Surgery Of Cerebral Arteriovenous Malformations Research Articles

Role of venous drainage in cerebral arteriovenous malformation surgery, as related to the development of postoperative hyperperfusion injury.

To elucidate the role of venous drainage in cerebral arteriovenous malformation (AVM) surgery, with respect to the development of postoperative hyperperfusion injury. For 52 patients with supratentorial AVMs, cortical capillary oxygenation (SaO(2)) was assessed intraoperatively, before and after resection, in the vicinity of the AVMs, by using a microspectrophotometric method. Assessed areas were defined as being related to feeding arteries or draining veins or as distant areas. Patients were divided into three groups on the basis of postoperative angiographic findings, as follows: Group 1, all former draining veins preserved (8 patients); Group 2, > or =1 former draining vein visible (12 patients); Group 3, no former draining veins visible (32 patients). Patients and SaO(2) values were pooled and compared by using paired and unpaired t tests (P < 0.05). Venous circulation times were calculated from digital subtraction angiography films. The postresectional relative increases in SaO(2) values were highest in draining vein areas (+40.8%, compared with +25% in feeder areas and +25.5% in distant areas). Five postoperative hyperemic complications occurred (9.6%), none in Group 1 (with all draining veins preserved), two (16.7%) in Group 2, and three (9.4%) in Group 3 (with all draining veins occluded). The lowest preresectional SaO(2) values (31.7 +/- 6.2%) were measured in the drainer areas of the five patients who subsequently developed hyperperfusion injuries. Among those patients, postresectional increases in SaO(2) values were significantly greater in drainer areas (+167.8%) than in feeder areas (+28.3%) or distant areas (+25.8%). Postoperative venous circulation times in former draining veins in Group 2 were significantly greater than those in Group 1 (8.9 +/- 1.5 s versus 6.3 +/- 0.6 s). Circulation times in normal veins in the five patients with hyperperfusion injury increased from 5.6 +/- 1.0 seconds (preoperatively) to 8.4 +/- 1.9 seconds (postoperatively). Postoperative hyperperfusion injury after resection of cerebral AVMs can be explained on the basis of unconstrained arterial inflow into cortical areas, which are rendered hypoxic/ischemic by longstanding preoperative venous hypertension. The risk for postoperative breakthrough complications seems higher in the presence of multiple draining veins, which also participate in the physiological venous drainage system of the ipsilateral hemisphere.

Role of Venous Drainage in Cerebral Arteriovenous Malformation Surgery, as Related to the Development of Postoperative Hyperperfusion Injury

Role of Venous Drainage in Cerebral Arteriovenous Malformation Surgery, as Related to the Development of Postoperative Hyperperfusion Injury

Significance of factors contributing to surgical complications and to late outcome after elective surgery of cerebral arteriovenous malformations

OBJECTIVESThis study focuses on the relevance of size, eloquence, type of venous drainage, the Spetzler-Martin scale as a whole, and other factors, such as rupture of cerebral arteriovenous malformations (AVMs)...

Normal perfusion pressure hyperperfusion in cerebral arteriovenous malformation surgery: model study on the hemodynamics and mechanisms

A simulation study was undertaken using a compartmental flow model of a large high-flow cerebral arteriovenous malformation to investigate the hemodynamic changes during obliteration procedures. Under certain autoregulatory conditions, marked hyperperfusion (92 ml/100 g/min) could be induced in association with increased wall stress of the arterioles. Narrowing of the autoregulatory pressure range and its shift to a low pressure level are suspected to be among the possible causes of normal perfusion pressure breakthrough phenomenon.

Surgery for cerebral arteriovenous malformation: risks related to lenticulostriate arterial supply.

