The immediately failed lumbar disc surgery: incidence, aetiologies, imaging and management.

Studies on immediate failed back surgery syndrome (iFBSS) following lumbar microdiscectomy are rare. Our aim is to describe the incidence and the causes of these immediate failures to define the value of radiological imaging for identification of the underlying pathology and to propose a management algorithm. We defined iFBSS as persistence, deterioration or recurrence (during hospital stay) of radicular pain and/or sensorimotor deficits and/or sphincter dysfunction after microdiscectomy, which was uneventful from the surgeon's perspective. The medical records of 1546 patients undergoing discectomy for mediolateral lumbar disc herniations were screened for iFBSS. The pre- and postoperative imaging, surgical records, therapy and outcome of patients with iFBSS were reviewed. Forty-four of 1546 patients (2.8%) with iFBSS were identified. All patients underwent reoperation. Overseen disc material/re-herniation (n = 22), epidural hematoma (n = 6), inadequate decompression of accompanying recessal stenosis (n = 2) and dural tear with fascicle herniation (n = 1) were found to be causative. In 13 patients, who revealed no clear pathology intraoperatively, we diagnosed a battered root syndrome (nerve root swelling due to excessive surgical manipulation). The correct diagnosis could be established by neuroradiological imaging in 25 of 43 radiologically investigated patients (57%). In our study, the radiological workup was of limited value for the correct differentiation of the various aetiologies of iFBSS. Therefore, the authors believe that the treatment strategy should strongly rely on the clinical presentation. To avoid unnecessary surgery in cases of battered root syndrome, we propose to proceed to reoperation only in patients with new or persistent radiculopathy despite adequate antiedematous medical therapy.

Blunted serum and enhanced salivary free cortisol concentrations in the chronic phase after aneurysmal subarachnoid haemorrhage--is stress the culprit?

Spontaneous aneurysmal subarachnoid haemorrhage (SAH) is a cause of stroke, which constitutes a severe trauma to the brain and may lead to serious long-term medical, psychosocial and endocrinological sequelae. Adrenocorticotrophic hormone deficiency, which is considered to occur in up to 20% of all survivors, is a possible consequence of bleeding. Moreover, preliminary data suggest that a poor psychosocial outcome in SAH survivors is linked to alterations in cortisol secretion. Despite these findings, investigation of diurnal cortisol profiles and the cortisol awakening response (CAR) in chronic SAH patients has not been done so far. In this study, basal serum cortisol and salivary cortisol concentration profiles were investigated in 31 SAH patients more than 1 year after the acute event and in 25 healthy controls. Additionally, low-dose dexamethasone (DEX) suppression tests were conducted, and sensitivity to stress was measured with a psychometric questionnaire (Neuropattern(TM)). Although significantly higher salivary cortisol concentrations were observed on waking in SAH patients (p = 0.013, ANOVA), without a CAR change, total serum cortisol concentrations were blunted, but only in patients with high levels of perceived stress (SAH high stress: 337 nmol/l, SAH low stress: 442 nmol/l, controls: 467 nmol/l; Controls vs. SAH high stress p = 0.018). DEX suppression of cortisol secretion was not significantly different between patients and controls. The results indicate that total (serum) and free (salivary) cortisol concentrations give different information about cortisol availability in patients after aneurysmal SAH. Enhanced free cortisol concentrations may reflect a meaningful biological coping mechanism in SAH patients.

Neurosurgical strategies and operative results in the treatment of tumors of or extending to the petrous apex.

