bluuebunny/crossref_metadata_2025 huggingface dataset:
Frameless Stereotactic Neurosurgery Using Intraoperative Magnetic Resonance Imaging: Stereotactic Brain Biopsy
Authors: Moriarty Thomas M. , Quinones-Hinojosa Alfredo , Larson Paul S. , Alexander Eben , Gleason P. Langham , Schwartz Richard B. , Jolesz Ferenc A. , Black Peter McL.
Published: September 2004

OBJECTIVE

To assess the application accuracy of intraoperative magnetic resonance imaging for frameless stereotactic surgery, and to evaluate the performance of intraoperative magnetic resonance imaging for the brain biopsy, a standard stereotactic procedure.

METHODS

A series of spatial coordinate and phantom experiments were performed to analyze the application accuracy of the system. A prospective analysis of 68 consecutive patients undergoing stereotactic brain biopsy was then performed.

RESULTS

The spatial coordinate experiments revealed a mean overall error in acquisition of 0.2 mm. The phantom experiments demonstrated a 1:1 correlation between the magnetic resonance image of a stereotactically guided probe and its relationship to a target and the actual relationship of the probe and target. Sixty-eight brain biopsies were successfully performed in all intracranial compartments except the sella. The radiographic abnormality was localized successfully in all patients (100%). Sixty-six (97.1%) of the biopsies yielded diagnostic tissue. Two biopsies (2.9%) were complicated by intraparenchymal hemorrhage. One expanding temporal lobe hemorrhage was evacuated by immediate craniotomy in the magnet with no postoperative sequelae. A deep hemorrhage from a lymphoma was managed conservatively with interval resolution of symptoms. There were no infections. There was no perioperative mortality.

CONCLUSION

Intraoperative magnetic resonance imaging allows excellent target localization, provides true real-time imaging to account for anatomic changes during surgery, and permits intraoperative confirmation that the biopsy needle has reached the targeted lesion. Immediate postoperative imaging in the operating room allows assessment of adverse events and the potential for immediate management of hemorrhagic complications.
Occlusive Hyperemia: A Radiosurgical Phenomenon?
Authors: Pollock Bruce E.
Published: September 2004

OBJECTIVE

Causes of neurological deficits after arteriovenous malformation (AVM) radiosurgery, including hemorrhage, radiation injury, and delayed cyst formation, are described.

CONCEPT

Occlusive hyperemia has been described as a reason for neurological deterioration after AVM resection. Thrombosis of draining veins or dural sinuses is thought to cause postoperative bleeding or neurological deficits secondary to venous hypertension. In a similar manner, local hemodynamic changes can occur in the brain adjacent to an AVM after radiosurgery if venous outflow is obstructed. Two patients are presented whose cases demonstrate this phenomenon.

CONCLUSION

Patients can experience clinical worsening after AVM radiosurgery from premature thrombosis of draining veins. Local hemodynamic changes could explain why imaging changes thought to be radiation related occur more frequently after radiosurgery of AVMs than of tumors.
Adenoviral Gene Transfer of Nitric Oxide Synthase Increases Cerebral Blood Flow in Rats
Authors: Lüders Jürgen C. , Weihl Conrad C. , Lin George , Ghadge Ghanashayam , Stoodley Marcus , Roos Raymond P. , Macdonald R. Loch
Published: September 2004

OBJECTIVE

Depletion of nitric oxide may play a role in the development of vasospasm after aneurysmal subarachnoid hemorrhage. Replenishment of nitric oxide might be a useful treatment for vasospasm. Using rats, we performed intracisternal injections of replication-defective adenovirus containing the endothelial nitric oxide synthase (eNOS) gene and determined the localization of and effect on cerebral blood flow of transgene expression.

METHODS

Rats underwent baseline measurement of cortical cerebral blood flow using laser Doppler flowmetry. Replication-defective adenovirus containing the Escherichia coliLacZ gene (Ad327β-Gal, n = 2/time point) or the bovine eNOS gene (AdCD8-NOS, n = 4/time point) or physiological saline solution was injected into the cisterna magna. Cerebral blood flow was measured 1, 2, 4, 7, or 14 days later, and the animals were killed. Expression of β-galactosidase activity from the LacZ gene was examined by histochemical staining and that of eNOS was examined by polymerase chain reaction assays of messenger ribonucleic acid. Brains were histopathologically examined for inflammation.

RESULTS

β-Galactosidase activity was observed throughout the leptomeninges and in some cells in the adventitia of small subarachnoid blood vessels in the Ad327β-Gal-injected rats. Messenger ribonucleic acid for eNOS was detected in the leptomeninges and brainstem 1 and 2 days after injection of AdCD8-NOS. Rats injected with Ad327β-Gal or physiological saline solution exhibited decreased cerebral blood flow beginning 2 days after virus injection and lasting up to 14 days after injection. Rats injected with AdCD8-NOS developed significant transient increases in cerebral blood flow 2 days after virus injection, followed by slight decreases in blood flow. There was inflammation in the subarachnoid space of all animals; the inflammation was qualitatively worse in animals injected with Ad327β-Gal, compared with rats injected with AdCD8-NOS or saline solution.

CONCLUSION

Intracisternal injection of replication-defective adenovirus containing the eNOS gene can transiently increase cerebral blood flow.
Idiopathic Hypertrophic Cranial Pachymeningitis Associated with a Dural Arteriovenous Fistula Involving the Straight Sinus: Case Report
Authors: Hamada Jun-ichiro , Yoshinaga Yutaka , Korogi Yukunori , Ushio Yukitaka
Published: September 2004

OBJECTIVE AND IMPORTANCE

Reports of idiopathic hypertrophic cranial pachymeningitis have increased as a result of advances in magnetic resonance imaging. This is the first documented case of idiopathic hypertrophic cranial pachymeningitis associated with a dural arteriovenous fistula involving the straight sinus. We discuss possible causes of the association and the treatment options.

