bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimized magnetic resonance image-guided stereotaxis: a technique with validation based on the anterior commissure-posterior commissure line
Authors: diPierro Charles G. , Francel Paul C. , Jackson Theodore R. , Kamiryo Toshifumi , Laws Edward R.
Published: January 2008

Some of the earliest successful frame-based stereotactic interventions directed toward the thalamus and basal ganglia depended on identifying the anterior commissure (AC) and posterior commissure (PC) in a sagittal venticulogram and defining the intercommissural line that connects them in the midsagittal plane. The AC-PC line became the essential landmark for the localization of neuroanatomical targets in the basal ganglia and diencephalon and for relating them to stereotactic atlases.

Stereotactic functional neurosurgery has come to rely increasingly on magnetic resonance (MR) imaging guidance, and methods for accurately determining the AC-PC line on MR imaging are being developed. Our technique uses MR sequences that minimize geometric distortion and registration error, thereby maximizing accuracy in AC-PC line determinations from axially displayed MR data. The techniques are based on our experience with the Leksell G-frame, but can be generalized to other MR imaging-based stereotactic systems.

This methodology has been used in a series of 62 stereotactic procedures in 47 adults (55 pallidotomies and seven thalamotomies) with preliminary results equivalent or superior to results reported using microelectrode recordings. The measurements of the AC-PC line reported here compare favorably with those based on ventriculography and computerized tomography previously reported. The methodology reported here is critical in maintaining the accuracy and utility of MR imaging as its role in modern stereotaxy expands. Accurate parameters such as these aid in ensuring the safety, efficacy, and reproducibility of MR-guided stereotactic procedures.
Long-term prognosis for atypical and malignant meningiomas: a study of 71 surgical cases
Authors: Palma Lucio , Celli Paolo , Franco Carmine , Cervoni Luigi , Cantore Giampaolo
Published: January 2008

To contribute to a better understanding of the prognostic differences between atypical and malignant meningiomas as defined by the World Health Organization (WHO) and the influence of the grade of initial surgical excision on postoperative course, 42 cases of atypical and 29 of malignant meningioma were studied, along with long-term follow up. The two groups were compared with respect to long-term survival, recurrence-free survival, and median time to recurrence. The prognostic significance of the Simpson grade of surgical resection and tumor location was also considered. Survival at 5 and 10 years was recorded in 95% and 79%, respectively, of patients with atypical meningioma and in 64.3% and 34.5% of patients with malignant meningioma (p = 0.001). Recurrence-free survival and median time to recurrence were also significantly longer in patients with atypical than in those with malignant meningiomas: 11.9 versus 2 years (p = 0.001) and 5 versus 2 years (p < 0.0041), respectively. Six (26%) of the 23 recurring atypical meningiomas became malignant. Simpson Grade I resection and location in the cerebral convexity, which were closely related, were found to be associated with a significantly better clinical course in the entire series (p ¾ 0.0016). Patients with atypical meningiomas fared better than those with malignant meningiomas after incomplete surgical excision (Simpson Grades II-III), but the difference was not statistically significant. Multivariate analysis using the Cox model indicated that radical extirpation (Simpson Grade I vs. II-III) and histological findings (atypical meningioma vs. malignant meningioma) were significantly related to prolonged survival (p < 0.0003 and p < 0.0388, respectively). In conclusion, the current study shows that for most patients with atypical meningioma the prognosis was less severe than for those with malignant meningioma, but the risk of a downhill course resulting from malignancy after incomplete resection and recurrence was not negligible (26%). In addition, the WHO classification was found to be inadequate for a minority of the atypical meningioma cases, which currently have the same unfavorable course as cases of malignant meningioma. The results also indicate that objective Simpson Grade I extirpation of convexity meningiomas can be successful despite histological findings of malignancy.
Characterization of cerebral hemodynamic phases following severe head trauma: hypoperfusion, hyperemia, and vasospasm
Authors: Martin Neil A. , Patwardhan Ravish V. , Alexander Michael J. , Africk Cynthia Zane , Lee Jae Hong , Shalmon Ehud , Hovda David A. , Becker Donald P.
Published: January 2008

The extent and timing of posttraumatic cerebral hemodynamic disturbances have significant implications for the monitoring and treatment of patients with head injury. This prospective study of cerebral blood flow (CBF) (measured using 133Xe clearance) and transcranial Doppler (TCD) measurements in 125 patients with severe head trauma has defined three distinct hemodynamic phases during the first 2 weeks after injury. The phases are further characterized by measurements of cerebral arteriovenous oxygen difference (AVDO2) and cerebral metabolic rate of oxygen (CMRO2). Phase I (hypoperfusion phase) occurs on the day of injury (Day 0) and is defined by a low CBF15 calculated from cerebral clearance curves integrated to 15 minutes (mean CBF15 32.3 ± 2 ml/100 g/minute), normal middle cerebral artery (MCA) velocity (mean VMCA 56.7 ± 2.9 cm/second), normal hemispheric index (mean HI 1.67 ± 0.11), and normal AVDO2 (mean AVDO2 5.4 ± 0.5 vol%). The CMRO2 is approximately 50% of normal (mean CMRO2 1.77 ± 0.18 ml/100 g/minute) during this phase and remains depressed during the second and third phases. In Phase II (hyperemia phase, Days 1-3), CBF increases (46.8 ± 3 ml/100 g/minute), AVDO2 falls (3.8 ± 0.1 vol%), VMCA velocity rises (86 ± 3.7 cm/second), and the HI remains less than 3 (2.41 ± 0.1). In Phase III (vasospasm phase, Days 4-15), there is a fall in CBF (35.7 ± 3.8 ml/100 g/minute), a further increase in VMCA (96.7 ± 6.3 cm/second), and a pronounced rise in the HI (2.87 ± 0.22).