BACKGROUND: Tumors originating from or involving the petrous apex are considered to be an operative challenge due to their deep location and close relationship to critical neural and vascular structures. Extensive skull base approaches have been developed to deal with these lesions. The purpose of this study is to review an institutional series of 57 petrous apex tumors, to report our operative experiences and to address the usefulness and limits of standard approaches. MATERIAL AND METHODS: 57 patients (22 men, 35 women) with petrous apex tumors were treated microsurgically. We analyzed the type of surgical approach, histological diagnoses, pre- and postoperative clinical findings, diagnostic imaging and surgery-associated complications. RESULTS: According to the location and its predominant extension, a retromastoid approach (n=27), subtemporal approach (n=18), subtemporal/anterosigmoid approach (n=5), transnasal-transsphenoidal approach (n=2), pterional approach (n=2) or a subtemporal/retrosigmoid approach, biphasic approach (subtemporal and pterional), transmastoidal approach (n=1 each) was chosen. In the majority of cases, histological analysis revealed a meningeoma (n=31) or neurinoma (n=7). A total tumor resection was accomplished in 37 patients (64.9%). New permanent neurological deficits, mainly cranial nerve palsies, were found in 18 (31.6%), transient deficits in 5 patients (9.6%). Postoperative improvements of neurological deficits were observed in 17 patients (29.8%), and the neurological status remained unchanged in 17 patients (32.7%). CONCLUSION: Complete resection of petrous apex tumors using standard neurosurgical approaches without permanent surgery-associated neurological deficits is achievable in the majority of cases.

The awakened intraspinal glass shard.

Penetrating spinal injuries from foreign bodies are an exceedingly rare pathological entity. In this report we present an unusual clinical report of an in-driven shard of glass in the cervical spine that remained without symptoms for many years and became symptomatic possibly because of narrowing of the diameter of the vertebral canal.

Diagnosing neuroendocrine dysfunction in patients after aneurysmal subarachnoid hemorrhage in clinical practice - does basal hormone screening make sense?

Recent studies indicate that neuroendocrine dysfunction is a more frequent sequel of aneurysmal subarachnoid hemorrhage (SAH), than has so far been recognized. However, from the available data it remains unclear whether certain subgroups of SAH patients carry a higher risk to sustain endocrine sequelae due to the hemorrhage than others and should be specifically followed up in terms of hormone assessment. To investigate whether a basal hormone screening is a practical method in clinical routine to single out patients in whom endocrine function testing is warranted, we established a screening protocol, based on the findings from a cohort of 40 SAH patients (study group) who had all been investigated by basal hormone para meters as well as standardized endocrinological function testing, within the framework of a previously published clinical study. We then applied this protocol to 45 newly investigated SAH-patients (screening group). According to the thus established protocol, 20 of the 45 screened patients (44.4 %) were recommended further investigations, 12 of whom agreed to undergo dynamic endocrine function testing. Altogether, the percentage of test-confirmed neuroendocrine dysfunction was only 13.3 % (6/ 45) in the screening group as compared to 55 % in the study group. Low IGF-I (2 SD below normal) did not serve to predict growth hormone deficiency, whereas low 9 am serum cortisol was of limited value to single out ACTH-deficiency in SAH-patients. In summary we conclude that basal hormone screening is not sufficient to identify SAH patients with impaired hypothalamo-pituitary function, at least not in the context of clinical routine practice.

Intramedullary hemangioblastomas: timing of surgery, microsurgical technique and follow-up in 23 patients.

Hemangioblastomas are highly vascularised tumors of the central nervous system and account for 1.5-2.5% of all spinal cord tumors. Because of the rarity of these tumors, surgical experience is often limited and, therefore, treatment and indications for timing of surgery are discussed controversial. The authors reviewed their data of 23 consecutive patients with respect to timing of surgery, microsurgical technique, and follow-up. Clinical records of 23 consecutive patients with intramedullary hemangioblastomas who underwent first surgery in our department between 1990 and 2005 were reviewed. In three cases the tumors were localised at the craniocervical junction; four patients had a single tumor in the cervical spine, six patients multiple tumors in the cervical and thoracic spine, eight patients in the thoracic spine only, one patient in the conus region, and one patient had multiple tumors located in the thoracic and lumbar spine. In eight patients, a von-Hippel-Lindau disease (VHL) was associated. The neurological follow-up was evaluated according to the classification of McCormick. Operation was recommended to every symptomatic patient as early as possible. In asymptomatic patients with a sporadic tumor surgery was discussed for diagnostic purposes at any time. In VHL patients, surgery was recommended if tumor growth was observed on MRI in the next practicable time. All tumors were diagnosed by magnetic resonance imaging and in all cases but one a DSA was performed. All patients were treated microsurgically through a posterior approach. The tumors in the spinal cord were removed microsurgically through a partial hemilaminectomy (n = 1), a hemilaminectomy (n = 15), or laminectomy (n = 4) and at the craniocervical junction (n = 3) through a suboccipital craniotomy. During follow-up after 6 months, 18 patients remained neurologically stable (17 in McCormick grade I and 1 in McCormick grade II) and 5 patients recovered to a better status (3 from grade III to II, 2 from grade II to I). There was one complication with a CSF fistula and one recurrence/incomplete removal. Following the above-mentioned principles of microsurgical removal of intramedullary hemangioblastomas, operation is possible with a low procedure-related morbidity and can be recommended especially in VHL patients with progressive symptoms or tumor growth during follow-up. Patients without VHL most frequently require hemangioblastoma resection for diagnostic purposes and/or because symptoms prompted an imaging work-up that lead to the discovery of the tumor.

