ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

STEAL IS A pathophysiological process in which increased blood flow through a low-resistance vascular bed is sufficient to divert flow away from a region of the central nervous system. Three disease states in which steal may cause neurological deficits due to central nervous system ischemia are reviewed. Subclavian steal occurs when stenosis of the subclavian artery proximal to the vertebral origin causes retrograde flow in the left vertebral artery. Patients with anatomic subclavian steal usually do not develop neurological symptoms but may rarely present with posterior circulation ischemia.Arteriovenous malformations alter cerebral blood flow patterns and regional perfusion pressure. It has been hypothesized that cerebral arteriovenous malformations may cause neurological deficits due to steal and that these deficits may be cured with arteriovenous malformation treatment. Intra-arterial pressure measurements and transcranial velocity studies show regional hemodynamic alterations. However, these changes have not been correlated with presenting symptoms. Evidence from single-photon emission computed tomography does suggest a relationship between regional hypoperfusion and neurological deficits.Coarctation of the aorta may divert flow from the spinal cord circulation through intercostal arteries distal to the stenosis. This is a possible but unproven mechanism of myelopathology.Steal syndromes may be amenable to treatment by open surgical or endovascular approaches. Experimental studies of the pathophysiology of steal are strengthened by precise definitions of the measured parameters and innovative applications of technology.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

SINCE ITS FIRST application in 1967, the methodology and technology of spinal cord stimulation for the management of chronic, intractable pain have evolved continuously. Despite these developments and improved knowledge of the effects of spinal anatomy and epidural contact configuration on paresthesia coverage, the clinical results of spinal cord stimulation—particularly the long-term effects—are still unsatisfactory in many patients. This dissatisfaction has come primarily from the failure of single-electrode configurations to provide consistent paresthesia coverage of the entire painful area. Therefore, new approaches were developed during the late 1990s that attempted to selectively cover one or more dermatomes with paresthesia as well as to provide sequential stimulation of different anatomic sites. These approaches have been applied both intraspinally and extraspinally by stimulating either the spinal nerves or the dorsal columns. To target parts of the latter, different methods have been developed and tested using either two-dimensional contact configurations or electronic field steering. These developments hold promise for improving long-term outcomes as well as increasing the number of pain conditions that can be treated with neuromodulation therapy. In this review, the history, theoretical basis, and evolution of these methodologies, as well as the ways in which they represent new trends in neuromodulation, are discussed.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

OBJECTIVEGlossopharyngeal neuralgia (GPN) is a rare condition that often presents with the seemingly benign symptom of deep throat pain. Medical management of this condition has not been very effective, and surgical therapy has ranged from nerve sectioning to microvascular decompression (MVD). We present our experience with more than 200 patients who underwent MVD for treatment of GPN at our institution.METHODSWe conducted a retrospective review of our database and identified patients who presented for treatment of presumed GPN. When possible, patients were contacted by telephone for collection of follow-up information regarding symptom relief, complications, functional outcomes, and patient satisfaction. Univariate and multivariate analyses were performed to identify predictors of good outcomes after MVD. Subgroup analyses were performed with quartiles of approximately 50 patients each, for assessment of the effects of improvements in techniques and anesthesia during this 20-year period.RESULTSWe observed GPN to be more common among female (66.8%) than male (33.2%) patients, with an overall mean patient age of 50.2 years (standard deviation, 14.4 yr). The most common presenting symptoms were throat and ear pain and throat pain alone, and the mean duration of symptoms was 5.7 years (standard deviation, 5.8 yr; range, 1–32 yr). Symptoms appeared almost equally on the left side (54.8%) and the right side (45.2%). The overall immediate success rate exceeded 90%, and long-term patient outcomes and satisfaction were best for the typical GPN group (with pain restricted to the throat and palate). Complication rates decreased across quartiles for all categories evaluated.CONCLUSIONMVD is a safe, effective form of therapy for GPN. It may be most beneficial for patients with typical GPN, especially when symptoms are restricted to deep throat pain only.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

