Cervical arthroplasty with ROTAIO® cervical disc prosthesis: first clinical and radiographic outcome analysis in a multicenter prospective trial.

BACKGROUND: Cervical Disc Arthroplasty (CDA) seems to be an alternative to Anterior Cervical Decompression and Fusion (ACDF) and was developed to minimize the risk of Adjacent Segment Disease (ASD). The ROTAIO Cervical Disc Prosthesis represents a new unconstrained implant with a variable centre of rotation which should enable physiological facet-guided movement. The aim of this current study was to evaluate the clinical outcomes after arthroplasty using ROTAIO Cervical Disc Prosthesis. METHOD: Twenty-seven female and 18 male patients (n = 45) with a mean age of 43.7 ± 7.8 years were prospectively followed up for a maximum of 24 month. Clinical outcomes were assessed by Neck Disability Index (NDI), visual analogue scale (VAS) scores for neck and arm pain, patients´ overall satisfaction and the usage of analgesics. Additionally, radiographic information including ROM of the functional spinal unit (FSU) and signs of adjacent segment disease were recorded. RESULTS: NDI and VAS scores showed significant improvement 6 months after surgery and at last follow-up (p < 0.001). Concerning overall satisfaction 95.7% of the patients showed good to excellent results at the last visit and a significant reduction of analgesic usage was observed (p < 0.001). Radiographic measurements showed a mean increase of ROM up to 8.40° in the treated FSU at last follow-up (p < 0.001). No signs of anterior migration or dislocation of the prosthesis and no subsidence was recorded radiographically. There were no major complications and a low rate of secondary procedures (2.2%). CONCLUSION: In the 24-months follow-up the ROTAIO Cervical Disc Prosthesis provided excellent clinical and radiographical results and seems to be safe and effective for the treatment of symptomatic single-level degenerative disc disease.

The combination of carmustine wafers and temozolomide for the treatment of malignant gliomas. A comprehensive review of the rationale and clinical experience.

Current treatment strategies in patients with newly-diagnosed glioblastoma include surgical resection with post-operative radiotherapy and concomitant/adjuvant temozolomide (the "Stupp protocol") or resection with implantation of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) wafers in the surgical cavity followed by radiotherapy. In clinical practice, patients with malignant glioma treated with BCNU wafer often also receive adjuvant temozolomide. However, current treatment guidelines are unclear on whether and how these treatment practices can be combined, and no prospective phase 3 study has assessed the safety and efficacy of combining BCNU wafers with temozolomide and radiation in high-grade malignant glioma. The rationale for multimodal therapy comprising surgical resection with adjunct local BCNU wafers followed by radiotherapy and temozolomide is based on complementary and synergistic mechanisms of action between BCNU and temozolomide in preclinical studies; a shared primary resistance pathway, methylguanine-DNA methyltransferase (MGMT); and the opportunity to overcome resistance through MGMT depletion to boost cytotoxic activity. A comprehensive review of the literature identified 19 retrospective and prospective studies investigating the use of this multimodal strategy. Median overall survival in 14 studies of newly-diagnosed patients suggested a modest improvement versus resection followed by Stupp protocol or resection with BCNU wafers, with an acceptable and manageable safety profile.

Continuous selective intraarterial infusion of nimodipine for therapy of refractory cerebral vasospasm.

