The anterior interhemispheric approach: a safe and effective approach to anterior skull base lesions.

Background: Many approaches to the anterior skull base have been reported. Frequently used are the pterional, the unilateral or bilateral frontobasal, the supraorbital and the frontolateral approach. Recently, endoscopic transnasal approaches have become more popular.

Standard open microdiscectomy versus minimal access trocar microdiscectomy: results of a prospective randomized study.

Objective: Minimal access surgery as a less invasive alternative to standard macro- and microsurgical approaches is becoming increasingly popular in the management of traumatic and degenerative spine diseases. However, data is lacking if minimal access spine surgery is indeed beneficial. This prospective randomized study was conducted to compare efficiency, safety, and outcome of standard open microsurgical discectomy (SOMD) for lumbar disc herniation with microsurgical discectomy using an 11.

Transmuscular trocar technique - minimal access spine surgery for far lateral lumbar disc herniations.

Objective: Minimal access spine surgery (MASS) is gaining increasing importance in microsurgery of the lumbar spine. From a current prospective series we present data on MASS for far lateral lumbar disc herniations (LLDH) via a transmuscular trocar technique (T(2)). The surgical procedure and operative results are demonstrated in detail.

How useful is the 3-dimensional, surgeon's perspective-adjusted visualisation of the vessel anatomy during aneurysm surgery? A prospective clinical trial.

We hypothesized that neuronavigational 3-dimensional display of vessel and aneurysm anatomy, which is adjusted to the actual surgeon's view, could be helpful during the critical steps of aneurysm treatment. A total number of 32 patients with 42 aneurysms entered this prospective clinical trial. With a neuronavigational system, a 3-dimensional image of the arterial vascular anatomy was generated by autosegmentation of a computerized tomography (CT) angiographic data set.

Delayed diagnosis of spinal dural arteriovenous fistula in the absence of pathological vessels on MRI.

The authors report on a 69-year-old man presenting with progressive leg weakness and gait ataxia over two years. A central intramedullary cord lesion ranging from T8-12 on MR imaging was misdiagnosed as a low-grade glioma and a biopsy was attempted followed by temporary clinical deterioration. Selective spinal angiography revealed a spinal dural arteriovenous (AV) fistula on the left L3 nerve root sheath despite the absence of pathological vessels on MR imaging.

Advanced neuronavigation in skull base tumors and vascular lesions.

Objective: The purpose of this study was to describe the usefulness of recent advances of neuronavigational technology in the management of skull base tumors and of vascular lesions, treated via a skull base approach.

Methods: In 16 patients (skull base meningioma n = 9, petrous apex epidermoid n = l, craniopharyngeoma n = 1, giant internal carotid artery aneurysm n = 1, basilar/vertebral artery aneurysm n = 2, brain stem cavernoma n = 2), "advanced" neuronavigation was used. In contrast to "conventional" neuronavigation, the information for the neurosurgeon was enhanced by the intraoperative screen display of 3-dimensional reconstructions of the lesion, vessels, nerves and fiber tracts at risk.

Frame-based and frameless stereotactic hematoma puncture and subsequent fibrinolytic therapy for the treatment of spontaneous intracerebral hemorrhage.

Objectives: Comparison of two minimally invasive procedures for the treatment of intracerebral hemorrhage and subsequent lysis with regard to technical implications and clinical outcome of the patients.

Methods: Retrospective analysis of 126 patients with spontaneous supratentorial intracerebral hemorrhage treated by frame-based (n=53) or frameless (n=75) hematoma aspiration and subsequent fibrinolysis with recombinant tissue plasminogen activator (rt-PA). Data were analysed for the whole group as well as for the two subsets of patients with regard to hematoma reduction, procedure-related complications, and the early and long term clinical outcome of the patients.

The role of endogenous versus exogenous tPA on edema formation in murine ICH.

To minimize the neurotoxic injury by clot-derived substances after intracerebral hemorrhage (ICH) on the surrounding brain tissue, minimally invasive neurosurgical protocols have evolved evacuating the hematoma by stereotaxic injection of a fibrinolytic agent such as recombinant tissue plasminogen activator (rtPA), followed by aspiration of the lysed clot. However, the possible contribution of the presence of exogenous tPA itself to the toxic effects of hematoma-derived factors complicates the rationale and efficacy of this therapeutic approach. To clarify the role of exogenous rtPA on edema development, we examined the extent of edema formation in a murine model of collagenase-induced ICH, which included tPA-deficient (tPA-/-) and wild-type (wt) mice.

