Showing papers in "Acta Neurochirurgica in 2004"

Non-operative treatment of spontaneous spinal epidural hematomas: a review of the literature and a comparison with operative cases

Abstract: Objective To identify factors that favour spontaneous recovery in patients who suffered a spontaneous spinal epidural hematoma (SSEH) Methods The literature was reviewed reguarding non-operative cases of SSEH (SSEHcons) Sixty-two cases from the literature and 2 of our own cases were collected, focusing on sex, age, medical history, position of the hematoma, segmental distribution and length of the hematoma, diagnostic imaging, neurological condition and outcome Those data were analysed and compared with the data from a literature review of 474 cases operated on because of a SSEH (SSEHoper) Results The mean length of the hematoma was significantly higher in SSEHcons, compared to SSEHoper (54 versus 42 vertebral segments; [standard error of the difference (SED) is 038 vertebral segments; 95% confidence limits for the difference are 045 to 195]) Also after exclusion of patients with coagulopathy, mean length of the hematoma was significantly higher in SSEHcons (47 versus 39 vertebral segments [SED is 039 vertebral segment; 95% confidence limits for the difference are 004 to 156]) Neurological signs and symptoms in SSEHcons were significantly less severe (P<0005) and diagnosis was based on Magnetic Resonance Imaging (MRI) in the majority of cases (P<00005), when compared to SSEHoper All other patient characteristics showed no correlation with spontaneous recovery Conclusion The recent increase of publications of SSEHcons has to be explained by the introduction of MRI in daily medical practice As a result, more patients with a mild or benign clinical course are being diagnosed In earlier times those patients would have escaped medical attention The mean length of the hematoma in SSEHcons appears to be significantly higher compared to SSEHoper This suggests that spontaneous regression of neurological symptoms may result from decompression of the neural structures by spreading of the (liquid) hematoma along the spinal epidural space in the early stages after haemorrhage Based on the present review, there appear to be no factors which promote conservative treatment in SSEH In the majority of cases with SSEH, the mainstay of treatment will remain surgical decompression of the neural structures and removal of the hematoma The decision for conservative treatment has to be based on the severity of the neurological deficit and on the clinical course Retrospectively, the length of the hematoma seems to give a clue to the spontaneous recovery which occurs in some cases of SSEH Nevertheless, hematoma-length can not be used as a guide to treatment

Impact of primary surgery on pituitary function in patients with non-functioning pituitary adenomas – a study on 721 patients

Abstract: ¶Introduction. The aim of this study was to define the impact of surgery on pituitary function in a large consecutive series of patients harbouring non-functioning pituitary adenomas.

Course of brain shift during microsurgical resection of supratentorial cerebral lesions: limits of conventional neuronavigation

Abstract: Background. The authors have conducted a prospective study to evaluate the amount and course of brain shift during microsurgical removal of supratentorial cerebral lesions, and to assess factors which potentially influence these shifts.

Intracranial hypertension: what additional information can be derived from ICP waveform after head injury?

Abstract: Objective. Although intracranial hypertension is one of the important prognostic factors after head injury, increased intracranial pressure (ICP) may also be observed in patients with favourable outcome. We have studied whether the value of ICP monitoring can be augmented by indices describing cerebrovascular pressure-reactivity and pressure-volume compensatory reserve derived from ICP and arterial blood pressure (ABP) waveforms. Method. 96 patients with intracranial hypertension were studied retrospectively: 57 with fatal outcome and 39 with favourable outcome. ABP and ICP waveforms were recorded. Indices of cerebrovascular reactivity (PRx) and cerebrospinal compensatory reserve (RAP) were calculated as moving correlation coefficients between slow waves of ABP and ICP, and between slow waves of ICP pulse amplitude and mean ICP, respectively. The magnitude of ‘slow waves’ was derived using ICP low-pass spectral filtration. Results. The most significant difference was found in the magnitude of slow waves that was persistently higher in patients with a favourable outcome (p<0.00004). In patients who died ICP was significantly higher (p<0.0001) and cerebrovascular pressure-reactivity (described by PRx) was compromised (p<0.024). In the same patients, pressure-volume compensatory reserve showed a gradual deterioration over time with a sudden drop of RAP when ICP started to rise, suggesting an overlapping disruption of the vasomotor response. Conclusion. Indices derived from ICP waveform analysis can be helpful for the interpretation of progressive intracranial hypertension in patients after brain trauma.