This is the first study in which CBF, metabolic, and TCD measurements are combined to define the characteristics and time courses of, and to suggest etiological factors for, the distinct cerebral hemodynamic phases that occur after severe craniocerebral trauma. This research is consistent with and builds on the findings of previous investigations and may provide a useful temporal framework for the organization of existing knowledge regarding posttraumatic cerebrovascular and metabolic pathophysiology.
Intravenous insulin-like growth factor-I (IGF-I) in moderate-to-severe head injury: a Phase II safety and efficacy trial
Authors: Hatton Jimmi , Rapp Robert P. , Kudsk Kenneth A. , Brown Rex O. , Luer Mark S. , Bukar Julie G. , Chen Sharon A. , McClain Craig J. , Gesundheit Neil , Dempsey Robert J. , Young Byron
Published: January 2008

The purpose of this study was to determine the effect of insulin-like growth factor-I (IGF-I) on the catabolic state and clinical outcome of head-injured patients. Thirty-three patients between the ages of 18 and 59 years with isolated traumatic head injury and Glasgow Coma Scale (GCS) scores of 4 to 10 were randomized to one of two groups. All patients received standard neurosurgical intensive care plus aggressive nutritional support; the patients in the treatment group also received intravenous therapy with continuous IGF-I (0.01 mg/kg/hour).

During the 14-day dosing period, the control patients lost weight, whereas treated patients gained weight despite a significantly higher measured energy expenditure and lower caloric intake (p = 0.02). Daily glucose concentrations and nitrogen outputs were greater in control patients (p = 0.03) throughout the study period. During Week 1, only treated patients achieved positive nitrogen balance. Fifteen of 17 treated and 13 of 16 control patients survived the 1st week. No deaths occurred in patients whose serum IGF-I concentrations were higher than 350 ng/ml. Dichotomized Glasgow Outcome Scale scores for patients with baseline GCS scores of 5 to 7 improved from poor to good for eight of 12 treated patients but for only three of 11 control patients (p = 0.06). Eight of 11 treated patients with serum IGF-I concentrations that were at least 350 ng/ml achieved moderate-to-good outcome scores at 6 months, compared to only one of five patients with lower concentrations (p < 0.05). These findings indicate that pharmacological concentrations of IGF-I may improve clinical outcome and nitrogen utilization in patients with moderate-to-severe head injury.
Cerebellar astrocytoma: experience with 54 cases surgically treated at the Mayo Clinic, Rochester, Minnesota from 1978 to 1990
Authors: Morreale Vittorio M. , Ebersold Michael J. , Quast Lynn M. , Parisi Joseph E.
Published: January 2008

A comprehensive review of the literature has shown that the treatment of choice for cerebellar astrocytomas has primarily been gross-total resection of the mass and gross-total resection of the enhancing portion of pilocytic astrocytomas. Most large scale studies of postresection survival rates of patients with cerebellar astrocytomas were conducted when computerized tomography (CT) or magnetic resonance (MR) imaging was not readily available. It has been shown that postoperative CT scans or MR images are more reliable than the surgeon's estimate of the degree of tumor resection at the time of surgery. It is not possible, therefore, to make an accurate determination regarding a postresection prognosis based on the degree of suspected tumor resection without the availability of appropriate radiographic imaging. In this study, the authors retrospectively evaluated the treatment of 54 patients with cerebellar astrocytoma who underwent surgery at the Mayo Clinic in Rochester, Minnesota from 1978 through 1990. Preoperative and postoperative CT scans or MR images were available in all 54 patients.
The anatomy of the Berrettini branch: implications for endoscopic carpal tunnel release
Authors: Kolic Zlatko , Micovic Vladimir , Zamolo Gordana , Golubovic Vesna , Uravic Miljenko , Stancic Marin F.
Published: January 2008

Hand dissections were performed in 100 fresh cadaver palms to determine the frequency with which superficial palmar communication between the median and ulnar nerves occurs and to what extent it might incur iatrogenic injury during endoscopic carpal tunnel release.

Superficial palmar communication between the median and ulnar nerves was present in 81% of the dissected hands. Superficial palmar communication, also known as the Berrettini branch, has been classified into four distinct types by Ferrari and Gilbert. Thirty hands were classified as Group 1 (communication in an oblique course from the ulnar to the median nerve), 16 hands were classified as Group 2 (communication parallel to the distal margin of the transverse carpal ligament), and 35 hands were classified as Group 3 (communication in an oblique course from the ulnar nerve to the third common digital nerve, originating below the distal margin of the transverse carpal ligament). No hand fit the Group 4 classification (atypical communication).

