Angiolipoma of the spinal cord. Magnetic resonance imaging and microsurgical management

Radiologic diagnosis of intramedullary lipomas has been unreliable for a long time and many of these tumors have not been recognized. The introduction of computed tomography, and lately of magnetic resonance imaging, has led to great progress in the accurate identification of spinal cord tumors as well as in the recognition of type specificity of these lesions. An evaluation of the diagnostic value of magnetic resonance imaging and microsurgical technique for the optimal therapeutic outcome is discussed.     

12 Years’ Experience with Intraoperative Radiotherapy (IORT) of Malignant Gliomas

Background:  

Even after surgery and radiotherapy, malignant gliomas still have a poor prognosis. The authors report on their experience with IORT in 71 patients.     

Neuroprotection of mild hypothermia: differential effects

To estimate whether mild hypothermia during repetitive hypoxia provides a neuroprotective effect on brain tissue, hippocampal slice preparations were subjected to repetitive hypoxic episodes under different temperature conditions. Slices of guinea pig hippocampus (n=40) were placed at the interface of artificial cerebrospinal fluid (aCSF) and gas (normoxia: 95% O₂, 5% CO₂; hypoxia: 95% N₂, 5% CO₂). Evoked potentials (EP) and direct current (DC) potentials were recorded from hippocampal CA1 region. Slices were subjected to two repetitive hypoxic episodes under the following temperature conditions: (A) 34°C/34°C, (B) 30°C/30°C and (C) 34°C/30°C. Hypoxic phases lasted until an anoxic terminal negativity (ATN) occurred. The recovery after first hypoxia lasted 30 min. Tissue function was assessed regarding the latency of ATN and the recovery of evoked potentials. The ATN latencies with protocol A (n=25) for the first and second hypoxia were 5.9±1.3 min (mean±S.E.M., 1st hypoxia) and 2.4±0.9 min (2nd hypoxia), with protocol B the latencies (n=7) were significantly longer: 25.2±7.1 min and 15.6±7.7 min. With protocol C (n=8), the latencies were 5.6±1.8 and 3.3±0.5 min. No differences were seen in the recovery of the EPs with protocols A–C. Our results suggest that a mild hypothermia is only neuroprotective if applied from an initial hypoxia onwards.     

Step activity monitoring in lumbar stenosis patients undergoing decompressive surgery

Symptomatic degenerative central lumbar spinal stenosis (LSS) is a frequent indication for decompressive spinal surgery, to reduce spinal claudication. No data are as yet available on the effect of surgery on the level of activity measured with objective long-term monitoring. The aim of this prospective, controlled study was to objectively quantify the level of activity in central LSS patients before and after surgery, using a continuous measurement device. The objective data were correlated with subjective clinical results and the radiographic degree of stenosis. Forty-seven patients with central LSS and typical spinal claudication scheduled for surgery were included. The level of activity (number of gait cycles) was quantified for 7 consecutive days using the StepWatch Activity Monitor (SAM). Visual analogue scales (VAS) for back and leg pain, Oswestry disability index and Roland–Morris score were used to assess the patients’ clinical status. The patients were investigated before surgery and 3 and 12 months after surgery. In addition, the radiographic extent of central LSS was measured digitally on preoperative magnetic resonance imaging or computed tomography. The following results were found preoperatively: 3,578 gait cycles/day, VAS for back pain 5.7 and for leg pain 6.5. Three months after surgery, the patients showed improvement: 4,145 gait cycles/day, VAS for back pain 4.0 and for leg pain 3.0. Twelve months after surgery, the improvement continued: 4,335 gait cycles/day, VAS for back pain 4.1 and for leg pain 3.3. The clinical results and SAM results showed significant improvement when preoperative data were compared with data 3 and 12 months after surgery. The results 12 months after surgery did not differ significantly from those 3 months after surgery. The level of activity correlated significantly with the degree of leg pain. The mean cross-sectional area of the spinal canal at the central LSS was 94 mm². The radiographic results did not correlate either with objective SAM results or with clinical outcome parameters. In conclusion, this study is the first to present objective data on continuous activity monitoring/measurements in patients with central LSS. The SAM could be an adequate tool for performing these measurements in spine patients. Except for leg pain, the objective SAM results did not correlate with the clinical results or with the radiographic extent of central LSS.     

EEG analysis for evaluating chronic cerebral ischemia treated by hyperbaric oxygenation and microneurosurgery

Summary Thirty-five chronic stroke patients, who had internal carotid occlusion that resulted in considerable neurological deficit persisting for an average of 10 weeks, were studied. First, hyperbaric oxygen (HO) therapy was administered to each patient. Subsequently an extra-intracranial anastomosis operation was performed on 21 of these patients. Serial neurological examinations and EEG analyses were performed to assess the clinical course of the cerebral lesion. According to the effect of HO treatment and of the subsequent extra-intracranial anastomosis operation these patients were divided into three groups. Group I—15 of the 35 patients—showed a significant improvement of cerebral function and electrical brain activity at the conclusion of HO therapy. Subsequently an extra-intracranial anastomosis operation was performed on each patient of group I. This resulted in further recovery of cerebral function and electrical brain activity. Postoperative angiography revealed patency of the anastomosis in 14 of the group I patients. Group IIa (14 patients) had only little change in the neurological deficit and electrical brain activity at the conclusion of HO therapy as well as at later examinations. Extra-intracranial anastomosis operation was not performed on the six patients in group IIb who also revealed only little change in their condition at the conclusion to HO treatment. Subsequent extra-intracranial anastomosis operation was, however, performed on these six patients. Although postoperative angiography demonstrated a patent anastomosis in each of these six cases only little change in their status was observed subsequently. The 35 patients were clinically very similar and were in a chronic poststroke stage where spontaneous recovery rarely occurs. None of them manifested any clinical evidence of reversibility of the cerebral alteration before beginning HO therapy. These findings indicate that (a) EEG interval-amplitude analysis is of value for an objective assessment of the course of the cerebral lesion, (b) EEG analyses performed during HO treatment can help to differentiate between reversible and irreversible ischemic hypoxic alterations of the brain, (c) unilateral internal carotid occlusion can lead to neurological deficits and, in particular to bilateral EEG alterations with an accentuated reduction of electrical brain activity over the ipsilateral hemisphere, (d) chronic ischemic alterations of the brain can be improved by HO therapy and additional recovery can take place after subsequent extra-intracranial anastomosis, and (e) brain tissue can tolerate chronic ischemia leading to considerable neurological deficit for an average period of 3 months.

