Embolization of cerebral arteriovenous malformations by fast-hardening acrylates

Svistov D.V., Voznesenskaya N.N.

(Chair of Neurosurgery of the Medicomilitary Academy, Saint Petersburg, Russia).

Arteriovenous malformations (AVM) occupy a leading place among cerebrovascular diseases, demanding surgical treatment. All patients with AVM should be regarded as candidates for surgical treatment, as severe disability and fatal outcomes are watched in 43% and 23% of them respectively. An annual risk of hemorrhage from AVM is 3%. As for a risk of recurrent hemorrhage during the first year after bleeding, it is equal to 6%. A direct neurosurgical intervention is a method of full value. However, it can be used as an independent method only in patients with a low risk of postoperative complications. Thus, embolization of AVM vessels, as a means of preoperative preparation of a patient or an independent method, is a pressing problem.

The goal of research was studying potentialities of embolization of AVM feeding vessels, as an independent method or as preoperative preparation of patients.

There were 36 cases with cerebral AVM, in whom 66 superselective embolizations (SSE) of feeding arteries were performed: 25 patients - 1 procedure, 14 patients - 2 procedures, 3 patients - 3 procedures and 1 patient - 4 procedures. Diagnosis of AVM and control of efficacy of treatment were carried out with the help of spiral CT angiography, MR angiography, selective cerebral angiography and transcranial Doppler. Distribution of AVM into anatomical-functional types according to Spetzler-Martin was as follows: I - 0, II - 7, III -20, IV -9, V - 0. Clinical manifestations of a hemorrhagic character were watched in 6 cases; pseudotumorous or epileptic types of a course were typical of 30 patients. AVM were localized in the following areas: a frontal lobe - 8, an area of central gyri - 6, a parietal lobe - 12, an occipital lobe - 4, a temporal lobe - 4, a paraventricular lobe - 2. Malformation volume varied from 1 up to 46 cm3. Drainage into the system of deep veins was observed in 14 cases.

When a histoacryl solution (N-butylcyanoacrylate) was used as an embolizing substance, a stable positive effect with subsequent recovery was achieved after 56 embolizations (96.6%).

Analyzing obtained data, one can come to a conclusion, that efficacy of one SSE procedure (malformation volume decrease) in small, middle-sized and big AVM was within the range of 50-100%, 30-60% and 30-40% respectively. As a rule, repeated procedures in small AVM are not necessary due to high efficacy of their embolization. Complications after an operation developed in 28.8% of all embolized patients; they were persistent in 9.1% of them. Ischemic-type complications were watched after 16 embolizations. They were represented by extremity paresis (25%), speech disturbances (25%) and hemianopsia (37.5%). Vision impairment, connected with disorders of blood supply of a visual tract and an analyzer cortical segment, were the most stable complications, resistant to therapy. The rest complications of an ischemic origin were corrected with the help of HBO. Treatment began on the first day after an operation, then it was decided to start it immediately after embolization. Positive dynamics of a neurologic state was observed in 9 out of 11 (81.8%) patients after some HBO sessions. Complete regress of neurologic deficit by the end of the HBO course took place in 5 patients (45.5%).

Thus, HBO is an adequate method of urgent correction of ischemic complications of embolization.

A direct intervention with total removal of AVM was performed in 6 patients after embolization of feeding vessels. It was characterized by minimum intraoperative blood loss. Embolization allowed to reduce a risk of intra- and postoperative complications, an operation volume and to facilitate a course of a postoperative period. Thus, embolization of AVM vessels is a prospective method, which can be used for preoperative preparation of patients, as it gives a chance to improve hemodynamics indices due to partial exclusion of malformation and its "critical" compartments and obliteration of difficult-of-access feeding arteries.