bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods and Design Considerations for Randomized Clinical Trials Evaluating Surgical or Endovascular Treatments for Cerebrovascular Diseases
Authors:   North American Trial of Unruptured and Ruptured Aneurysms Planning Committee, Qureshi Adnan I. , Hutson Alan D. , Harbaugh Robert E. , Stieg Philip E. , Hopkins L. Nelson
Published: August 2004

OBJECTIVE

The results of clinical trials affect the practice of surgery and endovascular therapy for cerebrovascular diseases. The purpose of this report is to review the basic components of the designs and methods for randomized clinical trials and to describe the influence of those components on the interpretation of trial results.

METHODS

The goal of an optimal clinical trial of a new procedure is to provide the most objective and rigorous evaluation of the safety and effectiveness of that procedure. Anything in the design, performance, or analysis that impairs such an assessment decreases the ability of the trial to achieve its goal and answer the research question. To highlight the components of a clinical trial, this report uses examples of Phase III clinical trials that have influenced the practice of cerebrovascular surgery and endovascular therapy in the past three decades, including the International Cooperative Study of Extracranial/Intracranial Arterial Anastomosis, the North American Symptomatic Carotid Endarterectomy Trial, the Asymptomatic Carotid Atherosclerosis Study, the Prolyse in Acute Cerebral Thromboembolism II study, and the International Subarachnoid Aneurysm Trial.

RESULTS

The research question (objective) of the trial must be clearly defined, with an objective measure of efficacy and a specified quantitative difference to define the superiority of one intervention over another, in a relatively homogeneous patient population. Allocation concealment, randomization with or without stratification, and blinding (or masking) are important strategies to prevent differences in the study populations that could adversely affect the conclusions of the study. The primary end point must correspond to the specific aims of the trial. It should be objectively defined, quantifiable, reliable, and reproducible. Commonly defined end points in surgical trials include changes from baseline illness or disease severity scores, morbidity and mortality rates, and relative risks of reaching an end point with time. The statistical methods used for interim and final analyses are important. The effects of dropouts, crossovers, and missing data should be understood in the context of the final analysis. Additional concepts, such as intention-to-treat analysis and use of actual versus predicted outcomes, are important with respect to interpretation of the final results of the study.

CONCLUSION

The neurosurgical and neuroendovascular communities are currently planning or conducting several clinical trials to evaluate new procedures for the treatment of cerebrovascular diseases. It is hoped that a better understanding of the components of clinical trials will facilitate the design and implementation of effective studies.
Carotid Angioplasty and Stenting versus Carotid Endarterectomy for Treatment of Asymptomatic Carotid Stenosis: A Randomized Trial in a Community Hospital
Authors: Brooks William H. , McClure Rick R. , Jones Michael R. , Coleman Timothy L. , Breathitt Linda
Published: August 2004

OBJECTIVE

Carotid endarterectomy (CEA) is effective in reducing the risk of stroke in individuals with more than 60% carotid stenosis. Carotid angioplasty and stenting (CAS) has been proffered as effective and used in treating individuals with asymptomatic carotid stenosis despite the absence of proven clinical equivalency. This randomized trial was designed to explore the hypothesis that CAS is equivalent to CEA for treating asymptomatic carotid stenosis.

METHODS

A total of 85 individuals presenting with asymptomatic carotid stenosis of more than 80% were selected randomly for CAS or CEA and followed up for 48 months.

RESULTS

Stenosis decreased to an average of 5% after CAS. The patency of the reconstructed artery remained satisfactory regardless of the technique, as determined by carotid ultrasonography. No major complications such as cerebral ischemia or death occurred. Procedural complications associated with CAS (n = 5) were hypotension and/or bradycardia; those concomitant with CEA (n = 3) were cervical nerve injury or complications related to general anesthesia (n = 4). Both procedures were well tolerated in the context of pain and discomfort. Hospital stay was similar in the two groups (mean, 1.1 versus 1.2 d). The occurrence of complications associated with CAS or CEA prolonged hospitalization by 3 days (mean, 4.0 versus 4.5 d). Return to full activity was achieved within 1 week by more than 85% of patients; all returned to their usual lifestyle by 2 weeks. Although hospital charges were slightly higher for CAS, costs were similar.

CONCLUSION

CAS and CEA may be equally effective and safe in treating individuals with asymptomatic carotid stenosis.
Transforaminal Lumbar Interbody Fusion: Surgical Technique and Results in 24 Patients
Authors: Salehi Sean A. , Tawk Rabih , Ganju Aruna , LaMarca Frank , Liu John C. , Ondra Stephen L.
Published: August 2004

OBJECTIVE

The advantage of anterior column support and fusion in addition to pedicle fixation in patients with degenerative spinal disorders has become increasingly clear. With the increase in popularity of this treatment, a variety of techniques have been used to achieve the goal of anterior column support, fusion, and segmental instrumentation. Posterior lumbar interbody fusion has been used since the late 1940s in the treatment of degenerative lumbar spine. We evaluated a modification to posterior lumbar interbody fusion called transforaminal lumbar interbody fusion (TLIF).

METHODS

A retrospective analysis was performed on 24 patients (9 women, 15 men) who underwent TLIF. The approach involved a unilateral laminectomy and inferior facetectomy at the level of fusion. The interbody fusion was achieved from this unilateral approach by performing discectomy, arthrodesis, and insertion of one or two titanium cages packed with autologous bone. The average age of the patients in this study was 42.6 ± 12.5 years. Five patients were smokers. Five cases were related to workmen's compensation. Seventeen patients' original symptoms were a combination of low back pain and radiculopathy. Ten patients had had a previous spine operation.