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Zusammenfassung Es wurden 35 Patienten im chronisch postapoplektischen Stadium untersucht. Diese zeigten einen Verschluß der A. carotis interna mit erheblichen neurologischen Ausfällen, die über eine durchschnittliche Dauer von 10 Wochen bereits bestanden. Zuerst wurde bei jedem Patienten eine hyperbare Sauerstoffbehandlung durchgeführt. Darauf wurde bei 21 dieser Patienten eine extra-intrakranielle Anastomosenoperation vorgenommen. Um den Verlauf der zerebralen Störungen zu erfassen, wurden neurologische Verlaufsuntersuchungen und EEG-Analysen durchgeführt. Entsprechend dem Effekt der hyperbaren Sauerstoffbehandlung und der nachfolgenden extra-intrakraniellen Anastomosenoperation wurden diese Patienten in 3 Gruppen eingeteilt. Gruppe I — 15 der 35 Patienten — zeigte bei Beendigung der hyperbaren Sauerstoffbehandlung eine deutliche Besserung der zerebralen Störungen und der elektrischen Hirnaktivität. Anschließend wurde bei jedem Patienten der Gruppe I eine extra-intrakranielle Anastomosenoperation durchgeführt. Dies erbrachte eine weitere Besserung der Hirnfunktionen und der elektrischen Hirnaktivität. Die postoperative Angiographie zeigte die Funktionsfähigkeit der Anastomose in 14 Fällen der Gruppe I. Gruppe II a besteht aus 14 Patienten, die am Ende der hyperbaren Sauerstoffbehandlung wie auch bei Langzeituntersuchungen nur geringe Änderungen der neurologischen Ausfälle und der elektrischen Hirnaktivität zeigten. Bei diesen Patienten der Gruppe IIa wurde keine extra-intrakranielle Anastomosenoperation durchgeführt. Gruppe IIb besteht aus 6 Patienten, die ebenso am Ende der hyperbaren Sauerstoffbehandlung nur geringe Befundänderungen zeigten. Jedoch wurde bei diesen 6 Patienten anschließend eine extraintrakranielle Anastomosenoperation vorgenommen. Obwohl die postoperative Angiographie bei jedem dieser 6 Fälle eine Funktionsfähigkeit der Anastomose zeigte, ließ sich bei der Langzeitbeobachtung nur eine geringe Befundänderung feststellen. Alle 35 Patienten boten ein sehr ähnliches klinisches Bild und befanden sich in einem chronischen postapoplektischen Stadium, wo eine spontane Besserung selten beobachtet wird. Keiner der Patienten bot vor Beginn der hyperbaren Sauerstoffbehandlung einen Anhalt für die Rückbildungsfähigkeit der zerebralen Störungen. Diese Untersuchungen zeigen, daß (a) die EEG-Intervall-Amplituden-Analyse wertvoll für die objektive Verlaufsuntersuchung bei Hirnläsionen ist, (b) die während der HO-Behandlung durchgeführte EEG-Analyse bei der Differenzierung zwischen reversiblen und irreversiblen ischämisch-hypoxischen Veränderungen des Hirns hilfreich sein kann, (c) der einseitige Verschluß der Arteria carotis interna zu neurologischen Ausfällen und vor allem aber zu bilateralen EEG-Veränderungen mit einer akzentuierten Reduktion der elektrischen Hirnaktivität über der ipsilateralen Hemisphäre führen kann, (d) chronischischämische cerebrale Störungen durch die hyperbare Sauerstoffbehandlung gebessert werden können und eine weitergehende Besserung durch nachfolgende extra-intrakranielle Anastomosenoperation erzielt werden kann und (e) Hirngewebe eine chronische Ischämie, die zu erheblichen neurologischen Ausfällen geführt hat, über eine durchschnittliche Dauer von 3 Monaten tolerieren kann.

     

Improvement of Endothelial Function by HMG-CoA Reductase Inhibitors

Endothelial dysfunction is the early and crucial state of atherosclerosis that is associated with a poor prognosis. Mechanistically, endothelial dysfunction is caused by reduced nitric oxide bioactivity. HMG-CoA reductase inhibitors (statins) effectively lower cholesterol plasma levels and profoundly decrease the cardiovascular risk of hypercholesterolemic patients. It is well established that statins improve endothelial dysfunction in those patients. The underlying mechanisms are less clear. It is thought that pleiotrophic, cholesterol-independent effects of statins such as increase of nitric oxide bioactivity and reduction of oxidative stress may contribute to the vasoprotective effects of statins. Therefore, it is speculated that statins, at least in part, improve endothelial function independent of plasma cholesterol concentrations and may thereby exert beneficial clinical effects. This notion of statins as general atheroprotective drugs has been underlined by in vitro experiments, animal studies and small clinical trials. However, large-scale clinical intervention studies are needed to confirm a positive influence of statins on endothelial dysfunction and cardiac event rates in normochlesterolemic patients. (c) 2002 Prous Science. All rights reserved.