CLINICAL PRESENTATION

A 64-year-old man presented with a headache and visual disturbance. Gadolinium-enhanced T1-weighted magnetic resonance imaging demonstrated homogeneously stained meninges and prominent enhancement of the tentorium and falx. Angiograms demonstrated a dural arteriovenous fistula of the straight sinus.

INTERVENTION

Although surgical excision of the straight sinus and subsequent corticosteroid therapy failed to relieve the patient's visual symptoms, subsequent surgical decompression of the optic nerve resulted in improvement and stabilization.

CONCLUSION

Narrowing or occlusion of the tentorial sinuses and narrowing of the straight sinus by extensive dural fibrosis of the tentorium and falx, attributable in turn to idiopathic hypertrophic cranial pachymeningitis, may have resulted in the development of a dural arteriovenous fistula. We propose surgical decompression of the optic nerve as an alternative treatment during the active phase of the disease in patients who exhibit resistance to corticosteroid therapy.
Fibrous Connective Tissue Lesion Mimicking a Vestibular Schwannoma: Case Report
Authors: Beni-Adani Liana , Umansky Felix , Sofer Dov , Gomori Moshe
Published: September 2004

OBJECTIVE AND IMPORTANCE

Cerebellopontine angle fibromas are rare pathological entities that can mimic the presentation of vestibular schwannomas (VSs). Diagnosis of these benign lesions, however, is important, because treatment options may be different. The clinical, radiological, and intraoperative features of these unusual lesions of the cerebellopontine angle are discussed, with review of the relevant literature.

CLINICAL PRESENTATION

A 41-year-old man presented with recurrent episodes of diminished hearing on the left side, accompanied by facial ticks and pain on the same side. Magnetic resonance imaging and computed tomographic scans revealed a 1.5-cm, primarily intracanalicular lesion, suggesting a left VS.

INTERVENTION

The lesion was partially removed through a retrosigmoid suboccipital craniotomy. Its intraoperative appearance and hard fibrotic consistency differed from the classic features of VSs. The pathological findings indicated nontumoral fibrous connective tissue. The lesion exhibited no features of inflammation or fat and was also negative for S-100 staining. Follow-up magnetic resonance imaging scans demonstrated a small residual lesion, which exhibited shrinkage in subsequent magnetic resonance imaging studies. The painful ticks disappeared and facial nerve weakness improved postoperatively.

CONCLUSION

Although cerebellopontine angle fibromas may present similar radiological features, their clinical presentation may be somewhat different from that of typical VSs. If a fibroma is suspected, radiosurgery should be avoided; limited surgery may be considered as an option for patients experiencing symptoms. Because fibromas may be intraoperatively noted to be fibrotic and vascular, radical removal may not be easy or justified. After the final diagnosis has been reached, conservative treatment of the residual lesion may be the best option.
Impact of Computed Tomographic and Magnetic Resonance Imaging Findings on Surgical Outcome in Petroclival Meningiomas
Authors: Carvalho Gustavo A. , Matthies Cordula , Tatagiba Marcos , Eghbal Rama , Samii Madjid
Published: September 2004

OBJECTIVE

The preoperative radiological findings of computed tomographic and magnetic resonance imaging scans of 70 patients with petroclival meningioma were evaluated and statistically compared with the degree of surgical resection and patients' outcomes to depict the most important radiological findings that may influence surgical radicality and outcome.

METHODS

The following parameters were evaluated: 1) tumor diameters; 2) tumor extension toward the middle fossa, the internal auditory canal, the brainstem, and the foramen magnum; 3) bone changes; 4) peritumoral edema; 5) signs of tumor infiltrative pattern; and 6) surgical radicality. Postoperative results were analyzed immediately after the surgery and in a long-term follow-up study.

RESULTS

Larger tumors affected a younger population and presented a significantly shorter time until symptom onset. In the majority of cases (67%), the tumor extended to the parasellar region. Tumor extension toward the jugular foramen was found in 24% of the patients and reached the level of the foramen magnum in 18%. Irregular tumor margins were found in 67% of the tumors, and 50% of them presented peritumoral edema in addition. Interestingly, edema also was found in 20% of tumors with well-delineated margins.

CONCLUSION

Tumor size, brainstem compression, and tumor extension laterally to the internal auditory canal did not influence either the degree of surgical resection or the long-term outcome (P > 0.05). Supratentorial tumor extension to the middle fossa and downward involving the caudal cranial nerves displayed a significant importance in regard to the surgical radicality and the patient's outcome, respectively (P < 0.05). Radiological evidence of infiltrative tumor pattern and peritumoral edema at the brainstem surface were important parameters regarding surgical radicality (P < 0.05). However, only peritumoral edema influenced the long-term results significantly.
Combined Anterior Craniofacial Resection for Tumors Involving the Cribriform Plate: Early Postoperative Complications and Technical Considerations
Authors: Solero Carlo L. , DiMeco Francesco , Sampath Prakash , Mattavelli Franco , Pizzi Natalia , Salvatori Pietro , Cantù Giulio
Published: September 2004

OBJECTIVE

Combined craniofacial resection has become the standard approach for malignant tumors involving the cribriform plate and anterior cranial fossa. Despite its widespread application, however, many surgeons agree that the procedure carries a risk of significant morbidity and even mortality. The purpose of this study was to analyze the experience at a single institution to determine the incidence of early postoperative complications encountered after combined craniofacial resection of tumors involving the cribriform plate and to provide information to improve management.