Intramedullary spinal cord metastases: diagnosis and treatment - an illustrated review.

Abstract: Background. Intramedullary spinal cord metastases (ISCM) are rare but, with increasing use of magnetic resonance imaging (MRI) are being encountered with increasing frequency. Optimum treatment remains controversial. On the basis of a review of previous reports and experience with a patient with an ISCM from a large cell lung cancer, we propose practical diagnostic and therapeutic approaches.

The Ki-67 proliferation antigen in meningiomas. Experience in 600 cases

Abstract: Background. Meningiomas are mostly benign tumours that can be cured by surgical resection. Because meningiomas tend to recur, long term management in patients with subtotal tumour resection remains controversial. Previous studies have shown that the proliferation potential of meningiomas by Ki-67 labelling indices (LI) might predict their natural history. The purpose of this study was to analyse the reliability of Ki-67-labelling index in predicting the behaviour of meningiomas, and to help the neurosurgeon in establishing better follow up criteria and long term management strategies for these patients.

Normal pressure hydrocephalus: survey on contemporary diagnostic algorithms and therapeutic decision-making in clinical practice

Abstract: Background. There is no agreement on the best diagnostic criteria for selecting patients with normal pressure hydrocephalus (NPH) for CSF shunting. The primary objective of the present study was to provide a contemporary survey on diagnostic algorithms and therapeutic decision-making in clinical practice. The secondary objective was to estimate the incidence of NPH. Method. Standardized questionnaires with sections on the incidence of NPH and the frequency of shunting, evaluation of clinical symptoms, and signs, diagnostic studies, therapeutic decision-making and operative techniques, postoperative outcome and complications, and the profiles of different centers, were sent to 82 neurosurgical centers in Germany known to participate in the care of patients with NPH. Findings. Data were analyzed from 49 of 53 centers which responded to the survey (65%). The estimated annual incidence of NPH was 1.8 cases/100.000 inhabitants. Gait disturbance was defined as the most important sign of NPH (61%). There was a wide variety in the choice of diagnostic tests. Cisternography was performed routinely only in single centers. Diagnostic CSF removal was used with varying frequency by all centers except one, but the amount of CSF removed by lumbar puncture differed markedly between centers. There was poor agreement on criteria for evaluation of continuous intracranial pressure recordings regarding both the amplitude and the relative frequency of B-waves. Both periventricular and deep white matter lesions were present in about 50% of patients being shunted, indicating that vascular comorbidity in NPH patients has gained more acceptance. Programmable shunts were used by more than half of the centers, and newer valve types such as gravitational valves have become more popular. Conclusions. According to the present survey, new diagnostic and therapeutic concepts on NPH have penetrated daily routine to a certain extent. Wide variability, however, still exists among different neurosurgical centers.

Intra-operative magnetic resonance imaging in neurosurgery

Abstract: Intra-operative MRI (iMRI) has been incorporated into modern neurosurgical operating rooms as a guide for neurosurgical interventions for almost ten years. This technology has been shown to be a useful modality in brain tumour surgery and biopsy; its use in spine, vascular and epilepsy surgery has been evolving. It is particularly useful in low-grade gliomas, pituitary adenomas and pediatric tumors. We evaluate currently available iMRI systems and their applications in neurosurgery. Future possibilities related to iMRI systems are mentioned in the light of current advances.

Cell index – a new parameter for the early diagnosis of ventriculostomy (external ventricular drainage)-related ventriculitis in patients with intraventricular hemorrhage?

