bluuebunny/crossref_metadata_2025 huggingface dataset:
Expanded endonasal approach: fully endoscopic, completely transnasal approach to the middle third of the clivus, petrous bone, middle cranial fossa, and infratemporal fossa
Authors: Kassam Amin B. , Gardner Paul , Snyderman Carl , Mintz Arlan , Carrau Ricardo
Published: January 2008

Object

The middle third of the clivus and the region around the petrous internal carotid artery (ICA) is a difficult area of the skull base in terms of access. This is a deep area rich with critical neurovascular structures, which is often host to typical skull base diseases. Expanded endoscopic endonasal approaches offer a potential option for accessing this difficult region. The objective of this paper was to establish the clinical feasibility of gaining access to the paraclival space in the region of the middle third of the clivus, to provide a practical modular and clinically applicable classification, and to describe the relevant critical surgical anatomy for each module.

Methods

The anatomical organization of the region around the petrous ICA, cavernous sinus, and middle clivus is presented, with approaches divided into zones. In an accompanying paper in this issue by Cavallo, et al., the anatomy of the pterygopalatine fossa is presented; this was observed through cadaveric dissection for which an expanded endonasal approach was used. In the current paper the authors translate the aforementioned anatomical study to provide a clinically applicable categorization of the endonasal approach to the region around the petrous ICA. A series of zones inferior and superior to the petrous ICA are described, with an illustrative case presented for each region.

Conclusions

The expanded endonasal approach is a feasible approach to the middle third of the clivus, petrous ICA, cavernous sinus, and medial infratemporal fossa in cases in which the lesion is located centrally, with neurovascular structures displaced laterally.
Endoneurosurgical hemostasis techniques: lessons learned from 400 cases
Authors: Kassam Amin , Snyderman Carl H. , Carrau Ricardo L. , Gardner Paul , Mintz Arlan
Published: January 2008

The increasing popularity of minimally invasive neurosurgery has led to the development of transnasal expanded approaches for the treatment of skull base lesions. One of the greatest challenges in safely accomplishing resection of tumors, particularly intradural lesions, is effective hemostasis. Over the past 7 years the authors have progressively developed an organized approach to address this challenge. This has required the development of new instrumentation as well as variations on standard techniques. In this report they present the technique that has evolved at their institution for endoneurosurgical hemostasis.
Evolution of reconstructive techniques following endoscopic expanded endonasal approaches
Authors: Kassam Amin , Carrau Ricardo L. , Snyderman Carl H. , Gardner Paul , Mintz Arlan
Published: January 2008

Harvey Cushing first popularized the transsphenoidal route to the sella turcica, and Jules Hardy subsequently refined it by adding the operating microscope. Over the ensuing decades, attempts at extending the application of this approach have been advanced by Edward Laws and others. With the evolution of endoscopic approaches, the natural expansion of their use to intradural lesions followed. For the expanded endonasal approach to become a viable option, the paramount concerns surrounding consistent reconstruction of the dura mater must be overcome. In this review the authors chronicle the evolution of the reconstruction technique they currently use after performing expanded endonasal approaches. They also report the use of a balloon stent to buttress the reconstruction and counter the effects of graft migration and cerebrospinal fluid fistula formation. The technique described in this report represents an important step forward in the reconstruction of defects resulting from expanded endonasal approaches.
Microsurgical resection of infratentorial arteriovenous malformations
Authors: O'shaughnessy Brian A. , Getch Christopher C. , Bendok Bernard R. , Batjer H. Hunt
Published: January 2008

Successful microsurgical resection of an infratentorial arteriovenous malformation (AVM) requires both surgical skill and intraoperative judgment. Extensive practical experience in treating these complex lesions, which is acquired over many years, is of substantial value during each new operation. The authors present the surgical approaches and techniques used for the treatment of posterior fossa AVMs based largely on the strategies acquired and developed by the senior author (H.H.B.). Emphasis is placed on conceptual principles of AVM excision, as well as principles incorporated for the treatment of each specific type of infratentorial malformation.
Endogenous stem cell proliferation after central nervous system injury: alternative therapeutic options
Authors: Bambakidis Nicholas C. , Theodore Nicholas , Nakaji Peter , Harvey Adrian , Sonntag Volker K. H. , Preul Mark C. , Miller Robert H.
Published: January 2008

The continuous regeneration of glial cells arising from endogenous stem cell populations in the central nervous system (CNS) occurs throughout life in mammals. In the ongoing research to apply stem cell therapy to neurological diseases, the capacity to harness the multipotential ability of endogenous stem cell populations has become apparent. Such cell populations proliferate in response to a variety of injury states in the CNS, but in the absence of a supportive microenvironment they contribute little to any significant behavioral recovery. In the authors' laboratory and elsewhere, recent research on the regenerative potential of these stem cells in disease states such as spinal cord injury has demonstrated that the cells' proliferative potential may be greatly upregulated in response to appropriate growth signals and exogenously applied trophic factors. Further understanding of the potential of such multipotent cells and the mechanisms responsible for creating a favorable microenvironment for them may lead to additional therapeutic alternatives in the setting of neurological diseases. These therapies would require no exogenous stem cell sources and thus would avoid the ethical and moral considerations regarding their use. In this review the authors provide a brief overview of the enhancement of endogenous stem cell proliferation following neurological insult.
Generating chimeric spinal cord: a novel model for transplantable oligodendrocyte progenitors derived from embryonic stem cells
Authors: Vadivelu Sudhakar , Becker Daniel , McDonald John W.
Published: January 2008

Object

To identify and evaluate stem cell–derived oligodendrocytes obtained for cell transplantation therapies, the authors developed a novel model to examine single, adult oligodendrocytes in situ.