These findings led the authors to conclude that changing the course of an incision in the distal part of the carpal ligament radially from the ulnar side a few millimeters is strongly recommended. Sensory branch iatrogenic injury can be avoided by using this technical alteration, in light of the fact that superficial palmar communication between the median and ulnar nerves may be the more likely anatomical finding.
Upper cervical spine fusion in the pediatric population
Authors: Lowry David W. , Pollack Ian F. , Clyde Brent , Albright A. Leland , Adelson P. David
Published: January 2008

The outcomes of 25 pediatric patients who underwent upper cervical or occipitocervical fusion at the authors' institution since 1983 were reviewed. At a mean age of 9 years, the patients presented with spinal instability that was associated with os odontoideum in 11 cases, rotatory subluxation in five cases, odontoid fracture in two cases, atlantooccipital dislocation in two cases, and congenital atlantoaxial instability in five patients, four of whom had Down's syndrome (trisomy 21). Ten children had abnormal findings on neurological examination preoperatively; however, nine experienced improvement or resolution of deficits as of their latest follow-up evaluation (mean 17 months). Fusion was achieved with the first operation in 21 of 25 patients; eventually it was attained in all but one. Four patients exhibited persistent spinal instability after an initial procedure. This was caused by erosion of a multistranded cable through the intact arch of C-2 in two cases, by pin site infection necessitating early halo removal in one case, and by slippage in a halo following a Gallie procedure, which was revised with a Brooks fusion in one case. This series, the largest yet published, shows that with appropriate surgical management, posterior upper cervical fusion in the pediatric population is highly successful. Careful attention to halo pin site care and caution in using multistranded cable in young patients may improve results.
Gene transfer and delivery in central nervous system disease
Authors: Tang Gordon , Chiocca E. Antonio
Published: January 2008

Gene transfer offers the potential to explore basic physiological processes and to intervene in human disease. The central nervous system (CNS) presents a fertile field in which to develop novel therapeutic modalities to treat intractable and pervasive malignant tumors and neurodegenerative disease. The extension of gene therapy to the CNS, however, faces the delivery obstacles of a target population that is postmitotic and isolated behind a blood-brain barrier (BBB). Approaches to this problem have included grafting of genetically modified cells to deliver novel proteins or introducing genes by viral or synthetic vectors geared toward the CNS cell population. Direct inoculation and bulk flow, as well as osmotic and pharmacological disruption, have been used to circumvent the BBB's exclusionary role. Once the gene is delivered, myriad strategies have been used to affect a therapeutic result. Genes activating prodrugs are the most common antitumor approach. Other approaches focus on activating immune responses, targeting angiogenesis, and influencing apoptosis and tumor suppression. At this time, therapy directed at neurodegenerative diseases has centered on ex vivo gene therapy for supply of trophic factors to promote neuronal survival, axonal outgrowth, and target tissue function. Despite early promise, gene therapy for CNS disorders will require advancements in methods for delivery and long-term expression before becoming feasible for human disease.
The descriptive epidemiology of craniopharyngioma
Authors: Bunin Greta R. , Surawicz Tanya S. , Witman Philip A. , Preston-Martin Susan , Davis Faith , Bruner Janet M.
Published: January 2008

The incidence of craniopharyngioma in the United States was estimated from two population-based cancer registries that include brain tumors of benign and borderline malignancy: the Central Brain Tumor Registry of the United States (CBTRUS) and Los Angeles county. Information on additional pediatric tumors was available from the Greater Delaware Valley Pediatric Tumor Registry (GDVPTR). The overall incidence of craniopharyngioma was 0.13 per 100,000 person years and did not vary by gender or race. A bimodal distribution by age was noted with peak incidence rates in children (aged 5-14 years) and among older adults (aged 65-74 years in CBTRUS and 50-74 years in Los Angeles county). Survival information was available from GDVPTR and the National Cancer Data Base (NCDB), a hospital-based reporting system. In the NCDB, the 5-year survival rate was 80% and decreased with older age at diagnosis. Survival is higher among children and has improved in recent years. Approximately 338 cases of craniopharyngiomas are expected to occur annually in the United States, with 96 occurring in children from 0 to 14 years of age.
Spasticity and strength changes as a function of selective dorsal rhizotomy
Authors: Engsberg Jack R. , Olree Kenneth S. , Ross Sandy A. , Park T. S.
Published: January 2008

This investigation quantified pre- and postsurgery (8 months) hamstring muscle spasticity and strength in children with cerebral palsy (CP) undergoing a selective dorsal rhizotomy. Nineteen children with CP (CP group) and six children with able bodies (AB group) underwent testing with a dynamometer. For the spasticity measure, the dynamometer measured the resistive torque of the hamstring muscles during passive knee extension at four different speeds. Torque angle data were processed to calculate the work done by the machine to extend the knee for each speed. Linear regression was used to calculate the slope of the line of best fit for the work velocity data. The slope simultaneously encompassed three key elements associated with spasticity (velocity, resistance, and stretch) and was considered the measure of spasticity. For the strength test, the dynamometer moved the leg from full knee extension to flexion while a maximum concentric contraction of the hamstring muscles was performed. Torque angle data were processed to calculate the work done on the machine by the child. Hamstring spasticity values for the CP group were significantly greater than similar values for AB group prior to surgery; however they were not significantly different after surgery. Hamstring strength values for the CP group remained significantly less than those for the AB group after surgery, but were significantly increased relative to their presurgery values. The results of spasticity testing in the present investigation agreed with previous studies indicating a reduction in spasticity for the CP group. The results of strength testing did not agree with those in the previous literature; a significant increase in strength was observed for the CP group.
Gait before and 10 years after rhizotomy in children with cerebral palsy spasticity
Authors: Subramanian Nivedita , Vaughan Christopher L. , Peter Jonathan C. , Arens Leila J.
Published: January 2008