METHODS

Between 1987 and 1997, 168 patients underwent combined craniofacial resection at the National Cancer Institute of Milan for tumors involving the cribriform plate. Patient charts, operative notes, follow-up clinic notes, radiographic studies, and pathology reports were analyzed. Morbidity encountered in the first 30 cases was compared with that encountered in the subsequent 138 cases.

RESULTS

The most frequently encountered pathological findings were adenocarcinoma (53.6%), squamous cell carcinoma (17%), and esthesioneuroblastoma (9.8%). Eight patients (4.7%) died, 6 of whom were among the first 30 patients to undergo resection. Among patients with fatal complications were three with meningoencephalitis, three with intracranial hemorrhage, and one with myocardial infarction. Fifty patients (29.7%) had nonfatal morbidity; 16 of these patients were among the first 30 patients operated. Transient cerebrospinal fluid leakage was the most frequent adverse effect (9.5%); 12 patients (7.1%) had pneumocephalus, 3 (1.8%) had meningitis, 4 (2.4%) had wound infections, 3 (1.8%) experienced transient impairment of mental status, 3 (1.8%) had transient diplopia, 2 (1.2%) had diabetes insipidus, and 1 (0.6%) had bone flap necrosis.

CONCLUSION

We observed a dramatic decrease in mortality and morbidity in patients who underwent combined craniofacial resection after the first 30 cases in our series. Improvement of specific aspects of surgical technique, such as more refined reconstructive methods and improved prophylactic antibiotic therapy, is at least partly responsible for this favorable trend.
Proliferation Index of Nonfunctioning Pituitary Adenomas: Correlations with Clinical Characteristics and Long-term Follow-up Results
Authors: Losa Marco , Franzin Alberto , Mangili Francesca , Terreni Maria Rosa , Barzaghi Raffaella , Veglia Fabrizio , Mortini Pietro , Giovanelli Massimo
Published: September 2004

OBJECTIVE

The recurrence of nonfunctioning pituitary adenomas (NFPAs) after surgical removal is common. The aim of our study was to investigate and correlate the growth fraction of NFPAs with clinical characteristics and long-term follow-up results.

METHODS

Tumor specimens were obtained from 101 consecutive patients with NFPAs (48 female patients and 53 male patients; mean age, 52.0 ± 1.5 yr). Specimens were immediately fixed in 10% buffered formalin and then embedded in paraffin. The Ki-67 antigen was assessed by immunocytochemical analysis using the monoclonal antibody MIB-1. The Ki-67 antigen labeling index (LI) was determined by counting a total of at least 1000 neoplastic nuclei.

RESULTS

The mean Ki-67 LI for the 101 patients was 2.4 ± 0.3% (range, 0–23.0%). Only age at surgery was inversely correlated with the Ki-67 LI; sex, maximal tumor diameter, and invasiveness into the cavernous sinuses did not significantly affect the Ki-67 LI. The mean follow-up period was 39.7 ± 2.1 months. During follow-up monitoring, 23 patients experienced tumor recurrence, after a mean period of 28.6 ± 4.8 months. Invasiveness of the tumor on preoperative magnetic resonance imaging scans was the strongest predictor of late tumor recurrence, followed by previous pituitary surgery, younger age, and lack of postoperative radiotherapy. The Ki-67 LI had no independent prognostic value.

CONCLUSION

Our study suggests that the clinical characteristics of patients with NFPAs, except for age at surgery, are not correlated with the Ki-67 LI. Moreover, the Ki-67 LI does not seem to provide independent information to identify patients at high risk for tumor recurrence.
Endovascular Treatment of Basilar Tip Aneurysms Using Guglielmi Detachable Coils: Anatomic and Clinical Outcomes in 73 Patients from a Single Institution
Authors: Tateshima Satoshi , Murayama Yuichi , Gobin Y. Pierre , Duckwiler Gary R. , Guglielmi Guido , Viñuela Fernando
Published: September 2004

OBJECTIVE

Seventy-three consecutive patients with 75 basilar tip aneurysms were treated with Guglielmi detachable coil (GDC) technology. Their anatomic and clinical outcomes are discussed.

METHODS

Seventy-five basilar tip aneurysms were treated with the GDC system at the University of California, Los Angeles Medical Center from 1990 to 1999. The average age of the population was 48.3 years (range, 28–82 yr). Forty-two patients (57.5%) presented with acute subarachnoid hemorrhage, 8 patients (10.9%) had unruptured aneurysms with mass effect, and 23 patients (31.5%) had incidental aneurysms. Thirty-one aneurysms (41.3%) were small with a small neck, 18 (24%) were small with a wide neck, 16 (21.3%) were large, and 10 (13.3%) were giant aneurysms.

RESULTS

Immediate anatomic outcomes demonstrated complete or near-complete occlusion in 64 aneurysms (85.3%) and incomplete occlusion in 7 aneurysms (9.3%). Four aneurysms (5.3%) could not be embolized because of anatomic difficulties. Of the 69 patients treated with GDCs, 63 patients (91.3%) remained neurologically intact or unchanged from their initial clinical status. Procedure-related morbidity and mortality were 4.1% and 1.4%, respectively. Long-term follow-up angiograms were obtained in 41 patients with 42 aneurysms. Thirty aneurysms (71.4%) demonstrated complete or near-complete occlusion. One incompletely embolized giant aneurysm ruptured during the follow-up period.