Methods

Green fluorescent protein–expressing, mouse embryonic stem cells (ESCs) were neural induced and additionally staged in an oligosphere preparatory step for high-yield derivation of oligodendrocyte progenitors. These transplantable, induced progenitors were injected into postnatal Day 2 rat pups, in which spinal cord sections were then examined at 3 and 9 weeks posttransplantation.

Conclusions

Transplanted oligosphere ESCs survived and integrated anatomically into postnatal and adult white matter, generating targeted regions of chimeric spinal cord. A simple model for identifying adult oligodendrocytes in situ is presented, which is suitable for use in further studies examining functional myelination and derivation of oligodendrocytes from genetically engineered ESC lines, including human ESCs. Results from the model presented here demonstrate a unique method for examining transplantable oligodendrocyte progenitors derived from ESCs for repair of white matter disease.
Use of a simple intraoperative hydrostatic pressure test to assess the relationship between mobility of the ventricular stoma and success of third ventriculostomy
Authors: Kamel Mahmoud Hamdy , Kelleher Michael , Aquilina Kristian , Lim Chris , Caird John , Kaar George
Published: January 2008

Object

Neuroendoscopists often note pulsatility or flabbiness of the floor of the third ventricle during endoscopic third ventriculostomy (ETV) and believe that either is a good indication of the procedure's success. Note, however, that this belief has never been objectively measured or proven in a prospective study. The authors report on a simple test—the hydrostatic test—to assess the mobility of the floor of the third ventricle and confirm adequate ventricular flow. They also analyzed the relationship between a mobile floor (a positive hydrostatic test) and prospective success of ETV.

Methods

During a period of 3 years between July 2001 and July 2004, 30 ETVs for obstructive hydrocephalus were performed in 22 male and eight female patients. Once the stoma had been created, the irrigating Ringer lactate solution was set at a 30-cm height from the external auditory meatus, and the irrigation valve was opened while the other ports on the endoscope were closed. The ventricular floor ballooned downward and stabilized. The irrigation valve was then closed and ports of the endoscope were opened. The magnitude of the upward displacement of the floor was then assessed. Funneling of the stoma was deemed to be a good indicator of floor mobility, adequate flow, and a positive hydrostatic test. All endoscopic procedures were recorded using digital video and recordings were subsequently assessed separately by two blinded experienced neuroendoscopists. Patients underwent prospective clinical follow up during a mean period of 11.2 months (range 1 month–3 years), computerized tomography and/or magnetic resonance imaging studies of the brain, and measurements of cerebrospinal fluid pressure through a ventricular reservoir when present. Failure of ETV was defined as the subsequent need for shunt implantation. The overall success rate of the ETV was 70% and varied from 86.9% in patients with a mobile stoma and a positive hydrostatic test to only 14.2% in patients with a poorly mobile floor and a negative test (p < 0.05). The positive predictive value of the hydrostatic test was 86.9%, negative predictive value 85.7%, sensitivity 95.2%, and specificity 66.6%.

Conclusions

The authors concluded that the hydrostatic test is an easy, brief test. A positive test result confirms a mobile ventricular floor and adequate flow through the created ventriculostomy. Mobility of the stoma is an important predictor of ETV success provided that there is no obstruction at the level of the arachnoid granulations or venous outflow. A thin, redundant, mobile third ventricle floor indicates a longstanding pressure differential between the third ventricle and the basal cisterns, which is a crucial factor for ETV success. A positive hydrostatic test may avert the need to insert a ventricular reservoir, thus avoiding associated risks of infection.
Bioinformatics and functional magnetic resonance imaging in clinical populations: practical aspects of data collection, analysis, interpretation, and management
Authors: Vincent Diana J. , Hurd Mark W.
Published: January 2008

In this paper the authors review the issues associated with bioinformatics and functional magnetic resonance (fMR) imaging in the context of neurosurgery. They discuss the practical aspects of data collection, analysis, interpretation, and the management of large data sets, and they consider the challenges involved in the adoption of fMR imaging into clinical neurosurgical practice. Their goal is to provide neurosurgeons and other clinicians with a better understanding of some of the current issues associated with bioinformatics or neuroinformatics and fMR imaging. Thousands to tens of thousands of images are typically acquired during an fMR imaging session. It is essential to follow an activation task paradigm exactly to obtain an accurate representation of cortical activation. These images are then interactively postprocessed offline to produce an activation map, or in some cases a series of maps. The maps may then be viewed and interpreted in consultation with a neurosurgeon and/or other clinicians. After this consultation, long-term archiving of the processed fMR activation maps along with the standard structural MR images is a complex but necessary final step in this process. The fMR modality represents a valuable tool in the neurosurgical planning process that is still in the developmental stages for routine clinical use, but holds exceptional promise for patient care.
Detected and overlooked cervical spine injury among comatose trauma patients: from the Pennsylvania trauma outcomes study
Authors: Piatt Joseph H.
Published: January 2008

Object

A rule for identifying patients with traumatic brain injury (TBI) who are at exceptionally low risk of cervical spine injury might be clinically useful. The goal in this study was to research case records to determine whether such a rule would be practicable.