BACKGROUND: For endovascular treatment of vasospasm after aneurysmal subarachnoid hemorrhage (aSAH), an intraarterial treatment course with the calcium channel antagonist nimodipine infused for 30 min is proposed. As some patients still show ongoing vasospasm thereafter, we report on our experience with an extended time period of selective intraarterial nimodipine administration. METHODS: In nine patients with aSAH and refractory cerebral vasospasm, we left the catheter in place within the internal carotid artery after angiography. On the neurosurgical ICU, a continuous infusion of intraarterial nimodipine was commenced, combined with intraarterial heparin anticoagulation. Therapy was controlled with extended neuromonitoring techniques. RESULTS: Three patients died from refractory vasospasm and a fourth suffered lethal sepsis. Three patients survived in a good clinical condition, two of them without apparent neurologic deficit. The efficacy of intraarterial nimodipine was best verified with regional CBF monitoring. TCD failed to detect vasospasm in two patients and missed improvement in four. Brain tissue oxygenation increased in all patients, but was not indicative of vasospasm in one. CT perfusion reflected the treatment course adequately in the qualitative scans. CONCLUSION: Selective continuous intraarterial nimodipine treatment for refractory cerebral vasospasm after aSAH seems feasible and may add to the endovascular therapeutic options. Appropriate monitoring technology is essential for further investigation of this novel technique.

Qualitative aspects of cranial CT perfusion scanning in a mixed neurosurgical patient collective.

BACKGROUND: In patients with ischemic stroke, computer tomography (CT) perfusion imaging provides rapid information on the penumbra adjacent to the infarct core. For neurosurgical patients with acute brain injury, the value of CT perfusion is undecided up to now. We present our experience in a series of 78 examinations in 35 patients with acute intracranial pathology. METHODS: CT perfusion was performed with a Siemens Emotion Duo CT scanner using a single slice at the level of the upper basal ganglia. Color maps of time to peak (TTP), cerebral blood flow (CBF) and cerebral blood volume (CBV) were analyzed according to qualitative criteria. Quantitative evaluation with self-defined regions of interest was not performed due to repeatability problems and inconsistent data. FINDINGS: TTP showed an interhemispheric difference in 45% and regional prolongation in 16% of the scans. Global TTP was prolonged in 60%, while global CBF was reduced in 43%. Two patients showed hyperemia. A CBF/CBV mismatch, indicating non-infarcted penumbra at risk, was seen in 67%. Six patients with aneurysmal SAH showed reduced CBF, and consecutive angiography confirmed vasospasm in every case. CONCLUSIONS: CT perfusion scanning gives valuable information at a low risk and with negligible additional time after a routine cranial CT. In our opinion, this modality may have considerable impact on the clinical management of severely brain injured patients in future.

Open lung ventilation in neurosurgery: an update on brain tissue oxygenation.

Recently, we showed the feasibility of ventilating neurosurgical patients with acute intracranial pathology and concomitant acute respiratory distress syndrome (ARDS) according the so-called Open Lung approach. This technique consists of low tidal volume, elevated positive expiratory pressure (PEEP) level and initial recruitment maneuvers to open up collapsed alveoli. In this report, we focus on our experience to guide recruitment with brain tissue oxygenation (pbrO2) probes. We studied recruitment maneuvers in thirteen patients with ARDS and acute brain injury such as subarachnoid hemorrhage and traumatic brain injury. A pbrO2 probe was implanted in brain tissue at risk for hypoxia. Recruitment maneuvers were performed at an inspired oxygen frcation (FiO2) of 1.0 and a PEEP level of 30 40 cmH2O for 40 seconds. The mean FiO2 necessary for normoxemia could be decreased from 0.85 +/- 0.17 before recruitment to 0.55 +/- 0.12 after 24 hours, while mean PbrO2 (24.6 mmHg before recruitment) did not change. At a mean of 17 minutes after the first recruitment maneuver, PbrO2 showed peak a value of 35.6 +/- 16.6 mmHg, reflecting improvement in arterial oxygenation at an FiO2 of 1.0. Brain tissue oxygenation monitoring provides a useful adjunct to estimate the effects of recruitment maneuvers and ventilator settings in neurosurgical patients with acute lung injury.

Cerebral vasodilatation causing acute intracranial hypertension: a method for noninvasive assessment.