A less invasive surgical concept for the resection of spinal meningiomas.

BACKGROUND: The surgical strategy for spinal meningiomas usually consists of laminectomy, initial tumour debulking, identification of the interface between tumour and spinal cord, resection of the dura including the matrix of the tumour, and duroplasty. The objective of this study was to investigate whether a less invasive surgical strategy consisting of hemilaminectomy or laminectomy, tumour removal and coagulation of the tumour matrix allows comparable surgical and clinical results to be obtained, especially without an increase of the recurrence rate as reported in the literature. PATIENTS AND METHODS: Between 1990 and 2005, 61 patients (11 men, 50 women) underwent surgery for spinal meningioma. All patients were treated microsurgically by a posterior approach. In 56 of the 61 patients, the above outlined - less invasive - surgical technique with tumour removal and coagulation of the tumour matrix was performed. In 5 patients, dura resection and duroplasty was additionally performed. Electrophysiological monitoring was routinely used since 1996. Recurrence was defined as new onset or worsening of symptoms and radiological confirmation of tumour growth. The pre-and post-operative clinical status was measured by the Frankel grading system. RESULTS: Pre-operatively, 40 patients were in Frankel grade D, 13 patients in grade C, 6 patients in grade E and 1 patient each in grade A and B. Following surgery no patient presented a permanent worsening of clinical symptoms. All patients who initially presented with a Frankel grades A-C (n = 15) recovered to a better grade at the time of follow-up. Patients who presented with Frankel grade D remained in stable condition (n = 27) or recovered to a better neurological status (n = 13). Two patients experienced a temporary worsening of their symptoms, but subsequently improved to a better state than pre-operatively. Two (3.3%) complications (pseudomeningocele, wound infection) requiring surgery, were encountered. The pseudomeningocele developed in a patient who underwent durotomy. During the follow-up period of 2 months to 10 years (mean 31.3 months), 3 patients (5%) required surgery for symptomatic recurrence: 1 patient had 2 recurrences that occurred 4 and 7 years after first tumour removal and matrix coagulation, 1 recurrence occurred 1 year after tumour removal that was accompanied by matrix coagulation in a patient with a diffuse anterocranial tumour extension and 1 occurred 3 years after tumour removal and durotomy. Two patients showed a small recurrence on MRI during follow-up after 2 and 5 years, respectively, without any symptoms requiring surgery. CONCLUSIONS: The high rate of favourable clinical results combined with the low rate of recurrences supports our less invasive surgical concept, which does not aim for resection of the dural matrix of the spinal meningioma.

Management of hydrocephalus in children with plasminogen deficiency.