RESULTS

Eleven patients had L4–S1 TLIFs. The rest of the patients had a single-level TLIF (L2–S1). Average intensive care unit and floor days were 1.1 ± 1.0 and 5.8 ± 2.2 days, respectively. The number of days to ambulation was 2.8 ± 1.6 days. There were a total of six self-limited complications in 24 patients (including one transient neurological complication). The average follow-up time was 16.9 ± 9.1 months. Twenty-two patients had solid fusions. A modified Prolo scale (4 worst, 20 best) was used to evaluate the clinical outcome. The average score was 16.1 ± 4.1.

CONCLUSION

TLIF is a reliable and safe technique for interbody support that can be performed with excellent clinical outcome. In the authors' experience, TLIF offers excellent exposure with minimal risk. This applies particularly in cases of repeat spine surgery, in which the presence of scar tissue makes traditional posterior lumbar interbody fusion techniques difficult or impossible. In addition, TLIF seems to be a viable alternative to anteroposterior circumferential fusion and/or anterior lumbar interbody fusion.
Translabyrinthine Approach for Acoustic Neuroma
Authors: Day John Diaz , Chen Douglas A. , Arriaga Moises
Published: August 2004

THE TRANSLABYRINTHINE APPROACH has been popularized during the past 30 years for the surgical treatment of acoustic neuromas. It serves as an alternative to the retrosigmoid approach in patients when hearing preservation is not a primary consideration. Patients with a tumor of any size may be treated by the translabyrinthine approach. The corridor of access to the cerebellopontine angle is shifted anteriorly in contrast to the retrosigmoid approach, resulting in minimized retraction of the cerebellum. Successful use of the approach relies on a number of technical nuances that are outlined in this article.
Evolution of Neuroendovascular Intervention: A Review of Advancement in Device Technology
Authors: Boulos Alan S. , Levy Elad I. , Bendok Bernard R. , Kim Stanley H. , Qureshi Adnan I. , Guterman Lee R. , Hopkins L. Nelson
Published: August 2004

NEUROENDOVASCULAR SURGERY IS a rapidly evolving field. Each year, numerous improvements are made in the endovascular surgeon's armamentarium. This evolution in technology, which is occurring at a dizzying pace, addresses many of the current limitations of neuroendovascular approaches. The potential to improve the outcomes of our patients is tremendous, particularly because one of the most common and most devastating neurological disorders, ischemic stroke, remains largely untreated. This article presents several of the new technologies that are currently being investigated or are under development and have the potential to lead to major advances in endovascular approaches for the treatment of intracranial and extracranial diseases.
Trochlear Nerve Palsy after Repeated Percutaneous Balloon Compression for Recurrent Trigeminal Neuralgia: Case Report and Pathogenic Considerations
Authors: Urculo Enrique , Alfaro Roger , Arrazola Mariano , Astudillo Edgar , Rejas Guillermo
Published: August 2004

OBJECTIVE AND IMPORTANCE

Repeated percutaneous balloon compression for the treatment of idiopathic trigeminal neuralgia is infrequent. When a second procedure is performed, the outcome is unknown. A patient developed an isolated trochlear nerve palsy after undergoing percutaneous trigeminal ganglion balloon compression for a second time. The mechanism of diplopia and the complications associated with this technique were studied.

CLINICAL PRESENTATION

The patient was a 67-year-old woman with a history of medically refractory idiopathic trigeminal neuralgia involving all three divisions of the right trigeminal nerve.

INTERVENTION

Percutaneous balloon compression was performed. Despite initial total relief from pain without complications, the patient again displayed manifestations of trigeminal neuralgia 3 months after the procedure. The pain disappeared after she underwent a second balloon compression procedure, but she developed an isolated trochlear nerve palsy, which spontaneously resolved in 2 months.

CONCLUSION

Isolated trochlear nerve palsy is a rare and reversible complication after percutaneous balloon compression for trigeminal neuralgia. This case illustrates that the mechanism of injury to the fourth nerve is the result of an erroneous technique: excessive penetration of the Fogarty catheter in Meckel's cave beyond the porus trigemini and compression of the cisternal segment of the trochlear nerve when the inflated balloon is pushed against the tentorium.
Spinal Accessory Schwannoma Mimicking a Tumor of the Fourth Ventricle: Case Report
Authors: Kurokawa Ryu , Tabuse Masanao , Yoshida Kazunari , Kawase Takeshi
Published: August 2004

OBJECTIVE AND IMPORTANCE

Spinal accessory schwannomas unassociated with neurofibromatosis are very rare, and only 30 cases have been reported in the literature. To our knowledge, this is the first report of a spinal accessory schwannoma mimicking a tumor of the fourth ventricle.

CLINICAL PRESENTATION

A 50-year-old man presented with neck pain after being involved in a motor vehicle accident. There were no neurological deficits, but a computed tomographic scan revealed a large hypodense mass with punctuate calcifications in the fourth ventricle. The tumor exhibited low intensity on the T1-weighted magnetic resonance imaging scan and high intensity on the T2-weighted scan, and it showed inhomogeneous contrast enhancement.

INTERVENTION

The tumor was totally removed by a bilateral suboccipital craniectomy and C1 laminectomy. Dissection of the surgical specimen revealed that the tumor had originated from the left spinal accessory nerve. Histopathological examination confirmed the diagnosis of schwannoma. The patient experienced transient postoperative cerebellar ataxia but recovered completely.