Methods

The Pennsylvania Trauma Outcomes Study database was used to find patients with TBI in whom Glasgow Coma Scale (GCS) scores at admission were 8 or less. Cases of cervical spine injury were identified from diagnostic codes. Associations between these injuries and a variety of clinical variables were tested using chi-square analysis. The probability of a cervical spine injury in these patients was modeled by logistic regression. Decision tree models were constructed and statistical determinants of overlooked cervical spine injury were examined.

The prevalence of cervical spine injury among 41,142 cases of TBI was 8%. The mechanism of injury, presence of thoracolumbosacral (TLS) spinal, limb and/or facial fracture, patient age, GCS score at admission, and the presence of hypotension were all factors associated with cervical spine injury. These were incorporated into the following logistic regression model: probability of cervical spine injury = 1/(1 + exp[4.030 − 0.417*mechanism − 0.264*age − 0.678*TLS − 0.299*limb + 0.218*GCS score − 0.231*hypotension − 0.157*facial]).

This model yielded a rule for clearance of 28% of cases, with a negative predictive value (NPV) of 97%. Decision tree analysis yielded an easily stated rule for clearance of 24% of cases, with an NPV of 98.2%. The prevalence of overlooked cervical spine injury among all patients with severe TBI was 0.3%; the prevalence of overlooked cervical spine injury among patients in whom it was later diagnosed was 3.9%. Overlooked cervical spine injury was less common among patients with associated TLS fractures (odds ratio 0.453, 95% confidence interval 0.245–0.837).

Conclusions

No acceptable rule for relaxation of vigilance in the search for cervical spine injury among patients with severe TBI has been identified. Levels of provider vigilance and consequent rates of overlooked cervical spine injury can be affected by environmental cues and presumably by other behavioral and organizational factors.
Molecular genetics of meningiomas
Authors: Ragel Brian T. , Jensen Randy L.
Published: January 2008

In this article the authors provide a brief description of the current understanding of meningioma genetics. Chromosome 22 abnormalities, especially in the Neurofibromatosis Type 2 (NF2) gene, have been associated with meningioma development. Loss of heterozygosity of chromosome 22 occurs in approximately 60% of meningiomas; however, loss of NF2 gene function occurs in only one third of these lesions. This discrepancy supports the theory that a second tumor suppressor gene exists on chromosome 22, and the authors introduce several possible gene candidates, including BAM22, LARGE, INI1, and MN1 genes. Deletions of 1p have also been shown to correlate with meningioma progression. The genetic similarities and differences among sporadic, NF2-associated, pediatric, and radiation-induced meningiomas are discussed, with the observation that the nonsporadic meningiomas have a higher incidence of multiple chromosomal abnormalities at presentation. Ultimately, a better understanding of the molecular pathways of meningioma tumorigenesis will lead to new, successful treatments.
Epigenetic events in medulloblastoma development
Authors: Lindsey Janet C. , Anderton Jennifer A. , Lusher Meryl E. , Clifford Steven C.
Published: January 2008

Over the last decade, the analysis of genetic defects in primary tumors has been central to the identification of molecular events and biological pathways involved in the pathogenesis of medulloblastoma, the most common malignant brain tumor of childhood. Despite this, understanding of the molecular basis of the majority of cases remains poor. In recent years, the emerging field of epigenetics, which describes heritable alterations in gene expression that occur in the absence of DNA sequence changes, has forced a revision of the understanding of the mechanisms of gene disruption in cancer. Accumulating evidence indicates a significant involvement for epigenetic events in medulloblastoma development. Recent studies have identified a series of candidate tumor suppressor genes (for example, RASSF1A, CASP8, and HIC1) that are each specifically epigenetically inactivated in a large proportion (> 30%) of medulloblastomas by promoter hypermethylation, leading to the silencing of their gene expression. These findings shed new light on medulloblastoma and offer great potential for an improved understanding of its molecular pathology. The authors review the current understanding of epigenetic events in cancer and their contribution to medulloblastoma development. Their nature, origins, and functional role(s) in tumorigenesis are considered, and the authors assess the potential utility of these events as a basis for novel diagnostic and therapeutic approaches.
Microelectrode recording-determined subthalamic nucleus length not predictive of stimulation-induced side effects
Authors: McClelland Shearwood , Kim Brian , Winfield Linda M. , Ford Blair , Edwards Tresha A. , Pullman Seth L. , Yu Qiping , McKhann Guy M. , Goodman Robert R.
Published: January 2008

Object

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become a popular treatment for patients with medically refractory Parkinson disease. Many surgeons believe that microelectrode recording (MER) during DBS electrode implantation is needed to optimize placement, whereas stimulation-induced side effects such as paresthesias, dystonic contractions, dyskinesias, and ocular motor signs that become apparent postoperatively may be an indicator of the proximity of the electrode to various boundaries of the STN. This study was performed to evaluate the relationship between mapping of the STN by using MER and postoperative stimulation-induced side effects.

