Temporary arterial occlusion in aneurysm surgery

Kashin-Beck disease (KBD), an endemic, chronic osteoarthritic disorder with necrosis of chondrocytes, commonly occurs in China. The humic substance present in the drinking water of endemic areas has been proposed as one of the causative factors. In this study an in vitro cell culture system was used to investigate the damaging effects of humic acid (HA), a constituent of humic substance, on cultured rabbit articular chondrocytes. The commercial Aldrich humic acid (AHA) was fractionated with a series of organic solvents including n-hexane, benzene, ethyl acetate, and methanol. Among the several fractions of AHA, the ethyl acetate fraction (AHA-[EA]) displayed the most potent inhibitory effect on the survival of chondrocytes in clonogenic assays. Cellular injury induced by AHA-[EA] was evaluated by measuring cell viability with methylthiazol tetrazolium (MTT) and by determining the release of intracellular lactate dehydrogenase (LDH). Incubation of chondrocytes with AHA-[EA] (100-500 microg/ml) for 12 h produced a concentration-dependent decrease in cell viability and increase in LDH release. In addition, AHA-[EA] triggered lipid peroxidation manifested by elevated malondialdehyde (MDA) formation. In chemiluminescence assay, AHA-[EA] at the concentrations of 150-600 microg/ml caused 6- to 15-fold increases of luminol-amplified chemiluminescence responses, which are considered to reflect the production of hydrogen peroxide (H2O2). Moreover, pretreating the cells with 500-750 U/ml of catalase significantly prevented the loss of cell viability, while superoxide dismutase (SOD) enhanced the adverse effect of 300 microg/ml AHA-[EA]. Data suggest that the injury to chondrocytes induced by AHA-[EA] may be first through O2.- production, which is then converted into H2O2, thus initiating lipid peroxidation and leading to chondronecrosis observed in KBD.     

Electrophysiological (EEG-SSEP) monitoring during middle cerebral aneurysm surgery

SSEPs were monitored during 38 procedures for aneurysms of the middle cerebral artery. In 13 selected patients intraoperative barbiturate protection with sodium thiopental was performed during temporary M1 occlusion. Combined EEG monitoring, showing burst suppression typical pattern of electrical cortical activity, allows a minimal dosage (3-6.5 mg/kg) of thiopental to achieve brain protection. Any patient with TYPE I SSEP changes had a new postoperative neurological deficit. Five patients during temporary middle cerebral artery clipping showed TYPE II SSEP changes and only one, not achieving burst suppression EEG pattern, had transient postoperative neurological deficit. In two other patients, a progressive worsening of TYPE II SSEP was observed; this was due to excessive brain retraction without brain protection and had a prolonged postoperative neurological deficit. Four patients showed TYPE IV SSEP changes during temporary M1 occlusion, one of whom was a 52-year-old woman, who, in spite of brain protection with thiopental, had serious postoperative neurological sequelae. In this patient N20 amplitude and central conduction time did not have full recovery to the preocclusive values. This study suggests that combined electrophysiological monitoring may reduce complications due to excessive retraction of cerebral tissue, make temporary clipping safer and improve the results of middle cerebral artery aneurysm surgery.     

Brain protection for cerebral aneurysm surgery

The modern management of patients undergoing surgery for intracranial aneurysm often includes temporary periods of cerebral ischemia to minimize the risks final dissection and clipping or to allow vascular reconstruction. This article reviews the concepts of ischemic thresholds and examines the effects of the physiologic variables that may affect outcome from an ischemic episode. The protective agents presently available and the agents in development that may limit the extent of ischemic injury are reviewed extensively as well.     

Hypothermic cardiac standstill for cerebral aneurysm surgery

Surgical management of giant cerebral aneurysms remains a major technical challenge for modern neurosurgeons. Endovascular approaches for giant aneurysms does not provide an acceptable alternative to direct surgical approaches. The use of deep hypothermic circulatory arrest as an adjunct during clipping of complex giant aneurysms shows promise as a treatment for otherwise incurable lesions. Patient selection and techniques of circulatory arrest surgery are discussed.     

Resumption of professional work after cerebral aneurysm surgery

The influence of various factors upon the resumption of professional work was examined in the group of 87 patients, who had undergone an operation of single cerebral aneurysms. Professional activity was resumed by 59.9% members of the examined group. The age and the level of education or professional training were found to be the most influential factor. The location of aneurysms and sex of patients was found to have no influence. The fact that greater percent of those living in the country resumed their professional activities than those living in towns or cities can be explained by greater difficulty in to suffering was a quite frequent factor which can be overcome due to proper information given to the patients, thereby the greater number of patients can resume their professional career.     