Abstract: Temporary intraventricular catheters for managing acute obstructive hydrocephalus caused by intraventricular haemorrhage carry a high risk of developing ventriculostomy-related ventriculitis (VRV). The aim of this prospective study was to validate a new parameter for the early detection of an intraventricular infection.

Intraventricular craniopharyngiomas: topographical classification and surgical approach selection based on an extensive overview

Abstract: Background. This retrospective study analyzes the clinical, neuroradiological, pathological and surgical characteristics of well-described intraventricular craniopharyngiomas with the aims of: (i) critically to review the criteria used to affirm the diagnosis of an intraventricular location (ii) defining more accurately this topographical diagnosis preoperatively, and (iii) to investigate factors influencing the surgical outcome.

Angio-architecture of spinal cord arteriovenous shunts at presentation. Clinical correlations in adults and children. The Bicêtre experience on 155 consecutive patients seen between 1981-1999.

Abstract: Objective. To analyse possible relationships between the symptoms and signs created by intradural spinal cord arteriovenous shunts (SCAVSs) and their angio-architecture.

Magnetic resonance artifact induced by the electrode Activa 3389: an in vitro and in vivo study.

Abstract: Background. The electrode Activa 3389 is widely implanted for deep brain stimulation (DBS) and MRI is often used to control the position of the electrode. However, induced distorsion artifacts may result in imprecise localization and may lead to misinterpretations of the clinical effects and mechanisms of DBS. Methods. In vitro 3D MR study: the proximal and distal contacts of one electrode were spotted by two localizers. The maximal artifact height (MAH) and width (MAW: measured on distal contact), and the distances between the artifact and the localizers (proximal, distal and lateral) were measured on 2 transverse and sagittal MR sequences with 90 degrees rotation of frequency-encoded gradient and phase direction. In vivo 3D MR study: coronal and sagittal reconstructions along the main axis of the electrode were performed on 10 postoperative MR (20 electrodes) to measure MAH and MAW. A Student t test was used to compare in vitro and in vivo measurements. Findings. In vitro study: A MAH of 10.35 mm (±0.23) and MAW of 3.6 mm (±0.2) were found. We measured symmetrical extensions of the artifact over the distal contact. In vivo study: A MAH of 10.36 mm (±0.44) and MAW of 3.56 mm (±0.30) were obtained. No significant different artifact dimensions were measured between in vitro and in vivo studies (p<0.0001). Interpretation. Precise 3D localization of the electrode in implanted patients is provided by MR identification of the limits of the distal contact artifact. The position of the other contacts is deduced given the size of the contacts and the intercontact distance.

The role of inflammatory processes in the pathophysiology and treatment of brain and spinal cord trauma

Abstract: Traumatic injury to the brain and spinal cord results in an early inflammatory response that is initiated by the release of proinflammatory cytokines followed by the infiltration and accumulation of polymorphonuclear leukocytes (PMNLs). The role of the inflammatory cascade on traumatic outcome remains controversial. Pleiotropic cytokines appear to function both protectively and destructively. The induction of cytokines can lead to the expression of the inducible form of nitric oxide synthase (iNOS), which in turn provokes the release of excessive amounts of nitric oxide (NO) that may participate in the pathogenesis of tissue injury. Hypothermia has been reported by various groups to be neuroprotective in brain and spinal cord trauma. We studied the effect of therapeutic hypothermia on cerebral IL-lβ concentrations, PMNL accumulation and iNOS activity after traumatic brain injury (TBI) and spinal cord injury (SCI). Based on current data therapeutic hypothermia may protect in models of traumatic injury by modulating deleterious inflammatory processes.

Management of hardware infections following deep brain stimulation.

