[Minimally invasive surgery of the anterior skull base: transorbital approaches]. / Minimal-invasive Chirurgie der vorderen Schädelbasis: Transorbitale Zugänge.

Minimally invasive approaches are becoming increasingly popular to access the anterior skull base. With interdisciplanary cooperation, endonasal endoscopic in particular approaches have seen an impressive expansion of indications over the past decades. The more recently described transorbital approaches represent minimally invasive alternatives with a differing spectrum of access corridors. The purpose of the present paper is to discuss transorbital approaches to the anterior skull base in the light of the current literature.The transorbital approaches allow excellent exposure of difficult to reach areas like the the anterior and posterior wall of the frontal sinus; working angles may be more favorable and the paranasal sinus system can be preserved while exposing the base of skull. Because of their minimal morbidity and the cosmetically excellent results, the transorbital approaches represent an important addition to established endonasal endoscopic and open approaches to the anterior skull base. Their execution requires an interdisciplinary team approach.

Levetiracetam compared to phenytoin for the prevention of postoperative seizures after craniotomy for intracranial tumours in patients without epilepsy.

Anticonvulsant drugs are frequently given after craniotomy. Phenytoin (PHT) is the most commonly used agent; levetiracetam (LEV) is a new anticonvulsant drug with fewer side effects. To compare the incidence of seizures in patients receiving either prophylactic PHT or LEV perioperatively, 971 patients undergoing a craniotomy were analysed retrospectively during a 2-year period. PHT was used routinely and LEV was administered when PHT was contraindicated. Seizures documented during the first 7 days after craniotomy were considered. A total of 235 patients were treated with an antiepileptic drug: 81 patients received LEV, and 154 patients, PHT. Two patients receiving LEV (2.5%) and seven receiving PHT (4.5%) had a seizure despite this treatment. No patient had a documented side effect or drug interaction. The data show that LEV may be an alternative option in patients with contraindications to PHT.

Analysis of risk factors influencing the development of severe dizziness in patients with vestibular schwannomas in the immediate postoperative phase.

OBJECTIVE: Dizziness, a common postoperative symptom in patients with vestibular schwannomas (VSs) has a negative effect on the course of recovery, particularly in patients with severe symptoms. Reports on incidence and possible risk factors contributing to these symptoms are inconsistent and sometimes even contradictory. In order to establish a profile of patients at risk of severe symptoms in the immediate postoperative phase we retrospectively analyzed data of patients with unilateral VSs focusing on the incidence of severe dizziness and nausea during the immediate postoperative period and up to 1 year after surgery. METHODS: In a retrospective study data of 104 consecutive patients with VSs were analyzed. All patients underwent microsurgical tumor resection via a lateral-suboccipital approach. Factors that were assumed to affect the development of severe dizziness, such as age, gender, tumor size, tumor side, and cranial nerve function, were analyzed by means of univariate and multivariate logistic regression analyses. A three step grading system was used to describe symptoms of patients included in this study: 0=no symptoms of dizziness, 1=slight dizziness including light-headedness or feeling of disequilibrium and 2=severe dizziness with nausea including imbalance or insecurity when walking, requiring antiemetic treatment. RESULTS: Data of 92 patients, 41 men and 51 women, were available for analyses. Mean age of treated patients was 53 years (range 17-81). There was no predilection of side (52.2% right/47.8% left). Before surgery 39 patients (42.4%) were symptom free (grade 0), 13 patients (14.1%) had slight symptoms (grade 1) and 40 patients (43.5%) suffered from severe symptoms (grade 2). Immediately after surgery two patients (2.2%) where symptom free (grade 0), 19 patients (20.7%) had slight symptoms (grade 1) and 71 patients (77.2%) suffered from severe symptoms (grade 2). All patients with grade 2 symptoms required antiemetic treatment ranging between 1 and 10 days (mean 4 days). Logistic regression analyses showed young age, large tumor size (T3/T4), female gender, and severe preoperative symptoms to be main factors increasing the odds for patients to develop severe symptoms postoperatively. CONCLUSION: Patients at risk to develop severe symptoms should receive antiemetic treatment even before surgery. If in doubt about the actual risk for a specific patient with a large tumor (T3 or T4) available data suggests that patients will benefit if antiemetic treatment is started early, even before surgery.

Elevated premorbid body mass index is not associated with poor neurological outcome in the subacute state after aneurysmal subarachnoid hemorrhage.

