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.

Lipofundin-induced intracranial pressure rise after severe traumatic brain injury--a case report.

Early nutrition is a recognized component of neurosurgical intensive care treatment. The authors present the case of a patient suffering from severe traumatic brain injury who responded with reproducible intracranial pressure (ICP) crisis to infusion of Lipofundin, a fatty soybean oil-based emulsion for parenteral nutrition. During the described ICP rise, the patient remained hemodynamically stable, therefore an anaphylactic reaction seems to be unlikely. An increase of brain tissue oxygenation parallel to the ICP rise in this case is suggestive for increased cerebral blood flow as a cause of ICP elevation after application of Lipofundin. Without multimodal monitoring and data storage, the described side effect of Lipofundin in our patient would have been difficult to identify.

Surgery and outcome for aneurysmal subarachnoid hemorrhage in elderly patients.

OBJECTIVE: The goal was to report treatment results of elderly patients (over 70 years) who underwent clipping of aneurysms after subarachnoid hemorrhage (SAH). MATERIAL AND METHODS: From 1994 to 2000 41/284 (14%) patients older than 70 years were operated on aneurysmal SAH in our department. Localization of ruptured aneurysm was anterior communicating artery (n = 14), middle cerebral artery (n = 14), internal carotid artery (n = 6), anterior cerebral artery (n = 2), pericallosal artery (n = 1) and multiple in 4 patients. We used the Hunt and Hess classification for initial grading and the Glasgow Outcome Score at day 30 after surgery. RESULTS: Patients with HH 1-3 had a low mortality (1/18, 6%), whereas 9 of 23 patients (39%) with HH 4-5 decreased within 30 days after surgery. Overall mortality was 24.5% (10/41) at 30 days after surgery. Most patients (n = 32) underwent early surgery (within 72 hours). Shunt dependent hydrocephalus developed in 15 patients (37%). The outcome was better in patients graded HH 1-3, in those without serious atherosclerotic changes in angiography, and in AcoA and ICA localization compared to MCA. CONCLUSION: Advanced age does not preclude successful surgery for ruptured aneurysm. Most important factor for outcome was a good initial clinical status, though the majority of our patients presented with poor grades. Early surgical clipping and postoperative intensive care can attain a favorable outcome in a significant percentage of elderly patients.

The safety of the open lung approach in neurosurgical patients.

A recent randomized controlled trial in patients with ARDS showed the beneficial effect of mechanical ventilation according to the so called Open Lung Approach, consisting of low tidal volumes and elevated PEEP settings after performing recruiting maneuvers. However, neurosurgical patients were excluded from this and other ARDS trials due to concerns of intracranial deterioration. In this report, we present the clinical data of eleven patients with known intracranial pathology and concomitant ARDS which was treated according to the Open Lung concept. The mean oxygenation index (paO2/FiO2) increased from 132 +/- 88 to 325 +/- 64 measured 24 hours after initiation of Open Lung ventilation (p < 0.001). Mean PEEP level after the first recruiting maneuver was 14.9 +/- 3.2 mmHg. Comparison of mean and peak ICP values over 24 hours of time before and after the first recruitment maneuver revealed a non-significant decline in ICP despite a moderate increase in mean paCO2. Although two patients needed additional ICP treatment, no patient had to be withdrawn from Open Lung ventilation. In our series, Open Lung ventilation in neurosurgical patients with ARDS was a safe method to improve oxygenation. Careful ICP monitoring provided, there is no reason to withhold this modern ARDS treatment in the neurosurgical intensive care unit.

Lhermitte-Duclos disease (dysplastic cerebellar gangliocytoma): a malformation, hamartoma or neoplasm?