OBJECTIVEThe concept of neurovascular decompression for the treatment of hemifacial spasm is now widely accepted. In this study, we report our long-term results for 145 cases treated with this procedure.METHODSThe results of 145 microvascular decompressions to treat hemifacial spasm (performed between 1980 and 1998) among 143 patients (62.2% female patients and 37.8% male patients; mean age, 54.5 yr) are presented. The onset of symptoms was typical in 95.9% of cases and atypical in 4.1%. Platysma muscle involvement was observed for 24.5% of patients, with a higher incidence among female patients (74.3%). Patients were monitored with annual questionnaires. Twenty-six patients were lost to follow-up monitoring, and 117 are still undergoing follow-up monitoring, with an average period of 9.6 years (range, 1–17.6 yr).RESULTSAt discharge, 69 patients (59%) were spasm-free and 48 patients (41%) experienced further spasm. At 6 months, the number of spasm-free patients had increased to 108 (92.3%), whereas only 9 patients (7.7%) complained of hemifacial spasm; 44 patients were spasm-free at an average time of 15 weeks. In follow-up examinations (average period, 9.4 yr), 106 patients were spasm-free. Seven patients experienced only temporary relief, with recurrence after 4.5 years. Two patients were spasm-free after 4 or 6 weeks, and the recurrence of spasm was observed 1 year later. Two patients were never completely spasm-free. Among the patients who did not undergo previous surgery elsewhere, only two experienced recurrence.CONCLUSIONDeafness was the main postoperative complication (8.3%); most of those cases (66%) occurred before the routine use of intraoperative evoked potential monitoring. Analysis of our series demonstrates that this surgical procedure involves very low risk, is well tolerated by elderly patients, is associated with very low recurrence rates, and is a definitive treatment for more than 90% of cases.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

OBJECTIVEThis study was performed to investigate the role of postoperative three-dimensional short-range magnetic resonance angiography in the prediction of clinical outcomes after microvascular decompression (MVD) for the treatment of hemifacial spasm.METHODSWe examined pre- and postoperative magnetic resonance imaging scans obtained between March 1999 and May 2000 for 122 patients with hemifacial spasm, to evaluate the degree of detachment of the vascular contact and changes in the positions of offending vessels. The degree of vascular decompression of the facial nerve root was classified into three groups, i.e., contact, partial decompression, or complete decompression. Contact was defined as unresolved compression, as indicated by postoperative three-dimensional short-range magnetic resonance angiography. Partial decompression was defined as incompletely resolved compression; vascular indentation of the facial nerve was improved, but contact with the facial nerve remained. Complete decompression was defined as completely resolved compression. These findings were compared with the surgical findings and clinical outcomes.RESULTSOf 122 patients with MVD, complete decompression of offending vessels at the root entry zone of the facial nerve was observed for 106 patients (86.9%), partial decompression was observed for 10 patients (8.2%), and contact with offending vessels was observed for 6 patients (4.9%) by using postoperative three-dimensional short-range magnetic resonance angiography. Our study demonstrated that the types of offending vessels affected neither the degree of decompression of the root entry zone of the facial nerve nor surgical outcomes (P> 0.05). Also, there was no significant relationship between the degree of decompression and improvement of symptoms (P> 0.05). Furthermore, there was no significant relationship between the degree of decompression and the timing of symptomatic improvement (P> 0.05).CONCLUSIONOur data suggest that MVD of the facial nerve alone may not be sufficient to resolve symptoms for all patients with hemifacial spasm. Therefore, unknown factors in addition to vascular compression may cause symptoms in certain cases, and it may be necessary to remove those factors, simultaneously with MVD, to obtain symptom resolution.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

OBJECTIVETo determine the value of delayed surgical resection in patients with central nervous system germ cell tumors who exhibit less than complete radiographic response despite declining serum and cerebrospinal fluid (CSF) tumor markers after initial chemotherapy.METHODSWe retrospectively analyzed 126 patients enrolled on two international multicenter clinical trials (the First and Second International Central Nervous System Germ Cell Tumor Studies) for patients with newly diagnosed central nervous system germ cell tumors. After at least three cycles of chemotherapy, 10 of these patients underwent delayed surgical resection owing to evidence of residual radiographic abnormalities despite declining or completely normalized serum and CSF levels of &agr;-fetoprotein and human chorionic gonadotropin.RESULTSEight of these patients demonstrated nongerminomatous germ cell tumor elements at the time of initial diagnosis. In these patients, either serum or CSF tumor markers were elevated initially. Two patients demonstrated pure germinomas with normal levels of serum and CSF tumor markers. After chemotherapy, radiographic evaluation revealed a partial response in seven patients, a minor response in one patient, and stable disease in two patients. All 10 patients had either normal or decreasing levels of serum and CSF tumor markers before second-look surgery. At delayed surgical resection, 7 of the 10 patients underwent gross total resection, and 3 patients underwent subtotal resection of residual lesions. Pathological findings at second-look surgery demonstrated three patients to have mature teratomas, two with immature teratomas, and five with necrotic or scar tissue alone. To date, 7 of the 10 patients have had no recurrence during an average follow-up time of 36.9 months (range, 3–96 mo). Three of four patients with nongerminomatous germ cell tumors who had tumor markers that were decreased, but not normalized, before second-look surgery eventually developed tumor dissemination/progression, and they required subsequent radiation therapy despite having teratoma or necrosis/scar tissue at delayed surgery. In contrast, three of four patients with nongerminomatous germ cell tumors and completely normalized markers did not progress and did not require radiation therapy.CONCLUSIONDelayed surgical resection should be considered in patients with central nervous system germ cell tumors who have residual radiographic abnormalities and normalized tumor markers, because these lesions are likely to be teratoma or necrosis/scar tissue. However, second-look surgery should be avoided in patients whose tumor markers have not normalized completely.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