The aim of this study was to compare complications of surgery in arteriovenous malformations (AVMs) supplied by the middle cerebral artery (MCA) with and without a lenticulostriate arterial contribution. Ninety-two consecutive surgical resections of AVMs with an angiographically demonstrated MCA supply were performed between January 1989 and July 1996. Ten of these cases had a significant lenticulostriate arterial contribution. The cases were graded according to the Spetzler-Martin classification. There were no deaths and 4.3% of cases developed new major neurological deficit by the 3-month follow-up examination. All cases had angiographically confirmed obliteration of the AVM. There were no complications in 16 patients with Spetzler-Martin Grade I AVMs, one case of complications in 40 patients with Grade II AVMs, eight cases of complications in 26 patients with Grade III AVMs, and seven cases of complications in 10 patients with Grade IV and V AVMs. The supply of blood from lenticulostriate branches was associated with complications in eight of the 10 cases. The effect of the presence of a lenticulostriate arterial supply was most apparent in cases of Grade III AVMs: complications were experienced in three of 20 patients whose AVMs were not supplied by the arteries and in five of six patients whose AVMs were fed by the lenticulostriate arteries. This difference is significant (p < 0.0001). The conclusions drawn from this study are that for Grade III AVMs, the presence of a lenticulostriate arterial supply can be considered a factor predictive of an increased risk of surgical complications.

Prediction of Obliteration after Gamma Knife Surgery for Cerebral Arteriovenous Malformations

Prediction of Obliteration after Gamma Knife Surgery for Cerebral Arteriovenous Malformations

Prediction of Obliteration after Gamma Knife Surgery for Cerebral Arteriovenous Malformations

Prediction of Obliteration after Gamma Knife Surgery for Cerebral Arteriovenous Malformations

AVM手術における術中, 術後出血および脳腫脹について

AVM手術における術中, 術後出血および脳腫脹について

Gamma knife surgery of cerebral arteriovenous malformations: Serial mr imaging studies after radiosurgery

Purpose: To investigate the temporal sequence of post radiosurgery magnetic resonance imaging changes in cerebral arteriovenous malformations. Methods and Materials: Eighteen patients were regularly followed up after gamma knife surgery. The follow-up intervals ranged from one day to 44 months. High signal lesion in or around arteriovenous malformations on T2-weighted magnetic resonance images corresponding to the treatment volume and developing after radiosurgery were defined as the adverse reaction of the irradiation. This high signal and the regression of arteriovenous malformations nidus after radiosurgery were evaluated. Results: Adverse reaction of irradiation was observed in nine cases. Seven of them were symptomatic. The reactions presented as focal high signal in three cases and focal high signal with extension along the neural tracts in six cases. The reactions were seen either immediately after treatment (one case), between 3 and 14 months (seven cases), and 40 months after treatment (one case). The regression of the adverse reaction was observed to start 5 ±3 months after its appearance. Regression of the arteriovenous malformations' nidus was found in 16 cases. In two cases the AVMs became invisible on magnetic resonance images but the angiogram still demonstrated abnormal shunts. In another one case with angiogram showing total obliteration, the nidus was erroneously interpreted as incomplete obliteration on magnetic resonance images. Conclusion: It is concluded that magnetic resonance imaging is a sensitive in vivo method for detecting cerebral radiation injury. Magnetic resonance imaging offers a method for evaluating the regression of arteriovenous malformations' nidus, but the diagnosis of complete obliteration of the nidus after radiosurgery still relies on the angiogram.

The Long-Term Postoperative Trinitroglycerin Hypotension in Normal Perfusion Pressure Breakthrough Syndrome

The authors describe a case of normal perfusion pressure breakthrough syndrome, a catastrophic hemorrhage complicating surgery for cerebral arteriovenous malformations, due to chronic loss of autoregulation. Successful treatment was achieved with prolonged postoperative trinitroglycerin hypotension, associated with barbiturate-induced coma and artificial ventilation.

Zum prognostischen Wert von Graduierungssystemen bei zerebralen arteriovenösen Mißbildungen

The interrelationship between angiographic grading, clinical presentation and outcome in arteriovenous malformations was examined. For this purpose the grading scales as proposed by Luessenhop and Genarelli, Shi and Chen, and Spetzler and Martin were applied to 93 patients who had undergone surgery for cerebral arteriovenous malformations and whose angiographies were completely available for retrospective examination. Additionally the patients' clinical presentation on admission as well as their outcome were assigned to a 5 point scale. 44 of the 93 patients had a previous hemorrhage and 49 had become symptomatic for other reasons. There were 68 (73.2%) good and excellent results, 16 patients (17.2%) remained moderately and 7 (7.5%) severely disabled. There were 2 fatalities (2.1%). The correlation between the clinical and angiographical grading, respectively, and the outcome was assessed by determining Spearman's rank correlation coefficient (rho). The best correlation was found between the clinical grading on admission and the outcome (rho = 0.34). The angiographical classification scheme with the best correlation with the outcome was the one of Spetzler and Martin (rho = 0.22). The scales of Luessenhop and Genarelli and Shi and Chen correlated only weakly with the outcome (rho = 0.14 and rho = 0.12, respectively). The rounded off average of the grade of Spetzler and Martin and the clinical grade was the best predictor of outcome in our material (rho = 0.4).