CONCLUSION

Intracisternal-type spinal accessory schwannomas sometimes mimic a tumor of the fourth ventricle. Total surgical resection can be achieved with good outcome.
Microvascular Decompression for Glossopharyngeal Neuralgia: Long-term Effectiveness and Complication Avoidance
Authors: Sampson John H. , Grossi Peter M. , Asaoka Katsuyuki , Fukushima Takanori
Published: August 2004

OBJECTIVE

To establish the long-term safety, efficacy, and durability of microvascular decompression (MVD) for the treatment of glossopharyngeal neuralgia, this study presents the immediate (<6 mo) postoperative and long-term results of a large series of 47 patients with treated with MVD.

METHODS

Operative reports and hospital charts were analyzed to collect demographic information, clinical presentation, and surgical findings. Surgical results and complications were ascertained by direct patient contact or by contact with the patient's family or physician if the patient was dead. Long-term (>10 yr) personal follow-up was available for 29 of 47 patients.

RESULTS

Forty-six (98%) of 47 patients experienced complete relief of pain immediately after MVD. Long-term follow-up was available for 29 of these 47 patients (range, 125–211 mo; median, 152 mo, or 12.7 yr), and 28 of these 29 patients continued to be pain-free. Permanent neurological deficits (>6 mo) attributed to the surgery were observed in 5 (11%) of 47 patients. Of these patients, 4 of 5 had mild hoarseness or dysphagia or both, and one had a Grade II/VI facial nerve paresis.

CONCLUSION

This study demonstrates that MVD is a safe, effective, and durable surgical procedure for producing prolonged pain relief in patients with medically intractable glossopharyngeal neuralgia.
Management of Cystic Craniopharyngiomas with Phosphorus-32 Intracavitary Irradiation
Authors: Hasegawa Toshinori , Kondziolka Douglas , Hadjipanayis Costas G. , Lunsford L. Dade
Published: August 2004

OBJECTIVE

The efficacy of stereotactic intracavitary irradiation with phosphorus-32 (32P) for patients with cystic craniopharyngiomas was assessed on the basis of patient survival, tumor control, and visual and endocrinological function before and after treatment. Limited data are available regarding long-term outcomes.

METHODS

Forty-nine patients were treated with stereotactic 32P intracavitary irradiation. Of these, 25 had had no prior treatment as the primary treatment, and 24 were treated for residual or recurrent tumor cysts. At the time of 32P intracavitary irradiation, 34 of the patients were adults, and 15 were children younger than 16 years of age. The mean cyst volume was 13 ml. The radiation dose varied from 189 to 250 Gy to the cyst wall during five half-lives of the isotope (mean, 224 Gy). The mean follow-up periods were 7 years after diagnosis and 4 years after 32P treatment.

RESULTS

The actuarial survival rates were 90% at 5 years after the diagnosis and 80% at 10 years. The actuarial tumor cyst control rates were 76% at 5 years and 70% at 10 years after the diagnosis. After treatment, 9 (23%) of 40 patients who underwent preoperative and postoperative visual testing were found to have delayed worsening in visual function, 6 as a result of tumor progression and 3 attributed to irradiation. Nineteen patients (48%) had improved visual function. Of 17 patients who had normal preoperative pituitary function or stalk effect, 12 (71%) had preserved and 5 (29%) had worsened visual function. No complications other than visual or endocrinological deterioration occurred in these patients.

CONCLUSION

For patients with cystic craniopharyngiomas, 32P intracavitary irradiation proved effective, with a low risk of complications, for the control of tumor cysts but not of solid tumor components.
Surgical Risks Associated with the Management of Grade I and II Brain Arteriovenous Malformations
Authors: Morgan Michael Kerin , Rochford Andrew Michael , Tsahtsarlis Antonio , Little Nicholas , Faulder Kenneth Charles
Published: August 2004

OBJECTIVE

Grade I and II arteriovenous malformations (AVMs) have been considered safe to resect. However, unoperated low-grade AVMs have not been considered in previously reported series. The aim of this study was to examine all cases, both operated and unoperated, to identify any characteristics of low-grade AVMs that comprise a subgroup that might pose a relatively higher risk.

METHODS

A prospectively enrolled AVM database included 237 patients in Spetzler-Martin Grade I or II. These patients were analyzed on the basis of demographic characteristics, angiographic and magnetic resonance imaging features, clinical presentation, method of treatment, and outcome.

RESULTS

Surgery was performed in 220 patients in Spetzler-Martin Grade I or II. Seventeen patients did not undergo treatment because of poor neurological condition (six patients), patient refusal (nine patients), and perceived surgical difficulty (AVM size approaching 3 cm adjacent to Broca's area) (two patients). The overall surgical morbidity rate was 0.9%, and the mortality rate was 0.5%. Adverse outcomes occurred in 1 (0.6%) of 180 patients with AVMs located away from eloquent cortex and in 2 (5%) of 40 patients with AVMs adjacent to eloquent cortex. None of 28 surgical patients with deep venous drainage had an adverse outcome. All 219 patients who survived surgery underwent postoperative angiography that confirmed cure. No postoperative hemorrhage has occurred in 1143 patient-years of follow-up (mean follow-up, 5.3 yr).