Congenital plasminogen deficiency is an infrequent disorder, which usually becomes symptomatic as ligneous conjunctivitis. However, pseudomembranous lesions in the mucosa of the pharynx, tracheobronchial tree, and the peritoneum may likewise occur. An accompanying hydrocephalus is extremely rare; only 16 cases have been reported to date. The reports indicate that hydrocephalus, even if treated by ventriculoperitoneal (VP) cerebrospinal fluid (CSF) shunting, worsens the prognosis substantially. Thus, VP CSF shunting does not seem to be the optimal therapy for hydrocephalic children with plasminogen deficiency. We add two cases to the literature, and, on the base of our experience, we propose a management strategy for the hydrocephalus. We report the case history of two children with plasminogen deficiency and associated hydrocephalus. Both children initially were treated with VP shunts and had a very similar clinical course with multiple shunt malfunctions due to nonabsorption by the peritoneum. In the first child, the attempt to treat the hydrocephalus with a ventriculoatrial (VA) shunt failed due to catheter thrombosis. Finally, a ventriculocholecystic shunt was placed in both children, which worked well. In patients with plasminogem deficiency and associated hydrocephalus, special care must be taken in the management of hydrocephalus. The absorptive capacity of the peritoneum is reduced by pseudomembrane formation, which results in VP shunt malfunction. The plasminogen deficiency results in early thrombus formation if atrial catheters are used. Therefore, the authors believe that ventriculocholecystic shunting should be considered early on in the course of the disease.

Activation in primary and secondary motor areas in patients with CNS neoplasms and weakness.

OBJECTIVE: To demonstrate whether cortical activation within different cortical motor regions in neurosurgical patients varies with the degree of paresis induced by mass lesions near the central region. METHODS: A total of 110 patients with brain tumors infiltrating the central region and with varying degrees of paresis were investigated employing fMRI during the performance of hand motor tasks. The percent signal change between rest and activation was calculated for four cortical regions: primary motor cortex (M1), supplementary motor area, premotor area, and superior parietal lobule. RESULTS: Significant decreases in activation with increasing degrees of paresis were found in M1, whereas significant increases in activation were noted in secondary motor areas that were not affected by the tumor. CONCLUSIONS: The signal loss in areas adjacent to tumor tissue may relate either to tumor-induced changes in cerebral hemodynamics or to a direct loss of cortical neurons resulting in a lesser degree of hemodynamic changes after motor activation. The increase in activation within secondary motor areas with increasing degrees of paresis supports the growing evidence of a practice- and lesion-dependent reorganization of the cortical motor system and the ability of the brain to modulate its excitatory output according to external demands.

Hemodynamic changes in simple partial epilepsy: a functional MRI study.

We performed functional MRI (fMRI) on a patient with a mass lesion while she happened to experience a simple partial seizure. We used regional T2* signal changes to localize seizure-related hemodynamic changes. Seizure activity was associated with changes in MR signal in different regions that showed sequential activation and deactivation. Our study has shown that epileptic activity leads to changes in cerebral hemodynamics. In selected patients, therefore, it might be possible to use fMRI as a noninvasive tool to detect and investigate cortical patterns of activation associated with seizure activity.

Fasting improves discrimination of grade 1 and atypical or malignant meningioma in FDG-PET.

UNLABELLED: We investigated the use of PET with 2[18F]fluoro-2-deoxy-D-glucose (FDG) to discriminate between atypical or malignant and grade 1 meningiomas. The influence of fasting state and high-dose corticosteroid medication was analyzed retrospectively. METHODS: Preoperative PET scans of 75 patients with suspected diagnosis of intracranial meningioma were evaluated using standardized uptake values (SUV) and tumor-to-contralateral gray matter ratios (TGR) of FDG uptake. Fifty-one of 75 patients fasted before the PET scan, and 27 of 75 patients were studied under high-dose corticosteroid medication. Eighteen tumors had recurred. PET results were compared to histopathological grading. RESULTS: PET correctly identified 8/9 atypical or malignant meningiomas and 58/66 grade 1 meningiomas using TGR and a threshold of 1.05 in primary meningioma and 0.85 in tumor recurrence. This corresponds to a specificity of 0.88 for the detection of higher tumor grading. Specificity was significantly higher in fasting compared to nonfasting subjects (0.96 versus 0.73; p < 0.025). SUV quantification lead to a reduced specificity of 0.77 at the same level of sensitivity. The only false-negative PET finding occurred in a recurrent meningioma, which had been operated on four times before. CONCLUSION: Overnight fasting before injection is needed to improve the diagnostic accuracy of FDG-PET for noninvasive metabolic grading of meningioma. Hyperglycemia in nonfasting patients and in diabetic patients may lead to overestimation of meningioma grading.

Monosomy 1p is correlated with enhanced in vivo glucose metabolism in meningiomas.