CONCLUSION

In contrast to surgical clipping of basilar tip aneurysms, the main technical challenge of the Guglielmi detachable coiling procedure depends on the shape of the aneurysm, not its location. The results of this study indicate that endovascular GDC technology is an appropriate therapeutic alternative in ruptured or unruptured basilar tip aneurysms regardless of patient age, clinical presentation, clinical status, or timing of treatment.
Gamma Knife Surgery for Epilepsy Related to Hypothalamic Hamartomas
Authors: Régis Jean , Bartolomei Fabrice , de Toffol Bertrand , Genton Pierre , Kobayashi Tatsuya , Mori Yoshimasa , Takakura Kintomo , Hori Tomokatsu , Inoue Hiroshi , Schröttner Oskar , Pendl Gerhard , Wolf Aizik , Arita Kazunori , Chauvel Patrick
Published: September 2004

OBJECTIVE

Drug-resistant epilepsy associated with hypothalamic hamartomas (HHs) can be cured by microsurgical resection of the lesions. Morbidity and mortality rates for microsurgery in this area are significant. Gamma knife surgery (GKS) is less invasive and seems to be well adapted for this indication.

METHODS

To evaluate the safety and efficacy of GKS to treat this uncommon pathological condition, we organized a multicenter retrospective study. Ten patients were treated in seven different centers. The follow-up periods were more than 12 months for eight patients, with a median follow-up period of 28 months (mean, 35 mo; range, 12–71 mo). All patients had severe drug-resistant epilepsy, including frequent gelastic and generalized tonic or tonicoclonic attacks. The median age was 13.5 years (range, 1–32 yr; mean, 14 yr) at the time of GKS. Three patients experienced precocious puberty. All patients had sessile HHs. The median marginal dose was 15.25 Gy (range, 12–20 Gy). Two patients were treated two times (at 19 and 49 mo) because of insufficient efficacy.

RESULTS

All patients exhibited improvement. Four patients were seizure-free, one experienced rare nocturnal seizures, one experienced some rare partial seizures but no more generalized attacks, and two exhibited only improvement, with reductions in the frequency of seizures but persistence of some rare generalized seizures. Two patients, now seizure-free, were considered to exhibit insufficient improvement after the first GKS procedure and were treated a second time. A clear correlation between efficacy and dose was observed in this series. The marginal dose was more than 17 Gy for all patients in the successful group and less than 13 Gy for all patients in the “improved” group. No side effects were reported, except for poikilothermia in one patient. Behavior was clearly improved for two patients (with only slight improvements in their epilepsy). Complete coverage of the HHs did not seem to be mandatory, because the dosimetry spared a significant part of the lesions for two patients in the successful group.

CONCLUSION

We report the first series demonstrating that GKS can be a safe and effective treatment for epilepsy related to HHs. We advocate marginal doses greater than or equal to 17 Gy and partial dose-planning when necessary, for avoidance of critical surrounding structures.
Efficacy of Vagal Nerve Stimulation in Children with Medically Refractory Epilepsy
Authors: Patwardhan Ravish V. , Stong Benjamin , Bebin E. Martina , Mathisen Jan , Grabb Paul A.
Published: September 2004

OBJECTIVE

The effects of vagal nerve stimulation (VNS) on seizure frequency and quality of life were analyzed retrospectively in children with medically refractory epilepsy.

METHODS

Thirty-eight children aged 11 months to 16 years underwent implantation of vagal nerve stimulators. Age of seizure onset, duration of epilepsy, and seizure type and frequency were recorded preoperatively. Age at implantation, length of follow-up, seizure type and frequency, and change in quality of life (QOL) were recorded postoperatively. Changes in QOL were assigned a QOL score by the caretakers on a visual analog scale of −1 (much worse) to +1 (much improved).

RESULTS

The median follow-up period was 12 months (range, 10–18 mo). Eleven (29%), 15 (39%), 5 (13%), and 7 (18%) children had greater than 90% reduction, 50 to 90% reduction, less than 50% reduction, and no reduction in seizure frequency, respectively. For all children, seizure reduction by seizure type was as follows: atonic (80%), absence (65%), complex partial (48%), and generalized tonicoclonic (45%). The mean change in QOL score was 0.61. Eighty-six percent of the children had QOL scores of 0.5 (improved) or higher. Follow-up of at least 6 months was associated with greater seizure reduction (P = 0.05) and higher QOL score (P < 0.01). Seizure reduction was greater in children with onset of epilepsy after 1 year of age (P < 0.05). The age of the child and duration of epilepsy were not associated with greater or lesser degrees of seizure reduction.

CONCLUSION

VNS provided improvements in seizure control for the majority of children regardless of age. QOL was improved in the majority of children with VNS. VNS should be considered for children with medically refractory epilepsy who have no surgically resectable focus.
Unruptured Intracranial Aneurysms: Appraisal of the Literature and Suggested Recommendations for Surgery, Using Evidence-based Medicine Criteria
Authors: Brennan Jeffrey W. , Schwartz Michael L.
Published: September 2004

OBJECTIVE

The literature on unruptured intracranial aneurysms is reviewed, and an attempt is made to stratify it according to the weight of the evidence. Recommendations for surgery are suggested, using evidence-based criteria.

METHODS

A MEDLINE search was performed for 1966 to 1999. The focus was restricted to surgical management rather than other types of management, such as endovascular treatments. Each article was classified as Class I, II, or III according to the weight of the evidence. Some articles, such as literature reviews and data analyses, did not fit this classification and were grouped separately. Recommendations are based on the evidence available.

RESULTS

Forty-five articles were reviewed. Thirteen articles contained information on the natural history, 19 contained data on the risks of surgery, and 2 contained information on both. In addition, 11 contained analyses of costs and benefits. None met the criteria for Class I evidence. Seven articles on the natural history and 7 on the risks of surgery met the criteria for Class II evidence, and 6 and 12, respectively, met those for Class III evidence. The remainder of the articles were analyses or review articles.