[Aneurysmal subarachnoid hemorrhage: role of computerized tomography for correct prediction of the ruptured aneurysm site].

Objective: To investigate if the intracisternal distribution of subarachnoid hemorrhage (SAH) following aneurysm rupture allows the correct prediction of the symptomatic aneurysm site. [nl]

Methods: Ninety-nine consecutive patients with acute SAH and angiographically proven aneurysm were included into the study. The parent vessel of the diagnosed aneurysms were the anterior communicating artery (ACoA) in 38 patients, the middle cerebral artery (MCA) in 26 patients, the internal carotid artery (ICA) in 25 patients, the pericallosal artery (A2) in 5 patients, the basilar artery (BA) in 4 patients and the vertebral artery (VA) in 1 patient.

Focused high frequency repetitive transcranial magnetic stimulation for localisation of the unexposed primary motor cortex during brain tumour surgery.

Objectives: To investigate if intraoperative focused high frequency repetitive transcranial magnetic stimulation (rTMS) can localise the primary motor cortex without exposure of the cortical surface.

Methods: A high frequency train (357 Hz) of four suprathreshold magnetic stimuli was delivered transcranially to the region of the rolandic area during brain tumour operations in 12 patients. To induce a focal magnetoelectric field, the flat figure of eight coil (outer diameter of each loop 7 cm) was used.

A case of gliosarcoma appearing as ischaemic stroke.

Objectives: Ischaemic stroke attributable to malignant brain tumour is a rarely reported phenomenon and even various imaging techniques including angiography do not necessarily lead to an accurate diagnosis.

Case Description: A 46-year-old, previously healthy man developed apoplectic symptoms with slight right sided hemiparesis and global aphasia. The computed tomography (CT) scan showed lesions of the left temporal lobe and the paraventricular white matter suggestive of left middle cerebral artery (MCA) infarction.

Second harmonic imaging: a new ultrasound technique to assess human brain tumour perfusion.

Background: Second harmonic imaging is a new ultrasound technique that allows evaluation of brain tissue perfusion after application of an ultrasound contrast agent.

Objective: To evaluate the potential of this technique for the assessment of abnormal echo contrast characteristics of different brain tumours.

Methods: 27 patients with brain tumours were studied.

Preoperative assessment of motor cortex and pyramidal tracts in central cavernoma employing functional and diffusion-weighted magnetic resonance imaging.

Background: Functional MRI (fMRI) combines anatomic with functional information and has therefore been widely used for preoperative planning of patients with mass lesions affecting functionally important brain regions. However, the courses of functionally important fiber tracts are not visualized. We therefore propose to combine fMRI with diffusion-weighted MRI (DWI) that allows visualization of large fiber tracts and to implement this data in a neuronavigation system.

Postshunt insertion CSF leaks in infants treated by an adjustable valve opening pressure reduction.

Objects: Cerebrospinal fluid (CSF) leakages through the operation wound following shunt placement are commonly treated by head elevation when the shunt is patent and signs of infection are absent.

Methods And Results: In two cases in which the standard therapy of head elevation failed, the leakage was successfully managed by temporary lowering of the opening pressure of the implanted programmable valve. Case 1 was that of a preterm baby with repaired meningomyelocele and shunted hydrocephalus.

Influence of intraventricular hemorrhage on outcome after rupture of intracranial aneurysm.

This study was performed to analyze the effect of intraventricular hemorrhage (IVH) on 14-day mortality, outcome at 6 months, and the occurrence of chronic hydrocephalus in patients with aneurysmal subarachnoid hemorrhage. Clinical grade of subarachnoid hemorrhage and the distribution of extravasated blood were evaluated in 219 patients with ruptured aneurysms. Computed tomographic scans performed within 72 h of hemorrhage were analyzed to determine the severity of intraventricular and subarachnoid hemorrhage and the volume of intracerebral hematomas.

Bleeding from a cavernous angioma mimicking rupture of a middle cerebral artery aneurysm.

Cavernous angiomas and aneurysms may both present with acute cerebral haemorrhage. We present a case in which the coexistence of an unruptured aneurysm obscured the diagnosis of cerebral haemorrhage from a cavernous angioma. Although this association was presumably coincidental, this case demonstrates that obvious pathology (an angiographically proven aneurysm at the site of haemorrhage) may reduce awareness of other, possibly more common, causes of cerebral haemorrhage.