Abstract: Objective. To report our experience on hardware-related infections following deep brain stimulation (DBS). Methods. The present article presents the retrospective clinical notes review of gained in a two-centre, single-surgeon study experience of 108 consecutive DBS cases between 1996 and 2002. In all patients the minimum follow-up was six months. One hundred and eight patients received an intracerebral electrode implantation and 106 underwent internalization. Results. In total 178 electrodes were implanted with a mean follow-up of 42.6 months and a cumulative follow-up of 367.7 patient-years. Four patients (3.8%) developed an infection related to the DBS-hardware and all were initially treated with antibiotics. Two patients eventually required additional surgical treatment. Conclusion. Infections due to DBS-hardware can result in considerable levels of morbidity. In certain cases antibiotic therapy may be adequate. In others, surgical intervention to externalise the electrodes may be necessary. In our experience, there was never a need to remove the electrodes.

Intra-operative mapping of the subcortical visual pathways using direct electrical stimulations.

Abstract: Despite the risk of postoperative visual field defect following surgery within the temporo-parieto-occipital region, visual mapping has rarely been described, in particular at the subcortical level.

Lumboperitoneal shunts: are the complications acceptable?

Abstract: Background. Lumboperitoneal shunts have long been used in the treatment of benign intracranial hypertension, postoperative pseudomeningocele, CSF leak and communicating hydrocephalus. Although they can provide a rapid and effective resolution of the symptoms there are major disadvantages associated with their use. Method. We retrospectively analyzed the records of 21 patients who underwent LP shunt insertion in our institution during the study period. Findings. Eighteen patients (85.7%) underwent at least one shunt revision with a total of 63 revisions. Shunt related infections were observed in 7 cases and 7 patients developed Chiari malformation, 2 (9%) of these requiring further treatment. Conclusions. Despite the symptomatic control achieved with lumboperitoneal shunts we find the complication and revision rates unacceptably high. The technique should be re-evaluated and other treatment strategies considered.

Quality of life after decompressive craniectomy in patients suffering from supratentorial brain ischemia

Abstract: Background. Decompressive craniectomy in patients suffering from severe ischemic stroke in the middle cerebral artery territory (MCA) decreases mortality to near 30%. Additionally functional outcome in patients after early craniectomy seems to be better than in patients without surgery. The aim of this study was to investigate the quality of life of patients who were treated with a decompressive craniectomy for severe ischemic stroke. Methods. We retrospectively investigated the patient records of 48 patients (26 men, mean age 48 years) suffering from ischemic strokes who underwent craniectomy since 1993. We registrated the preoperative neurological status, the diagnostic data as well as the operative procedure. The outcome was assessed using the Barthel Index, the Glasgow outcome score and a questionnaire to assess the quality of life according to Blau consisting of eleven items at follow-up. Findings. The mortality rate was 26%, age correlated to mortality (44.5 versus 60.3 years GOS 1, mean, p<0.0006). Craniectomy without dura patch correlated to mortality (58% versus 14% GOS 1 with dura patch, p<0.005). The quality of life index was 6 points mean. The quality of life index did neither differ significantly between patients with left or right sided lesions nor in patients with and without aphasia. 83% of the surviving patients and/or dependents would agree to surgery in the future. Conclusion. Despite the fact that some patients remain in a poor neurological condition, quality of life after decompressive surgery for ischemic stroke seems to be acceptable to the patients.

Glial scar and axonal regeneration in the CNS: lessons from GFAP and vimentin transgenic mice.

Abstract: Astrocytes play an active role in the brain and spinal cord. For example, they have a function in formation and maintenance of the blood-brain barrier, ion homeostasis, neurotransmitter transport, production of extracellular matrix, and neuromodulation. Moreover, they play a role in preserving or even restoring the structural and physiological integrity after tissue injury. Currently, the function of astrocytes was studied with regard to the controversially discussed aspects of permissivity on the one-hand-side and inhibition of the other side exerted by reactive astrocytes for axonal regrowth in the adult CNS. Accordingly, knock-out mice deficient in vimentin (VIM) and/or glial fibrillary acidic protein (GFAP), the two major IF-proteins of astrocytes, were investigated. In addition, in vitro studies were carried out, on whether the absence of one or both proteins (VIM, GFAP) influences axonal regeneration. In experimental animals, a hemisection of the spinal cord was performed utilizing the above mentioned double-mutant mice. The knock-out mice were generated by gene targeting. Double-mutants were obtained by crossing single null mice.