CONCLUSION

When considering adverse outcome in the surgical series of Grade I and II AVMs alone, no statistical difference between non-eloquently located AVMs (0.6%) and eloquently located AVMs (5% adverse outcome) can be detected. However, consideration of all Grade I and II AVMs, both surgical and nonsurgical, may prove that a difference in outcome exists between these two groups masked by case selection. Generalization of the chances of adverse outcomes to all Grade I and II AVMs (both operated and unoperated) suggests that the risk of performing surgery on noneloquent brain in our series was 0.6% and that in eloquent brain could have been as high as 9.5%, had all such patients undergone surgery.
Preoperative Blood Oxygen Level-dependent Functional Magnetic Resonance Imaging in Patients with Primary Brain Tumors: Clinical Application and Outcome
Authors: Håberg Asta , Kvistad Kjell Arne , Unsgård Geirmund , Haraldseth Olav
Published: August 2004

OBJECTIVE

This study sought to evaluate the ability of blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to successfully identify functional cortical areas in patients with primary brain tumors, to evaluate the use of the fMRI results in presurgical planning, and to assess the functional outcome of the patients with respect to the functional maps obtained with fMRI.

METHODS

The study included 25 consecutive preoperative fMRI sessions in patients with primary brain tumors in or near sensorimotor and/or language cortices. All fMRI paradigms were analyzed and rated according to the degree of success. Several distances between tumor and functional cortex as delineated with BOLD fMRI were measured to assess the topographic relationship between these two structures. Pre- and postoperative neurological statuses were obtained from the patients' journals.

RESULTS

Acquisition of BOLD fMRI images was successful in 80% of the cases. The primary cause of unsuccessful fMRI was echo-planar imaging signal voids that were the result of previous craniotomy; the secondary cause was excessive motion. The neurosurgeons used the fMRI results for preoperative planning in 75% of the cases in which fMRI was successful. The risk of postoperative loss of function tested with fMRI was significantly lower when the distance between tumor periphery and BOLD activity was 10 mm or more.

CONCLUSION

The majority of patients with primary brain tumors were capable of satisfactorily performing the fMRI paradigms, and the information obtained was used in the preoperative planning. A distance of 10 mm or more between the functional cortex, as delineated with fMRI, and the tumor significantly reduced the risk of postoperative loss of function.
Transcranial Motor Evoked Potentials during Basilar Artery Aneurysm Surgery: Technique Application for 30 Consecutive Patients
Authors: Quiñones-Hinojosa Alfredo , Alam Mirza , Lyon Russ , Yingling Charles D. , Lawton Michael T.
Published: August 2004

OBJECTIVE

Microsurgical clipping of basilar artery aneurysms carries a risk of neurological compromise resulting from midbrain or thalamic ischemia. Somatosensory evoked potential (SSEP) monitoring and electroencephalography are the standard techniques for assessing the level of cerebroprotective anesthesia and monitoring ischemia during temporary occlusion or after permanent clipping. Transcranial motor evoked potential (TcMEP) monitoring was added to determine whether this modality improved intraoperative monitoring.

METHODS

Combined SSEP/electroencephalographic/TcMEP monitoring was used for 30 consecutive patients with basilar artery apex aneurysms in the past 1.5 years. Voltage thresholds were recorded before, during, and after aneurysm treatment for the last 10 patients.

RESULTS

All 30 patients underwent an orbitozygomatic craniotomy for clipping (28 patients), wrapping (1 patient), or superficial temporal artery-superior cerebellar artery bypass (1 patient). Electrophysiological changes occurred for 10 patients (33%), elicited by temporary clipping (6 patients), permanent clipping (3 patients), or retraction (1 patient). Isolated SSEP changes were observed for one patient, isolated TcMEP changes for five patients, and changes in both TcMEPs and SSEPs for four patients. Among patients with simultaneous changes, TcMEP abnormalities were more robust and occurred earlier than SSEP abnormalities. Impaired motor conduction was detected first with an increase in the voltage threshold (from 206 ± 22 to 410 ± 49 V, P < 0.05, n = 3) and then with loss of TcMEP responses. SSEP and TcMEP signals returned to baseline values for all patients after corrective measures were taken.

CONCLUSION

TcMEP monitoring can be safely and easily added to traditional neurophysiological monitoring during basilar artery aneurysm surgery. These results suggest that TcMEPs may be more sensitive than SSEPs to basilar artery and perforating artery ischemia. This additional intraoperative information might minimize the incidence of ischemic complications attributable to prolonged temporary occlusion or inadvertent perforator occlusion.
Systematic Review of Ablative Neurosurgical Techniques for the Treatment of Trigeminal Neuralgia
Authors: Lopez Benjamin C. , Hamlyn Peter J. , Zakrzewska Joanna M.
Published: August 2004

OBJECTIVE

There are no randomized controlled trials comparing retrogasserian percutaneous radiofrequency thermocoagulation, glycerol rhizolysis, balloon compression of the gasserian ganglion, and stereotactic radiosurgery, nor are there systematic reviews using predefined quality criteria. The objective of this study was to systematically identify all of the studies reporting outcomes and complications of ablative techniques for treatment of trigeminal neuralgia, from the development of electronic databases, and to evaluate them with predefined quality criteria.

METHODS

Inclusion criteria for the outcome analysis included thorough demographic documentation, defined diagnostic and outcome criteria, a minimum of 30 patients treated and median/mean follow-up times of 12 months, not more than 20% of patients lost to follow-up monitoring, Kaplan-Meier actuarial analysis of individual procedures, less than 10% of patients retreated because of failure or early recurrence, and a minimal dose of 70 Gy for stereotactic radiosurgery. High-quality studies with no actuarial analysis were used for the evaluation of complications.