Deep spontaneous vasodilatatory events are frequently recorded in various cerebral diseases, causing dramatic increases (A-waves) in intracranial pressure (ICP) and subsequently provoking ischemic brain insults. The relationship between fluctuations in CBF, ICP, and arterial blood pressure (ABP) is influenced by properties of cerebrovascular control mechanisms and the cerebrospinal pressure-volume compensation. The goal of this study was to construct a mathematical model of this relationship and to assess its ability to predict the occurrence and time course of A-waves. A group of 17 severely head-injured patients were included in the study. In our model ICP was derived from the ABP waveform using a linear signal transformation. The transformation was modified during the simulation by a relationship between ABP and flow velocity, i.e., by the characterization of the cerebrovascular bed. In this way the ICP could be calculated from the ABP waveform. This model was verified by comparison of simulated and directly measured ICP during A-waves recorded in seven of the patients. In all simulations, plateau elevations of ICP were well replicated. The mean absolute error between real and simulated ICP was 8.3 +/- 5.4 mm Hg at the baseline and 7.9 +/- 4.3 mm Hg at the top of plateau waves. The correlation coefficient between real and simulated increase in ICP was R = 0.98; P < .001. Similarly, correlation between real and simulated increase in pulse amplitude of ICP was highly significant (R = 0.94; P < .001). The mathematical model of the relationship between ABP, flow velocity, and ICP is of potential clinical use for the noninvasive detection of A-waves in patients in whom invasive ICP assessment is not conducted.

First experience with I-123-alpha-methyl-tyrosine spect in the 3-D radiation treatment planning of brain gliomas.

PURPOSE: This study compares the results of iodine-123-alpha-methyl-tyrosine single photon computed emission tomography (IMT-SPECT) with magnetic resonance imaging (MRI) in tumor volume definition of brain gliomas. Furthermore, it evaluates the influences of the information provided from IMT-SPECT for three-dimensional (3D) conformal treatment planning. METHODS AND MATERIALS: In 30 patients with nonresected, histologically proven brain gliomas (glioblastoma-13 patients, astrocytoma Grade III-12 patients, astrocytoma Grade II-3 patients, oligodendroglioma Grade III-1 patient, oligodendroglioma Grade II-1 patient), IMT-SPECT and MRI were performed pretherapeutically in the same week. A special software system allowed the coregistration of the IMT-SPECT and MRI data. The gross tumor volume (GTV) defined on the IMT-SPECT/T2-MRI fusion images (GTV-IMT/T2) was compared with the GTV-T2, defined on the T2-MRI alone. On the IMT-SPECT/T1Gd-MRI overlays, the volume of the IMT tumor uptake (GTV-IMT) was compared with the volume of the gadolinium (Gd) enhancement (GTV-T1Gd). The initial planning target volume (PTV) and the boost volume (BV) outlined on the IMT-SPECT/T2-MRI co-images were analyzed comparatively to the PTV and BV delineated using the T2-MRI alone. RESULTS: In all 30 patients a higher IMT uptake of tumor areas, compared to the normal brain tissue was observed. Mean GTV-IMT, mean GTV-T2, and mean GTV-T1Gd were 43, 82, and 16 cm(3), respectively. IMT tumor uptake outside the contrast enhancement regions was observed in all patients. Mean relative increase of tumor volume defined on the fusion images, GTV-IMT/T1Gd versus GTV-T1Gd alone was 78%. IMT tumor uptake areas outside the GTV-T2 were registered in 7 patients (23%). In these patients, the mean increase GTV-IMT/T2 was 33% higher than GTV-T2, defined according to the T2-MRI data alone. The additional information provided by IMT-SPECT modified minimally the initial PTV (mean relative increase PTV-IMT/T2 versus PTV-T2, 5%) but significantly the BV (mean relative increase BV-IMT/T2 versus BV-T2, 37%). CONCLUSION: In a significant number of patients, the IMT-SPECT investigation improves tumor detection and delineation in the planning process. This has important consequences in the 3D conformal treatment planning, especially in the delineation of BV and in dose escalation studies.

