sacral). There were 11 benign and 45 metastatic lesions.

Tumor volume ranged from 0.3 to 168 ml (mean 26.7 ml). Thirty-one lesions had previously received external-beam radiotherapy with maximum spinal cord doses. Dose plans were calculated based on computerized tomography scans acquired using 1.25-mm slices. Tumor dose was maintained at 12 to 18 Gy to the 80% isodose line; spinal cord lesions receiving greater than 8 Gy ranged from 0 to 1.3 ml (mean 0.3 ml). All patients tolerated the procedure in an outpatient setting. No acute radiation-induced toxicity or new neurological deficits occurred during the follow-up period. Axial and radicular pain improved in all patients who were symptomatic prior to treatment.

Conclusions

Spinal stereotactic radiosurgery involving a frameless image-guided system was found to be feasible and safe. The major potential benefits of radiosurgical ablation of spinal lesions are short treatment time in an outpatient setting with rapid recovery and symptomatic response. This procedure offers a successful alternative therapeutic modality for the treatment of a variety of spinal lesions not amenable to open surgical techniques; the intervention can be performed in medically untreatable patients, lesions located in previously irradiated sites, or as an adjunct to surgery.
Management of malignant tumors of the anterior skull base: experience with 76 patients
Authors: Bulsara Ketan R. , Fukushima Takanori , Friedman Allan H.
Published: January 2008

As the management of anterior cranial fossa malignancies has undergone significant evolution, decreases in morbidity and mortality rates have occurred. In this article, the authors discuss the clinical presentation, neuroimaging findings, and management options for common anterior skull base malignancies. Also discussed are surgery-related indications and principles.
Malignant tumors of the skull base
Authors: Shah Jatin P. , Bilsky Mark H. , Patel Snehal G.
Published: January 2008

Malignant tumors of the skull base have traditionally been difficult to control because of adjacent crucial anatomical structures and because of the inherent difficulty in accessing/resecting tumors and reconstructing surgical defects. Techniques in craniofacial surgery for malignant tumors of the skull base have advanced significantly since their first description. Advances in neuroimaging, surgical technique, perioperative care, and adjuvant treatment have contributed to improved results. Because the majority of malignant tumors requiring craniofacial resection involve the anterior skull base, this review focuses mainly on state-of-the-art surgical techniques as well as pertinent variations, complications and results.
Seizure-related outcome after corticoamygdalohippo-campectomy in patients with refractory temporal lobe epilepsy and mesial temporal sclerosis evaluated by magnetic resonance imaging alone
Authors: Cukiert Arthur , Buratini Jose Augusto , Machado Elcio , Sousa Alcione , Vieira Joaquim , Forster Cassio , Argentoni Meire , Baldauf Cristine
Published: January 2008

Object

The authors conducted a study to assess the efficacy of surgery in patients who underwent magnetic resonance (MR) imaging alone for localization of foci in temporal lobe epilepsy (TLE).

Methods

One hundred patients (43 men, 57 women) with a clinical diagnosis of TLE were prospectively studied (mean age 28 ± 9 years [± standard deviation {SD}]). All patients underwent high-resolution MR imaging, and in all unilateral mesial temporal sclerosis (MTS) was diagnosed by visual inspection. All patients underwent interictal pre-operative electroencephalography (EEG) and in 87 patients pre- and 1-year postoperative neuropsychological testing was performed. Both EEG and neuropsychological examinations were conducted in a blinded fashion, and these data were not taken into account during the surgery-related decision-making process. All patients underwent a corti-coamygdalohippocampectomy at the side of the MTS. Surgery-related outcome was rated as Class I (seizure free or simple partial seizures only) or Class II (⩾ 90% improvement). The follow-up period ranged from 18 to 48 months (mean 24 ± 5 months [±SD]). No patient underwent prolonged video-EEG monitoring, Wada testing, positron emission tomography, or single-photon emission computerized tomography.

In eighty-nine patients Class I results were achieved, and 11 Class II results were achieved postoperatively. There was no mortality in this series. Except for in two patients who underwent surgery in the dominant temporal lobe, there was no postoperatively cognitive decline. In these two patients verbal memory decline occurred, which was associated with posterior temporal cortical damage, demonstrated postoperatively on MR imaging. Twenty-five percent of the patients experienced improved memory function related to the nonoperated side, and 54% experienced a 10% gain in general intelligence quotient status.

Conclusions

In patients with clinically suspected TLE, MR imaging alone is able to localize temporal lobe foci correctly. Ruling out pseudoseizures remains the only indication for prolonged video-EEG recordings in this group of patients.
Status of fetal tissue transplantation for the treatment of advanced Parkinson disease
Authors: Greene Paul E. , Fahn Stanley
Published: January 2008