OBJECTIVES: Dysplastic gangliocytoma (Lhermitte-Duclos disease) is a rare disorder, characterized by a slowly progressive unilateral tumour mass of the cerebellar cortex. The fundamental nature of this apparently benign entity and in particular its pathogenesis remain unknown. The debate, whether it represents a neoplastic, malformative or hamartomatous lesion, is still in progress. Lhermitte-Duclos disease was recently encountered to be part of a multiple hamartoma-neoplasia complex (Cowden's syndrome). METHODS: The present account gives a review of the pertinent literature with emphasize on clinical presentation, radiological findings, surgical procedures, histopathological features and pathogenetic considerations of dysplastic cerebellar gangliocytoma. RESULTS: Dysplastic cerebellar gangliocytoma clusters within the third to fourth decades of life. Cranial nerve palsies, unsteadiness of gait, ataxia and sudden neurological deterioration as a result of occlusive hydrocephalus are frequent signs and symptoms. Associations with other congenital malformations, such as megalencephaly, polydactylia, multiple haemangioma and skull abnormalities are common. Magnetic resonance imaging (MRI) is the diagnostic modality of choice and reveals characteristic non-enhancing gyriform patterns with enlargement of cerebellar folia. Surgery is the therapeutic procedure generally performed and complete resection was attempted in the majority of cases. The histopathological findings of Lhermitte-Duclos disease include widening of the molecular layer, which is occupied by abnormal ganglion cells, absence of the Purkinje cell layer and hypertrophy of the granule cell layer. CONCLUSIONS: Dysplastic gangliocytoma of the cerebellum is of benign behaviour and its incidence is extremely rare. The disease should be considered when confronted with a young adult presenting with clinical signs of progressive mass effect in the posterior fossa. The lesion is hypointense on T1- and hyperintense on T2-weighted magnetic resonance images. Recognition of the disease is of particular importance, as the frequent but under-reported coexistence with Cowden syndrome, should prompt thorough clinical and apparative investigation to detect or exclude concomitant malignancies.

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.

Neuroendoscopy combined with frameless neuronavigation.

Minimal invasive neurosurgery is becoming more and more standard in neurosurgical procedures. Several types of lesions are now approached endoscopically. The surgical planning and intraoperative orientation during endoscopic surgical procedures are sometimes difficult. To solve this problem, a combination of the endoscopic procedure with a frameless, armless neuronavigation system is used in our service. The combination of the endoscope and the frameless navigation system was used in tumour surgery, ventriculostomies and arachnoid cyst operations. All procedures were performed successfully. The combination of both systems has proved to be advantageous because of safe surgical planning using the frameless stereotactic technique and the possibility of real time orientation of the endoscope. This technique is very useful in removing intraventricular and large brain mass lesions.

Hollow-spheres: a new model for analyses of differentiation of pancreatic duct epithelial cells.

We discovered a unique feature of a subclone of the pancreatic carcinoma cell line A818. A818-1-derived hollow-spheres developed under three-dimensional growth conditions. Hollow-spheres consist of a single layer of 50-200 epithelial cells surrounding an inner lumen. In contrast to A818-1, the subclone A818-4 and all other pancreatic tumor cell lines tested (n = 5), formed spheroids as the only three-dimensional phenotype. A dramatically reduced proliferation rate compared to the corresponding monolayer was observed in hollow-spheres when bromodeoxyuridine (BrdU) incorporation was measured. This finding was confirmed by immunostaining using the MIB-1 antibody. Mechanically disrupted hollow-spheres not only attached but also grew as monolayer with the same doubling time as the founder cells. Hollow-spheres developed in fetal calf serum (FCS) containing RPMI 1640 medium without additionally added cytokines. A818-1 hollow-sphere formation and integrity was influenced by interferon-gamma. Tumor necrosis factor-alpha (TNF-alpha) led to cell death. Exogenously added hepatocyte growth factor (HGF) showed no effect neither on hollow-sphere formation nor on the integrity of completely developed hollow-spheres. Moreover, no changes were observed when cells were treated with a neutralizing antibody for HGF. Interestingly, hollow-spheres showed intensive immunoreactivity for the HGF-receptor (c-met) and its ligand (HGF). Immunostaining for the biliary glycoprotein (BGP), the non-specific cross-reacting antigen 95 (NCA95) and beta-catenin revealed a polar organization of hollow-spheres. Immunhistochemically, hollow-spheres were negative for the carcinoembryonic antigen (CEA). When hollow-spheres were embedded into matrigel, duct-like tubes grew out. Taken together, A818-1 hollow-spheres resemble normally differentiated duct-like structures and will serve as an excellent model to study differentiation of human pancreatic epithelial cells.