CONCLUSION

There is insufficient evidence to recommend a standard of management. As a therapeutic guideline, conservative treatment is recommended for small aneurysms (<10 mm) and asymptomatic nongiant aneurysms in older people, whereas surgery is recommended for larger aneurysms in younger people and symptomatic aneurysms in fit patients. Other recommendations can be justified only as therapeutic options, using evidence-based criteria. Areas for future investigation are discussed.
Consistent and Selective Expression of the Discoidin Domain Receptor-1 Tyrosine Kinase in Human Brain Tumors
Authors: Weiner Howard L. , Huang Hongyun , Zagzag David , Boyce Hayden , Lichtenbaum Roger , Ziff Edward B.
Published: September 2004

OBJECTIVE

Few molecular targets are both consistently and selectively expressed in a majority of central nervous system (CNS) neoplasms. Receptor tyrosine kinases have been implicated in brain tumor oncogenesis. We previously isolated one such receptor, discoidin domain receptor-1 (DDR1), from high-grade pediatric brain tumors. Here, we analyze the cellular origin and distribution of DDR1 expression in human brain tumors and its expression in tumor cells relative to surrounding brain.

METHODS

By use of a digoxigenin-labeled DDR1 riboprobe, we investigated the expression of DDR1 messenger ribonucleic acid in a prospective series of 30 resected human primary and metastatic brain neoplasms, nonneoplastic human brain, and mouse embryonic brain, as well as a mouse glioblastoma model, by in situ hybridization.

RESULTS

All the high-grade primary brain and metastatic brain tumors showed unequivocal, intense DDR1 expression within the majority of tumor cells, whereas expression was not observed in hyperplastic tumor blood vessels, normal brain blood vessels, inflammatory cells, or in the normal brain tissue that surrounded the tumor. Receptor expression was limited to tumor cells located within solid tumor tissue. Overall, 27 of 29 resected CNS tumors exhibited tumor cell-specific DDR1 expression, whereas one specimen composed of isolated glioblastoma cells within invaded brain parenchyma showed no detectable staining for this receptor. DDR1 was also expressed preferentially in the ventricular zone (a region of highly proliferating precursor cells) of mice at embryonic Day 15.5.

CONCLUSION

We found that DDR1 is consistently expressed in all high-grade brain neoplasms studied and is selective for tumor cells in the specimens analyzed. The expression of DDR1 by tumor cells of CNS neoplasms and by primitive cells of the embryonic ventricular zone suggests that DDR1 is a potentially useful marker of tumor cells within the CNS.
Intramedullary Clear Cell Ependymoma in the Cervical Spinal Cord: Case Report
Authors: Akutsu Hiroyoshi , Shibata Yasushi , Okazaki Masao , Hyodo Akio , Matsumura Akira
Published: September 2004

OBJECTIVE AND IMPORTANCE

Clear cell ependymoma of the spinal cord has not been reported in the literature, although ependymoma in the cerebral and cerebellar hemispheres has been described. We present the first case report of this rare histological type of ependymoma arising in the cervical spinal cord and emphasize the importance of recognizing this histological entity.

CLINICAL PRESENTATION

A 42-year-old woman presented with numbness in both upper limbs and spastic gait. Magnetic resonance imaging revealed an intramedullary tumor at the C6–T1 level with syringomyelia.

INTERVENTION

The tumor was totally removed. Histological analysis revealed that the tumor was composed of round cells with perinuclear halos similar to those observed in oligodendroglioma. However, we diagnosed clear cell ependymoma because these tumor cells exhibited epithelial features and ependymal rosettes under light microscopic examination.

CONCLUSION

Histological diagnosis was crucial to our determining whether to perform postoperative adjuvant therapy in this patient. Neurosurgeons should be aware of the possibility of this histological entity among intramedullary spinal cord tumors.
Congenital Absence of a Cervical Pedicle: Report of Two Cases and Review of the Literature
Authors: Sheehan Jason , Kaptain George , Sheehan Jonas , Jane John
Published: September 2004

OBJECTIVE AND IMPORTANCE

The congenital absence of a cervical pedicle is a rare clinical entity. Patients with this anomaly tend to present with cervical pain or after a traumatic incident. Initial evaluations with conventional radiography frequently lead to misinterpretation and misguided intervention. We report two cases of absent cervical pedicles and describe the presentation, diagnosis, and treatment of these patients. Moreover, we review the literature on this clinical entity.

CLINICAL PRESENTATION

The first patient was a 4-year-old boy who presented with neck pain after falling off a trampoline. His neurological examination did not reveal any focal abnormalities, but radiographs were thought to be consistent with a right, C4–C5, unilateral, jumped facet. The second patient was a 27-year-old woman who presented with severe neck, back, and left upper extremity pain and paresthesias after an alleged incident of spousal abuse. Her neurological examination results were remarkable for left upper extremity weakness and hemibody sensory changes. Conventional radiographs were thought to reveal a left, C3–C4, unilateral, locked facet.

INTERVENTION

For both patients, reduction attempts were made with Gardner-Wells tongs and traction. After failure to achieve adequate reduction, evaluations using two-dimensional computed tomography confirmed congenitally absent cervical pedicles. Both patients were ultimately treated conservatively and experienced resolution of their presenting symptoms.