In the first double-blind, placebo-controlled randomized study of fetal tissue transplantation for the treatment of patients with advanced Parkinson disease (PD), investigators found that implanted dopaminergic tissue can produce measurable improvement in young PD in the absence of medication (that is, the “off” state). The results of the study, however, also highlighted several serious limitations of transplantation. In the group of older patients in the study (in the typical age range of individuals afflicted with PD) no improvement was derived from the implant despite positron emission tomography–documented scan evidence that the graft survived and produced dopamine. Patients in the study were selected because they experienced motor fluctuations, and the transplant did not improve dyskinesias or the time required to remain “on” medication for any subgroup of patients, including young patients. Five of 33 implant-treated patients developed involuntary movements (dyskinesias or dystonia) that could not be eliminated by reducing antiparkinsonian medications. These included four patients with the best responses to transplantation. Finally, some sham-operated patients experienced a dramatic placebo effect lasting at least 1 year, which justified the controversial sham surgery. The authors believe that these problems must be solved before fetal tissue transplantation can be considered a therapeutic option for PD.
Bone morphogenetic proteins: basic concepts
Authors: Rengachary Setti S.
Published: January 2008

The cellular and molecular events governing bone formation in the embryo, healing of a fractured bone, and induced bone fusion follow a similar pattern. Discovery, purification, and recombinant synthesis of bone morphogenetic proteins (BMPs) constiute a major milestone in the understanding of bone physiology. In this review the author discusses the mechanism of action, clinical applications, dosage, and optimum carriers for BMPs. The roles played by other growth factors are also discussed.
Cervical osteotomy for the correction of chin-on-chest deformity in ankylosing spondylitis
Authors: Mummaneni Praveen V. , Mummaneni Valli P. , Haid Regis W. , Rodts Gerald E. , Sasso Rick C.
Published: January 2008

The correction of chin-on-chest deformity is challenging and requires combined anterior and posterior approaches to the cervical spine. The authors describe a cervical osteotomy technique for the correction of chin-on-chest deformity in patients with ankylosing spondylitis (AS). This procedure can be accomplished using a posterior screw rod construct combined with an anterior hybrid plate system.

In patients with AS, a “front-back-front” approach may be necessary because of the deformity's rigidity. The authors describe the complicated intubation and anesthetic requirements for this approach. They performed an anterior discectomy, cervical osteotomy, and unilateral pediculectomy but did not place anterior instrumentation. Via a posterior approach, laminectomies, facetectomies, and the contralateral pediculectomy were then undertaken. A posterior cervical screw/rod system was placed and loosely connected to titanium rods. Intraoperatively the deformity was corrected by placing the neck in extension combined with compression of the posterior screws on the rods. The posterior construct is then tightened. Finally, an anterior cervical approach is performed to place a structural interbody graft and a hybrid anterior cervical plate construct.

The authors have successfully used this approach to correct a chin-on-chest deformity in a patient with ankylosing spondylitis. At 1-year follow-up examination, excellent resolution of the deformity and solid fusion had been achieved. They prefer to perform this procedure by using state-of-the-art anterior and posterior instrumentation systems.
Novel bioabsorbable interbody fusion spacer–assisted fusion for correction of spinal deformity
Authors: Austin Rebekah C. , Branch Charles L. , Alexander Joseph T.
Published: January 2008

Object

The authors report the cases of 12 patients with medically refractory mechanical low-back pain and intermittent radicular symptoms in whom radiography demonstrated evidence of multilevel lumbosacral degenerative kyphotic and scoliotic deformity and spondylolisthesis.

Methods

These patients underwent multilevel posterior lumbar interbody fusion in which Macropore bioabsorbable spacers were placed. Each patient underwent at least 1 year of clinical and radiographic follow up.

Conclusions

This series illustrates the novel use of bioabsorbable interbody spacers and fusion technique for correction of spinal deformity due to advanced degenerative kyphoscoliosis and spondylolisthesis.
Correction of adult scoliosis via a posterior-only approach
Authors: Lippman Caleb R. , Spence Caple A. , Youssef A. Samy , Cahill David W.
Published: January 2008

Object

Adult scoliosis is a pathologically different entity from adolescent idiopathic scoliosis. The curves are more rigid, and rotational deformity and multilevel sagittal vertebral slippages compound the coronal malalignment. To correct these deformities, a surgical anterior release procedure is usually required, as well as posterior instrumentation-assisted fusion. This exposes the patient to the risks of a second procedure and of a thoracotomy or laparotomy. To decrease these risks, the authors have performed an anterior release, posterior release, and reduction via a posterior-only approach. The purpose of this study was to analyze quantitatively the degree of pre- and postoperative coronal deformity, the extent of correction, and related complications.

Methods

Data obtained in 20 patients with adult scoliosis were retrospectively studied. Patients presented with persistent back or lower-extremity pain, progressive deformity, or progressive neurological deficit. Sixteen patients underwent Gill-type laminectomy, radical discectomy (including fracture of any anterior and lateral osteophytes), and posterior lumbar interbody fusion (PLIF) of all apical and adjacent segments. One to four anterior release procedures were performed in each patient. Posterior instrumentation was placed over three to 15 levels. Autograft was obtained from the laminectomy sites and posterior iliac crest for fusion. There were no deaths; all patients were followed for a minimum of 1 year. The mean coronal Cobb angle improved from 36° to 14.7°. All spondylolisthetic lesions were reduced to at least Grade I. At the most recent follow-up examination, evidence of fusion was demonstrated in all patients. Reoperation for adjacent-segment failure, cephalad to the highest level of fusion, was required in two cases.