治療困難な脳動静脈奇形に対する ethylene-vinyl-alcohol-copolymer (EVAL) による塞栓術

Embolization is used as a radical therapy, as well as an adjunctive therapy with surgery for cerebral arteriovenous malformations (AVM). Although several liquid embolic agents, including IBCA, NBCA and others, are available and are reported to be useful for this purpose, these cyanoacrylic agents share common disadvantages. They are strong adhesives and become a hard mass after polymerization. Therefore, a new liquid embolic agent which overcomes these disadvantages, has been considered necessary. EVAL(ethylene-vinyl-alcohol copolymer) is a newly developed liquid embolic agent, which is not an adhesive and takes a soft spongy shape. We used this agent for embolization in 9 cases of AVMs, of which 4 were deep seated and 5 were large AVMs in the dominant hemisphere. A 90% or greater reduction in size was achieved in 3 cases by embolization; and in 2 cases, the size was reduced by more than 50%. In 3 cases, the embolization facilitated the surgical removal of the AVMs.

Evaluation of prognostic factors in cerebral arteriovenous malformations.

In a retrospective study of 48 patients who underwent elective surgery for cerebral arteriovenous malformations, a statistical analysis of demographic, clinical, and neuroradiological data was undertaken in order to discover the best predictors of operative morbidity. In addition, the predictive value of different clinical grading systems as applied to this series was compared. All patients had a computed tomographic scan and a positive angiogram before surgery. Complete resection was proven angiographically. The univariate Mann-Whitney-Wilcoxon rank sum test, the Fisher exact test, Spearman's rank correlation coefficient analysis, and multivariate logistic regression were used as statistical methods. Duration of surgery, the development, of either new deficits or an increase in the preoperative neurological signs immediately after surgery, and rehabilitation (as measured by the Karnofsky index) were taken as target variables for the difficulty of operation and for postoperative morbidity, respectively. The largest diameter of the nidus of the arteriovenous malformation, eloquence of the adjacent brain, and deep venous drainage showed the most consistent correlation with these target variables. Intracerebral hematoma and other single factors, such as the age of the patient or localization of the arteriovenous malformation did not affect the outcome. The clinical grading scale of Spetzler and Martin provided better prediction of surgical risks than other proposed systems.

Benefits of embolization without surgery for cerebral arteriovenous malformations.

Embolization may be the primary and exclusive treatment of cerebral arteriovenous malformations. To evaluate its benefits, a group of 27 patients was studied for the incidence of hemorrhages, headaches, seizures, and neurologic deficits, both before and after Silastic sphere embolization. Questionnaires to patients and physicians were used. Embolization was found to decrease the frequency of headaches in most patients with this symptom, but had no effect on the frequency of seizures when patients in whom medical therapy was altered were excluded nor on the progression or incidence of neurologic signs and symptoms. The effect of embolization on the incidence of recurrent hemorrhages is as yet undetermined.

Intraoperative evaluation of cerebral hemodynamics using directional Doppler technique

The use of a pulsed echo Doppler technique during surgery for cerebral arteriovenous malformation is described. The equipment and the methods employed are presented. The main advantages are easy determination of flow direction and pattern of the vasculature involved, allowing a precise discrimination between inflow and outflow channels. Deep-seated malformations, not visible at the brain surface, can be located with the Doppler technique. The ultrasound probe was placed on the brain surface with a slight pressure on the intact pia mater. The precise direction and depth of the malformation could be determined in relation to the recording site. This facilitated the planning of cortical incisions, identification of vessels involved, and the vascular procedure to be employed.