Embolización de MAVs intracraneales coadyuvante de cirugía o radiocirugía

[Endovascular treatment of intracranial arteriovenous malformation with n-butyl cyanoacrylate. Working methods and experience in 58 cases]

BACKGROUND AND PURPOSE

Arteriovenous malformations (AVMs) constitute malformative lesions of the central nervous system vasculature and cause significant morbidity and mortality. Endovascular embolization with n-butyl cyanoacrylate is a well established modality of AVM treatment, usually combined with surgery or radiosurgery. The purpose of this study was to characterise the AVMs that were treated endovascularly with n-butyl cyanoacrylate and to evaluate the post-embolization results in the Cuban population.

MATERIALS AND METHODS

From February 2006 to February 2011, a group of 58 consecutive patients with brain AVMs were embolized using n-butyl cyanoacrylate in the endovascular therapy unit of the Medical Surgical Research Centre in Havana (Cuba). In all, 91sessions were carried out with intranidal embolization and mainly partial devascularization, 25-30% per session, and closing 123 arterial pedicles. Safety times for n-butyl cyanoacrylate injection were established by calculating the polymerisation times for different dilutions, using post-embolisation hypotension systematically, as well as a superselective test with propofol to determine cerebral eloquence.

RESULTS

Haemorrhagic signs were the initial presentation in 68.8% of the patients, 24.1% presented with epileptic episodes and 1.7% with ischemic stroke. Of the AVMs, 93.2% were supratentorial; according to the Spetzler and Martin classification, 13.8% were grade II, 56.9% were grade III, 22.4% were grade IV and 6.8%, grade V. One hundred and twenty-eight selective tests with propofol were performed and 118 (92.2%) of those were negative. Partial devascularization (20-30%) prevailed; complete obliteration was achieved in 17.2% of the patients and 70%-99% in 27.5% of the patients. Safety times for n-butyl cyanoacrylate injection were established and the use of post-procedure hypotension was settled. Morbidity of 17.2%, with 6.9% haemorrhagic complications and mortality of 3.4% were registered in the whole series.

CONCLUSIONS

The rates of total occlusion and of morbidity and mortality in the series are in the internationally described ranges. The implementation of intranidal closings with 20-30% devascularization per session and the use of post-embolization hypotension after the haemorrhage complications described resulted in the total absence of haemorrhagic complications.

[Linear accelerator radiosurgery for brainstem arteriovenous malformations. Long-term results]

OBJECTIVE

Arteriovenous malformations (AVM) in the brainstem carry a high risk of recurrent haemorrhage, mortality and morbidity. Treatment options are limited and mainly based on stereotactic radiosurgery. We studied the results of our series of brainstem AVM treated with linear accelerator (LINAC) and with a long-term follow-up.

METHODS

We retrospectively analysed the clinical and radiological data of 41 consecutive patients with brainstem AVM treated by radiosurgery with a 6MV linear accelerator between 1992 and 2010. Twenty five lesions were located in the mesencephalon, 14 in the pons, one in the medulla oblongata and one was bulbopontine. We analysed the treatment results in relation to survival, rate of radiological obliteration, rebleeding, and treatment toxicity.

RESULTS

The obliteration rate confirmed by angiography/MRA was 59.5% on 38 controlled patients. The mean follow-up period was 61 months (range: 6.7-178) and the margin dose was 14Gy in most treatments. Up to 39% of patients received more than one radiosurgery procedure to achieve closure of the malformation. No statistical correlation was found with the margin dose, presence of pretreatment haemorrhage, nidus diameter or score on the Pollock-Flickinger grading system. The annual haemorrhage rate after radiosurgery was 3.2%. Three patients died from rebleeding and actuarial survival rate was 88% at 5 and 10 years after treatment. Four patients suffered new transient neurological deficits due to toxicity, and only one presented a permanent deficit (2.6%).

CONCLUSIONS

Nidus obliteration in brainstem AVM must be achieved according to three main criteria: maximum obliteration rate forced by the high rate of rebleeding, minimal morbidity given its critical location, and the greatest possible accuracy. Stereotactic radiosurgery with our moderate-dose protocol, which we believe achieved these three premises, may become an elective therapeutic modality for these patients.

[Arteriovenous malformation of the middle and posterior third section of the corpus callosum treated with embolization and surgery]

We are presenting the case of a 58 year-old woman with an arteriovenous malformation (AVM) of the middle and posterior thirds of the corpus callosum which had produced two episodes of bleeding before admission to our Department, when the patient was neurologically intact. The nidus was fed by the anterior and posterior pericallosal arteries draining through the left medial atrial vein to the vein of Galen, by parasagittal cortical veins to the superior sagittal sinus and by right temporal veins to the sphenoparietal sinus. The patient underwent embolization of the anterior and posterior feeders in two sessions separated by a week interval, and then the AVM was removed through a left paramedial parietooccipital craniotomy in a single stage. The patient showed transient mild short term memory deficit, but the final outcome was excellent.

[Parasplenial arteriovenous malformations. Report of 15 surgically treated cases]

INTRODUCTION

Yasargil called paraesplenial those AVMs located at the confluence of the hippocampus, the isthmus of the cingulate girus and the girus occipitotemporalis medialis. Large AVMs at this location are among the most difficult to delineate and to treat.

OBJECTIVE

Analyze the clinical presentation, the findings in the imaging studies, the surgical management and the final outcome in 15 patients with paraesplenial AVMs treated with embolization (the last 4 cases), and microsurgical removal.

RESULTS

Nine patients (60%) were female and 6 males of ages between 15 and 39 years (mean = 24 yrs). Eleven (75%) presented with hemorrhage, (intraventricular in most cases) and the remaining with epilepsy. The Spetzler-Martin grade was II in one Case, III in 5 cases, IV in 8 cases and V in one case. Preoperative embolization clearly improved surgical management. All the patients had complete resection of the lesion, 13 in a single stage and 2 in two stages. The final outcome was good but four patients developed defects of the visual field not seen preoperatively.

CONCLUSIONS

The authors comment the peculiarities of paraesplenial AVMs which can be safely and completely removed with microsurgery and the aid of preoperative embolization.