Dual-switch valve: clinical performance of a new hydrocephalus valve.

The Dual-Switch valve (DSV) is the first construction on the market which changes between two different valve-chambers in parallel depending on the posture of the patient. In the lying position the valve acts like a conventional differential pressure valve, in the vertical position the high-pressure chamber only opens, when the pressure exceeds the hydrostatic pressure difference between the formanen of Monro and the peritoneal cavity. The new device has been implanted in 32 adult patients with hydrocephalus of different etiology. The clinical results are excellent to good accompanied by a remarkable slight reduction of the ventricular size. Apart from one case with a nonsymptomatic transient hygroma, we saw no valve related complications like overdrainage, underdrainage or dysfunction. Contrary to conventional differential-pressure valves, adjustable devices and other hydrostatic constructions like the Anti-Siphon-device (ASD) or Deltavalve, the DSV reliably controls the IVP independently of the posture of the patient, the CSF viscosity or the subcutaneous pressure. In contrast to the Orbis-Sigma-valve (OSV) or the Diamond-valve, the DSV does not control the flow but the physiological IVP avoiding the increased risk of mechanical failure. The results of this study give strong evidence that the shunt-therapy of adult hydrocephalic patients can be significantly improved by the DSV.

Percutaneous dilatational tracheostomy--early results and long-term outcome of 326 critically ill patients.

OBJECTIVE: To analyze perioperative and postoperative complications and long-term sequelae following percutaneous dilatational tracheostomy (PDT). DESIGN: A prospective clinical study of patients undergoing PDT. SETTING: Seven intensive care units at a University hospital PATIENTS: 326 intensive care patients (202 male, 124 female; age: 11-95 years) with indications for tracheostomy. INTERVENTIONS: Using tracheoscopic guidance, 337 PDTs were performed according to Ciaglias' method. In 106 decannulated patients, tracheal narrowing was assessed by plain tracheal radiography. RESULTS: Two procedure-related deaths were seen (0.6%). Perioperative and postoperative complications occurred with 9.5% of the PDTs. One of 106 patients, who were followed-up for at least 6 months, showed a clinically relevant tracheal stenosis. Subclinical tracheal stenosis of at least 10% of the cross-sectioned area was recognized in 46 of 106 patients (43.4%). In the univariate analysis, the degree of stenosis was influenced by the age of the patient (p = 0.044), the duration of intubation prior to PDT (p = 0.042) and by the duration of cannulation (p = 0.006). These parameters had no statistical significance in a multiple regression model. CONCLUSION: When performed by experienced physicians, percutaneous dilatational tracheostomy under fiberoptic guidance is a safe method. The risks of early complications and of clinically relevant tracheal stenoses are low. Subclinical tracheal stenoses are found in about 40% of patients following PDT.

The dual-switch valve. A new hydrostatic valve for the treatment of hydrocephalus.

The currently available hydrocephalus valves are still far from perfect. Whereas the design principles of differential pressure valves and adjustable devices involve the danger of overdrainage, hydrostatic valves have a tendency to clog. The new dual-switch valve (DSV) avoids overdrainage-related problems such as subdural hygromas/hematomas or slit-like ventricles with the high risk of proximal catheter obstruction by means of two parallel chambers in a titanium casing: one for the the horizontal and the other for the vertical position. The control chamber for the horizontal position is closed by a gravity-activated tantalum ball as soon as the patient moves into an upright position. Now the drainage of CSF is directed into the appropriate controller for the erect position. Thus, the hydrostatic differential pressure between ventricles and peritoneal cavity is counterbalanced and the intraventricular pressure (IVP) remains within physiological values independently of the CSF flow and the position of the patient. To avoid the problem of clogging, the newly designed valve introduces large-area diaphragms to create extensive acting forces. The forces generated in this way are able to overcome sticking forces set up as a result of high protein content or cellular debris. By this mechanism the IVP is maintained in physiological ranges regardless of the CSF composition. The new valve has been investigated with a computer controlled test apparatus especially designed to simulate different positions of the body. The in vitro test results according to ASTM standards document a superior performance in comparison with other valves. When the new device was interposed in external drainage systems precision of its function was confirmed even in the presence of elevated protein content and high CSF flow. Simulation of the upright position of the patient allowed documentation of the valve's reliability in maintaining the IVP within physiological ranges. A clinical trial with implantation of the new dual-switch valve was started at the beginning of 1995; so far follow up has been short. Clinical and computer tomographic monitoring has provided evidence of the valve's capacity to avoid the problems of overdrainage and early clogging.