Methods

Eighty-two electrodes implanted in 75 patients between March 1999 and March 2003 were retrospectively examined to evaluate the length of the STN defined by MER, and the number of and threshold for postoperative stimulation-induced side effects. Electrodes were typically tested with increasing stimulation amplitudes (maximum 6 V) by using a monopolar array.

The 82 electrodes were associated with 97 stimulation-induced side effects. The mean time between surgery and testing stimulation-induced side effects was 3.9 months. Statistical analysis (two-tailed t-test) revealed no significant difference in the number of stimulation-induced side effects (or the mean threshold for paresthesias, the most common side effect) for electrodes associated with an STN length less than 4.5 mm (13 electrodes) compared with those associated with an STN greater than or equal to 4.5 mm (69 electrodes, p = 0.616). For every electrode, the target adjustment based on MER results was within 2 mm of the image-planned target (usually 1 mm anterior). In the x axis (medial–lateral orientation), there was no systematic difference in adjustments made for the electrodes associated with the shorter compared with the longer STN lengths. In the y axis (anterior–posterior orientation), there was a very small statistically significant difference in the mean adjustment (0.4 mm) between the two groups.

Conclusions

Analysis of these results suggests that a shorter MER-determined STN length alone does not reliably predict the incidence of stimulation-induced side effects.
Arachnoid cyst resulting in tonsillar herniation and syringomyelia in a patient with achondroplasia
Authors: Bauer Andrew M. , Mueller Diane M. , Oró John J.
Published: January 2008

Achondroplasia has been associated with varying degrees of cervicomedullary and spinal compression, although usually in the pediatric population. Large arachnoid cysts have also been found to result in tonsillar herniation and syringomyelia. The authors present the case of a patient with achondroplasia who presented with symptoms of foramen magnum compression and syringomyelia, and who was subsequently found to have a large posterior fossa arachnoid cyst.

This 38-year-old woman with achondroplasia presented with an 8-month history of headache and numbness of the hands and fingers. Admission magnetic resonance (MR) imaging of the head and spine revealed a large arachnoid cyst in the posterior cranial fossa, a 6-mm tonsillar herniation consistent with an acquired Chiari malformation, and a large cervicothoracic syrinx. The patient was treated using suboccipital craniectomy, C-1 laminectomy, fenestration of the arachnoid cyst, and decompression of the acquired Chiari malformation with duraplasty.

Surgical decompression resulted in improvement of the presenting symptoms, adequate decompression of crowding at the foramen magnum, and resolution of the syrinx. Although there was only partial reduction in the retrocerebellar cisternal space on follow-up MR imaging, no residual symptoms were related to this.
Molecular genetics of oligodendrogliomas: a model for improved clinical management in the field of neurooncology
Authors: Nutt Catherine L.
Published: January 2008

Over the last several years, oligodendroglial tumors have become a model for the positive role of molecular genetics in improved treatment of patients with brain tumors. Oligodendrogliomas, in contrast to astrocytic gliomas, frequently respond to chemotherapy and have a better overall prognosis. Combined loss of chromosomes 1p and 19q has proven to be a powerful predictor of chemotherapeutic response and survival in oligodendrogliomas. In contrast, other genetic alterations, such as TP53 and PTEN mutations, EGFR amplification, and homozygous deletion of CDKN2A have been correlated with worse outcome in these tumors. Furthermore, 1p/19q loss has been shown to correlate with unequivocal oligodendroglial tumor histology, location and growth pattern of tumors within the brain, and magnetic resonance imaging characteristics. Although much is also known about the molecular pathological characteristics of astrocytic gliomas, the significance of this information to clinical management in patients with these tumors has not been as striking as has been the case for oligodendrogliomas; possible reasons for this are discussed. In this paper the author will summarize these advances, thus attempting to highlight the molecular genetic study of oligodendrogliomas as a model for improved clinical management in the field of neurooncology.
Role of the neurofibromatosis Type 2 gene in the development of tumors of the nervous system
Authors: Ruttledge Martin H. , Rouleau Guy A.
Published: January 2008

Germ line and somatic mutations in the neurofibromatosis Type 2 (NF2) tumor suppressor gene predispose individuals to tumors of the nervous system, including schwannomas and meningiomas. Since identification of the NF2 gene more than a decade ago, a large body of information has been collected on the nature and consequences of these alterations in patients with NF2 and in individuals in whom sporadic tumors associated with NF2 develop. The catalog of mutations identified thus far has facilitated extensive genetic analysis, including studies of patients with mosaicism and phenotype–genotype correlations, and has also led to experiments that have begun to unravel the molecular biology of the NF2 gene and its role in tumorigenesis. The authors describe some of the most significant findings in NF2 genetics and biology over the last decade.
Endoscopic third ventriculostomy in adult patients
Authors: Amini Amin , Schmidt Richard H.
Published: January 2008