RESULTS

Of 175 studies identified, 9 could be used to evaluate rates of complete pain relief on a yearly basis and 22 could be used to evaluate complications. In mixed series, radiofrequency thermocoagulation offered higher rates of complete pain relief, compared with glycerol rhizolysis and stereotactic radiosurgery, although it demonstrated the greatest number of complications.

CONCLUSION

Radiofrequency thermocoagulation offers the highest rates of complete pain relief, although further data on balloon microcompression are required. It is essential that uniform outcome measures and actuarial methods be universally adopted for the reporting of surgical results. Randomized controlled trials are required to reliably evaluate new surgical techniques.
Microsurgical Excision of a Retro-odontoid Disc Hernia via a Far-lateral Approach: Successful Treatment of a Rare Cause of Myelopathy: Case Report
Authors: Matsuno Akira , Nakashima Michi , Murakami Mineko , Nagashima Tadashi
Published: August 2004

OBJECTIVE AND IMPORTANCE

Among mass lesions causing myelopathy at the craniovertebral junction, retro-odontoid intervertebral disc hernias are very rare, with only four such cases reported in the literature.

CLINICAL PRESENTATION

A 77-year-old woman with this rare condition complained of motor and sensory disturbances in her extremities. Magnetic resonance imaging scans demonstrated an extradural mass lesion at the craniovertebral junction, compressing the lower medulla oblongata and the upper cervical cord posteriorly.

INTERVENTION

The lesion, which was partly mucinous cartilaginous and partly fatty and fibrous, was meticulously removed via a left far-lateral approach. The lesion was not neoplastic but was determined to be composed of fibrocartilaginous tissue, consistent with disc material. Postoperatively, the patient's sensory disturbances and motor weakness improved, and magnetic resonance imaging scans demonstrated marked shrinkage of the lesion.

CONCLUSION

Sagittal, T1-weighted, magnetic resonance imaging scans demonstrated a low-intensity band between the odontoid process and the body of the axis, which suggested a persistent cartilaginous band. Although upward migration of a herniated disc from the lower cervical spine and degeneration of retro-odontoid ligaments might be possible causes, a persistent cartilaginous band extending between the odontoid process and the body of the axis was considered to be the more likely origin of the retro-odontoid intervertebral disc hernia. Because the far-lateral surgical approach does not require retraction of the cervical cord and provides safe access to the lesion at the craniovertebral junction, it is a suitable surgical method for this condition.
Endoscope-assisted Microsurgery for Microvascular Compression Syndromes
Authors: Rak Ramin , Sekhar Laligam N. , Stimac Dinko , Hechl Peter
Published: August 2004

OBJECTIVE

To discuss the results of endoscope-assisted surgery in microvascular decompression (MVD) of Cranial Nerves (CNs) V, VII, and VIII.

METHODS

Neuroendoscopy was used as an adjunct to the surgical microscope in the MVD of the trigeminal (17 patients), facial (10 patients), and vestibulocochlear (1 patient) nerves in a series of 28 consecutive patients. After a standard microsurgical approach to CNs V, VII, and VIII, the endoscope was used to inspect all aspects of neural anatomy, to assess vascular compression, and to check the results of the decompression. Endoscope use was graded in four categories: Grade I, used but no definite role; Grade II, visualization assisted; Grade III, procedure assisted; and Grade IV, primary role. The usefulness of the endoscope was evaluated in each case.

RESULTS

The endoscope was useful in visualizing the anatomy in all cases. It was especially useful in establishing trigeminal vein compression of CN V in Meckel's cave; observing multiple sources of vascular compression; ensuring adequate decompression after cauterization of vein, insertion of the Teflon felt, or a pexy procedure; and permitting observation of the compression of CN VII at the root exit zone by small arteries and veins. In six patients with trigeminal neuralgia, the trigeminal vein was cauterized and divided by using endoscopic vision only because the venous compression was not completely visualized with the microscope. During a follow-up period of 6 to 52 months (mean, 29 mo; median, 40 mo), all patients were asymptomatic and receiving no medication.

CONCLUSION

The endoscope is a useful adjunct to MVD in the treatment of trigeminal neuralgia, hemifacial spasm, and disabling positional vertigo or tinnitus.
Outcomes of Cubital Tunnel Surgery among Patients with Absent Sensory Nerve Conduction
Authors: Taha Assad , Galarza Marcelo , Zuccarello Mario , Taha Jamal
Published: August 2004

OBJECTIVE

To report the outcomes of cubital tunnel surgery for patients with absent ulnar sensory nerve conduction.

METHODS

The charts of 34 patients who exhibited clinical symptoms of ulnar nerve entrapment at the elbow and who had electromyography-confirmed prolonged motor nerve conduction across the cubital tunnel in association with absent sensory nerve conduction were reviewed. The mean age was 63 years, and the mean symptom duration was 17 months. Four patients had bilateral symptoms. Surgery was performed for 38 limbs, i.e., neurolysis for 21 limbs and subcutaneous transposition for 17 limbs. Fifteen limbs demonstrated associated ulnar nerve-related motor weakness. The mean postoperative follow-up period was 4 years (range, 3 mo to 11 yr).