CONCLUSION

The congenital absence of a cervical pedicle is a rare entity that is frequently misdiagnosed. Diagnoses can be accurately confirmed with two-dimensional computed tomography. Conservative treatment resulted in successful management of this clinical entity.
Recurrent (Nonfamilial) Hemangioblastomas Involving Spinal Nerve Roots: Case Report
Authors: Raghavan Ravi , Krumerman Jon , Rushing Elisabeth J. , White Charles L. , Chason David P. , Watson Mark L. , Coimbra Caetano
Published: September 2004

OBJECTIVE AND IMPORTANCE

Spinal nerve root hemangioblastomas are rare and are reported mainly in patients with von Hippel-Lindau (VHL) syndrome. The pathogenesis of so-called nonfamilial lesions is virtually unknown. We discuss, mainly from a molecular perspective, a unique patient with sporadic, recurrent hemangioblastomas restricted to spinal nerve roots.

CLINICAL PRESENTATION

A 53-year-old man who had had a surgically corrected lumbosacral meningomyelocele presented on at least three occasions during a 17-year period with multifocal capillary hemangioblastomas involving spinal nerve roots. On each occasion, tumors appeared on a different nerve root, with the majority located in the midcervical segments. The patient had no clinical features or family history of VHL syndrome.

TECHNIQUE

To obtain a clearer understanding of the pathogenesis of this unusual case and its relationship to VHL syndrome, molecular analysis of the VHL gene was performed by use of complete sequence analysis and loss of heterozygosity studies on deoxyribonucleic acid derived from the patient's blood leukocytes and three separately resected hemangioblastomas.

CONCLUSION

Germ-line molecular analysis performed on all three exons in the VHL gene coding region did not indicate that any mutations were present. Loss of heterozygosity analysis of deoxyribonucleic acid from the three hemangioblastoma resections showed normal heterozygosity in the 3p25–26 region. Complete VHL gene sequence analysis did not demonstrate a somatic mutation in the coding region of the VHL gene in any of the three tumors, thereby supporting the loss of heterozygosity data that a molecular event directly involving the VHL gene may not be the causative factor in their tumorigenesis.
Transdural Cauda Equina Incarceration after Microsurgical Lumbar Discectomy: Case Report
Authors: Kothbauer Karl F. , Seiler Rolf W.
Published: September 2004

OBJECTIVE AND IMPORTANCE

Complications usually occur when they are least expected. We present an unusual case of nerve entrapment after microsurgical discectomy.

CLINICAL PRESENTATION

A patient undergoing uneventful first lumbar microsurgical discectomy developed severe back and leg pain and a progressive neurological deficit during the first postoperative night. Herniation of cauda equina nerve roots had occurred through an unnoticed minimal defect in the dura, which had not caused cerebrospinal fluid leakage. The roots were incarcerated and swollen, and they filled the space of the resected nucleus pulposus. It was presumed that elevation of intra-abdominal pressure and consequent increased intraspinal pressure during extubation led to the herniation of arachnoid and cauda equina roots. The nerve roots were then trapped and incarcerated in the manner of bowel loops in an abdominal wall hernia.

INTERVENTION

During reoperation, the nerve roots were repositioned into the dural sac. The patient recovered without further complications and without long-term sequelae.

CONCLUSION

All dural tears that occur during intraspinal surgery, even if they are small and the arachnoid is intact, should be closed with stitches or at a minimum with a patch of muscle or gelatin sponge with fibrin glue. Care should be taken to avoid increased intra-abdominal pressure during extubation. Excessive pain and progressive neurological dysfunction occurring shortly after microsurgical lumbar discectomy or any intraspinal procedure is indicative of possible hemorrhage with subsequent compression of nerve roots. The case reported here provides anecdotal evidence that this situation can also be caused by a herniation of cauda equina nerve roots through a small dural defect that was not evident during the initial operation.
Shoulder Numbness in a Patient with Suprascapular Nerve Entrapment Syndrome: Cutaneous Branch of the Suprascapular Nerve: Case Report
Authors: Harbaugh Kimberly S. , Swenson Rand , Saunders Richard L.
Published: September 2004

OBJECTIVE AND IMPORTANCE

The ability to diagnose peripheral nerve disorders is dependent on knowledge of the anatomic course and function of the nerves in question. The classic teaching regarding the suprascapular nerve (SScN) is that it has no cutaneous branches, despite the fact that a cutaneous branch was first reported in the anatomic literature 20 years ago.

CLINICAL PRESENTATION

We describe a case of a 35-year-old male patient who presented with right shoulder pain and atrophy and weakness of the right supra- and infraspinatus muscles. During the examination, he was also noted to have an area of numbness involving the right upper lateral shoulder region. Electrical study results were consistent with SScN entrapment at the suprascapular notch.

INTERVENTION

The patient underwent surgical decompression 7 months after the onset of his symptoms. The patient noted resolution of his shoulder pain immediately after the procedure, and his shoulder sensory disturbance had improved by 2 weeks. At 9 months after surgery, he remained pain-free, his shoulder sensation was normal, and his motor abnormalities had improved significantly.

CONCLUSION

This case provides clinical evidence for the presence of a cutaneous branch of the SScN, as described in cadaveric studies. Although shoulder numbness demands a search for alternative diagnoses, it does not necessarily exclude the diagnosis of SScN entrapment.
Femoral Ring Allograft for Anterior Cervical Interbody Fusion: Technical Note
Authors: Shapiro Scott , Bindal Raj
Published: September 2004

OBJECTIVE

Cadaveric fibula with locking plate internal fixation has been reported to be associated with fewer complications and better long-term results, compared with autologous iliac crest. With the knowledge that cortically dense allografts collapse less with time, new machined femoral ring allografts were developed for anterior cervical fusion after anterior cervical discectomy. We describe the system and the technique for placement.