Conclusions

In many cases of adult scoliosis, a satisfactory multiplanar correction may be obtained via a single posterior approach and by using extended PLIF techniques. Cephalad adjacent-segment failure remains a significant problem in patients with osteoporosis, and routine extension of posterior instrumentation to the upper thoracic spine should be considered in these cases.
Thoracic hemivertebra excision in adults via a posterior-only approach
Authors: Polly David W. , Rosner Michael K. , Monacci William , Moquin Ross R.
Published: January 2008

Hemivertebrae are a common cause of congenital scoliosis. Depending on their location and the magnitude of the resultant deformity, they may be asymptomatic or require treatment. In the past, treatment has focused on prevention of deformity progression in growing children. Little has been written about congenital scoliosis presenting in adulthood. Because the aging of the spine is a kyphosing process and hemivertebrae often present with a local segmental kyphotic alignment, this can become symptomatic. Excision of hemivertebrae is well established as a safe and effective procedure when treatment is required. Initially this was conducted via a combined anterior–posterior approach. Recently some authors have indicated that in the lumbar spine hemivertebra resection can safely and effectively be achieved via a single posterior transpedicular approach. The authors report two adult cases in which they performed posterior transpedicular lateral extracavitary excision of a thoracic, fully segmented hemivertebrae. Essentially complete correction of the deformity was achieved. There were no neurological complications. The patients were spared a thoracotomy and no chest tubes were required.
Cohen I, Navarro V, Clemenceau S, Baulac M, Miles R:On the origin of interictal activity in human temporal lobe epilepsy in vitro. Science 298:1418–1421, 2002
Authors: Couldwell William T.
Published: January 2008

The origin and mechanisms of human interictal epileptic discharges remain unclear. Here, we describe a spontaneous, rhythmic activity initiated in the subiculum of slices from patients with temporal lobe epilepsy. Synchronous events were similar to interictal discharges of patient electroencephalograms. They were suppressed by antagonists of either glutamatergic or gamma-aminobutyric acid (GABA)-ergic signaling. The network of neurons discharging during population events comprises both subicular interneurons and a subgroup of pyramidal cells. In these pyramidal cells, GABAergic synaptic events reversed at depolarized potentials. Depolarizing GABAergic responses in neurons downstream to the sclerotic CA1 region contribute to human interictal activity.
Okadaic acid–induced apoptosis in malignant glioma cells
Authors: Rami Bimal G. , Chin Lawrence S. , Lazio Barbara E. , Singh Satyendra K.
Published: January 2008

Object

Okadaic acid (OA), a potent protein phosphatase inhibitor, has been known to induce apoptosis in a variety of cell types. The authors attempted to characterize further this model by identifying proteins involved in this form of programmed cell death.

Methods

Cellular proliferation was assessed using a colorimetric nonradioactive proliferation assay and cell counts. Apoptosis was determined by fluorescent microscopy. Activation of the mitogen-activated protein kinase (MAPK) pathways was determined by immunoprecipitation of extracellular signal–regulated kinase (ERK), c-Jun-n-terminal kinase (JNK), and p38 followed by in vitro kinase assays. Western blot analyses were conducted to show inhibitory-κB (IκB) phosphorylation and degradation as well as Bax upregulation. The binding of nuclear factor–κB (NFκB) was shown by electrophoretic mobility shift assay.

Okadaic acid induced cell death in T98G human malignant cell lines (50% inhibiting concentration = 20–25 nM). In T98G cells YO-PRO fluorescent staining was identified, thus indicating an apoptotic mechanism with a smaller percentage of cells undergoing necrotic cell death. Additionally OA induced JNK and MAPK activities in a time-dependent manner, increased the expression of Bax, and increased IκB phosphorylation and NFκB activation. There was a temporal correlation between these subcellular events and the detection of apoptosis morphology in glioma cells.

Conclusions

The authors believe that OA acts by blocking dephosphorylation events, thus activating apoptotic pathways through ERK and JNK activity. Additionally Bax, IκB and NFκB may also play a role in regulating these pathways.
Bone grafting
Authors: Zipfel Gregory J. , Guiot Bernard H. , Fessler Richard G.
Published: January 2008

In recent years our understanding of spinal fusion biology has improved. This includes the continued elucidation of the step-by-step cellular and molecular events involved in the prototypic bone induction cascade, as well as the identification and characterization of the various critical growth factors governing the process of bone formation and bone graft incorporation. Based on these fundamental principles, growth factor technology has been exploited in an attempt to improve rates of spinal fusion, and promising results have been realized in preclinical animal studies and initial clinical human studies. In this article the authors review the recent advances in the biology of bone fusion and provide a perspective on the future of spinal fusion, a future that will very likely include increased graft fusion rates and improved patient outcome as a result of the successful translation of fundamental bone fusion principles to the bedside.
The Carotid Occlusion Surgery Study
Authors: Grubb Robert L. , Powers William J. , Derdeyn Colin P. , Adams Harold P. , Clarke William R.
Published: January 2008

The St. Louis Carotid Occlusion Study demonstrated that ipsilateral increased O2 extraction fraction (OEF) (Stage II hemodynamic failure) measured by positron emission tomography (PET) is a powerful independent risk factor for subsequent stroke in patients with symptomatic complete carotid artery (CA) occlusion. The ipsilateral ischemic stroke rate at 2 years has been shown to be 5.3% in 42 patients with normal OEF and 26.5% in 39 patients with increased OEF (p = 0.004). In patients in whom hemispheric symptoms developed within 120 days, the 2-year ipsilateral stroke rates were 12% in 27 patients with normal OEF and 50% in 18 patients with increased OEF. Previous PET studies have demonstrated that anastomosis of the superficial temporal artery (STA) to a middle cerebral artery (MCA) cortical branch can restore OEF to normal.