Selective dorsal rhizotomy is a neurosurgical procedure performed for the relief of spasticity in children with cerebral palsy, but its long-term functional efficacy is still unknown. The authors sought to address this issue by means of an objective, prospective study in which quantitative gait analysis was used. Eleven children with spastic diplegia (mean age at initial surgery 7.8 years) were evaluated preoperatively in 1985 and then at 1, 3, and at least 10 years after surgery. For comparison, 12 age-matched normal individuals were also studied. Retroreflective targets were placed over the hip, knee, and ankle joints, and each individual's gait was videotaped. The video data were subsequently entered into a computer for extraction and analysis of the gait parameters. An analysis of variance yielded a significant time effect (p < 0.05), and post hoc comparisons revealed differences before and after surgery and with respect to the normal control subjects. The knee and hip ranges of motion (59š and 44š, respectively, for controls) were significantly restricted prior to surgery (41š and 41š, respectively), but were within normal limits after 10 years (52š and 45š, respectively). The knee and hip midrange values (31š and 3š, respectively, for controls), indicative of posture, were significantly elevated preoperatively (42š and 15š) and increased sharply at 1 year (56š and 18š), but by 10 years they had decreased to within normal limits (36š and 9š). Step length and velocity improved postoperatively but were not within the normal range after 10 years. Ten years after surgery our patients not only had increased ranges of motion, they also used that movement about a normal midrange point. Selective dorsal rhizotomy is an effective method for alleviating spasticity; furthermore, the authors provide evidence to show that lasting functional benefits, as measured by improved gait, can also be obtained.
Bone morphogenetic protein gene therapy for the induction of spinal arthrodesis
Authors: Alden Tord D. , Hankins Gerald R. , Beres Elisa J. , Kallmes David F. , Helm Gregory A.
Published: January 2008

Gene therapy has many potential applications in neurosurgery. One application involves bone morphogenetic protein-2 (BMP-2), a low-molecular-weight glycoprotein that induces bone formation in vivo. Numerous studies have demonstrated that the BMP-2 protein can enhance spinal fusion. This study was undertaken to determine whether direct injection of an adenoviral construct containing the BMP-2 gene can be used for spinal fusion. Twelve athymic nude rats were used in this study. Recombinant, replication-defective type-5 adenovirus with a universal promoter and BMP-2 gene (Ad-BMP-2) was used. A second adenovirus constructed with a universal promoter and ß-galactosidase (ß-gal) gene (Ad-ß-gal) was used as a control. Seven and one-half microliters of virus was injected percutaneously and paraspinally at the lumbosacral junction in three groups (four animals each): 1) Ad-BMP-2 bilaterally, 2) Ad-BMP-2 on the right, Ad-ß-gal on the left, and 3) Ad-ß-gal bilaterally. Computerized tomography (CT) scans of the lumbosacral spine were obtained at 3, 5, and 12 weeks. At 12 weeks, the animals were killed for histological inspection. Ectopic bone formation was seen both on three-dimensional CT reconstruction and histologically in all rats at sites treated with Ad-BMP-2. Histological analysis revealed bone at different stages of maturity adjacent to the spinous processes, laminae, and transverse processes. This study clearly demonstrated that it is possible to produce in vivo endochondral bone formation by using direct adenoviral construct injection into the paraspinal musculature, which suggests that gene therapy may be useful for spinal fusion in the future.
Microsurgical anterior cervical foraminotomy for radiculopathy: a new approach to cervical disc herniation
Authors: Jho Hae-Dong
Published: January 2008

A new technique of microsurgical anterior foraminotomy was developed to improve the treatment of cervical radiculopathy. This technique provides direct anatomical decompression of the compressed nerve root by removing the compressive spondylotic spur or disc fragment. The nerve root is decompressed from its origin in the spinal cord to the point at which it passes behind the vertebral artery laterally. Because most of the disc within the intervertebral space is undisturbed, a functioning motion segment of the disc remains intact. This technique differs from that of Verbiest in that it does not directly transpose the vertebral artery. Unlike Hakuba's technique, the disc within the intervertebral disc space is not removed.
The transfacet pedicle-sparing approach for thoracic disc removal: cadaveric morphometric analysis and preliminary clinical experience
Authors: Stillerman Charles B. , Chen Thomas C. , Day J. Diaz , Couldwell William T. , Weiss Martin H.
Published: January 2008

A number of operative techniques have been described for the treatment of herniated thoracic discs. The transfacet pedicle-sparing approach allows for complete disc removal with limited spinal column disruption and soft-tissue dissection. Fifteen cadaveric spinal columns were used for evaluation of exposure, development of thoracic microdiscectomy instrumentation, and establishment of morphometric measurements. This approach was used to remove eight thoracic discs in six patients. Levels of herniation ranged from T-7 through T-11. Preoperatively, all patients had moderate to severe axial pain, and three (50%) of the six had radicular pain. Myelopathy was present in four (67%) of the six patients. Through a 4-cm opening, the ipsilateral paraspinal muscles were reflected, and a partial facetectomy was performed. The disc was then removed using specially designed microscopic instrumentation. Postoperatively, the radiculopathy resolved in all patients. Axial pain and myelopathy were completely resolved or significantly improved in all patients.