RESULTS

Sensory symptoms (i.e., pain, paresthesia, and two-point discrimination) improved in 20 limbs (53%), and muscle strength improved in 2 limbs (13%). Improvements in sensory symptoms were not related to patient age, symptom duration, cause, severity of prolonged motor nerve conduction, select psychological factors, associated medical diseases, associated cervical pathological conditions, or type of surgery. Improvements in sensory symptoms were significantly decreased among patients who had experienced cervical disease for more than 1 year and patients with bilateral symptoms.

CONCLUSION

Patients with cubital tunnel syndrome who have absent sensory nerve conduction seem to experience less improvement of sensory symptoms after surgery, compared with all patients with cubital tunnel syndrome described in the literature. Bilateral symptoms and delayed surgery secondary to associated cervical spine disease seem to be significant negative factors for postoperative improvement of sensory symptoms. Sensory symptoms improved similarly among patients who underwent neurolysis or subcutaneous transposition
Far-lateral Lumbar Disc Herniation: The Microsurgical Transmuscular Approach
Authors: Tessitore Enrico , de Tribolet Nicolas
Published: August 2004

INTRA- AND EXTRAFORAMINAL disc herniations can be treated via a lateral approach. The far-lateral approach is a muscle-splitting approach that allows surgeons to reach the disc herniation without any facet bone removal. The target of the surgical exposure is the isthmus. Good knowledge of the anatomic features of the intervertebral foramen and intertransverse space is mandatory. The transmuscular approach is discussed. We provide illustrations and a video to emphasize some operative aspects.
Bleeding after Radiosurgery for Cerebral Arteriovenous Malformations
Authors: Nataf François , Ghossoub May , Schlienger Michel , Moussa Ronald , Meder Jean-François , Roux François-Xavier
Published: August 2004

OBJECTIVE:

Obliteration is progressive after radiosurgery (RS) for cerebral arteriovenous malformation (AVM), and until it is complete, there is still a risk of hemorrhage. The aim of our study was to evaluate the severity of hemorrhage after RS, the actuarial risk of hemorrhage, and the parameters associated with hemorrhage.

METHODS:

Of 756 patients treated by linear accelerator RS for AVM, 51 (6.5%) had one or more hemorrhages after the RS. We studied the clinical, anatomic, and dosimetric parameters and obliteration rate before hemorrhage and then calculated the actuarial risk per patient and per hemorrhage before and after RS. Correlations between parameters and risk were studied by univariate and multivariate analysis using Kaplan-Meier hemorrhage-free survival curves and the Cox model.

RESULTS:

Apart from one exclusively ventricular hemorrhage, which caused the death of the patient, only parenchymal hemorrhages were associated with morbidity and neurological deficits (64.5% of all cases of hemorrhage had neurological deficits, 45% had a permanent deficit). The overall mortality rate per hemorrhage was 7.14%. The overall morbidity rate was 47.6%, 26.2% with a permanent deficit. In all but one patient, the AVM was not cured before hemorrhage; thus, the mean obliteration rate before hemorrhage was 24%. The actuarial hemorrhage rates were 3.08% per year per patient and 3.31% per year per hemorrhage. The actuarial rate per patient increased from 1.66% the 1st year to 3.87% in the 5th year after RS but was not statistically different from the rate before radiosurgery. The parameters found to be correlated with hemorrhage risk after RS using multivariate analysis were intranidal or paranidal aneurysms, complete coverage, and minimum dose.

CONCLUSION:

The risk of hemorrhage after RS would seem to be the sum of hemorrhage risk factors of the AVM and factors predicting a poor level of obliteration. These factors can be predicted in some cases but rarely avoided.
Evidence for a Clinically Distinct New Subtype of Grade II Astrocytomas in Patients with Long-term Epilepsy
Authors: Schramm Johannes , Luyken Cordelia , Urbach Horst , Fimmers Rudolf , Blümcke Ingmar
Published: August 2004

OBJECTIVE:

The authors tested the hypothesis that among Grade II astrocytomas with a particularly long seizure history, a subgroup is hidden with a different prognosis and possibly histological characteristics. To do so, clinical and histological characteristics of two groups of World Health Organization Grade II astrocytoma patients were analyzed: the long-term epilepsy-associated tumor (LEAT) astrocytoma group, with a mean duration of 12.5 years of seizures (n = 19), and the ordinary astrocytomas (n = 87), with a mean length of seizure history of 1.5 years (Non-LEAT).

METHODS:

All astrocytomas operated on between 1988 and 1999 were collected and followed up for 2 to 13 years (median, 7.0 yr). The 19 LEAT astrocytomas belonged to a group of 207 long-term epilepsy-associated tumors from the epilepsy surgery program. The 87 Non-LEAT cases were 60 so-called ordinary or diffuse World Health Organization Grade II astrocytomas and 27 oligoastrocytomas without long-term epilepsy operated on during the same time period. All tumor cases have been reviewed and partly reclassified as a result of the use of modern immunohistochemical techniques. Statistical analyses for possible discriminating factors included χ2 test, Fisher's exact test, Kaplan-Meier curves, and multifactorial analysis.

RESULTS:

Histological subtyping revealed a possible new isomorphic astrocytoma subtype in seven patients. By use of Kaplan-Meier curves, this isomorphic subtype had 50% fewer recurrences at 7.5 years and an estimated long-term survival of 80%. LEAT astrocytomas differed from ordinary Non-LEAT astrocytomas in overall length of history, younger age at first seizure, and higher percentage of 10-year survivors (80%). Temporal location did not influence outcome, and the presence of epilepsy per se was also not a prognostic factor.