The authors discuss the undertaking of a study that will test the hypothesis that STA–MCA anastomosis, when combined with the best medical therapy, can reduce ipsilateral ischemic stroke by 40% at 2 years in patients with symptomatic internal CA occlusion and Stage II hemodynamic failure occurring within 120 days after surgery. Only patients with increased OEF distal to a symptomatic occluded CA will be randomized to surgery or medical treatment. The primary endpoint will be all strokes and death occurring between randomization and the 30-day postoperative cut off (with an equivalent period in the nonsurgical group), as well as subsequent ipsilateral ischemic stroke developing within 2 years. It is estimated that 186 patients will be required in each group. Assuming that 40% of PET scans will demonstrate increased OEF, this will require enrolling 930 clinically eligible individuals.
Selective cerebral revascularization as an adjunct in the treatment of giant anterior circulation aneurysms
Authors: O'Shaughnessy Brian A. , Salehi Sean A. , Mindea Stefan A. , Batjer H. Hunt
Published: January 2008

Cerebral revascularization, an indispensable component of neurovascular surgery, has been performed in the treatment of cranial base tumors, complex cerebral aneurysms, and occlusive cerebrovascular disease. The goal of a revascularization procedure is to augment blood flow distally. It can therefore be used as an adjunctive measure in the treatment of complex neurosurgical disease processes that require parent artery sacrifice for definitive treatment. In the treatment of giant anterior circulation aneurysms, for instance, a cerebral revascularization procedure may be considered in patients in whom the collateral circulation is marginal and in whom lesions may be treated either using a Hunterian-based strategy or clip-assisted reconstruction requiring a prolonged period of temporary occlusion. To date, there is no entirely effective method known to produce long-term tolerance to carotid artery (CA) sacrifice and, largely for that reason, some neurovascular surgeons advocate universal revascularization. The authors of this report, however, prefer to perform revascularization only in the limited subset of patients in whom preoperative assessment has revealed risk factors for cerebral ischemia due to hypoperfusion. In this paper, the authors introduce their protocol for assessing cerebrovascular reserve capacity, indications for cerebral revascularization in the treatment of complex anterior circulation aneurysms, and discuss their rationale for choosing to practice selective, rather than universal, revascularization.
Hypotensive endovascular test occlusion of the carotid artery in head and neck cancer
Authors: Dare Amos O. , Gibbons Kevin J. , Gillihan Matthew D. , Guterman Lee R. , Loree Thom R. , Hicks Wesley L.
Published: January 2008

Object

To evaluate the reliability of balloon test occlusion with hypotensive challenge (BTO and HC) as a predictor of neurological complications before internal carotid artery (ICA) sacrifice in patients with advanced head and neck cancer, the authors retrospectively reviewed the medical records of patients presenting to their institutions between 1992 and 1997 in whom this preoperative assessment was performed.

Methods

Eleven patents who were candidates for extended comprehensive neck dissection (ECND) and potential ICA sacrifice were included in the study. Eight patients tolerated the test and underwent endovascular occlusion or surgical ligation of the ICA before ECND (four patients), preservation of the ICA at the time of surgery (three patients), or palliative therapy (one patient). Of three patients in whom BTO and HC failed, one patient received palliative treatment only; the other two underwent ECND with preservation of the ICA. In the group of patients who passed the test and underwent ICA occlusion or ligation before ECND, fatal thromboembolic stroke occurred within 24 hours of permanent balloon occlusion in one patient, resulting in a combined neurological morbidity/mortality rate of 25% in this subset of patients and an overall complication rate of 9% in this series.

Conclusions

The authors found that BTO and HC offers a simple and reliable method of preoperative risk assessment when ICA resection is planned for regional control of disease in advanced head and neck cancer. This management option, however, is associated with a potential for neurological complication that must be weighed against the natural course of the disease and the risks and benefits of other treatment modalities.
Extracranial–intracranial bypass for symptomatic occlusive cerebrovascular disease not amenable to carotid endarterectomy
Authors: Tummala Ramachandra P. , Chu Ray M. , Nussbaum Eric S.
Published: January 2008

Object

The role of cerebral revascularization remains unclear in symptomatic occlusive cerebrovascular disease refractory to medical therapy. Despite the disappointing findings of the Cooperative Study on Extracranial–Intracranial Bypass, a subpopulation of patients with ischemic cerebrovascular disease and poor hemodynamic reserve may benefit from extracranial–intracranial (EC–IC) bypass. The authors reviewed the records of 65 patients who underwent 71 EC–IC bypass procedures at their institution over the past 6 years.