Multimodality management of 26 skull-base chordomas with 4-year mean follow-up: experience at a single institution

Abstract: Objective. To analyze a series of patients with pathologically confirmed skull-base chordoma, and to develop an algorithm for the management of this challenging disease based on the data, our experience, and the current literature.

Gamma knife surgery for epilepsy related to hypothalamic hamartomas.

Abstract: Objective Drug resistant epilepsy associated with hypothalamic hamartoma (HH) can be cured by microsurgical resection of the lesion. Morbidity and mortality risks of microsurgery in this area are significant. Gamma Knife Surgery's (GKS) reduced invasivity seems to be well adapted. In view of the severity of the disease and risks of surgical resection it is crucial to evaluate GKS for this indication. A first retrospective study has shown a very good safety and efficacy level but for a more reliable evaluation a prospective study would be required. Methods Between Oct 1999 and July 2002, 30 patients with HH and associated severe epilepsy were included. Seizure semiology (video EEG) and frequency, behavioural disturbances, neuropsychological performance, endocrinological status, sleep electroclinical abnormalities, MR imaging, and visual function were systematically evaluated before and after GKS (6, 12, 18, 24, 36 months). Twenty patients had experienced precocious puberty at a median age of 3,7 (0-9). Range of maximum diameter was from 7,5 to 23 mm with only 3 larger than 18 mm. The median marginal dose was 17 gy (14-20). Results Sufficient follow up for final evaluation is not yet available. Only 6 patients have a follow-up of more than 12 months and 19 more than 6 months. However a lot of very dramatic changes did occur during that period in this group. Among the 19 patients with more than 6 months of follow-up, a lot had already experienced an increase of gelastic seizures around 3 months (3), an improvement in their seizure rate (18), behaviour (9), sleep (3), and EEG background activity (3), a cessation of partial complex seizures (7). No complications have occurred till now except one patient experiencing at 5 months a hyperthermia without infection and concomitant increase of gelastic seizures both ceasing suddenly and spontaneously after 15 days. Conclusion Our first results indicate that GKS is as effective as microsurgical resection and very much safer. GKS also allows to avoid the vascular risk related to radiofrequency lesioning or stimulation. The disadvantage of radiosurgery is its delayed action. Longer follow-up is mandatory for a serious evaluation of the role of GKS. Results are faster and more complete in patients with smaller lesions inside the 3rd ventricle (grade II). The early effect on subclinical discharges turns out to play a major role in the dramatic improvement of sleep quality, behaviour, developmental acceleration at school.

Mild head injury: revisited.