A case of middle cerebral artery occlusion caused by dissecting aneurysm

We reported a case of middle cerebral artery occlusion caused by a dissecting aneurysm that was successfully treated by intra-arterial fibrinolysis. A 38-year-old man suddenly developed left hemiparesis and became confused. He was transferred to our hospital one hour and 27 minutes after the ictus. Right carotid angiogram (CAG) revealed aneurysmal dilatation of the horizontal portion of the middle cerebral artery and occlusion of the anterior trunk. Twelve million IU of tissue plasminogen activator was injected to fibrinolyze the thrombus of the occlusion site through a microcatheter. After this, the patient became alert and hemiparesis disappeared. It took three hours and 30 minutes to gain recanalization after the ictus. Right CAG obtained the next day demonstrated the patency of the anterior trunk and the characteristic finding of the dissecting aneurysm viz "double lumen" as a result of fibrinolysis of the thrombus in the false lumen. Right CAG obtained two weeks later demonstrated "string and pearl sign" instead of the "double lumen" as a result of partial thrombosis in the false lumen. Follow-up CAG obtained nine months after the ictus demonstrated marked reduction of the aneurysmal size as the result of progressing thrombosis of the false lumen. The characteristic angiographic findings of the dissecting aneurysm such as "double lumen" and "string and pearl sign" seemed to be mostly influenced by the status of the thrombus in the false lumen. In case of major cerebral arterial occlusion caused by the embolus or thrombus from the dissecting aneurysm, intra-arterial fibrinolysis seems to be a possible treatment modality, even though it is accompanied by the risk of giving rise to subarachnoid hemorrhage.     

Proximal occlusion of the dominant anterior cerebral artery for anterior communicating aneurysm

A series of six experiments examined the neural loci responsible for caerulein's suppression of eating. Caerulein is a decapeptide chemically and physiologically similar to cholecystokinin, a naturally occurring gut hormone in rats. Rats with lesions in the ventromedial hypothalamus (VMH) showed reduced sensitivity to caerulein (1 mug/kg); rats with lateral hypothalamic (LH) destruction showed heightened sensitivity. Microinjections of caerulein into the VMH, but not into the LH, limited feeding. Finally, tritiated caerulein was selectively bound to tissue in the VMH. The results are discussed in terms of the hypothesis that the VMH manages postprandial inhibition in the rat.     

Allogeneic versus autologous blood during abdominal aortic aneurysm surgery

OBJECTIVES: To determine if cell-salvaged autologous blood can serve as an alternative to homologous blood, and to examine the incidence of infected complications and length of postoperative stay. DESIGN: A prospective randomised study comprising autologous and homologous blood transfusions in patients undergoing elective infrarenal abdominal aortic surgery. METHODS: Fifty patients undergoing AAA surgery were prospectively randomised to homologous blood (n = 27), or autologous blood transfusion (n = 23), using a cell salvage autotransfusion device. RESULTS: The haemoglobin at the time of hospital discharge was similar for both groups (11.0 vs. 10.8 g/dl) with no difference in perioperative mortality. The length of stay was reduced in those patients who received autologous blood (9 days vs. 12 days, p < 0.05 Mann-Whitney U test). There were four infected cases in the autologous group and 12 in the homologous group (p = n.s., Fisher's exact probability test). However, patients who received 3-4 units of homologous blood had an increased risk of infection compared to those who received a similar amount of autologous blood (50% vs. 0%). CONCLUSIONS: Cell salvage autologous blood can safely replace, or at least decrease, exposure to homologous blood transfusion, with a reduction in the mean hospital stay.     

Skull base techniques for aneurysm occlusion

Low back pain (LBP) is a common symptom seen by nurses who provide care for people with orthopedic problems. Many women experience their first episodes of LBP during pregnancy. Two perspectives for exploring LBP, biomedical and feminist, are described in this article. A combination of these perspectives might best serve women. Also, examples from a research project that used both perspectives is provided.     

Hyperdense middle cerebral arteries identified on CT as a false sign of vascular occlusion

PURPOSE: To evaluate the middle cerebral artery (MCA) on CT, including its relationship to cerebral infarction. METHODS: Thirteen patients with either a unilateral or bilateral hyperdense M1 segment of the MCA were evaluated. History of hypertension, diabetes, and hematocrit were obtained and compared with a control group of patients without a hyperdense MCA. RESULTS: None of the patients had a unilateral hyperdense MCA ipsilateral to a clinically identifiable stroke. Patients with a hyperdense MCA had a statistically higher hematocrit and also a higher prevalence of hypertension and diabetes mellitus than patients without a hyperdense MCA. The higher hematocrit may have increased the density of the blood, while both diabetes and hypertension are associated with calcification within blood vessel walls. CONCLUSION: A hyperdense MCA is not a reliable indicator of occlusion of this vessel or subsequent infarction.     