OBJECTIVEDorsal midbrain gliomas (DMGs) involving the tectum occur more commonly in children than in adults. These lesions are often indolent in nature, and patients require treatment only for obstructive hydrocephalus. Because limited information is available concerning adults with this type of lesion, we describe our experience and management strategy in adults with DMGs.METHODSWe retrospectively reviewed the charts and magnetic resonance imaging scans of five adult patients (four men, one woman; mean age, 51.6 yr; range, 23–69 yr) who were treated from March 1992 to August 2001 for DMGs involving the tectum. The mean follow-up time for these patients was 71.4 months (range, 25–113 mo). We analyzed the data to determine the optimal treatment strategy and outcomes of patients with DMGs. Tumor volume was analyzed objectively with Scion Image software (Scion Corp., Frederick, MD) to document changes in volume and determine whether treatment strategy differed significantly with tumor size.RESULTSTumors in two of these patients were found incidentally, and three others presented with obstructive hydrocephalus. Magnetic resonance imaging scans demonstrated an isolated tectal glioma in one patient, tectal and tegmental (periaqueductal) gliomas in three patients, and a tectal glioma with right thalamic extension in one patient. Treatment consisted of routine follow-up for the two asymptomatic patients and cerebrospinal fluid diversion surgery for the three patients with hydrocephalus. Volumetric analysis demonstrated that all asymptomatic patients had tumors smaller than 9.3 cm3, and symptomatic patients had tumors larger than 28.5 cm3. All follow-up magnetic resonance imaging scans revealed stable dorsal midbrain lesions, and no patient required tumor-specific therapy.CONCLUSIONAlthough tumors of the dorsal midbrain occur primarily in the pediatric population, similar tumors may occur in adults. As has been learned from experience with children, these lesions are often clinically and radiographically stable and require only appropriate therapy for obstructive hydrocephalus. We advocate a similar conservative strategy of routine imaging follow-up and treatment for hydrocephalus in adult patients. Surgery and other therapy should be reserved for patients with progressive lesions.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

OBJECTIVETo evaluate the occurrence and distribution of direct brain injury caused by acute subarachnoid hemorrhage (SAH) by the use of magnetic resonance imaging.METHODSComputed tomography and magnetic resonance imaging, including diffusion-weighted imaging (DWI), were performed in 32 patients with SAH by use of a 1.5-T whole-body superconductive scanner equipped with an echo planar imaging system. In all cases, computed tomographic and magnetic resonance imaging scans were obtained at the time of admission, before angiography and surgical intervention.RESULTSNo abnormalities were revealed by DWI in any of the low-grade SAH patients. However, five (71%) of seven patients diagnosed as having poor-grade SAH (World Federation of Neurosurgical Societies Grades 4 and 5) displayed multiple, patchy focal abnormalities on DWI. Computed tomographic scans obtained at admission failed to clearly demonstrate all of the damaged areas of the brain that were visualized by DWI. These lesions were located in supratentorial cerebral parenchyma, but not in the thalamus, basal ganglia, or cerebellar hemisphere. These multiple widespread lesions exhibiting laminar involvement of the cerebral cortex were not associated with the site of the ruptured aneurysm.CONCLUSIONDWI revealed widespread multifocal lesions in the cerebral cortex of acute poor-grade SAH patients. DWI provides accurate images of all areas of brain damage directly attributable to SAH.

ISSN:0148-396X    

出版商:OVID    

年代:2002

数据来源: OVID