Abstract: Objective. 1. To define the incidence of positive CT scans in patients with different grades of mild head injury (MHI), 2. To identify clinical predictors of positive CT scans, 3. To evaluate the usefulness of plain radiographs in the triage of patients with MHI, 4. To evaluate frequency and nature of surgical intervention in MHI, 5. To evaluate the risk of deterioration in MHI, and 6. To find out whether patients with normal neurological examination and normal CT can be safely discharged. Methods. In a prospective study conducted over a period of four months in our center, all patients with mild head injury (defined as Glasgow Coma Scores (GCS) 13–15) were admitted to the head injury unit. Patients underwent standard clinical examination, skull radiography and cranial CT. No clinical criteria were used to select patients for CT scanning and all the patients were subjected to CT. Patients with negative findings on CT and a normal neurological examination were discharged after 24 hours of observation. Patients with positive findings on cranial CT were treated either medically or surgically as deemed necessary. Outcome measures included safe discharge, clinical deterioration, need for surgical intervention or death. The following factors were analyzed statistically to find out whether they can be used as predictive factors for positive cranial CT. They were: age, sex, mode of injury, loss of consciousness, post-traumatic seizures, ear/ nose/throat bleeding, vomiting, admission GCS score, scalp injury, polytrauma, focal neurological deficit, fractures visualized on skull radiography. Results. Three hundred and eighty one patients were included in the study. Of these males constituted 63%, females 17% and children 20%. RTA was the most common mode of injury. Seventy five percent of the patients had GCS of 15, 15% had GCS of 14 and 10% had GCS of 13. Thirty eight percent of the patients had positive findings on the CT. Age, mode of injury, loss of consciousness, post-traumatic seizures, ENT bleeding, vomiting, scalp injury and polytrauma were not found to be predictors of positive CT. Admission GCS score, focal neurological deficits, and fractures detected by skull radiography were found to be statistically significant predictors of positive findings on CT. Seven percent of patients required surgical intervention. Six percent of patients showed neurological deterioration and there was one death in this series of MHI patients. Patients with multiple lesions on CT had a higher chance of deterioration than those with a single lesion. No patient who had a GCS of 15 and normal CT developed any complication during the hospital stay or after discharge. Conclusions. The incidence of positive CT scans in this prospective, consecutive, unselected cohort of MHI patients was 38%. Lower admission GCS scores, focal neurological deficits, and fractures detected by skull x-rays were found to be significant predictors of positive CT. Other clinical parameters were not found to be predictors of positive CT. CT was found to be superior to plain x-rays in detecting skull fractures. Seven percent of this cohort required neurosurgical intervention. Six percent showed neurological deterioration and there was one death in this series. Patients with multiple lesions on CT had a higher chance of deterioration than those with single lesions. The duration of hospital stay was prolonged in patients with positive CT. As no patient with a normal neurological examination and a normal CT deteriorated, we believe these patients can be safely discharged without need for admission and observation.

A case of delayed brain abscess due to a retained intracranial wooden foreign body: a case report and review of the last 20 years

Abstract: A 13-year-old female is presented. When she was six years old, she had fallen, holding wooden chopsticks and got stuck with a chopstick in the right upper eyelid. She was brought to a physician immediately, but a residual foreign body was missed and no particular symptom had developed during 7 years. She visited our department with fever and headache, and a brain abscess and an intracranial foreign body were found on computed tomography (CT) and magnetic resonance image (MRI) 7 years after the penetrating injury. She underwent removal of the object and abscess by craniotomy and recovered without neurological abnormalities. Since intracranial retained wooden foreign bodies frequently cause delayed complications of severe central nervous system infection, surgical removal is necessary even in the absence of symptoms.

Robot-assisted navigated endoscopic ventriculostomy: implementation of a new technology and first clinical results

Abstract: Background. Important landmarks in the evolution of advanced neurosurgical techniques during the past decades include microneurosurgery, neuro-endoscopy and its minimally invasive nature, as well as neuronavigation and advanced intra-operative imaging. With conventional neuroendoscopic techniques, e.g. free-hand endoscopy or the use of mechanical or pneumatic holding devices, a definitive and controlled movement of the endoscope within the brain does depend on the experience and manual skill of the individual neurosurgeon. Therefore, the development of robotic systems to assist surgeons in performing complex neurosurgical procedures is a growing field of interest. Method. With the precision robot “Evolution 1” (U.R.S. Universal Robot Systems, Schwerin, Germany) a new neurosurgical tool has just become available for the precise steering of instruments within the cranium. After preclinical anatomical as well as precision studies the system was used for robot-assisted navigated endoscopic third ventriculostomies in six patients with hydrocephalus related to aqueductal stenosis. Findings. All robot-assisted navigated endoscopic procedures were successfully completed. The time for the registration procedure and setup of the robot decreased from 60 min. for the first procedure down to 30 min. The time for the surgical part of the neuro-endoscopic procedure itself ranged from 17 to 35 min. During all procedures no system-related complications occured. Interpretation. The use of robotic technology for neuro-endoscopic third ventriculostomies is a major step towards the controlled movement of the neuro-endoscope within the cranium. The start up procedure and calibration of the robot is still time consuming, but the real operation time is comparable to free hand neuro-endoscopy. The steering of the endoscope is facilitated and the precision of the endoscopic movements is noteworthy.