Methods

All patients except one presented with repeated transient ischemic attacks (TIAs) that were referable to the involved vascular region. Eight patients underwent EC–IC bypass urgently for “crescendo” TIAs refractory to anti-platelet and anticoagulation therapy. Indications for surgery included cervical internal carotid artery (ICA) occlusion in 28, supraclinoid ICA stenosis in two, middle cerebral artery stenosis or occlusion in 14, moyamoya disease in 18, and ICA dissection in three. Cerebral angiography demonstrated poor collateral flow to the involved region in each case. There were no postoperative strokes or deaths in this series. Following EC–IC bypass, the vast majority (95.4%) of patients experienced cessation of their ischemic events and stabilization of preexisting neurological dysfunction. Of the eight patients who underwent EC–IC bypass urgently for crescendo TIAs, two awoke with increased neurological deficits that improved rapidly within 24 hours of surgery.

Conclusions

Although the Cooperative Study failed to show benefit from this treatment modality, the authors have continued to perform EC–IC bypass in certain cases. Carefully selected individuals with occlusive cerebrovascular disease and persistent ischemic symptoms refractory to maximal medical therapy appear to benefit from cerebral revascularization.
Intracranial hypertension and cerebral ischemia after severe traumatic brain injury
Authors: Hlatky Roman , Valadka Alex B. , Robertson Claudia S.
Published: January 2008

Arterial hypotension and intracranial hypertension are detrimental to the injured brain. Although artificial elevation of cerebral perfusion pressure (CPP) has been advocated as a means to maintain an adequate cerebral blood flow (CBF), the optimal CPP for the treatment of severe traumatic brain injury (TBI) remains unclear. In addition, CBF evolves significantly over time after TBI, and CBF may vary considerably in patient to patient. For these reasons, a more useful approach may be to consider the optimal CPP in an individual patient at any given time, rather than having an arbitrary goal applied uniformly to all patients. Important information for optimizing CBF is provided by monitoring intracranial pressure in combination with assessment of the adequacy of CBF by using global indicators (for example, jugular oximetry), supplemented when appropriate by local data, such as brain tissue oxygen tension.
De novo cerebellar medulloblastoma in a 26-year recurrence-free case of temporal glioblastoma multiforme
Authors: Fandino Javier , Siegel Adrian M. , Laeng R. Hubert , Yaºargil M. Gazi
Published: January 2008

The authors describe a patient who survived 26 years after resection of a right temporal glioblastoma multiforme (GBM) without signs of tumor recurrence. Preoperative emergency angiography demonstrated a hypovascular mass localized in the right temporal lobe with right-to-left shift of the vascular structures. At surgery, the tumor had cystic and solid components localized in the lateral occipitotemporal gyrus, reaching the posterolateral wall of the inferior horn of the right lateral ventricle and extending to the trigone and posterior horn. The initial pathological diagnosis of a GBM was reviewed and confirmed throughout the follow-up period. Twenty-six years after surgery and subsequent radiosurgery, the patient underwent resection of a medulloblastoma localized in the right cerebellum as well as stereotactic biopsy sampling of tissue at the original GBM site. Neither radiological nor histological evidence of recurrence of the GBM could be documented. The intraoperative, histological, and radiological findings are described.
Molecular genetic analysis of phosphatase and tensin homolog and p16 tumor suppressor genes in patients with malignant glioma
Authors: Abdullah Jafri Malin , Zainuddin Norafiza , Sulong Sarina , Jaafar Hasnan , Isa Mohamad Nizam
Published: January 2008

Object

Several genes have been shown to carry mutations in human malignant gliomas, including the phosphatase and tensin homolog (PTEN) deleted on chromosome 10 and p16 tumor suppressor genes. Alterations of this gene located on chromosome 10 q23 and 9p21, respectively, may contribute to gliomagenesis. In this study, the authors analyzed 20 cases of malignant gliomas obtained in patients living on the east coast of Malaysia to investigate the possibilities of involvement of the PTEN and p16 genes.

Methods

Samples of DNA were amplified by polymerase chain reaction (PCR), analyzed by single-stranded conformation polymorphism (SSCP), and subsequently by sequencing. Two cases of glioblastoma multiforme, three cases of anaplastic astrocytoma, one case of anaplastic pleomorphic xanthoastrocytoma, and one case of anaplastic ependymoma showed SSCP band shifts in PTEN mutational analyses. The DNA sequencing analyses of these samples revealed missense and nonsense mutations, with cluster of mutations in the region 5' to the core phosphatase motif of exon 5 and the 5'-end of exon 6. No abnormal migration shifts were detected in the glioma samples analyzed for point mutations of the p16 gene. Homozygous deletions of p16 were also not detected in all samples.