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.

Morphological changes following experimental intraventricular haemorrhage and intraventricular fibrinolytic treatment with recombinant tissue plasminogen activator.

Intraventricular haemorrhage (IVH) occurs in up to 50% of patients with primary intracerebral haemorrhage and aneurysmal subarachnoid haemorrhage. It is a significant and independent contributor to mortality and morbidity in these intracranial haemorrhages. Using a model of isolated IVH, we assessed the morphological changes induced by intraventricular bleeding and investigated the effects of intraventricular fibrinolytic treatment following IVH.

Subdural-atrial and subdural-peritoneal shunting in infants with chronic subdural fluid collections.

Background: In symptomatic infants with chronic subdural fluid collections a variety of treatment strategies, such as observation, repeated subdural tapping, external or internal subdural drainage, and craniotomy have been advocated. Until now, the ideal management for this etiologically heterogenous group of children seems controversial.

Methods: The authors present their treatment with subdural-peritoneal and subdural-atrial shunts and the follow-up in 8 infants (mean age, 7 months) with bifrontal subdural hygromas and hematomas caused by different etiologic conditions.

Frameless stereotactically guided catheter placement and fibrinolytic therapy for spontaneous intracerebral hematomas: technical aspects and initial clinical results.

Objective: Frame-based stereotactic puncture and catheter placement followed by fibrinolytic therapy and drainage is one treatment option in the management of spontaneous intracerebral hemorrhage (sICH). This minimally invasive procedure could even be simplified by frameless stereotaxy. The authors present their experiences with frameless stereotactic image-guided catheter placement for lysis and drainage of sICH, with emphasis on technical aspects.

Primary intradural pontocerebellar chordoma metastasizing in the subarachnoid spinal canal.

Chordomas that are entirely extraosseous and intradural are rare. Additionally subarachnoid spinal implantation from such a cranial, intradural chordoma has never been reported before. The authors present a case of a widespread primary intradural chordoma in the basal cisterns of a 48-year-old woman which shows seeding of neoplastic cells to the spinal leptomeninges.

Fibrinolytic treatment of intraventricular haemorrhage preceding surgical repair of ruptured aneurysms and arteriovenous malformations.

Previous studies have indicated that intraventricular administration of tissue-type plasminogen activator (TPA) might improve the prognosis of patients with intraventricular haemorrhage (IVH). In aneurysmal IVH, fibrinolytic treatment was always preceded by surgical repair of the aneurysm, since the risk of recurrent haemorrhage from a non-occluded aneurysm was estimated to be high. We reviewed a series of patients with IVH secondary to ruptured aneurysms (n = 4) or arteriovenous malformation (AVM; n = 1) who underwent emergency intraventricular administration of TPA before repair of the bleeding source.

Functional outcome after aneurysmal subarachnoid hemorrhage.

The introduction of the operating microscope, the principle of early surgery, specialized intensive care units, the calcium antagonist nimodipine, the sophisticated pre- and postoperative management and an aggressive antiischemic pharmacological management have substantially reduced morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH). In spite of this progress, many patients after rupture and surgical repair of an intracranial aneurysm exhibit substantial cognitive deficits and emotional problems although their neurological outcome was rated as good according to the Glasgow Outcome Scale (GOS = I). Therefore, a comprehensive neuropsychological examination is called for in order to evaluate the factual functional outcome after SAH.

Four-year experience with the routine use of the programmable Hakim valve in the management of children with hydrocephalus.

Objective: Cerebrospinal fluid (CSF) over- and underdrainage symptoms are frequent sequelae of shunt placement in patients with hydrocephalus, sometimes requiring repeated operations. To achieve more adequate CSF drainage, the non-invasively programmable Hakim valve has been developed. Because the clinical experiences with this valve so far are confined to adults, we describe our experiences with the routine use of the programmable Hakim valve in childhood hydrocephalus.

Surgically treated traumatic synchondrotic disruption of the odontoid process in a 15-month-old girl.

A case of traumatic synchondrotic disruption in a 15-month-old girl is reported; she was treated with interlaminar wiring of C1-C2 without grafting. Reduction of the dislocation and angulation and stability were achieved without evidence of growth disturbance. However, the child's initial poor neurological status with tetraplegia below the level of C7 remained unchanged.