Endoscopic third ventriculostomy (ETV) has gained popularity and has become the treatment of choice for certain pediatric and adult hydrocephalic conditions. The authors report their experience with 36 adult patients and evaluate the long-term outcome and safety of ETV. They discuss several improvements to the surgical techniques that they have developed based on their experience, including the use of intraoperative Doppler imaging before fenestration to trace the location of vessels underlying the floor of the third ventricle. They also report the use of a Rickham reservoir and endoventricular stent in selected cases and discuss the indications for their use. In cases of obstructive hydrocephalus due to congenital or acquired aqueductal stenosis in adults, the success rate of ETV in avoidance of shunt placement is 72%. Twenty-two percent of the patients in this series in whom ETV was initially successful later experienced closure of the fenestration and recurrent symptoms at a mean interval of 3.75 years. Thus, in patients who undergo this treatment, long-term periodic follow-up review should be performed.
Endoscopic navigation of the fourth ventricle
Authors: Longatti Pierluigi , Basaldella Luca , Feletti Alberto , Fiorindi Alessandro , Billeci Domenico
Published: January 2008

Transaqueductal navigation of the fourth ventricle has long been considered dangerous and of no clinical relevance. After the refinement of the endoscopic technique and supported by the extensive experience gained at the authors' institution since 1994, endoscopic exploration of the fourth ventricle has been performed by the same surgeon in 54 patients. In all cases reviewed, endoscopic navigation of the fourth ventricle was successfully performed with no related neurological deficit. This preliminary experience shows the feasibility of transaqueductal navigation of the fourth ventricle, which is made possible by the use of small, flexible endoscopes in expert hands.
Neuroendoscopy for spinal disorders: a brief review
Authors: Baron Eli M. , Levene Howard B. , Heller Joshua E. , Jallo Jack I. , Loftus Christopher M. , Dominique Devanand A.
Published: January 2008

Neuroendoscopy has grown rapidly in the last 20 years as a therapeutic modality for treating a variety of spinal disorders. Spinal endoscopy has been widely used to treat patients with cervical, thoracic, and lumbosacral disorders safely and effectively. Although it is most commonly used with minimally invasive lumbar spine surgery, endoscopy has gained widespread acceptance for the treatment of thoracic disc herniations and for anterior release and rod implantation in the correction of thoracic spinal deformity. The authors review the use of endoscopy in spine surgery and in the treatment of spinal disorders as well as in the treatment of intrathoracic nonspinal lesions. Endoscopy has some significant advantages over open or other minimally invasive techniques in that it can allow for better visualization of the lesion, smaller incision sizes with reduced morbidity and mortality, reduced hospital stays, and ultimately lower cost. In addition, spinal endoscopy allows observers and operating room staff to be more involved in each case and fosters education. Spinal endoscopy, like any novel modality, carries with it additional risks and the surgeon must always be prepared to convert to an open procedure. The learning curve for spinal endoscopy is steep and the procedure should not be attempted alone by a novice surgeon. Nevertheless, with training and experience, the spine surgeon can achieve better outcomes, reduced morbidity, and better cosmesis with spinal endoscopy, and the operating times are comparable to open procedures. As technology evolves and more experience is obtained, neuroendoscopy will likely achieve further roles as a mainstay in spine surgery.
Endoscopic-assisted repair of craniosynostosis
Authors: Murad Gregory J. A. , Clayman Mark , Seagle M. Brent , White Sno , Perkins Leigh Ann , Pincus David W.
Published: January 2008

Object

The goal of the craniofacial surgeon has always been the correction of form and function with prevention of associated morbidity and death. Through the pioneering work of Jimenez and Barone, minimally invasive approaches to the surgical correction of craniosynostosis are now gaining wider acceptance. Here the authors review the technique for endoscopic-assisted repair of craniosynostosis from the perspective of a new minimally invasive approach. They also assess the safety, efficacy, and results of the early treatment of infants with craniosynostosis in a small series of children who underwent surgery at this institution.

Methods

Data regarding synostosis type, operative time, patient age, blood loss, transfusion rates, duration of hospitalization, and complications were collected. Nineteen patients (12 girls and seven boys) between the ages of 1.2 and 5 months of age were treated with the endoscope-assisted technique. The mean operative time was 97 minutes. Five (26%) of 19 children received a blood transfusion. Most patients were discharged home the morning after surgery. The clinical courses of two patients who required additional major craniofacial reconstructions are discussed. There were no deaths, dural sinus tears, cerebrospinal fluid leaks, neurological injuries, or infections, and there were no complications related to the use of helmet therapy. Seventeen of the 19 patients achieved excellent cosmetic results with a single surgery.

Conclusions

This small series supports larger experiences and indicates that early treatment of craniosynostosis with minimally invasive, endoscope-assisted techniques is safe; limits blood transfusion, hospital stay, and operative time; and represents a valuable alternative to the traditional calvarial reconstruction methods.
Endoscopic management of intracranial cysts
Authors: Greenfield Jeffrey P. , Souweidane Mark M.
Published: January 2008

Object

Endoscopic fenestration has been recognized as an accepted treatment choice for patients with symptomatic arachnoid cysts. The success of this procedure, however, is greatly influenced by individual cyst anatomy and location as well as the endoscopic technique used. This review was conducted to assess what variables influence the treatment success for different categories of arachnoid cysts.