Conclusions

These findings indicate that mutations of the PTEN genes were likely to contribute to the tumorigenesis and morphological transformations of gliomas. In addition, the alterations of the p16 gene might not play a major role in tumorigenesis of malignant gliomas in Malaysian patients.
Stereotactic radiosurgery for pituitary tumors
Authors: Witt Thomas C.
Published: January 2008

Pituitary adenomas frequently pose challenging clinical problems. Stereotactic radiosurgery (SRS) is one treatment option in selected patients. The purpose of this report is to identify the advantages and disadvantages of radiosurgery in cases of pituitary tumors to assess better its role in relation to other treatment. Methods for optimizing outcome are described. The author reviews several recent series to determine rates of growth control, endocrine response, and complications. In general, growth control is excellent, complications are very low, and reduction of excessive hormone secretion is fair. Depending on the clinical situation, SRS may be the treatment of choice in selected patients.
Long-term results of gamma knife surgery for craniopharyngioma
Authors: Kobayashi Tatsuya , Kida Yoshihisa , Hasegawa Toshinori
Published: January 2008

Object

One hundred seven cases of craniopharyngiomas were treated using gamma knife surgery (GKS) at Komaki City Hospital during the past 12 years. The authors report the long-term results obtained in 100 patients who were followed for 6 to 148 months (mean 65.5 months).

Methods

All patients underwent GKS. The mean tumor diameter and volume were 18.8 mm and 5.8 ml, respectively; lesions were treated with a maximum dose of 21.8 Gy and marginal dose of 11.5 Gy (mean isocenters 4.5). Overall tumor responses were complete in 19, partial in 44, no change in 14, and disease progression in 23, yielding a complete response rate of 19%, overall response rate of 63%, control rate of 77%, and progression rate of 23%. Considering factors such as patient age, nature of the tumor (solid, mixed, cystic), frequency of previous treatments, and tumor size, the age and nature of the tumor were significant prognostic factors.

Changes in neurological and pituitary–hypothalamic symptoms after GKS were evaluated in 91 patients. Overall improvement was demonstrated in 17 (18.7%), no change in 59 (64.8%), and deterioration in 15 (16.5%). Outcome was documented in 93 cases: excellent in 42, good in 23, fair in seven, poor in three, and dead in 18 patients.

Conclusions

Stereotactic GKS is a safe and effective treatment as an adjuvant or boost therapy for postresection residual and/or recurrent craniopharyngiomas; the effects are durable and side effects acceptable.
Stereotactic radiosurgery for meningiomas
Authors: Chin Lawrence S. , Szerlip Nicholas J. , Regine William F.
Published: January 2008

Meningiomas are benign tumors attached to the dura that typically have a slow growth rate. After gliomas, they are the most common primary tumor of the brain. They are ideal radiobiological targets because single-fraction radiation has a high biologically effective dose. Furthermore, a highly conformal radiation plan can provide effective treatment to the tumor while sparing the surrounding brain. Meningioma control rates range from 90 to 95%, and the risk of morbidity is low. Radiosurgery is an excellent treatment for asymptomatic, small- to moderate-sized meningiomas. It is also ideal for patients with incompletely resected meningiomas, recurrent meningiomas, and risk factors precluding conventional surgery.
Use of the Leksell gamma knife C with automatic positioning system for the treatment of meningioma and vestibular schwannoma
Authors: Levivier Marc , Lorenzoni Jose , Massager Nicolas , Ruiz Salvador , Devriendt Daniel , Brotchi Jacques
Published: January 2008

Object

The authors report their experience using the Leksell gamma knife C (GK-C) for the treatment of meningioma and vestibular schwannoma (VS).

Methods

In December 1999, the first commercially available clinical GK-C was installed at the Université Libre de Bruxelles (Erasme Hospital, Brussels, Belgium). In January 2000, the system was upgraded and equipped with the automatic positioning system (APS). Between February 2000 and February 2003, the APS-equipped GK-C was used to perform 532 radiosurgical treatments, including those in 97 meningiomas and 101 VSs.

Meningioma and VS represent 18 and 19%, respectively, of lesions in patients treated with GK-C at the authors' center. The mean number of isocenters per lesion was 9.5 (range 1–36): 18.1 (range 1–36) for meningioma and 12.8 (range 1–27) for VS. In 77.6% of the cases, the authors used a single helmet of collimators (55.5% in meningioma and 74.3% in VS). The most frequently used collimator size was 4 mm (46.7%). Whereas it was 4 mm in cases of VS (64.3%), it was 8 mm in cases of meningioma (41.6%). The APS could be used in 86% of the cases, either alone (79%) or in combination with trunnions (7%). There was a difference in the APS-based treatment success rate in meningiomas (85%) and VSs (94%). A significant difference was also noted in the conformity of the radiosurgical treatments between the two lesions.

Conclusions

The APS-equipped GK-C represents an evolutionary step in radiosurgery. It requires adjustments by the treating team for its specific limitations, which vary among indications, as exemplified by the differences inherent between meningioma and VS in this series.
Avoidance of structural pitfalls in spinal meningioma resection
Authors: Misra Sanjay N. , Morgan Howard W.
Published: January 2008

Creating a surgical avenue through which to resect an intraspinal meningioma requires dissection of the musculoligamentous structures of the spine. Variable vertebral components must be removed to create a corridor to the intraspinal compartment. The cardinal principles of intraspinal tumor resection are to minimize the intraoperative risk of deformation and traumatic injury of the spinal cord. Therefore, the appropriate planning for access to and removal of the osseous elements is critical. Of equal importance is the consideration of the biomechanics of the spine. In cases of potential spinal instability instrumentation-assisted fusion should be performed at the time of tumor resection. The authors discuss the techniques for creating access to these tumors and propose a simple classification scheme to assist with this decision-making process.
Falcotentorial meningiomas: clinical, neuroimaging, and surgical features in six patients
Authors: Quinones-Hinojosa Alfredo , Chang Edward F. , McDermott Michael W.
Published: January 2008

Object

Meningiomas arising from the falcotentorial junction are rare. As a result, their clinical presentation and surgical management are not well described. During the past 3 years, the authors have treated six patients with falcotentorial meningiomas.