Ibuprofen and diclofenac sodium in the treatment of osteoarthritis: a comparative trial of two once-daily sustained-release NSAID formulations.

An investigator-blind, parallel-group, multicentre study was undertaken to compare the efficacy and tolerability of once-daily, sustained-release (s-r) ibuprofen and diclofenac sodium in patients (mean age 59.8 years) suffering from painful osteoarthritis affecting chiefly the knee and/or hip. Patients attending eight Swiss centres received either two s-r tablets of ibuprofen (daily dose 1600 mg; n = 30) or a single s-r diclofenac 100 mg tablet (n = 31) each evening for 21 days. Clinical assessments were performed prior to initiating therapy and after 7 and 21 days of treatment. Both treatments were efficacious, but statistically significant differences in favour of s-r ibuprofen were observed for the principal measure of efficacy, the investigator's assessment of the overall change in clinical condition; by Day 21, 37% of ibuprofen-treated patients vs 10% of diclofenac-treated patients were 'much improved' (p = 0.04). Patients' assessments of the efficacy of their treatment also favoured s-r ibuprofen at Day 7 for the relief of night pain (p = 0.048), at Day 21 for alleviation of day pain (p = 0.006) and for the ability to carry out normal activities (p = 0.01), and at both Days 7 and 21 for quality of sleep (p = 0.04 and 0.03, respectively). The patients' overall opinion of treatment was also significantly in favour of s-r ibuprofen, which was rated 'good or excellent' by 80% (24/30), compared with only 38% of patients (11/29) receiving s-r diclofenac sodium (p = 0.002). Two patients (6%) receiving s-r diclofenac sodium ceased treatment owing to dizziness and severe diarrhoea, respectively; there were no withdrawals in the ibuprofen-treated group. Ten (32%) patients in the s-r diclofenac group reported a total of 12 adverse events (mostly gastrointestinal in nature), compared with three (10%) patients in the s-r ibuprofen group who reported only three events (abdominal pain, insomnia and constipation). In conclusion, although both NSAID treatments improved the clinical condition of patients with painful osteoarthritis, statistically significant differences in favour of once-daily s-r ibuprofen (1600 mg) were demonstrated in terms of efficacy, indicating a potential therapeutic advantage for this formulation. Ibuprofen was also better tolerated than diclofenac sodium (100 mg/day), the latter being associated with gastrointestinal side effects in a significant proportion of patients. Sustained-release ibuprofen (Brufen Retard) thus represents an important addition to the available therapeutic armamentarium of once-daily NSAID formulations.

Is there a reasonable differential indication for different hydrocephalus shunt systems?

We tested various shunt systems for pressure/flow characteristics and long-term reliability. In addition, we used a model to simulate activities of daily life postural changes, blood and airway pressure changes and their impact on CSF pressure and flow through various ventriculo-peritoneal shunt systems. In the recumbent position, the changes in flow rate and CSF pressure depended on the valve resistance. Various valves showed deviations from the pressure/flow characteristics claimed for them and proved to be unreliable during long-term perfusion. The flow rate increased in the head-up position. Negative intracranial CSF pressure was due to the continued flow through the shunt system afforded by the siphon effect. The siphon effect was so marked in the upright position that valves of various kinds and with various resistances did not make any significant difference in the resulting intracranial pressure (ICP). The shunt systems, however, differed in the maximum flow rate in the upright position, leading to a different steep fall in ICP following elevation of the body. Ball-and-spring valves had the highest flow rates (> 500 ml/h), leading to negative ICP within seconds. Diaphragm valves, and especially the self-adjusting diaphragm valve, demonstrated a slower drop in ICP, taking several minutes to reach negative ICP. ASD and SCD, however, did prevent any siphoning effects, leading to an ICP within the corresponding valve opening/closing pressure range. Our results demonstrate that in most patients there is no significant difference in various different shunting systems as long as the patient is mobile.(ABSTRACT TRUNCATED AT 250 WORDS)

"Ultrahigh" dexamethasone in acute brain injury. Results from a prospective randomized double-blind multicenter trial (GUDHIS). German Ultrahigh Dexamethasone Head Injury Study Group.