Methods

Thirty-three consecutive patients who underwent endoscopic fenestration for treatment of an intracranial arachnoid cyst were identified from a prospective database. The surgical indications and techniques were reviewed, and surgical success rates and patient outcomes were assessed. Specific examples of each cyst category are included to illustrate the technical aspects of endoscopic cyst fenestration.

Endoscopic fenestration of arachnoid cysts was successful when judged by cyst decompression, and symptom resolution was noted in 32 (97%) of 33 cases. The one patient with short-term treatment failure underwent a successful repetition of the operation. There were no surgery-related morbidities or deaths.

Conclusions

Arachnoid cysts are a relatively benign pathological entity that can be managed by performing endoscopically guided cyst wall fenestrations into the ventricular system or cerebrospinal fluid–containing cisterns. Proper patient selection, preoperative planning of endoscope trajectory, use of frameless navigation, and advances in endoscope lens technology and light intensity combine to make this a safe procedure with excellent outcomes.
A novel minimally invasive presacral approach and instrumentation technique for anterior L5–S1 intervertebral discectomy and fusion
Authors: Marotta Nicola , Cosar Murat , Pimenta Luiz , Khoo Larry T.
Published: January 2008

Object

The authors describe a new paracoccygeal approach to the L5–S1 junction for interbody fusion with transsacral instrumentation. The purpose of this technical note is to demonstrate a novel surgical approach, technique, and instrumentation system for the treatment of L5–S1 instability in degenerative disc disease and spondylolisthesis.

Methods

This technical note highlights the AxiaLif (TranS1) transsacral system as an alternative method to transforaminal lumbar interbody fusion or posterior lumbar interbody fusion. Via a novel presacral approach corridor, a truly percutaneous L5–S1 discectomy, interbody distraction, and fixation are achieved, and retroperitoneal viscera and dorsal neural elements are avoided. Percutaneous pedicle screw fixation is then used to provide additional stabilization at the treated level.

Conclusions

This novel technique of interbody distraction and fusion via a truly percutaneous approach corridor allows for circumferential treatment of the lower lumbar segments with minimal risk to the anterior organs and dorsal neural elements.
Genetics of choroid plexus tumors
Authors: Kamaly-Asl Ian D. , Shams Navid , Taylor Michael D.
Published: January 2008

Choroid plexus tumors consist of papillomas and carcinomas. A variety of germline and somatic genetic changes have been demonstrated for each of these subtypes. In this paper, the authors summarize the current knowledge of the genetic bases of these tumors.
Molecular genetics of atypical teratoid/rhabdoid tumors
Authors: Biegel Jaclyn A.
Published: January 2008

Rhabdoid tumors are extremely aggressive malignancies that generally occur in infants and young children. The most common locations are the kidney and central nervous system (atypical teratoid/rhabdoid tumor [RT]), although RTs can also arise in most soft-tissue sites. Rhabdoid tumors in all anatomical locations have a similar molecular origin. Mutation or deletion of both copies of the hSNF5/INI1 gene that maps to chromosome band 22q11.2 is observed in approximately 70% of primary tumors. An additional 20 to 25% of tumors have reduced expression at the RNA or protein level, indicative of a loss-of-function event. The INI1 protein is a component of the SWI/SNF chromatin-remodeling complex. The complex is recruited to promoters of a large variety of genes involved in cell signaling, growth, and differentiation. This review summarizes what is currently known regarding the molecular genetics of RTs.
Tuberous sclerosis: a syndrome of incomplete tumor suppression
Authors: McCall Todd , Chin Steven S. , Salzman Karen L. , Fults Daniel W.
Published: January 2008

Tuberous sclerosis (TS) is a congenital neurocutaneous syndrome (or phacomatosis) characterized by widespread development of hamartomas in multiple organs. For affected individuals, neurological and psychiatric complications are the most disabling and lethal features. Although the clinical phenotype of TS is complex, only three lesions characterize the neuropathological features of the disease: cortical tubers, subependymal nodules, and subependymal giant cell astrocytomas. The latter is a benign brain tumor of mixed neuronal and glial origin. Tuberous sclerosis is caused by loss-of-function mutations in one of two genes, TSC1 or TSC2. The normal cellular proteins encoded by these genes, hamartin and tuberin, respectively, form a heterodimer that suppresses cell growth in the central nervous system by dampening the phosphatidylinositol 3–kinase signal transduction pathway. The authors review the clinical and neuropathological features of TS as well as recent research into the molecular biology of this disease. Through this work, investigators are beginning to resolve the paradoxical findings that malignant cancers seldom arise in patients with TS, even though the signaling molecules involved are key mediators of cancer cell growth.
Retracted Tuberous sclerosis complex: molecular pathogenesis and animal models
Authors: Piedimonte Leandro R. , Wailes Ian K. , Weiner Howard L.
Published: January 2008