Methods

Most patients presented with symptoms related to raised intracranial pressure, including headaches, papilledema, and visual and gait disturbances. Magnetic resonance imaging revealed a smooth, oval, or round mass, which was typically homogeneously enhancing. Angiography was useful in evaluating arterial supply for embolization, when possible, and determining the status of venous collateral supply and sinus patency. The authors detail the surgical technique used in all six patients. Postoperatively, patients experienced transient cortical blindness, which in all cases spontaneously resolved during the course of several days to weeks. They provide a comprehensive description of the presentation and surgical management of falcotentorial meningiomas.

Conclusions

An excellent outcome can be expected when surgery is predicated on detailed preoperative neuroimaging and knowledge of the nuances of the surgical technique.
Olfactory groove meningiomas
Authors: Hentschel Stephen J. , DeMonte Franco
Published: January 2008

Object

Olfactory groove meningiomas (OGMs) arise over the cribriform plate and may reach very large sizes prior to presentation. They can be differentiated from tuberculum sellae meningiomas because OGMs arise more anterior in the skull base and displace the optic nerve and chiasm inferiorly rather than superiorly.

Methods

The authors searched the neurosurgery database at the M. D. Anderson Cancer Center for cases of OGM treated between 1993 and 2003. The records of these patients were then reviewed retrospectively for details regarding clinical presentation, imaging findings, surgical results and complications, and follow-up status.

Thirteen patients, (12 women and one man, mean age 56 years) harbored OGMs (mean size 5.7 cm). All patients underwent bifrontal craniotomies and biorbital osteotomies. There were 11 complete resections (including the hyperostotic bone and dura of the cribriform plate and any extension into the ethmoid sinuses) and two subtotal resections with minimal residual tumor left in patients with recurrent lesions. No complication directly due to the surgery occurred in any patient. There were no recurrences in a mean follow-up period of 2 years (range 0–5 years).

Conclusions

With current microsurgical techniques, the results of OGM resection are excellent, with a high rate of total resection and a low incidence of complications. All hyperostotic bone should be removed with the dura of the anterior skull base to minimize the risk of recurrence.
Management of surgical clinoidal meningiomas
Authors: Tobias Samuel , Kim Chang-Hyun , Kosmorsky Gregory , Lee Joung H.
Published: January 2008

Object

Clinoidal meningiomas remain a major neurosurgical challenge. Surgery-related outcome has been less than desirable in the past, and little attention has been directed toward improving visual deficits. The authors advocate a skull base technique for the removal of these difficult tumors and describe its advantages in terms of improving extent of resection and enhancing overall outcome, particularly visual function.

Methods

A retrospective analysis was performed on data obtained in 26 consecutive patients with clinoidal meningiomas (including one patient with hemangiopericytoma) who underwent resection between June 1995 and January 2003. In 24 cases the skull base procedure involved extradural anterior clinoidectomy, optic canal unroofing, and optic sheath opening; in two cases a standard pterional craniotomy was performed. Fourteen of the 26 patients suffered significant preoperative visual deficits. All patients underwent thorough pre- and postoperative ophthalmological evaluations. The follow-up period ranged from 3 to 91 months (mean 42.3 months). Total resection was achieved in 20 patients (77%), and the majority (76.9%) of patients with preoperative visual impairment experienced significant improvement.

Conclusions

With the use of the skull base technique, total resection and excellent visual outcome may be achieved with minimal morbidity in most patients with clinoidal meningiomas.
Surgical management of posterior petrous meningiomas
Authors: Liu James K. , Gottfried Oren N. , Couldwell William T.
Published: January 2008

Posterior petrous meningiomas (commonly termed posterior pyramid meningiomas and/or meningiomas of the posterior surface of the petrous pyramid) are the most common meningiomas of the posterior cranial fossa. They are located along the posterior surface of the temporal bone in the region of the cerebellopontine angle. They often mimic vestibular schwannomas, both clinically and on neuroimaging studies. Common clinical symptoms include hearing loss, cerebellar ataxia, and trigeminal neuropathy. The site of dural origin determines the direction of cranial nerve displacement. Total resection can be achieved in most cases with a low morbidity rate and an excellent prognosis. The authors review the surgical management of posterior petrous meningiomas.
Anatomy of the combined retrolabyrinthine–middle fossa craniotomy
Authors: Oghalai John S. , Jackler Robert K.
Published: January 2008