The minimal amount of bone resection and muscle dissection involved in the operation allows for: 1) decreased operative time and blood loss; 2) diminished perioperative pain; 3) shorter hospitalization time and faster return to premorbid activity; 4) avoidance of closed chest tube drainage; and 5) preservation of the integrity of the facet-pedicle complex, with potential for improvement in outcome related to axial pain. This technique appears best suited for the removal of all centrolateral discs, although it has been used successfully for treating a disc occupying nearly the entire ventral canal. The initial experience suggests that this approach may be used to safely remove appropriately selected thoracic disc herniations with good results.
Neurofibromatosis type 2 and central neurofibromatosis
Authors: Malis Leonard I.
Published: January 2008

Neurofibromatosis type 2 (NF2) is a rare disease, affecting only approximately 1000 patients in the entire United States. The diagnosis requires the presence of bilateral acoustic neuromas, but many other tumors of the nervous system are also present. It is a very different disease from von Recklinghausen's neurofibromatosis, NF1. The remarkable genetic research in recent years has defined the origin of NF2 to be the lack of a specific suppressor protein, known as Merlin. While we await a method to replace this protein, the neurosurgical care of these patients is a formidable problem. The author reviews his personal series of 41 patients with NF2 treated during the past 30 years and presents 10 cases in detail to demonstrate their considerable range of differences and the treatment problems they have posed.
Neurofibromatosis type 2: growth stimulation of mixed acoustic schwannoma by concurrent adjacent meningioma: possible role of growth factors
Authors: Pallini Roberto , Tancredi Angelo , Casalbore Patrizia , Mercanti Delio , Larocca Luigi M. , Consales Alessandro , Lauretti Liverana , Fernandez Eduardo
Published: January 2008

The authors report the case of a young man suffering from neurofibromatosis type 2 (NF2) who harbored bilateral acoustic schwannomas and a parasellar meningioma. Neuroimaging studies performed during a 4-year follow-up period showed that the bilateral schwannomas had grown very little and at similar rates. However, after the meningioma had infiltrated the tentorium and approached the ipsilateral schwannoma at the incisura, both Schwann cell tumors started to grow rapidly, particularly the one adjacent to the meningioma, of which the percentage of annual growth rate increased by approximately a factor of 102. At the same time, magnetic resonance imaging showed that this tumor also changed its features. During surgery, the acoustic schwannoma was firmly adherent to both meningioma and tentorium. Histological examination revealed meningotheliomatous cells in the schwannoma adjacent to the meningioma. Antiphosphotyrosine immunoblotting of PC12 cells was compatible with the presence of an epidermal growth factor (EGF)-like molecule in the cerebrospinal fluid (CSF) of the patient. This factor was not detected in the CSF of five other NF2 patients, two of whom bore associated bilateral acoustic schwannomas and meningioma in remote locations. It is hypothesized that the meningotheliomatous cells infiltrating the schwannoma triggered an autocrine/paracrine growth-stimulatory mechanism that involved an EGF-like factor.
Dysembryoplastic neuroepithelial tumor and oligodendroglioma: the diagnostic value of magnetic resonance spectroscopy
Authors: Sherburn Eric W. , Bahn Mark M. , Gokden Murat , Silbergeld Daniel L. , Rich Keith M.
Published: January 2008

Preoperative differentiation between dysembryoplastic neuroepithelial tumor (DNT) and low-grade glioma is often not possible. Dysembryoplastic neuroepithelial tumor is a recently described entity of uncertain origin; however, the diagnosis has important clinical implications. Clinical and radiological findings of DNT and low-grade glioma, especially oligodendroglioma, may be similar. Treatment options and prognosis differ significantly between these two lesions; consequently, accurate diagnosis is imperative. The authors describe two individuals who presented simultaneously at their institution: one patient with an oligodendroglioma and a second patient with DNT. The natural history, neurodiagnostic, and pathological features of each are reviewed with special emphasis on the potential utility of magnetic resonance spectroscopy in differentiating these lesions.
Spinal cord ependymomas
Authors: Brotchi Jacques , Fischer Georges
Published: January 2008