Mutations in one of two genes, TSC1 and TSC2, result in a similar disease phenotype by disrupting the normal interaction of their protein products, hamartin and tuberin, which form a functional signaling complex. Disruption of these genes in the brain results in abnormal cellular differentiation, migration, and proliferation, giving rise to the characteristic brain lesions of tuberous sclerosis complex (TSC) called cortical tubers. The most devastating complications of TSC affect the central nervous system and include epilepsy, mental retardation, autism, and glial tumors. Relevant animal models, including conventional and conditional knockout mice, are valuable tools for studying the normal functions of tuberin and hamartin and the way in which disruption of their expression gives rise to the variety of clinical features that characterize TSC. In the future, these animals will be invaluable preclinical models for the development of highly specific and efficacious treatments for children affected with TSC.
Pediatric subaxial cervical spine injuries: origins, management, and outcome in 51 patients
Authors: Dogan Seref , Safavi-Abbasi Sam , Theodore Nicholas , Horn Eric , Rekate Harold L. , Sonntag Volker K. H.
Published: January 2008

Object

In this study the authors evaluated the mechanisms and patterns of injury and the factors affecting management and outcome of pediatric subaxial cervical spine injuries (C3–7).

Methods

Fifty-one pediatric patients (38 boys and 13 girls; mean age 12.4 years, range 10 months–16 years) with subaxial cervical spine injuries were reviewed retrospectively. Motor vehicle accidents (MVAs) were the most common cause of injury. Overall, 12% presented with a dislocation, 63% with a fracture, 19% with a fracture–dislocation, and 6% with a ligamentous injury. The most frequently injured level was C6–7 (33%); C3–4 (6%) was least frequently involved. Sixty-four percent of patients were neurologically intact, 16% had incomplete spinal cord injuries (SCIs), 14% had complete SCIs, and three patients (6%) died after admission and before assessment. Treatment was conservative in 64%: seven (13%) wore a halo vest and 26 (51%) wore a rigid cervical orthosis. Surgery was performed in the other 18 patients (36%), with the breakdown as follows: 15 (30%) underwent an anterior approach, two (4%) had posterior approaches, and one (2%) had a combined approach. Postoperatively, four patients (8%) who had a neurological deficit improved. The overall mortality rate was 8%; all deaths were related to MVAs. There were no surgery-related deaths or complications.

Conclusions

Subaxial cervical spine injuries are common in children 9 to 16 years of age, and occur principally between C-5 and C-7. Multilevel injury is more common in children 8 years of age and older than in younger children and infants. Most patients with subaxial cervical spine injuries can be treated conservatively. Both anterior and posterior approaches are safe and effective.
Cervical spine trauma in children: a review
Authors: McCall Todd , Fassett Dan , Brockmeyer Douglas
Published: January 2008

✓ Injuries of the cervical spine are relatively rare in children but are a distinct clinical entity compared with those found in adults. The unique biomechanics of the pediatric cervical spine lead to a different distribution of injuries and distinct radiographic features. Children younger than 9 years of age usually have upper cervical injuries, whereas older children, whose biomechanics more closely resemble those of adults, are prone to lower cervical injuries. Pediatric cervical injuries are more frequently ligamentous in nature, and children are also more prone to spinal cord injury without radiographic abnormality than adults are. Physial injuries are specific only to children. Radiographically benign findings, such as pseudosubluxation and synchondrosis, can be mistaken for traumatic injuries. External immobilization with a halo brace can be difficult and is associated with a high complication rate because of the thin calvaria in children. Surgical options have improved with the development of instrumentation specifically for children, but special considerations exist, such as the small size and growth potential of the pediatric spine.
Cervical epidural hematoma in children: a rare clinical entity
Authors: Fountas Kostas N. , Kapsalaki Eftychia Z. , Robinson Joe Sam
Published: January 2008

✓ Pediatric spinal epidural hematoma is a very rare clinicopathological entity. In the vast majority of cases, spinal epidural hematomas have a nonspecific clinical presentation; this, along with their rapid progression, makes their early diagnosis and prompt surgical evacuation critical. Magnetic resonance imaging is the neuroimaging modality of choice, whereas hemilaminectomy or laminectomy is the indicated surgical intervention. The outcome is good when hematoma evacuation is performed before the onset of complete sensorimotor paralysis.

In this communication, the authors describe a 12-year-old girl with a traumatic acute cervical epidural hematoma. This lesion was successfully evacuated through a hemilaminectomy, and the patient had an excellent outcome. The pertinent literature is reviewed in terms of the incidence, origin, management, and prognosis of this rare and potentially disastrous clinical entity.
Intraventricular meningiomas: a clinicopathological study and review of the literature
Authors: Bhatoe Harjinder S. , Singh Prakash , Dutta Vibha
Published: January 2008

Object

Intraventricular meningiomas are rare tumors. The origin of these tumors can be traced to embryological invagination of arachnoid cells into the choroid plexus. The authors analyzed data that they had collected to study the clinicopathological aspects and review the origin, presentation, imaging, and management of these tumors.