The 2-[18F]fluoro-2-deoxy-D-glucose (FDG) uptake of 25 human meningiomas was preoperatively evaluated in vivo by positron-emission tomography (PET). After surgery, meningioma biopsies were analyzed cytogenetically. Five meningiomas showed partial monosomy for chromosome 1p additional to other typical chromosome aberrations. This aberrant karyotype was correlated with increased FDG uptake. Three of five meningiomas with monosomy 1p were classified as grade II according to WHO, while only one of 20 tumors without monosomy 1p was classified as grade II. Thus, monosomy 1p and elevated FDG uptake in PET are to be regarded as cytogenetic and metabolic parameters for the aggressiveness of meningiomas.

Dural arteriovenous fistulae at the foramen magnum.

Spinal dural arteriovenous fistulae (DAVF) affect predominantly levels of the lower thoracic and lumbar segments; only 13 cases have been reported of DAVF at the foramen magnum. We present three surgically treated patients with DAVF at the foramen magnum. In none of our three patients could the site of the arteriovenous fistula be suspected from the clinical presentation. The clinical course varied from acutely developing signs and symptoms to a 10-year history of very slowly progressing symptoms. After neuroradiological diagnosis the patients were operated on direct microsurgical disconnection of the arteriovenous shunt via an enlargement of the foramen magnum and a hemilaminectomy of C1. DAVF at the foramen magnum may thus present with slowly to acutely progressing clinical symptoms and signs. Spinal angiographic examination should include the level of the foramen magnum if standard spinal angiography of thoracic, lumbar, and sacral segments is negative in suspected spinal DAVF since the nidus of the shunt can be situated remote from the level of neurological disorder. DAVF at the foramen magnum can be treated very effectively and with minimal surgical trauma by direct microsurgical disconnection of the shunt. This surgical procedure is indicated if embolization with glue is not possible or is unsuccessful.

In vivo 3D visualization of normal pyramidal tracts in human subjects using diffusion weighted magnetic resonance imaging and a neuronavigation system.

We describe the potential of anisotropic diffusion weighted imaging to visualize the course of large cerebral fiber tracts. Five healthy volunteers were investigated at a field strength of 1.5 Tesla, employing a spin-echo diffusion weighted sequence with gradient sensitivity in six non-collinear directions to visualize the course of the pyramidal tracts. The pyramidal tracts were segmented and reconstructed for three-dimensional visualization. Reconstruction results together with a fusioned high resolution 3D T1 weighted image data set were available in a customized neuronavigation system. Origination in the primary motor cortex, convergence in the centrum semiovale, the posterior limb of the internal capsule, the cerebral peduncles, the splitting at the level of the pons, and the pyramidal decussation were identified in all subjects. Fiber tract maps might have the prospect of guiding neurosurgical interventions, especially when being linked to a neuronavigation system. Other potential applications include the demonstration of the anatomical substrate of functional connectivity in the human brain.

Which neuropsychological deficits are hidden behind a good outcome (Glasgow = I) after aneurysmal subarachnoid hemorrhage?

A series of 31 patients with good neurological 6-month outcomes (Glasgow Outcome Scale = I) was examined with a battery of cognitive tests 1 to 5 years after aneurysmal subarachnoid hemorrhage (SAH) and early operation. The results showed a marked disability in 28 to 62% of these patients in the subtests of a complex choice reaction task. Short-term memory was impaired in 53% of the patients neuropsychologically examined, whereas 21% of them had a reduced long-term memory. Concentration was impaired in 7 to 16% of the SAH patients. Also, 10% of the patients rated Glasgow Outcome Scale = I had an indication for an aphasic language disturbance. Multivariate analysis proved significant harmful effects of the severity of the bleeding seen on computed tomographic scan (Fisher scale) on information processing and word-finding capacity. Patients who were older at the time of the SAH were significantly more disturbed in concentration, short-term memory, and information-processing capacity at follow-up. It can be concluded from these results that a good neurological outcome (Glasgow Outcome Scale = I) does not exclude persisting neuropsychological deficits. Therefore, the value of the clinical use of the Glasgow Outcome Scale is limited. As a consequence, a differentiated neuropsychological examination is proposed to evaluate the exact outcome of SAH patients.