METHODS

The femoral ring allograft set consists of color-coded graft-sizers that correspond precisely to the size of the precut grafts. The purple set is primarily intended for petite cervical vertebral bodies; the purple sizers and grafts are 11 mm wide and 11 mm deep and vary in height from 5 to 9 mm. The green sizers and grafts are 14 mm wide and 11 mm deep and vary in height from 5 to 11 mm. The blue sizers and grafts are 14 mm wide and 14 mm deep and vary in height from 5 to 11 mm. The rostral and caudal faces of the grafts are corrugated, to improve their holding capacity in the interspace. The bone is sterilely packaged in vacuum-sealed bottles, the tops of which are color-coded and precisely labeled. The set also includes a graft holder (to facilitate insertion into the interspace), impactors, and a barrel-shaped cutting burr (to prepare the endplates for fusion).

RESULTS

After anterior cervical discectomy to treat spondylotic radiculopathy or myelopathy, a femoral ring allograft was inserted, with allogeneic demineralized bone matrix and a locking cervical plate, in 20 cases, with no complications. Use of the system decreased the operating time by an average of 10 to 15 minutes.

CONCLUSION

The femoral ring allograft system is easy to use, and there have been no complications to date. The long-term fusion rate remains to be determined.
Use of Internal Fiducial Markers in Frameless Stereotactic Navigational Systems during Spinal Surgery: Technical Note
Authors: Salehi Sean A. , Ondra Stephen L.
Published: September 2004

OBJECTIVE

The use of frameless stereotaxy has expanded the spine surgeon's ability to perform surgical procedures with instrumentation in areas of narrow anatomic tolerance. In many circumstances, however, it is difficult to register the frameless stereotactic probe using known anatomic landmarks. This occurs typically because landmarks are indistinct, and congenital or surgical defects limit the availability of anatomic fiducials. We propose an accurate and efficient method for registering the frameless stereotactic probe for spinal surgery when a staged procedure is planned.

METHODS

During the first stage of a planned two-stage procedure, a minimum of four cranial fiducial screws are implanted in the posterior element of each vertebra in which stereotactic registration is desired. Stage 1 is completed, and all suture closure is performed. A computed tomographic scan formatted for the frameless stereotactic unit is obtained postoperatively. In the second stage of surgery, registration is performed using cranial screws as internal fiducial markers.

RESULTS

Registration is performed easily and quickly using cranial screws as internal fiducial markers. No more than four registration points are necessary to calibrate the system to accuracy within 1.5 mm.

CONCLUSION

Implantation of fiducial markers during Stage 1 of a complex staged spinal surgery renders the frameless stereotactic navigational system registration extremely fast and accurate. We advocate the technique to enhance the use of frameless navigational systems for reliable and quick registration of the spine.
Convulsive Seizures Following Subdural Application of Fibrin Sealant Containing Tranexamic Acid in a Rat Model
Authors: Schlag Michael G. , Hopf Rudolf , Redl Heinz
Published: September 2004

OBJECTIVES

Tranexamic acid (t-AMCA) has been shown to cause severe convulsions in humans and cats when applied topically to the central nervous system. We wanted to determine whether pure t-AMCA or fibrin sealant (FS) containing t-AMCA would induce similar effects when applied to the spinal cord in a rat model.

METHODS

Following low-thoracic laminectomy, the dura was incised to expose the dorsal surface of the lumbar enlargement. Rats were allocated to one of the following treatments: 1) t-AMCA (10 mg/ml), 2) vehicle (phosphate buffered saline), 3) FS containing t-AMCA, 4) FS containing aprotinin. The response of the rats was evaluated based on neurological and behavioral observations. Additionally, motor function was scored in the rats that had received FS.

RESULTS

Application of either 10 mg/ml t-AMCA or FS containing t-AMCA caused severe hind limb spasms that developed into spontaneous generalized convulsions. Two of the three rats that had received FS containing t-AMCA died of respiratory failure. In contrast, application of vehicle or FS containing aprotinin did not cause any abnormal conditions of the animals.

CONCLUSION

Tranexamic acid may cause severe complications when used in the central nervous system. Thus, fibrin sealants containing t-AMCA should not be used in neurosurgery.
Hemangioblastomas of the Central Nervous System in von Hippel-Lindau Syndrome and Sporadic Disease
Authors: Conway James E. , Chou Dean , Clatterbuck Richard E. , Brem Henry , Long Donlin M. , Rigamonti Daniele
Published: September 2004

OBJECTIVE

The presentation, screening, management, and clinical outcomes of patients who presented to our institution from 1973 to 1999 with central nervous system (CNS) hemangioblastomas in von Hippel-Lindau (VHL) syndrome and sporadic disease were analyzed.

METHODS

The surgical pathology database of our institution was searched to identify all patients with histologically verified CNS hemangioblastomas occurring from 1973 to 1999. The medical, radiological, surgical, pathological, and autopsy records from these patients were reviewed retrospectively and statistically analyzed.

RESULTS

Forty patients (21 males and 19 females) presented with CNS hemangioblastomas. Twenty-five patients (62%) harbored sporadic hemangioblastomas. Fifteen patients (38%) had VHL syndrome. These 40 patients presented with 61 hemangioblastomas (8 patients had multiple lesions). Ten patients (25%) harbored spinal cord hemangioblastomas (5 patients had multiple lesions). Patients with VHL disease tended to present with neurological symptoms and signs at a younger age than patients with sporadic disease (P = 0.09), to present with multiple lesions (53%), and to develop new lesions (rate, 1 lesion/2.1 yr). Hemangioblastomas of the spinal cord were more prevalent in patients with VHL syndrome (P = 0.024). Neuroradiological screening of patients with VHL syndrome allowed identification of more than 75% of new lesions before they became symptomatic. Sixty-six surgical procedures were performed (12 patients required multiple operations). Six patients with VHL syndrome required surgery for new lesions. Surgical complications occurred in six patients (15%). Symptom resolution or arrest of progression at 1 year was documented in 88% of patients. Recurrence of symptoms from partially resected lesions occurred in eight patients (20%). No deaths associated with surgery occurred. One patient with sporadic disease and one patient with VHL syndrome (5%) died as a result of late medical complications from CNS hemangioblastomas.