Methods

In this retrospective analysis, the authors describe the cases of 12 patients who had received a diagnosis of intraventricular meningioma and underwent surgery for the tumors. Nine of these patients were men and three were women. Features of neurofibromatosis Type 2 were present in two of the women. Nine of the tumors were located in the lateral ventricles, one was in the third ventricle, and two were in the fourth ventricle. Raised intracranial pressure (ICP) was the universal presentation in all the patients, and the preoperative diagnoses were confirmed on neuroimaging studies. Excision was performed using the parietooccipital (trigonal) approach for lateral ventricle tumors, the transcortical–transventricular route for the third ventricle tumor, and suboccipital craniectomy for fourth ventricle tumors. Postoperatively, one patient died and the others experienced resolution of their symptoms. Histopathological features of these tumors were similar to those seen in meningiomas in other locations.

Conclusions

Intraventricular meningiomas are slow-growing tumors that become large prior to detection. Although they are commonly seen in the lateral ventricles, they occur in the third and fourth ventricles as well. Presentation is in the form of raised ICP with no localizing features; therefore the diagnosis is based on imaging studies. Hydrocephalus occurs due to obstruction of cerebrospinal fluid pathways. Excision requires planning to avoid eloquent cortex incision. The histopathological features are varied, although most of the tumors in the study were angiomatous meningiomas. These tumors are no different histologically from tumors that are dural in origin. No recurrence has been reported.
Minimally invasive transforaminal lumbar interbody fusion with unilateral pedicle screw fixation
Authors: Deutsch Harel , Musacchio Michael J.
Published: January 2008

Object

Posterior lumbar interbody fusion (PLIF) has been shown to be effective in the treatment of axial low-back pain. Minimally invasive spine surgery for arthrodesis has several advantages, including quicker patient recovery, less postoperative pain, and less destruction of adjacent tissue. The purpose of this paper is to evaluate the clinical outcomes after PLIF procedures in which unilateral pedicle screw fixation was used.

Methods

Prospective data were collected in 34 patients undergoing a one-level minimally invasive transforaminal lumbar interbody fusion (TLIF) in 2003. Conservative therapy, including physical therapy and aggressive multimodality pain management, had failed in all patients. Selection was based on magnetic resonance imaging studies demonstrating degenerative disc disease. All patients underwent a unilateral TLIF procedure in conjunction with posterior unilateral pedicle screw fixation. Twenty patients in whom the follow-up duration was longer than 6 months were included in this study.

The follow-up duration in all patients ranged from 6 to 12 months. Seventeen (85%) of 20 patients had a good result, which was defined as a greater than 20-point reduction in the Oswestry Disability Index (ODI) score. The other three patients had no improvement. The mean preoperative ODI score of 57 improved to 25 after surgery (p < 0.005). In the 17 patients who demonstrated improvement, the mean ODI score improved from 57 to 18. The patients' visual analog scale pain scores improved from 8.3 to 1.4 (p < 0.005) after surgery. In patients who received Workers' Compensation, three (75%) of four improved. Follow-up computerized tomography scans were obtained in all 20 patients at 6 months. At that time, 13 of the patients demonstrated some degree of fusion, and no symptomatic pseudarthrosis was noted.

Conclusions

Minimally invasive TLIF in conjunction with unilateral pedicle screw instrumentation is an effective treatment for axial low-back pain in appropriately selected patients.
Diagnosis and management of juxtafacet cysts
Authors: Choudhri Haroon Fiaz , Perling Lance Harlan
Published: January 2008

✓ Juxtafacet cysts are lesions that are associated with spinal facet joints. Although these lesions are frequently noted as incidental findings on imaging studies of the spine, they may produce symptoms in some patients. Juxtafacet cysts can mimic herniated discs, resulting in symptoms from focal nerve root and/or spinal cord compression. Some of these lesions are associated with spinal instability, and patients may require spinal fusion to address this underlying disorder. Conservative therapy for symptomatic lesions is often unsuccessful, although there are reports of spontaneous resolution of these cysts as well as the symptoms associated with them. Surgical therapy should be focused on decompression of the lesions causing nerve root compression and the accompanying symptoms, while recognizing that instability requiring fusion may be present in some but not all cases.
Anterior transvertebral interbody cage with posterior transdiscal pedicle screw instrumentation for high-grade spondylolisthesis
Authors: Beringer Will Forest , Mobasser Jean-Pierre , Karahalios Dean , Potts Eric Alfred
Published: January 2008

✓Adult high-grade degenerative spondylolisthesis represents the extreme end of the spectrum for spondylolisthesis and is consequently rarely encountered. Surgical management of high-grade spondylolisthesis requires constructs capable of resisting the shear forces at the slipped L5–S1 interspace. The severity of the slip, sacral inclination, and slip angle may make conventional approaches to 360° fusion difficult or hazardous. Transdiscal pedicle screw fixation, transvertebral fibular graft fusion, and transvertebral cage fixation are techniques that have been developed to establish anterior column load sharing and to resist shear forces at the L5–S1 interspace, given the anatomical constraints accompanying high-grade spondylolisthesis. In this technical note the authors describe the procedure for implanting an in situ anterior L5–S1 transvertebral cage and performing L4–5 anterior lumbar interbody fusion, followed by placement of posterior S1–L5 vertebral body transdiscal pedicle screws for management of high-grade spondylolisthesis.