Ependymomas are the most frequent spinal cord tumors in adult patients. Although magnetic resonance imaging can be a highly accurate diagnostic tool, it does not always provide accurate differentiation between ependymomas and astrocytomas. This is why the authors recommend surgical resection and histological evaluation in all intraspinal cord tumors. It cannot be said that a tumor is unresectable without first attempting to remove it. Complete removal should be accomplished whenever possible, and patients should undergo operation before they become neurologically impaired. Quality of life depends on preoperative neurological status. Postoperative radiotherapy should be avoided in all low-grade ependymomas even after partial removal. Radiotherapy may be used to treat anaplastic ependymomas, which are quite rare in the spinal cord. Patients with low-grade ependymomas must be followed for years and undergo reoperation if necessary. In our experience treating 93 spinal cord ependymomas, complete removal was achieved in 86 patients and only one patient underwent reoperation 18 years later for tumor recurrence. The gold standard in treatment protocol is gross-total resection without adjunctive radiation therapy. Good long-term outcomes have been achieved by using this strategy.
Bias, benefit, or both: evaluating new glioma therapies
Authors: Perry James R.
Published: January 2008

Despite the development of many new promising therapies for malignant glioma, virtually all randomized controlled trials testing them have proven negative. These disappointing results are largely due to complex mechanisms of treatment resistance, but increasingly there is evidence that experimental bias rather than benefit accounts for both the promising early phase I/II trial results and later phase III failures. This paper highlights the aspects of clinical trial design and outcome analysis that specifically affect interpretation of results from therapeutic trials for malignant glioma. Phase II trials of both tumor response and tumor control are subject to selection bias; the early promising results seen with interstitial brachytherapy and intraarterial chemotherapy and yet negative phase III results are examples of this. Methods for detecting selection bias include modeling techniques in which databases of patients with known outcomes are used to emulate phase III outcomes. Modeling may assist in the determination of whether a given phase II result appears to exceed that expected by selection bias alone. Such an experiment on paper is quite unlikely to replace a well-designed randomized trial; however, in this time of increasing numbers of novel therapies but shrinking resources, these techniques should find utility in selecting those therapies most suitable for testing in cooperative group randomized trials.
Efficacy of pedicle screw fixation in the treatment of spinal instability and failed back surgery: a 5-year review
Authors: Masferrer Roberto , Gomez Carlos H. , Karahalios Dean G. , Sonntag Volker K. H.
Published: January 2008

Object

The goal of this study was to review retrospectively the outcome of 95 patients with various disorders leading to instability of the thoracolumbar and lumbar spine who were treated consecutively via a posterior surgical approach with pedicle screw fixation in which the Texas Scottish Rite Hospital system was used.

Methods

All cases were managed according to the same protocol. Follow-up review averaged 29.6 months. Radiographic evidence of osseous union and the patient's current status were analyzed. Four screws were malpositioned, and there were two dural lacerations of a nerve root and one pedicle fracture. Deep wound infections developed in five patients (5.2%) and three patients had postoperative radicular pain. In one case, the rods disengaged from the screws; in four cases, hardware was removed but there were no broken screws. Neurological deficits improved in 85% of the patients and no patient was worse neurologically after surgery. The rate of osseous union was 96.8%. Three patients developed pseudarthrosis, one of whom was asymptomatic. Back pain improved in 80 patients (85%). A solid bone fusion, however, was not necessarily associated with decreased back pain.

Conclusions

These results support the use of pedicle screw fixation as an effective and safe procedure for fusion of the thoracolumbar and lumbar spine and support the finding that complications can be minimal when a meticulous surgical technique is used. The proper selection of patients for surgery is probably the most important factor associated with good outcomes.
Trigeminocardiac reflex during surgery in the cerebellopontine angle
Authors: Schall Bernhard , Probst Rudolf , Strebel Stephan , Fuhr Peter , Gratzl Otmar
Published: January 2008

In different experimental studies authors have analyzed the autonomic responses elicited by the electrical, mechanical, or chemical stimulation of the trigeminal nerve system. The trigeminocardiac reflex (TCR) is a well-recognized phenomenon that consists of bradycardia, arterial hypotension, apnea, and gastric hypermotility. It occurs during ocular surgery and during other manipulations in and around the orbit. Thus far, it has not been shown that central stimulation of the trigeminal nerve can also cause this reflex.

The TCR was defined as clinical hypotension with a drop in mean arterial blood pressure (MABP) of more than 20% and bradycardia lower than 60 beats/minute. Pre-, intra-, and postoperative heart rate (HR) and blood pressure were reviewed retrospectively in 125 patients who underwent surgery for tumors of the cerebellopontine angle (CPA), and they were divided into a TCR group and a non-TCR group. Of the 125 patients, 14 (11%) showed evidence of TCR during dissection of the tumor near the trigeminal nerve at the brainstem. Their HR fell 38% and their MABP fell 48% during operative procedures as compared with preoperative levels. After cessation of manipulation, the HR and the MABP returned to preoperative levels. Risk factors for the occurrence of TCR were compared with results from the literature.