Fluorine-18-FDG PET and iodine-123-IMT SPECT in the evaluation of brain tumors.

UNLABELLED: The high glucose utilization of normal gray matter limits the detection of brain tumor tissue by PET using 18F-fluorodeoxyglucose (FDG). The aim of this study was to evaluate whether the examination of amino acid transport with the SPECT tracer 123l-alpha-methyl-L-tyrosine (IMT) allows better identification of tumor tissue than FDG-PET. METHODS: Nineteen patients (16 with gliomas, 3 with nontumorous lesions) were included in the study. Two independent observers classified PET and SPECT images as positive or negative for tumor tissue and defined the extent of tumor with regions of interest. Tracer uptake of FDG and IMT was quantified by calculating the tumor uptake relative to contralateral gray and white matter. RESULTS: SPECT studies were interpreted concordantly in 18 patients (kappa = 0.77) and all tumors were identified by both observers. PET studies were interpreted discordantly in 4 patients (kappa = 0.52) and only 10 tumors were identified by both observers, interobserver variability in definition of tumor extent was significantly lower in the IMT-SPECT than in the FDG-PET studies (p = 0.03). Mean tumor uptake relative to gray and white matter was 1.93 +/- 0.42 and 2.25 +/- 0.46 for IMT and 0.93 +/- 0.32 and 1.61 +/- 0.52 for FDG. All tumor uptake ratios were significantly (p < 0.01) higher for IMT than FDG, even when only glioblastomas were analyzed. No significant correlation was observed between the various uptake ratios of FDG and IMT. CONCLUSION: Despite the lower resolution and lower sensitivity of SPECT compared with PET, IMT-SPECT was clearly superior to FDG-PET in the detection and delineation of tumor tissue.

Correlation between postoperative 3-[(123)I]iodo-L-alpha-methyltyrosine uptake and survival in patients with gliomas.

UNLABELLED: The aim of this study was to evaluate the prognostic value of SPECT imaging using the amino acid analog 3-[(123)I]iodo-L-alpha-methyltyrosine (IMT) in patients with gliomas. METHODS: One hundred fourteen consecutive patients with newly diagnosed gliomas were examined by IMT SPECT (low-grade glioma, n = 12; anaplastic astrocytoma or oligodendroglioma, n = 46; glioblastoma, n = 56). Seventy-one of these patients had undergone tumor resection 4-6 wk before SPECT imaging (group A). Forty-three patients with unresectable tumors were examined after stereotactic biopsy (group B). IMT uptake at the site of the tumor was assessed visually and quantified relative to a contralateral reference region (IMT uptake ratio). After IMT SPECT, all patients were treated with conformal radiotherapy. The median follow-up time was 27 mo. RESULTS: In group A, focal IMT uptake at the resection site was visible in 52 of 71 patients (73%). Median survival was only 13 mo in these patients, whereas median survival was reached in patients without focal IMT uptake (P = 0.02). Furthermore, the intensity of IMT uptake significantly correlated with survival: patients with an IMT uptake ratio > 1.7 were at a 4.6 times higher risk of death than were patients with a lower IMT uptake (P < 0.001). The IMT uptake ratio remained a significant prognostic factor when age and grading were included in a multivariate model. In contrast, IMT uptake did not correlate with survival in group B (P = 0.95). CONCLUSION: In patients with unresectable high-grade gliomas, IMT uptake appears not to correlate with the biologic aggressiveness of tumor cells. Nevertheless, the clear association between focal IMT uptake after tumor resection and poor survival suggests that IMT is a specific marker for residual tumor tissue. Therefore, IMT SPECT is expected to become a valuable tool for the planning and monitoring of local therapeutic modalities.

Protein and amino acid metabolism after severe cerebral trauma.