Nocardia brain abscess mimicking brain tumour in immunocompetent patients: report of two cases and review of the literature

Abstract: Nocardia brain abscess is a rare intracranial lesion and has been reported in immunocompromised patients. An optimal treatment approach has not been established. However, early diagnosis and appropriate antimicrobial therapy are very important factors for a good outcome. We report two unusual cases of Nocardia brain abscess simulating brain tumour in immunocompetent patients. One of the cases was presumed to be a primary brain tumour and the other a metastatic brain tumour. They underwent surgical gross total resection. After Nocardia asteroides was seen on Gram’s stain and subsequently identified by culture, appropriate antibiotic therapy was initiated.

The ELANA technique: Constructing a high flow bypass using a non-occlusive anastomosis on the ICA and a conventional anastomosis on the SCA in the treatment of a fusiform giant basilar trunk aneurysm

Abstract: A patient with a partially thrombosed fusiform giant basilar trunk aneurysm presented with devastating headache and symptoms of progressive brain stem compression. Having an aneurysm inaccessible for endovascular treatment, and after failing a vertebral artery balloon occlusion test, he was offered bypass surgery in order to exclude the aneurysm from the cerebral circulation and relieve his symptoms. A connection between the intracranial internal carotid artery and the superior cerebellar artery was created whereupon the basilar artery was ligated just distally to the aneurysm. The proximal anastomosis on the internal carotid artery was made using the excimer laser-assisted non-occlusive anastomosis (ELANA) technique, while a conventional end-to-side anastomosis was used for the distal anastomosis on the superior cerebellar artery. Intra-operative flowmetry showed a flow through the bypass of 40 ml/min after ligation of the basilar artery. An angiogram 24 hours later showed normal filling of the bypass and the vessels supplied by it, but also disclosed a subtotal occlusion of the proximal ipsilateral middle cerebral artery with delayed filling distally. The patient, who had a known thrombogenic coagulopathy, died the following day. Autopsy showed no signs of ischemia in the territories supplied by the bypass, but a thrombus in the proximal middle cerebral artery and massive acute hemorrhagic infarction with swelling in its territory and uncal herniation. Multiple fresh thrombi were found in the lungs. The ELANA anastomosis showed re-endothelialisation without thrombus formation on the inside.

A modified technique for using elastase to create saccular aneurysms in animals that histologically and hemodynamically resemble aneurysms in human.

Abstract: Background. Treatment of intracranial aneurysms is evolving with the development of novel therapies. It is important to have an animal model which simulates human aneurysms. We describe a new modified technique to the elastase aneurysm model which creates aneurysms that histologically and hemodynamically resemble human aneurysms. Methods. Twelve New Zealand white rabbits underwent the aneurysm creation procedure, and 2 underwent a control procedure. In the aneurysm creation procedure, the right common carotid artery (RCCA) origin is surgically exposed and temporarily occluded with a temporary aneurysm clip. The RCCA is ligated distally, and the trapped segment is infused with elastase for 20 minutes, afterwhich the clip is removed. In the control procedure, the RCCA is ligated distally with no elastase. Animals were assessed neurologically using a previously described rabbit neurologic grading scale and food intake scale. Intravenous digital subtraction angiography (IVDSA) was performed 21 days after the procedure. Aneurysms were harvested and stained with H&E and Verhoeff’s stain. Findings. All 14 rabbits had normal neurologic and food intake assessments. All 12 rabbits that underwent aneurysm creation procedures demonstrated saccular aneurysms on IVDSA. Mean aneurysm size was 5.9±1.9 mm; range 4.3–10.8 mm. The close proximity of the LCCA to the origin of the RCCA on the aortic arch of the New Zealand white rabbit closely resembles a bifurcation aneurysm. Both rabbits that underwent control procedures showed no aneurysm and retrograde thrombosis of the RCCA. Histologic analysis showed the aneurysms had histology characteristic of true human aneurysms. Conclusion. We have developed a new modified technique to the elastase aneurysm model which creates aneurysms that hemodynamically and histologically resemble human aneurysms. There have been previous elastase models described, however we find our model is easier to perform and highly reproducible. The aneurysms can be accessed transfemorally making the model ideal for testing endovascular therapies.