CONCLUSION:

Differences between astrocytomas with a very long seizure history and those with a very short seizure history do exist. Significant factors for prognosis were age at surgery and presence of postoperative tumor residue but not the presence of epilepsy per se. A new subtype of astrocytomas, provisionally called isomorphic LEA astrocytoma, has putatively been identified with significantly better survival and lower recurrence rate. The negative prognostic factor of a gemistocytic differentiation pattern in diffuse astrocytomas was confirmed.
The Accessory Atlantoaxial Ligament
Authors: Tubbs R. Shane , Salter E. George , Oakes W. Jerry
Published: August 2004

OBJECTIVE:

The stability of the joints connecting the cranium to the upper cervical spine is of vital importance. The ligaments of this region, for the most part, have been thoroughly investigated, with the exception of the accessory atlantoaxial ligament.

METHODS:

Ten cadaveric specimens were examined to observe the anatomy of this ligament.

RESULTS:

This ligament was found in all specimens, and in each, it not only connected the atlas to the axis but also continued cephalically to the occipital bone. The approximate dimensions of this structure were 3 cm ×5 mm. Functionally, this ligament became maximally taut with a rotation of the head of 5 to 8 degrees. Laxity was observed with cervical extension, and maximal tautness was seen at 5 to 10 degrees of cervical flexion.

CONCLUSION:

The accessory atlantoaxial ligament seems to participate in craniocervical stability and perhaps should be renamed the accessory alar ligament or accessory atlantoaxialoccipital ligament; both of these terms better denote its anatomic characteristics. Perhaps in the future, better magnetic resonance imaging techniques and machines will be able to identify this structure so as to appreciate its integrity after upper cervical spine trauma.
Endoscopic Aqueductoplasty and Interventriculostomy for the Treatment of Isolated Fourth Ventricle in Children
Authors: Fritsch Michael J. , Kienke Sven , Manwaring Kim H. , Mehdorn H. Maximilian
Published: August 2004

OBJECTIVE:

There are different approaches for the treatment of isolated fourth ventricle in children, including a suboccipital ventriculoperitoneal shunt, suboccipital craniotomy with microsurgical fenestration, and endoscopic fenestration. We discuss the indications, surgical methods, and outcome of 18 patients who underwent endoscopic treatment for isolated fourth ventricle.

METHODS:

We retrospectively reviewed the medical histories of 18 patients with an isolated fourth ventricle. Surgical procedures included endoscopic aqueductoplasty, endoscopic aqueductoplasty with a stent, endoscopic interventriculostomy (lateral ventricle or third ventricle to fourth ventricle), and endoscopic interventriculostomy with a stent. Operations were performed between July 1997 and June 2002. The mean age of the patients at the time of surgery was 3 years. The mean follow-up was 29 months. All patients had a supratentorial ventriculoperitoneal shunt.

RESULTS:

Clinical symptoms (impairment of consciousness, tetraparesis, and ataxia) improved in all patients. Reduction of the size of the fourth ventricle was observed in all patients. Seven patients required reoperation because of restenosis (39% revision rate). Restenosis occurred between 2 weeks and 7 months after surgery (average, 3 mo). Four patients underwent reoperation with stent placement, and three patients underwent reaqueductoplasty. We had the following complications: one infection, one asymptomatic subdural hygroma, one transient oculomotor paresis, and one permanent oculomotor paresis (4 [22%] of 18 patients).

CONCLUSION:

The significant failure rate of fourth ventricle shunts has led to the development of alternative treatment methods. Endoscopic aqueductoplasty or inter-ventriculostomy presents an effective, minimally invasive, and safe procedure for the treatment of isolated fourth ventricle in pediatric patients. Compared with suboccipital craniotomy and microsurgical fenestration, endoscopic aqueductoplasty is less invasive, and compared with fourth ventricle shunts, it is more reliable and effective.
Crumbs homologue 1 is required for maintenance of photoreceptor cell polarization and adhesion during light exposure
Authors: van de Pavert Serge A. , Kantardzhieva Albena , Malysheva Anna , Meuleman Jan , Versteeg Inge , Levelt Christiaan , Klooster Jan , Geiger Sylvia , Seeliger Mathias W. , Rashbass Penny , Le Bivic Andre , Wijnholds Jan
Published: August 2004

Loss of Crumbs homologue 1 (CRB1) function causes either the eye disease Leber congenital amaurosis or progressive retinitis pigmentosa, depending on the amount of residual CRB1 activity and the genetic background. Crb1 localizes specifically to the sub-apical region adjacent to the adherens junction complex at the outer limiting membrane in the retina. We show that it is associated here with multiple PDZ protein 1 (Mupp1), protein associated with Lin-7 (Pals1 or Mpp5) and Mpp4. We have produced Crb1-/- mice completely lacking any functional Crb1. Although the retinas are initially normal, by 3-9 months the Crb1-/- retinas develop localized lesions where the integrity of the outer limiting membrane is lost and giant half rosettes are formed. After delamination of the photoreceptor layer, neuronal cell death occurs in the inner and outer nuclear layers of the retina. On moderate exposure to light for 3 days at 3 months of age, the number of severe focal retinal lesions significantly increases in the Crb1-/- retina. Crb2, Crb3 and Crb1 interacting proteins remain localized to the sub-apical region and therefore are not sufficient to maintain cell adhesion during light exposure in Crb1-/- retinas. Thus we propose that during light exposure Crb1 is essential to maintain, but not assemble, adherens junctions between photoreceptors and Müller glia cells and prevents retinal disorganization and dystrophy. Hence, light may be an influential factor in the development of the corresponding human diseases.
The peroxisomal lumen in Saccharomyces cerevisiae is alkaline
Authors: van Roermund Carlo W. T. , de Jong Mark , IJlst Lodewijk , van Marle Jan , Dansen Tobias B. , Wanders Ronald J. A. , Waterham Hans R.
Published: August 2004