Fourteen patients (20-48 years) suffering from severe head injury were followed for changes in amino acid and protein metabolism during the first 8 days after trauma. All patients received a standardized intravenous nutrition containing 15.7 g of nitrogen per day and additional carbohydrates. Electrolytes, free water, and blood constituents were given as needed. Additional treatment included surgical decompression of space-occupying hematomas, high dose dexamethasone therapy, and controlled hyperventilation for at least 5 days. Gross changes of protein metabolism were observed particularly on the days 5 and 6. The duration and chronological sequence of these changes are different from those usually found in patients with multiple injuries.

BrainLab VectorVision Neuronavigation System: technology and clinical experiences in 131 cases.

OBJECTIVE: The BrainLab VectorVision neuronavigation system was used in 131 cases of different brain pathological conditions. The neuronavigation system was used without problems in 125 cases. These cases included 114 microsurgical operations, 4 endoscopic procedures, 4 frameless stereotactic biopsies, and 3 catheter placements. METHODS: The BrainLab VectorVision neuronavigation system is an intraoperative, image-guided, frameless, localization system. The system consists of a computer workstation for registration of images and physical spaces, an intraoperative localization device, and a computer image display. The system provides real-time responses regarding the locations of surgical instruments. VectorVision is based on passive reflections of infrared flashes. Universal adapters with reflective markers for surgical instruments, endoscopes, and the operating microscope are used. RESULTS: In six cases, the system could not be used because of system failure or mishandling. In 125 neurosurgical cases, the neuronavigation system was useful, with a target-localizing accuracy of 4+/-1.4 mm (mean+/-standard deviation). For small cerebral lesions, we never performed an exploration with negative results. CONCLUSION: The BrainLab neuronavigation system has been shown to be very helpful and user-friendly for routine neurosurgical interventions. Its advantage lies in its mobility, based on wireless reflective adapters for surgical instruments, endoscopes, and the operating microscope.

Measurements of brain-stem auditory evoked potentials in patients with spontaneous intracerebral hemorrhage.

Brain-stem auditory evoked potentials (BAEP's) were recorded in 19 patients with spontaneous intracerebral hemorrhage. More than half of the patients were deeply comatose. There was no correlation between BAEP changes and different types of spontaneous intracerebral hemorrhage or between BAEP's and coma grading by the Glasgow Coma Scale. However, BAEP's were a significant prognostic aid in these cases and useful in indicating the level of the brain-stem lesion.

Stabilizing effect of posterior lumbar interbody fusion cages before and after cyclic loading.

OBJECT: The function of interbody fusion cages is to stabilize spinal segments primarily by distracting them as well as by allowing bone ingrowth and fusion. An important condition for efficient formation of bone tissue is achieving adequate spinal stability. However, the initial stability may be reduced due to repeated movements of the spine during everyday activity. Therefore, in addition to immediate stability, stability after cyclic loading is of remarkable relevance; however, this has not yet been investigated. The object of this study was to investigate the immediate stabilizing effect of three different posterior lumbar interbody fusion cages and to clarify the effect of cyclic loading on the stabilization. METHODS: Before and directly after implantation of a Zientek, Stryker, or Ray posterior lumbar interbody fusion cage, 24 lumbar spine segment specimens were each evaluated in a spine tester. Pure lateral bending, flexion-extension, and axial rotation moments (+/- 7.5 Nm) were applied continuously. The motion in each specimen was measured simultaneously. The specimens were then loaded cyclically (40,000 cycles, 5 Hz) with an axial compression force ranging from 200 to 1000 N. Finally, they were tested once again in the spine tester. CONCLUSIONS: In general, a decrease of movement in all loading directions was noted after insertion of the Zientek and Ray cages and an increase of movement after implantation of a Stryker cage. In all three cage groups greater stability was demonstrated in lateral bending and flexion than in extension and axial rotation. Reduced stability during cyclic loading was observed in all three cage groups; however, loss of stability was most pronounced when the Ray cage was used.

Evaluation of a method for noninvasive intracranial pressure assessment during infusion studies in patients with hydrocephalus.