Cognitive deficits in the acute stage after subarachnoid hemorrhage.

OBJECTIVE: In spite of fundamentally improved medical management of subarachnoid hemorrhage (SAH), many patients remain mentally impaired. However, the causes of these disturbances are unclear. The present study was performed to elucidate the significance of the hemorrhage itself and related events in the neuropsychological performance of patients in the acute stage after SAH. METHODS: A series of 51 patients were examined, by means of a battery of cognitive tests, 1 to 13 days (mean, 5.9 d) after SAH. Thirty-three patients had experienced ruptured aneurysms, and 18 had sustained SAH of unknown origin. Furthermore, 25 patients who had undergone surgical treatment (a mean of 5.0 d earlier) of prolapsed lumbar discs served as a control group. RESULTS: The cognitive deficits of the patients after aneurysmal SAH proved to be comparable to those after spontaneous SAH of unknown origin, with the single exception of a significantly worse (P = 0.003) concentration capacity in the surgically treated group. The severity of SAH in computed tomographic scans correlated (up to r = 0.57, P < 0.001) with poor performance on tests of memory, concentration, divided attention, and perseveration. Frontal intracerebral hemorrhage led to significantly more errors in an aphasia screening test (P < 0.001) and a test of perseveration (P < 0.001). If acute hydrocephalus was present, the patients exhibited worse long-term memory (P < 0.001), showed slower reaction times (P = 0.01), and made more errors in the perseveration test (P = 0.004). Patients with intraventricular blood performed at significantly lower levels in the concentration (P = 0.001), divided attention (P = 0.01), long-term memory (P < 0.001), and perseveration (P = 0.003) tests. CONCLUSION: The results emphasize that the severity of SAH (Fisher score) is the most important factor related to cognitive dysfunction, but frontal hematoma, intraventricular hemorrhage, and acute hydrocephalus were also associated with cognitive deficits, compared with patients with SAH without these findings.

Endovascular occlusion of experimental aneurysms with detachable coils: influence of packing density and perioperative anticoagulation.

OBJECTIVE: This study was designed to assess the intraluminal biological changes after endovascular coil occlusion of arterial aneurysms with detachable coils, to analyze the relationship between histological occlusion and mechanical packing density, and to evaluate the influence of perioperative anticoagulation on the occlusion rate. METHODS: In rabbits, 30 microsurgically produced arterial bifurcation aneurysms were occluded with coils (18 with platinum coils, electrically detached; 12 with tungsten coils, mechanically detached). Coils were placed until no further coils fit into the aneurysmal lumen and it was no longer filled with radiographic contrast material. The individual degree of occlusion was then determined by the "packing density" on the angiograms. Complete occlusion was considered only if no neck remnant was visible on the films. Anticoagulation during and 2 days after the treatment was performed in 11 cases. After an observation period ranging from 3 to 6 months, angiographic and histological analyses were performed to obtain control data. RESULTS: Complete occlusion was achieved in 9 cases, subtotal occlusion (i.e., > 95% occlusion, residual filling at the neck of the aneurysm) in 10 cases, and partial occlusion in 11 cases. Angiographically documented recanalization was detected in 14 aneurysms. In the remaining 16 aneurysms, the initially documented angiographic results were unchanged. A discrepancy between angiographic and pathological findings was frequently observed. Five of nine angiographically completely occluded aneurysms were recanalized. Endothelial-like tissue at the orifice of the aneurysm was able to be observed in only four of the nine initially completely occluded aneurysms. CONCLUSION: The results suggest that even dense packing does not always guarantee permanent occlusion, although there was a positive relationship between packing density and occlusion rate. Anticoagulation did not have any negative effect on the results.

Three-dimensional visualization of the pyramidal tract in a neuronavigation system during brain tumor surgery: first experiences and technical note.