Peroxisomes have a central function in lipid metabolism, including the β-oxidation of various fatty acids. The products and substrates involved in the β-oxidation have to cross the peroxisomal membrane, which previously has been demonstrated to constitute a closed barrier, implying the existence of specific transport mechanisms. Fatty acid transport across the yeast peroxisomal membrane may follow two routes: one for activated fatty acids, dependent on the peroxisomal ABC half transporter proteins Pxa1p and Pxa2p, and one for free fatty acids, which depends on the peroxisomal acyl-CoA synthetase Faa2p and the ATP transporter Ant1p. A proton gradient across the peroxisomal membrane as part of a proton motive force has been proposed to be required for proper peroxisomal function, but the nature of the peroxisomal pH has remained inconclusive and little is known about its generation. To determine the pH of Sacharomyces cerevisiae peroxisomes in vivo, we have used two different pH-sensitive yellow fluorescent proteins targeted to the peroxisome by virtue of a C-terminal SKL and found the peroxisomal matrix in wild-type cells to be alkaline (pHper 8.2), while the cytosolic pH was neutral (pHcyt 7.0). No ΔpH was present in ant1Δ cells, indicating that the peroxisomal pH is regulated in an ATP-dependent way and suggesting that Ant1p activity is directly involved in maintenance of the peroxisomal pH. Moreover, we found a high peroxisomal pH of >8.6 in faa2Δ cells, while the peroxisomal pH remained 8.1±0.2 in pxa2Δ cells. Our combined results suggest that the proton gradient across the peroxisomal membrane is dependent on Ant1p activity and required for the β-oxidation of medium chain fatty acids.
The neuropsychology of dementia
Authors: Sabin Neil , O'Brien John
Published: August 2004

Dementia is a common disorder which may be due to a number of different conditions including Alzheimer's disease, vascular dementia, dementia with Lewy bodies and frontal lobe dementias. Neuropsychological assessment has an important role to play in establishing differential diagnosis and in terms of informing management and monitoring response to recently introduced antidementia drugs. This review briefly summarises the key clinical and neuropsychological features of the different dementias and then discusses both clinically useful screening tests and more detailed cognitive assessment batteries that are frequently used in dementia, as well as the purpose and content of clinical neuropsychological testing.
Hormone replacement therapy, cardiovascular risk factors and diabetes
Authors: Smith Martin R. , Feher Michael D.
Published: August 2004

The woman with type 2 diabetes mellitus is at increased risk of developing coronary heart disease at all ages compared to the nondiabetic woman, due not only to the presence of the diabetic state but also to the increased prevalence of multiple cardiovascular risk factors. This coronary risk increases further following natural or surgical menopause. Through an improvement in some of the modifiable risk factors with oestrogen replacement, this absolute risk may be reduced. There is emerging evidence in diabetic groups that oral oestrogen improves insulin sensitivity, dyslipidaemia, fibrinolysis and may improve endothelial dysfunction, with no apparent adverse effect on blood pressure, body weight or anthropometry. The use of 17β-oestradiol appears advantageous over conjugated equine oestrogen especially with regard to improvement in dyslipidaemia and the threat of oestrogen induced hypertriglyceridaemia. The choice of progestagen is less clear, but micronised progesterone or dydrogesterone would seem to have the least adverse effect on insulin sensitivity and HDL cholesterol concentrations. Long term studies are clearly required to identify whether this improvement in cardiovascular risk profile reduces coronary heart disease events for those women with type 1 or type 2 diabetes. Hormone replacement therapy is indicated for use in women with diabetes who require relief of symptoms of oestrogen deficiency or preservation of bone mineral density. It may be considered for improvement of cardiovascular risk, even though data on end-points specific for women with diabetes are still awaited.
Imaging in the dementias
Authors: Shepstone Basil J.
Published: August 2004

There are over 50 causes of dementia. Some of these may have clear clinical features, but others may be difficult to diagnose. A diagnosis and a prognosis is important to both patients and families so that appropriate care and drug therapies can be employed. Neuroimaging techniques are considered in two categories: structural and functional. The former include computed tomography and magnetic resonance imaging, and the latter singlephoton emission tomography and positron emission tomography. A more recent synthesis of both methods is image registration whereby the functional image is superimposed on the structural one, which can then demonstrate the anatomical region in which the functional defect has occurred.
Imaging of the endometrium in postmenopausal women
Authors: Ballard Paul A. , Rogerson Lynne
Published: August 2004

Ultrasound can offer cheap, quick, relatively non-invasive assessment of the endometrium in postmenopausal women. Its inability to effectively discriminate benign from malignant pathology means its place is to select those in whom further investigation is required. Saline instillation sonography may allow clarification of the image and allow the discrimination of a submucosal fibroid with thin overlying endometrium from a central uterine homogeneous mass seen on standard transvaginal ultrasound. In addition it may identify eccentric endometrial thickening or other intracavity lesions. The role of three-dimensional ultrasound is ill defined at present and magnetic resonance because of its cost should be confined to complex cases.