Pharmacological prophylaxis against postoperative graft occlusion after peripheral vascular surgery: a world-wide survey

Aquaporin CHIP, a 28 kDa channel forming protein, has been proposed to function as water channel in both erythrocyte and kidney proximal tubule. Recently, we have reported that in frog urinary bladder, a model of the kidney collecting tubule, polyclonal antibodies against human erythrocyte CHIP recognize and immunoprecipitate a 30 kDa protein from the epithelial cell homogenate. In the present work confocal fluorescence microscopy was used to determine the cellular and subcellular localization of CHIP28-like proteins in the urinary epithelium. A clear labeling of the apical border was found after Triton X-100 permeabilization. The labeling was distributed throughout the apical domain and not restricted to specific domains of the membrane. The staining was also present in the deeper confocal sections where the fluorescence seems to be localized at the cellular contour. No difference in the labeling patterns was observed between resting and ADH-treated bladder. Specificity of the staining was confirmed by the absence of the labeling pattern when antiserum was preadsorbed on CHIP28 protein immobilized on Immobilon P stripes. Our results suggest that CHIP-like proteins are not proteins inserted in the apical membrane during the antidiuretic response. Moreover, we do not know whether the labeling was due to the presence of CHIP28 itself or an as-yet-unidentified protein sharing immunological analogies with aquaporin CHIP.     

Transcranial Doppler sonographic monitoring during cerebral aneurysm embolization: a preliminary report

BACKGROUND AND PURPOSE: The wide application of embolization in the treatment of aneurysms has created the need for an intraprocedural means to anticipate a poor outcome by monitoring hemodynamic changes in the brain. METHODS: Transcranial Doppler sonography was used to monitor flow velocity in the middle cerebral artery (MCA) in 23 patients undergoing embolization with Guglielmi detachable coils (GDCs) of either incidental or symptomatic intracranial aneurysms. Sonographic values were recorded from the ipsilateral MCA at the beginning, middle, and end of the interventional procedure and 24 hours afterward. RESULTS: No complications occurred in 15 patients. In these cases, sonography showed an average decrease in MCA flow velocity of 2.7% after GDC application, returning to baseline at the end of treatment and then increasing by about 17% 24 hours later. In four patients with vasospasm on posttreatment angiograms, MCA flow velocity increased to values higher than 120 cm/s after GDC application, returning to baseline after 24 hours. In four patients with ischemic complications (two transient ischemic attacks, one stroke, one vascular death), MCA flow velocity decreased more than 30% and did not return to preoperative values within 24 hours. CONCLUSION: The application of transcranial Doppler sonographic monitoring during endovascular treatment may help to identify patients at risk for posttreatment cerebral ischemia.     

Regional cerebral blood flow during and after 2 hours of middle cerebral artery occlusion in the rat

In this study we explored if the secondary bioenergetic failure, which occurs a few hours after recirculation, following transient middle cerebral artery occlusion (MCAO) in rats, is caused by a compromised reflow. We induced 2 hours of MCAO and measured CBF at the end of the ischemia, as well as 15 minutes, 1, 2, and 4 hours after the start of recirculation, using autoradiographic or tissue sampling 14C-iodoantipyrine techniques. After 2 hours of MCAO, the autoradiographically measured CBF in the ischemic core areas was reduced to 3 to 5% of contralateral values. The reduction in CBF was less in neighboring, penumbral areas. After recirculation, flow already normalized in core tissues after 15 minutes, and remained close to normal for the 4 hours recirculation period studied. However, in penumbral tissues, recovery CBF values were usually below normal. The results show that tissues that are heavily compromised by the 2-hour period of ischemia and are destined to incur infarction, show a "relative hyperemia" during recirculation. In fact, some areas of the previously densely ischemic tissue showed overt hyperperfusion. This finding raises the question whether the relative or absolute hyperemia reflects events that are pathogenetically important. Because drugs that clearly ameliorate the final damage incurred fail to alter the relative hyperperfusion of previously ischemic tissues, it is concluded that vascular events in the reperfusion period do not play a major role in causing the final damage.     

Delayed traumatic cerebral aneurysm after brain injury

Traumatic aneurysms (TAs) are an unusual etiology for late neurological deterioration after traumatic brain injury (TBI) and represent less than 1% of all cerebral aneurysms. TAs most often are diagnosed acutely but may be delayed in presentation. To increase awareness of this serious but treatable condition when diagnosed early, we report a delayed TA after a motor vehicle accident. The patient experienced a seizure on day 46 postinjury while in rehabilitation and demonstrated persistent lethargy and hemiparesis. Neuroimaging revealed a large, ruptured left pericallosal artery TA, which was surgically clipped. The patient completed his rehabilitation course and was eventually discharged home with family. Among TBIs, TAs are associated with penetrating injuries and skull base or anterior cranial fossa fractures. Associated mortality is high, especially if rupture has occurred. Although TAs are rare, the clinician should be vigilant in the at-risk patient.     

Ruptured fusiform cerebral aneurysm in a neonate

An 11-day-old male infant presented with subarachnoid and intraventricular haemorrhage caused by a ruptured intracranial aneurysm. Magnetic resonance (MR) angiogram and digital subtraction angiography (DSA) revealed a fusiform aneurysm 10 mm in diameter supplied by the proximal segment of the anterior cerebral artery (A1), with both distal segments (A2) arising from the aneurysm. The right A1 was aplastic. There have been 13 previous case reports of neonatal cerebral artery aneurysms, but only 1 of these has been fusiform. None of the earlier reports has mentioned dysplastic segments or other anomalies of the circle of Willis.