The authors' results show the possibility of occurrence of a TCR during manipulation of the central part of the trigeminal nerve when performing surgery in the CPA.
Hemorrhagic vestibular schwannoma: an unusual clinical entity
Authors: Chou Dean , Sampath Prakash , Brem Henry
Published: January 2008

Hemorrhagic vestibular schwannomas are rare entities, with only a few case reports in the literature during the last 25 years. The authors review the literature on vestibular schwannoma hemorrhage and the presenting symptoms of this entity, which include headache, nausea, vomiting, sudden cranial nerve dysfunction, and ataxia. A very unusual case is presented of a 36-year-old man, who unlike most of the patients reported in the literature, had clinically silent vestibular schwannoma hemorrhage. The authors also discuss the management issues involved in more than 1000 vestibular schwannomas treated at their institution during a 25-year period.
Quality of life following acoustic neuroma surgery
Authors: Schwartz Marc S. , Riddle Seth A. , Delashaw Johnny B. , Horgan Michael A. , Kellogg Jordi X. , McMenomey Sean O.
Published: January 2008

In the treatment of acoustic neuroma, operative results have improved greatly during recent years, with high rates of functional cranial nerve preservation. Because of this, it has become more important to consider issues of patient satisfaction and quality of life (QOL) following treatment for these lesions. The authors have developed a novel questionnaire designed to measure QOL in patients with acoustic neuromas, and they administered it to 50 consecutive patients at least 6 months after acoustic neuroma surgery. Overall QOL was judged to be good but with definite minor difficulties, including some problems with hearing, facial nerve function, headache, tinnitus, dizziness, activity level, enjoyment of life, and emotional well-being. No significant differences were found between age groups and different operative approaches, and only minor differences were found in relation to tumor size. Patients with intracanalicular tumors fared no better than those with cerebellopontine angle tumors. Analysis of the data suggests an overall good outcome from acoustic neuroma surgery; however, when discussing the possible effects on postoperative QOL, even the potential minor problems should not be minimized, especially in patients undergoing operation for small or intracanalicular tumors.
Facial nerve injury in acoustic neuroma (vestibular schwannoma) surgery: etiology and prevention
Authors: Sampath Prakash , Holliday Michael J. , Brem Henry , Niparko John K. , Long Donlin M.
Published: January 2008

Facial nerve injury associated with acoustic neuroma surgery has declined in incidence but remains a clinical concern. A retrospective analysis of 611 patients surgically treated for acoustic neuroma between 1973 and 1994 was undertaken to understand patterns of facial nerve injury more clearly and to identify factors that influence facial nerve outcome.

Anatomical preservation of the facial nerve was achieved in 596 patients (97.5%). In the immediate postoperative period, 62.1% of patients displayed normal or near-normal facial nerve function (House-Brackmann Grade 1 or 2). This number rose to 85.3% of patients at 6 months after surgery and by 1 year, 89.7% of patients who had undergone acoustic neuroma surgery demonstrated normal or near-normal facial nerve function.

The surgical approach appeared to have no effect on the incidence of facial nerve injury. Poor facial nerve outcome (House-Brackmann Grade 5 or 6) was seen in 1.58% of patients treated via the suboccipital approach and in 2.6% of patients treated via the translabyrinthine approach. When facial nerve outcome was examined with respect to tumor size, there clearly was an increased incidence of facial nerve palsy seen in the immediate postoperative period in cases of larger tumors: 60.8% of patients with tumors smaller than 2.5 cm had normal facial nerve function, whereas only 37.5% of patients with tumors larger than 4 cm had normal function. This difference was less pronounced, however, 6 months after surgery, when 92.1% of patients with tumors smaller than 2.5 cm had normal or near normal facial function, versus 75% of patients with tumors larger than 4 cm.

The etiology of facial nerve injury is discussed with emphasis on the pathophysiology of facial nerve palsy. In addition, on the basis of the authors' experience with these complex tumors, techniques of preventing facial nerve injury are discussed.
Current concepts on carotid artery-cavernous sinus fistulas
Authors: Kellogg Jordi X. , Kuether Todd A. , Horgan Michael A. , Nesbit Gary M. , Barnwell Stanley L.
Published: January 2008

With greater understanding of the pathophysiological mechanisms by which carotid artery-cavernous sinus fistulas occur, and with improved endovascular devices, more appropriate and definitive treatments are being performed. The authors define cartoid cavernous fistulas based on an accepted classification system and the signs and symptoms related to these fistulas are described. Angiographic evaluation of the risk the lesion may pose for precipitating stroke or visual loss in the patient is discussed. The literature on treatment alternatives for the different types of fistulas including transvenous, transarterial, and conservative management is reviewed.
Arteriovenous malformation in association with moyamoya disease
Authors: Nakashima Toshihiko , Nakayama Noriyuki , Furuichi Masahiro , Kokuzawa Jouji , Murakawa Takatsugu , Sakai Noboru
Published: January 2008

The authors report two rare cases of arteriovenous malformation (AVM) associated with moyamoya disease. An AVM, supplied by transdural communicating arteries, was located in the right occipital lobe in one patient who presented with ischemia. The second AVM, which was supplied by basal moyamoya vessels, was located in the posterior part of the left frontal lobe in a patient who developed intracerebral hemorrhage that occupied the left basal ganglion.