CONCLUSION

Surgical outcomes for patients with CNS hemangioblastomas are favorable. However, management of hemangioblastomas is a more difficult and prolonged endeavor for patients with VHL syndrome. In patients with VHL syndrome, neuroradiological screening allows identification of lesions before they become symptomatic. Because patients with VHL syndrome are at risk for development of new lesions, they require lifelong follow-up.
Influence of Smoking, Hypertension, and Sex on the Phenotypic Expression of Familial Intracranial Aneurysms in Siblings
Authors: Connolly E. Sander , Choudhri Tanvir F. , Mack William J. , Mocco J , Spinks Theodore J. , Slosberg Jason , Lin Tina , Huang Judy , Solomon Robert A.
Published: September 2004

OBJECTIVE

To investigate the effects of smoking, hypertension, and sex on the phenotypic expression of familial intracranial aneurysms (FIAs).

METHODS

We retrospectively reviewed the case records of 806 consecutive patients undergoing aneurysm surgery at our institution (1986–1995) and discovered 24 families with at least two affected siblings. Prevalence rates for the smoking, hypertension, and sex risk factors in these nuclear families were compared with those of patients with sporadic intracranial aneurysms (SIAs) and population-based control patients.

RESULTS

Affected family members with FIAs exhibited prevalence rates of smoking and hypertension (74% and 43%, respectively) that tended to be higher than those of population-based control patients (52% [P < 0.005] and 36% [P = not significant (NS)], respectively) and comparable to those of patients with SIAs (64% [P = NS] and 40% [P = NS], respectively). A positive association existed between FIA formation and female sex but was somewhat less strong than that observed in the SIAs (59% FIAs, 71% SIAs, 50% control patients). In addition, the prevalence rates of smoking, hypertension, and female sex were higher in affected family members with FIAs than in their unaffected siblings (58% [P < 0.05], 28% [P = 0.06], and 39% [P < 0.05], respectively). Individuals in families with expressed FIAs who had high aneurysmal penetrance had a greater tendency to be smokers, hypertensive, and female (74%, 59%, and 55%, respectively) than did their low-penetrance counterparts (61% [P = 0.1], 27% [P < 0.05], and 45% [P = NS], respectively).

CONCLUSION

Together these data suggest that hypertension, smoking, and female sex increase the likelihood that a member of a family with an expressed FIA will have an aneurysm. These observations may prove helpful in guiding the use of screening studies and encouraging education about the potential risks of continued tobacco use and untreated hypertension in this patient cohort.
Stereotactic Radiosurgery for Motor Cortex Region Arteriovenous Malformations
Authors: Hadjipanayis Constantinos G. , Levy Elad I. , Niranjan Ajay , Firlik Andrew D. , Kondziolka Douglas , Flickinger John C. , Lunsford L. Dade
Published: September 2004

OBJECTIVE

The optimal management of arteriovenous malformations (AVMs) in critical brain locations remains controversial. To reduce the risk of an AVM hemorrhage and to enhance the possibility of preserving neurological function, stereotactic radiosurgery was performed in 33 patients with newly diagnosed or residual AVMs located within the motor cortex. The role of embolization also was examined.

METHODS

During a 9-year study period, 33 patients with AVMs located primarily in the motor cortex region were treated with stereotactic radiosurgery. These patients were followed up radiographically for a minimum of 36 months, or less if obliteration was documented before 36 months had elapsed. Of the 33 patients, 9 underwent embolization and 1 underwent microsurgery before radiosurgery. Nine patients required a second radiosurgery. The mean AVM target volume was 4.35 cc, and the average radiation dose to the AVM margin was 20 Gy. The median follow-up was 36 months (range, 10–91 mo), and angiographic follow-up of eligible patients was performed 24 or 36 months after radiosurgery.

RESULTS

Results were stratified by radiosurgical target volumes: less than 3 cc (Group 1), 3 to 10 cc (Group 2), and greater than 10 cc (Group 3). Overall (including second radiosurgery), 13 (87%) of 15 patients in Group 1 had complete obliteration confirmed by angiography. Nine (64%) of 14 patients in Group 2 exhibited nidus obliteration, and one (25%) of four patients in Group 3 demonstrated obliteration on a magnetic resonance imaging scan. Eight patients (24%) underwent second-stage radiosurgery after angiography revealed a persistent AVM nidus; three patients demonstrated complete obliteration on follow-up angiography. The obliteration rate was higher (87%) for AVMs with less than 3 cc target volume and lower (56%) for those with target volumes larger than 3 cc. One patient experienced worsening neurological function after radiosurgery, and one died from delayed AVM hemorrhage during the latency period. No patient bled after angiographically confirmed AVM obliteration.

CONCLUSION

Stereotactic radiosurgery is a successful and safe management option for patients with motor cortex AVMs. The obliteration of AVMs and the attendant low morbidity rates indicate a primary role for radiosurgery in these patients. Staged radiosurgery may be necessary to increase obliteration rates for larger AVMs or for those that are not obliterated after the first procedure.