BACKGROUND: An elevated body mass index (BMI) is suggested to be a risk factor for a poor outcome after intracranial aneurysm rupture and is considered to be associated with cerebral infarction in patients with aneurysmal subarachnoid hemorrhage (SAH). The aim of this study was to analyze the association between permorbid BMI and neurological outcome. METHODS: In this retrospective study, the patients' BMI at the time of their admission to hospital was correlated to their neurological outcome as measured by the Glasgow outcome score after two weeks and two months of treatment. RESULTS: In contrast to other studies, there were no significant correlations between premorbid BMI and neurological outcome, shunt requirement, tracheotomy requirement and duration of stay on the intensive care unit (ICU). CONCLUSIONS: Overweight patients have no higher risk of a poor neurological outcome after aneurysmal SAH if premorbid risk factors such as hypertension and hyperglycemia are carefully modified throughout the period of critical care.

Extended extra- and intracerebral ulceration and brain abscess following self-mutilation in an auto-aggressive 51-year-old woman: case report.

In neurosurgical practice, the operative treatment of deep or infected wounds caused by auto-mutilation is quite rare, especially in the neurocranium. We present an extraordinary case of an auto-aggressive 51-year-old female suffering from a deeply ulcerated wound on the right frontal skull with consecutive brain abscess, caused manually with needles and forceps over a period of 8 months. The clinical course is present ed together with a description of the conservative and surgical regimen and is illustrated with photographs and CT and MRI images.

Cognitive decline as an important sign for an operable cause of dementia: chronic subdural haematoma.

BACKGROUND: Cognitive decline, slow psychomotor regression and confusion, especially in the elderly, often result in medical consultation. Frequently, these rather unspecific symptoms are interpreted as signs of beginning dementia. When mental regression is joined by tremor or motor deficits, neurodegenerative disease is commonly considered and the need for neuroimaging is underestimated. Chronic subdural haematoma (CSH) is known to be the most frequent type of intracranial bleeding, appearing mostly in the elderly after minor trauma with unspecific symptoms. The aim of this retrospective study was the identification of the leading clinical symptoms in patients with the diagnosis CSH who had been treated surgically in our Neurosurgical Department. PATIENTS AND METHOD: 356 patients with symptomatic CSH (225 male, 131 female; mean age 68.3 years), who were admitted to our Neurosurgical Department between 1992 and 2003, were included in the study. We reviewed the charts documenting preoperative clinical status, radiological signs, history of trauma, operative complications, postoperative clinical status, days of hospitalisation as well as gender and age. RESULTS: The primary surgical procedure performed in 343 patients (96.4%) was burr-hole trepanation. The leading preoperative symptoms were mnestic deficits (cognitive decline, confusion) in 192 patients (55.8%), followed by headache in 150 patients (45.5%) and motor deficit in 144 patients (41.1%). Furthermore, we found a statistically significant correlation (p<0.005) between the thickness of the left-sided haematoma and the symptoms aphasia and psychosyndrome. CONCLUSION: The leading clinical symptoms identified in our cohort were mnestic deficits, headache and motor deficit, signs that mostly appear at the beginning of demential diseases. Thus, CSH should be taken into account as an important differential diagnosis for demential and neurodegenerative diseases and neuroimaging should be demanded. Once a CSH is detected this way, the patient should be transferred to a neurosurgical department where an easy standard procedure may potentially lead to early recovery.

A study of possible correlation between subarachnoid haemorrhage related vasospasm and the post-bleed blood platelet count chart in a Caucasian population.

INTRODUCTION: There has been controversy about the aetiology and pathophysiology of subarachnoid haemorrhage (SAH) related vasospasm. Several pathogenic factors like endothelin and adhesion molecules have been discussed. A recently published study concerning an exclusively Asian population suggested a relationship between SAH related vasospasm and the blood platelet count. The aim of our study was to examine this relationship in a European population. METHOD: We carefully reviewed 88 patients with aneurysmal SAH (54 females, 34 males; mean age 52.5 years, range from 22 to 78 years) treated in our centre with regard to the occurrence of vasospasm and the blood platelet count in a ten day interval after initial SAH. Symptomatic vasospasm was defined as a focal neurological deficit or deterioration in the level of consciousness with or without confirmation of infarction on a CT scan. Thirty-seven patients (42%) developed clinically relevant vasospasm. RESULTS: There was no statistically significant correlation between the blood platelet count chart (maximum and minimum values) and vasospasm or clinical outcome; we also found no gender or age-related influence on the above mentioned relationships. CONCLUSIONS: In our opinion there appears to be a difference between Caucasian and Asian populations regarding the influence of platelets in the pathophysiology of SAH and vasospasm.

Ultrasonic blood flow volume assessment in the extracranial internal carotid artery in arteriovenous malformations.