OBJECT: A mathematical model previously introduced by the authors allowed noninvasive intracranial pressure (nICP) assessment. In the present study the authors investigated this model as an aid in predicting the time course of raised ICP during infusion tests in patients with hydrocephalus and its suitability for estimating the resistance to outflow of cerebrospinal fluid (Rcsf). METHODS: Twenty-one patients with hydrocephalus were studied. The nICP was calculated from the arterial blood pressure (ABP) waveform by using a linear signal transformation, which was dynamically modified by the relationship between ABP and cerebral blood flow velocity. This model was verified by comparison of nICP with "real" ICP measured during lumbar infusion tests. In all simulations, parallel increases in real ICP and nICP were evident. The simulated Rcsf was computed using nICP and then compared with Rcsf computed from real ICP. The mean absolute error between real and simulated Rcsf was 4.1 +/- 2.2 mm Hg minute/ml. By the construction of simulations specific to different subtypes of hydrocephalus arising from various causes, the mean error decreased to 2.7 +/- 1.7 mm Hg minute/ml, whereas the correlation between real and simulated Rcsf increased from R = 0.73 to R = 0.89 (p < 0.001). CONCLUSIONS: The validity of the mathematical model was confirmed in this study. The creation of type-specific simulations resulted in substantial improvements in the accuracy of ICP assessment. Improvement strategies could be important because of a potential clinical benefit from this method.

Findings confirming brainstem generators of auditory evoked potentials by stereotactic lesions in the rabbit.

The origin of brainstem auditory evoked potentials (BAEP) was investigated experimentally with morphologically verified stereotactic lesions in eleven rabbits. Waves were recorded before and after thermocoagulation. The loss of waves III and V following coagulation in the inferior colliculus and the upper pons respectively, supports Jewett's hypothesis.

Magnetic stimulation for monitoring of motor pathways in spinal procedures.

Transcranial magnetic stimulation was used for intraoperative motor evoked potential monitoring during surgery of intramedullar, extramedullar, and extradural spinal tumors in 13 patients. Anesthesia was based on etomidate. Magnetic stimulation for motor evoked potential monitoring was successful in 10 of 13 patients, 12 of whom were neurologically impaired. Motor evoked potentials were recorded from limb muscles or from the fibers of the cauda equina. Amplitudes of baseline recordings (the initial recording obtained after induction of anesthesia) were decreased by 64 +/- 34% (mean +/- SD) and baseline latencies were increased by 7 +/- 8% compared with the preoperative recordings. Subsequent recordings were analyzed for amplitude and latency changes in comparison to baseline. Amplitude changes exceeding 50% and latency changes higher than 3 ms compared with the baseline correctly indicated an impending lesion of motor pathways with increased paresis postoperatively. In cases where motor evoked potential monitoring was successful prediction of short-term postoperative motor outcome was always correct. There were no "false-negatives" or "false-positives."

Xanthogranuloma of the Erdheim-Chester type within the sellar region: case report.

Manifestations of Erdheim-Chester disease in the central nervous system are very rare. Cases with localization in the retroorbital space, hypothalamic area and posterior pituitary as well as intracerebral lesions are known. In our neurosurgical unit, a 51-year-old male patient with a history of hypophyseal insufficiency and visual deficits underwent surgery for a pituitary lesion. Histological and immunohistochemical examination revealed a xanthogranulomatous lesion composed of very large CD68-positive foam cells with small nuclei and some Touton-like giant cells, histiocytes, as well as loci with small lymphocytes and isolated eosinophilic granuolcytes, embedded in fibrotic tissue. Based on these findings, the histological diagnosis was a xanthogranuloma of the Erdheim-Chester type.

Lhermitte-Duclos disease (Dysplastic gangliocytoma of the cerebellum).