In a prospective randomized double-blind multicenter trial, the efficacy and safety of a 51-hour ultra-high intravenous dexamethasone dosing regimen was investigated in patients with moderate and severe head injury. 300 patients between 15 and 55 years of age were randomized to receive either placebo or dexamethasone: 500 mg intravenous infusion within 3 h after trauma initially, followed by 200 mg after 3 h, thereafter 8 times 200 mg at 6 hourly intervals, resulting in a total administered dose of 2,3 g in 51 hours. Primary end points for assessment of efficacy were: Modified Glasgow Coma Scale (grading 3-16) on Day 5, modified Glasgow Outcome Scale (grading 1-6) 10-14 months after injury, and the time interval until consciousness improved above a level of modified GCS > or = 8. Secondary endpoints were CT results and neurological and laboratory data. The two groups were well matched with respect to important prognostic variables, such as age, severity of trauma, and interval between trauma and application of the drug. 269 patients (89.7%) were available for final examination after 10-14 months. Results were surprisingly favourable in both groups: Lethality in the dexamethasone and placebo group was 14.3 and 15.4%, respectively, and 61.7 and 57.4%, respectively, achieved social and professional rehabilitation after 10-14 months (outcome scale 6). No statistical difference was seen between the dexamethasone and the placebo group in any of the primary end points of efficacy and safety (incidence of upper gastrointestinal bleeding, infection, and thrombosis).(ABSTRACT TRUNCATED AT 250 WORDS)

Advances in diagnosis and treatment of spinal hemangioblastomas.

Spinal hemangioblastoma usually leads to large intramedullary cysts. Until recently clinical and conventional radiological examination was often not able to detect single or multiple tumor niduses at the wall of a secondary syringomyelia cyst. Thus during surgical exploration the tumor not infrequently was missed, leading to misinterpretation of the pathological entity as syringomyelia, spinal gliosis or low grade spinal astrocytoma. This often resulted in explorative biopsy or decompressive laminectomy. Clinical deterioration postoperatively was not uncommon due to the remaining tumor and increasing spinal cord enlargement. Now magnetic resonance imaging allows the exact preoperative localization of the medullary lesion apart from the accompanying cysts and facilitates differential diagnosis of primary syringomyelia or other spinal cord neoplasms. Microsurgical techniques and laser-assisted resection have improved the outcome. We report on eight patients with spinal hemangioblastoma treated in our clinic since the installation of magnetic resonance imaging and laser-assisted microneurosurgery.

Plasma osmolality, osmoregulation and prognosis after head injury.

108 Patients with severe brain damage were examined for the course of plasma osmolality. In addition plasma values of Na+, K+, glucose and blood urea nitrogen (BUN) were measured simultaneously by auto-analyzer. The clinical status was registered daily by using a modified Glasgow coma scale. Outcome of the injured patients was registered by using the Glasgow outcome scale. 60 patients survived, 48 died, 39 of brain damage and 9 of secondary diseases, such as infection or embolism. Sustained severe brain damage is generally followed by disturbances of metabolic regulation. Quite often the osmotic regulation is disturbed. In most cases these disturbances are of hyperosmolar nature, their extent and duration being correlated to the prognosis. Hyposmolar deregulation occurs less frequently, and occasionally lead to peracute brain oedema (e.g. SIADH-syndrome). These dysregulations are interpreted as disturbances of the central function of the diencephalon, in lethal cases even as "hypothalamic death". Blood osmolality measurements should therefore be made early in states of acute cerebral disease to help establish a prognosis, control the treatment of water imbalance and to determine contra-indications to osmotherapy.