Angle-independent ultrasound assessment of the volume flow in the extracranial internal carotid artery (ICA) is a new approach to evaluate the perfusion status of the human brain. Normal values using a new technical device (Quantix ND, Cardiosonix Ltd, Israel) and correlation analysis to quantitative CBF measurements were recently published. Aim of this study was to evaluate this device in arteriovenous malformations where cerebral blood flow is known to be increased. Five patients suffering from large supratentorial arteriovenous malformations (AVM) could be examined. All patients showed pre-operatively elevated flow volumes in the internal carotid artery on the side harbouring the pathological lesion compared with normal values evaluated in 50 volunteers. The contralateral internal carotid artery showed volume flow values within the normal limit. After surgical resection of the malformation normal values could be measured in all patients. Pathological elevated increases in cerebral blood flow can be evaluated by ultrasonic blood flow volume assessment in the extracranial internal carotid artery. Therefore, the Quantix ND seems a valuable tool in diagnosing cerebral hyperemia.

Normal values of volume flow in the internal carotid artery measured by a new angle-independent Doppler technique for evaluating cerebral perfusion.

BACKGROUND: Cerebral blood flow is an important parameter when monitoring critically ill patients. Blood flow volume within the internal carotid artery (ICA) was shown to be correlated with the cerebral blood flow. The aim of our study was to provide normal values of the internal carotid artery volume flow using this new technology (QuantixND, Cardiosonix Ltd., Israel). METHOD: The QuantixND System is an angle-independent Doppler system that employs two digital high resolution ultrasound heads within one probe in an defined angle to each other. Thus several flow velocities within the vessel and the vessel diameter can be measured. 77 healthy patients (41 women, 36 men) were included and divided into age groups of ten-year intervals (mean age 48.9 years). Internal carotid artery flow was evaluated as well as physiological and hematological parameters (hematocrit, arterial blood pressure etc). FINDINGS: We found that the blood flow volume in the ICA decreased significantly with age. No side-to-side effects as well as no gender-related differences could be observed. There was no influence of hemoglobin, hematocrit and blood pressure in this healthy population. CONCLUSIONS: There is an age-related decrease in blood flow volume with age that can be easily and exactly determined by the use of the new angle-independent Doppler technique.

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

OBJECTIVE: The aim of our study was to evaluate MRI/Ultrasonography fusion accuracy depending on three ultrasonographic parameters. METHOD: An ultrasonography and MRI compatible model was created, consisting of a plastic box, which contained 3 objects. MRI scans were performed with 128 sagittal slices. The objects were segmented and 3D reconstructions were created. A special ultrasound adapter with 3 reflective markers was fixed to the ultrasound probe. Thus, the probe could be tracked by the navigation system (Vector Vision(2), BrainLab, Heimstetten, Germany) and the segmented shape of the 3D-objects obtained from the MR images were overlaid onto the ultrasound display (Elegra, Siemens, Erlangen, Germany). The dependency of fusion accuracy on different depth of ultrasound display, different distances between probe and objects and different angles between the axis of the ultrasound probe and the centre of the spheres was evaluated. 435 single measurements were performed. FINDINGS: Overall fusion accuracy was 1.08 mm+/-0.61 mm (mean +/- standard deviation) for spheres and 1.6 mm+/-1.1 mm for arrow heads. If the ultrasound probe was directed more tangentially to the surface of the spheres the fusion became increasingly inaccurate (P<0.05). Fusion accuracy decreased the more distant the US probe was held to the object (P<0.05). Different depth of ultrasound display had no significant effect on fusion accuracy. CONCLUSIONS: Highly accurate fusion of MR images and real-time ultrasonography could be achieved. However, careful interpretation of the fused data is necessary, when different angles and distances of the US probe to the object are concerned.

Internal carotid artery volume flow correlates to rCBF measurements.

BACKGROUND: There is no simple, cost effective bedside method available for measuring global cerebral blood flow (CBF) rapidly and repeatedly. METHOD: Based on the ultrasound technique a device was developed to measure flow volume per unit of time in the internal carotid artery. The system utilizes dual beam, angle-independent Doppler technology, and employs simultaneous sampling and full spectrum determination. The aim of this study was to evaluate this device in comparison with cerebral blood flow measurements using the well established Xenon(133) clearance technique. FINDINGS: 10 patients suffering from SAH were included. 20 measurements were performed. CBF was measured employing the Xenon(133) clearance technique. Velocity profiles across the ICA were obtained with the high-resolution FlowGuard Doppler ultrasound flow system (Cardiosonix Ltd., Israel). According to the statistical analysis the ICA flow correlated significantly to the mean rCBF15 index of the hemisphere (p<0.0001). CONCLUSIONS: This new device seems to be promising for monitoring cerebral blood flow in critically ill neurological and neurosurgical patients.