The goal of combined retrolabyrinthine–middle fossa craniotomy is to provide exposure of both the middle and posterior cranial fossae via a partial petrosectomy and division of the tentorium. Its major benefits over others are that hearing and facial nerve function are preserved and only minimal brain retraction is required. The retrolabyrinthine approach involves a presigmoid posterior fossa craniotomy that preserves the structures of the inner ear. Additionally, a middle fossa craniotomy, extending to the zygomatic root, is performed to gain access to the superior aspect of the temporal bone in the middle cranial fossa. This approach works well in cases of lesions involving the petroclival junction, including petroclival meningiomas, trigeminal schwannomas, epidermoids, and large chondrosarcomas or chordomas with intradural components. The authors describe the surgical technique of this approach.
Meningiomas of the velum interpositum: surgical considerations
Authors: Lozier Alan P. , Bruce Jeffrey N.
Published: January 2008

Meningiomas of the third ventricle are a rare subtype of pineal region tumor that arise from the posterior portion of the velum interpositum, the double layer of pia mater that forms the roof of the third ventricle. The authors review the literature concerning these meningiomas and present a case in which the lesion was resected via the supracerebellar–infratentorial approach. The relationship of the tumor to the deep venous system and the splenium of the corpus callosum guides the selection of the most advantageous surgical approach. Posterior displacement of the internal cerebral veins demonstrated on preoperative imaging provides a strong rationale for use of the supracerebellar–infratentorial approach.
Neurotrophic factor in the treatment of Parkinson disease
Authors: Yoo Young Mi , Kim Yong Jung , Lee Uhn , Paik Doo Jin , Yoo Hyun Tae , Park Cheol Wan , Kim Young Bo , Lee Sang Goo , Kim Woo Kyung , Yoo Chan Jong
Published: January 2008

Object

Parkinson disease (PD) is a well-known degenerative disease resulting in the depletion of dopamine-producing neurons in the pars compacta of the substantia nigra. Adenoviral vector delivery of neurotrophic factors may provide a potential therapy for PD. The authors examined whether glial cell line–derived neurotrophic factor (GDNF) delivered via adenoviral vector (Ad-GDNF) could promote functional recovery in a rat model of PD. Additionally, they examined whether neural precursor cells (NPCs) provide the therapeutic potential of cultured neural cells for cell regeneration and replacement in PD.

Methods

All animals underwent stereotactic injection of 6-hydroxydopamine into the right substantia nigra. Eight weeks later, the rats were tested for apomorphine-induced rotational asymmetry and evaluation of explanted grafts infected with the complementary DNA for GDNF containing NPCs and NPCs alone. In the NPC cultures of embryonic rat striata, the authors found that basic fibroblast growth factor induced the proliferation of stem cells, which give rise to spheres of undifferentiated cells that generate neurons and glia.

Conclusions

In this study the authors found that the reduction of apomorphine-induced rotation was more prominent in parkinsonian rats that received Ad-GDNF-treated grafts containing NPCs (61%) than in those that received grafts of NPCs alone (16%).
Applications and limitations of perfusion-dependent functional brain mapping for neurosurgical guidance
Authors: Pouratian Nader , Sheth Sameer , Bookheimer Susan Y. , Martin Neil A. , Toga Arthur W.
Published: January 2008

Perfusion-dependent brain mapping modalities, such as functional magnetic resonance imaging, positron emission tomography, and optical imaging of intrinsic signals, have become increasingly popular for neurosurgical guidance because they offer a relatively rapid and noninvasive means of mapping brain function. These modalities are unique because they rely on perfusion-related signals that are coupled with neuronal activity to map the brain instead of measuring electrophysiological responses. They consequently present unique challenges to the clinician in terms of understanding the significance and limitations of the maps they produce. In particular, one must be aware of limitations of the modalities with respect to spatial specificity, sensitivity, and reliability of these maps and how the presence of intracranial lesions may further complicate these issues.

The authors review the evolution, interpretation, and limitations of perfusion-based brain mapping techniques, with special attention to clinical implications of the brain maps.
Nerve sheath tumors involving the sacrum
Authors: Klimo Paul , Rao Ganesh , Schmidt Richard H. , Schmidt Meic H.
Published: January 2008

Nerve sheath tumors that involve the sacrum are rare. Delayed presentation is common because of their slow-growing nature, the permissive surrounding anatomical environment, and nonspecific symptoms. Consequently, these tumors are usually of considerable size at the time of diagnosis.

The authors discuss a case of a sacral nerve sheath tumor. They also propose a classification scheme for these tumors based on their location with respect to the sacrum into three types (Types I–III). Type I tumors are confined to the sacrum; Type II originate within the sacrum but then locally metastasize through the anterior and posterior sacral walls into the presacral and subcutaneous spaces, respectively; and Type III are located primarily in the presacral/retroperitoneal area. The overwhelming majority of sacral nerve sheath tumors are schwannomas. Neurofibromas and malignant nerve sheath tumors are exceedingly rare. Regardless of their histological features, the goal of treatment is complete excision. Adjuvant radiotherapy may be used in patients in whom resection was subtotal. Approaches to the sacrum can generally be classified as anterior or posterior. Type I tumors may be resected via a posterior approach alone, Type III may require an anterior approach, and Type II tumors usually require combined anterior–posterior surgery.