OBJECTIVE: Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) is a rare hamartomatous lesion of the cerebellar cortex. The pathogenesis of the disease is still poorly understood. Lhermitte-Duclos disease was recently considered to be part of a multiple hamartoma-neoplasia syndrome (Cowden disease). We add two further cases to this rare entity. PATIENTS: A 24-year old woman presented with occipital headaches, blurred vision, diplopia and ataxia of gait. Physical examination revealed turricephaly. The second patient was a 37-year old woman, who presented with progressive occipital headache with nausea and vomiting. Physical examination revealed congenital facial asymmetry. Computed tomography and NMR-imaging, respectively demonstrated a space occupying mass of a cerebellar hemisphere in both cases. RESULTS: Suboccipital craniotomy and complete removal of the infratentorial tumour were performed in both patients. Histopathological findings clinched the diagnosis of Lhermitte-Duclos disease. Postoperative course was uneventful in the first and complicated by progressive occlusive hydrocephalus in the second patient, necessitating permanent surgical shunt drainage. Both patients were discharged free of complaints. CONCLUSIONS: Dysplastic cerebellar gangliocytoma is commonly associated with progressive mass effects in the posterior fossa and typically presents with headaches, cerebellar dysfunction, occlusive hydrocephalus and cranial nerve palsies. The disease usually manifests in young adults, but the age at presentation ranges from birth to the sixth decade. There is no sex predilection. NMR-imaging became a useful clue to the diagnosis within the last decade. Therapy consists of decompression of the posterior fossa by total surgical removal of the tumour mass.

Effects of cerebellar retraction on brainstem auditory evoked potentials in an experimental animal model of cerebellopontine angle tumor.

The effects of cerebellar retraction on brainstem auditory evoked potentials (BAEPs) were studied in 15 New Zealand rabbits. In the first series, a Fogarty catheter was placed in the cerebellopontine angle of 5 rabbits. When a balloon volume of 0.2 mL was produced, only the latencies of waves III-V of the ipsilateral side increased. With a volume of 0.4 mL the ipsilateral BAEPs were irreversibly lost and the contralateral one reversibly changed. A volume of 0.6 mL caused loss of the BAEP on both sides and death of the animal. In another series, the cerebellum of 10 rabbits was retracted by a self-retaining retractor laterally to medially, so an approach to the cerebellopontine angle was simulated. With a retraction of up to 36 power units (p) the ipsilateral BAEPs were reversibly changed. A retraction of 54 p caused irreversible loss of wave V on both sides. With 84 p ipsilateral and contralateral waves III-V were immediately lost. The animals died within 7 minutes. Our experimental investigation shows that not only a defined volume in the cerebellopontine angle can cause irreversible impairment of brainstem function, but also uncontrolled retraction of the cerebellum.

Therapeutic management of grade IV aneurysm patients.

BACKGROUND: The timing of surgery in patients suffering from subarachnoid hemorrhage grade IV and V according to Hunt and Hess, is still controversial. Several authors advocate early surgery for patients in poor clinical condition. Improved outcome and decreased mortality rates were reported. Others exclude patients in poor condition from early aneurysm surgery. METHODS: Forty grade IV aneurysm patients were admitted to our department. After ventriculostomy and cerebral angiography, 28 of them were operated on within 72 hours. The postoperative treatment included hypertensive, hypervolemic, hemodilutional therapy (triple-H therapy) and intensive monitoring (intracerebral pressure, blood pressure, hemodynamic parameters). The mean follow-up time was 6 months. RESULTS: Out of the 28 patients who underwent early surgery, 64% were in good health, 11% in poor health, 25% died; there were no survivors in a vegetative state. Twelve patients were treated conservatively; 50% died from infarction and rebleeding, before the operation was performed. Six underwent delayed aneurysm surgery after clinical improvement. In this group, 25% had good clinical outcome. CONCLUSIONS: Our results favor an aggressive treatment of grade IV aneurysm patients by means of ventricular drainage, early surgery and triple-H therapy.