Clinical outcome of standard extracranial-intracranial bypass surgery in patients with symptomatic atherosclerotic occlusion of the internal carotid artery

Abstract: Objective. In this retrospective study we wanted to determine the role of cerebral revascularization in patients with symptomatic occlusive cerebrovascular disease. Special emphasis was put on subsequent cerebrovascular events, benefit in neurological functioning and bypass patency, as evaluated during the follow-up period. Methods. A total of 73 superficial temporal artery to the middle cerebral artery bypasses were performed on 67 patients from 1986–2000. All patients exhibited a symptomatic occlusion of the internal carotid artery verified by angiography. All patients in our group were refractory to medical treatment. 65 patients (69 bypasses) with a mean age of 61 years (range: 38–79 years) were followed up over an average time of 44 months (range: 1.5–150 months). Results. The peri-operative morbidity rate was 3% with no mortality. 55 patients (85%) had no further cerebrovascular events after surgery, and only 7 (11%) patients experienced another cerebrovascular event. 57 (88%) patients showed an improvement of symptoms after surgery and only 1 patient fared worse during the follow-up peroid due to a stroke he suffered two years after bypass surgery. 90% of all bypasses remained patent during the follow-up. Conclusions. Although bypass surgery for occlusive cerebrovascular disease is still controversial, our retrospective study suggests both an improvement of symptoms and signs and a risk-reduction for future cerebrovascular events after surgery.

Image fusion of MR images and real-time ultrasonography: evaluation of fusion accuracy combining two commercial instruments, a neuronavigation system and a ultrasound system.

Abstract: Objective. The aim of our study was to evaluate MRI/Ultrasonography fusion accuracy depending on three ultrasonographic parameters.

Intradural en-bloc removal of the anterior clinoid process.

Abstract: Background. Anterior clinoidectomy is useful in the surgical treatment of paraclinoid and parasellar lesions. Previously reported procedures require expertise in drilling, the alternative method reported here reduces the drilling procedure. Methods and results. En-bloc clinoidectomy is performed intradurally via the standard pterional approach. A 1 to 2 mm-wide narrow drill line is placed with a 1 mm-wide diamond burr through the lesser sphenoid wing. It encircles the medial border of the optic canal and the lateral border of the lesser sphenoid wing over the superior orbital fissure, and is located about 1 cm anterior to the posterior margin of the optic canal. After drilling, one bony piece that includes the anterior clinoid process (ACP) and the optic canal roof remains connected to the basisphenoid bone by the optic strut alone. The optic strut is then fractured easily by applying leverage near its junction with the basisphenoid bone and the piece is removed en bloc with the major part of the optic strut, requiring little or no additional drilling of the residual bony fragments. Of 37 patients who underwent our en-bloc clinoidectomy, only one suffered complications consisting of cerebrospinal fluid (CSF) leakage through the sphenoid sinus. Our procedure requires an average of 20 min. Conclusions. Intradural en-bloc removal of the ACP with fracture of the optic strut requires minimal drilling, resulting in decreased risk of injury to the optic nerve and a shortened time for clinoidectomy.

Treatment of pain from osteoporotic vertebral collapse by percutaneous PMMA vertebroplasty.

Abstract: Background. Vertebral compression fractures are common complications in advanced osteoporosis. In general, this disease of the elderly patient is characterized by severe local back pain. Pathophysiologically, bony instability triggers local pain during body movement. Serious pain immobilizes the patients and forces them to bed rest. As a result, complications like thrombosis or pneumonia occur. Invasive treatment with surgical instrumentation for vertebral stabilization is not indicated in elderly patients especially with additional diseases.