A review of the literature revealed a total of 12 AVMs in 11 patients with moyamoya disease including our cases. All AVMs were cerebral and two were supplied by normal cerebral arteries, whereas six AVMs were supplied by basal moyamoya vessels at the base of the brain and four AVMs were supplied by external carotid arteries through the transdural communicating arteries. Every AVM drained into deep or cortical cerebral veins. These findings suggest that the hyperangiogenic character of moyamoya disease occasionally induces the development of acquired arteriovenous shunts that mimic AVM.
Sylvian aqueduct syndrome and global rostral midbrain dysfunction associated with shunt malfunction
Authors: Cinalli Giuseppe , Sainte-Rose Christian , Simon Isabelle , Lot Guillaume , Sgouros Spiros
Published: January 2008

Object

This study is a retrospective analysis of clinical data obtained in 28 patients affected by obstructive hydrocephalus who presented with signs of midbrain dysfunction during episodes of shunt malfunction.

Methods

All patients presented with an upward gaze palsy, sometimes associated with other signs of oculomotor dysfunction. In seven cases the ocular signs remained isolated and resolved rapidly after shunt revision. In 21 cases the ocular signs were variably associated with other clinical manifestations such as pyramidal and extrapyramidal deficits, memory disturbances, mutism, or alterations in consciousness. Resolution of these symptoms after shunt revision was usually slow. In four cases a transient paradoxical aggravation was observed at the time of shunt revision. In 11 cases ventriculocisternostomy allowed resolution of the symptoms and withdrawal of the shunt.

Simultaneous supratentorial and infratentorial intracranial pressure recordings performed in seven of the patients showed a pressure gradient between the supratentorial and infratentorial compartments with a higher supratentorial pressure before shunt revision. Inversion of this pressure gradient was observed after shunt revision and resolution of the gradient was observed in one case after third ventriculostomy. In six recent cases, a focal midbrain hyperintensity was evidenced on T2-weighted magnetic resonance imaging sequences at the time of shunt malfunction. This rapidly resolved after the patient underwent third ventriculostomy.

It is probable that in obstructive hydrocephalus at the time of shunt malfunction, the development of a transtentorial pressure gradient could initially induce a functional impairment of the upper midbrain, inducing upward gaze palsy. The persistence of the gradient could lead to a global dysfunction of the upper midbrain.

Conclusions

Third ventriculostomy contributes to equalization of cerebrospinal fluid pressure across the tentorium by restoring free communication between the infratentorial and supratentorial compartments, resulting in resolution of the patient's clinical symptoms.
Angioplasty and stenting for carotid artery stenosis: indications, techniques, results, and complications
Authors: Lanzino Giuseppe , Fessler Richard D. , Mericle Robert A. , Wakhloo Ajay K. , Guterman Lee R. , Hopkins L. Nelson
Published: January 2008

Following the favorable results obtained in the treatment of coronary artery disease, combined angioplasty and stenting has been advocated for the treatment of carotid artery stenosis as well. Although widespread application of angioplasty and stenting for carotid artery disease is neither indicated nor recommended, it may be a viable alternative therapy for select patients who are high-risk patients for surgery. The results of early series have suggested that endoluminal revascularization in these high-risk patients can be performed with an acceptable degree of safety. Although the incidence of death and major stroke rates following angioplasty and stenting procedures compares favorably with surgery, results of more recent clinical series have suggested that the incidence of perioperative transient neurological events and minor strokes may be higher than suggested by earlier reports, especially in patients with recent neurological symptoms and “unstable” plaques. In this article, the authors review the current potential indications for and preliminary results of angioplasty and stenting and describe their procedural technique. In addition, potential applications of stenting to intracranial thromboocclusive carotid artery disease are reviewed.
Apoptosis after traumatic human spinal cord injury
Authors: Emery Evelyne , Aldana Philipp , Bunge Mary Bartlett , Puckett William , Srinivasan Anu , Keane Robert W. , Bethea John , Levi Allan D. O.
Published: January 2008

Apoptosis is a form of programmed cell death seen in a variety of developmental and disease states, including traumatic injuries. The main objective of this study was to determine whether apoptosis is observed after human spinal cord injury (SCI). The spatial and temporal expression of apoptotic cells as well as the nature of the cells involved in programmed cell death were also investigated.

The authors examined the spinal cords of 15 patients who died between 3 hours and 2 months after a traumatic SCI. Apoptotic cells were found at the edges of the lesion epicenter and in the adjacent white matter, particularly in the ascending tracts, by using histological (cresyl violet, hematoxylin and eosin) and nuclear staining (Hoechst 33342). The presence of apoptotic cells was supported by staining with the terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick-end labeling technique and confirmed by immunostaining for the processed form of caspase-3 (CPP-32), a member of the interleukin-1-beta-converting enzyme/Caenorhabditis elegans D 3 (ICE/CED-3) family of proteases that plays an essential role in programmed cell death. Apoptosis in this series of human SCIs was a prominent pathological finding in 14 of the 15 spinal cords examined when compared with five uninjured control spinal cords. To determine the type of cells undergoing apoptosis, the authors immunostained specimens with a variety of antibodies, including glial fibrillary acidic protein, 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase), and CD45/68. Oligodendrocytes stained with CNPase and a number of apoptotic nuclei colocalized with positive staining for this antibody.

These results support the hypothesis that apoptosis occurs in human SCIs and is accompanied by the activation of caspase-3 of the cysteine protease family. This mechanism of cell death contributes to the secondary injury processes seen after human SCI and may have important clinical implications for the further development of protease inhibitors to prevent programmed cell death.