OBJECTIVE: To integrate spatial three-dimensional information concerning the pyramidal tracts into a customized system for frameless neuronavigation during brain tumor surgery. METHODS: Four consecutive patients with intracranial tumors in eloquent areas underwent diffusion-weighted and anatomic magnetic resonance imaging studies within 48 hours before surgery. Diffusion-weighted datasets were merged with anatomic data for navigation purposes. The pyramidal tracts were segmented and reconstructed for three-dimensional visualization. The reconstruction results, together with the fused-image dataset, were available during surgery in the environment of a customized neuronavigation system. RESULTS: In all four patients, the combination of reconstructed data and fused images was a helpful additional source of information concerning the tumor seat and topographical interaction with the pyramidal tract. In two patients, intraoperative motor cortex stimulation verified the tumor seat with regard to the precentral gyrus. CONCLUSION: Diffusion-weighted magnetic resonance imaging allows individual estimation of large fiber tracts applicable as important information in intraoperative neuronavigation and in planning brain tumor resection. A three-dimensional representation of fibers associated with the pyramidal tract during brain tumor surgery is feasible with the presented technique and is a helpful adjunct for the neurosurgeon. The main drawbacks include the length of time required for the segmentation procedure, the lack of direct intraoperative control of the pyramidal tract position, and brain shift. However, mapping of large fiber tracts and its intraoperative use for neuronavigation have the potential to increase the safety of neurosurgical procedures and to reduce surgical morbidity.

Early aneurysm surgery and preventive therapy with intravenously administered nimodipine: a multicenter, double-blind, dose-comparison study.

A European, multicenter, prospective, randomized, double-blind, dose-comparison study on preventive therapy with intravenously administered nimodipine was performed to evaluate the efficacy and tolerability of two different doses: 2 and 3 mg/h. Two hundred four patients fulfilled the criteria for enrollment in the study: surgery within 72 hours after the last subarachnoid hemorrhage, and age between 16 and 72 years. All patients who had Hunt and Hess grades of I to III were operated upon; patients who had poor Hunt and Hess grades (IV-V) were operated on according to the surgeon's choice. This treatment regimen was associated with a low incidence of delayed neurological dysfunction with no significant difference between the two dosage groups: three patients (1.5%) remained severely disabled and two (1%) moderately disabled due to vasospasm with or without additional complications. Among the patients with Hunt and Hess grades of IV or V, the long-term outcome was favorable (good-fair) for 40% and unfavorable for 60%. Among the patients with grades of I to III, the long-term outcome was favorable for 89% and unfavorable for 11%.

Time course of blood velocity changes related to vasospasm in the circle of Willis measured by transcranial Doppler ultrasound.

Fifty patients with ruptured aneurysms were operated on within 72 hours after the first subarachnoid hemorrhage (SAH). To prevent symptomatic vasospasm, the patients were given the calcium channel blocker, nimodipine, intravenously (2 mg/hr) for 14 days and orally (60 mg four times daily) for another 7 days. At short intervals (at least every 3rd day) the blood flow velocity in the different segments of the circle of Willis was measured with a noninvasive transcranial Doppler ultrasonography method. Within the first 72 hours after SAH, the velocity was normal in the large branches of the circle of Willis and angiography revealed no signs of vasospasm. The Doppler frequency changes that relate to blood flow accelerated between Days 3 and 10, and maximum blood flow velocities were recorded between Days 11 and 20, with normalization occurring within the following 4 weeks. The changes showed a significant relationship to the source of SAH, the side of the operative approach, and the method of nimodipine administration. A comparison between the angiographically proven diameter of spastic arteries and the Doppler-measured blood flow velocity showed an inverse relationship in flow of the middle cerebral artery and the internal carotid artery that was statistically highly significant (p less than 0.001) while this correlation was only slightly significant in the A1 segment of the anterior cerebral artery (p = 0.054). Seven patients (14%) developed delayed ischemic deficits (DID's), which were all functionally reversible. One patient (2%) died as a result of decompensated vasospasm. Based on the information provided by Doppler measurement of the individual blood flow velocity changes due to vasospasm, preventive hypertensive treatment was introduced to improve the perfusion pressure while patients were still in an asymptomatic stage. Among the last 40 patients who were treated according to this regimen, reversible DID's were observed in only three patients (7.5%) and postoperative angiography to detect vasospasm was not necessary.