RU2497457C1 - Method of embolisation of cerebral arteriovenous malformations - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to neurosurgery. Microcatheter with detachable distal part for introduction of ONYX 18 is installed to patient with wide afferent at the background of small-vessel racemose net and high-speed direct AB fistulas. After that DMSO-compatible reinforced microcatheter is installed in the same afferent. Its distal label is placed between proximal and distal labels of microcatheter with detachable part. After that, embolised afferent is blocked with several detachable microspirals through reinforced microcatheter. ONYX 18 in amount sufficient for complete afferent occlusion is introduced additionally through the same microcatheter between coils of spirals. Labels of microcatheter with detachable distal part must not be included into conglomerate from microspirals and ONYX. After that, reinforced catheter is removed and 5-10 minutes after ONYX polimerisation step-by-step embolisation of ABM through microcatheter with detachable distal part is performed. After introduction of required quantity of embolisate microcatheter is removed by separation of its distal part.

EFFECT: method makes it possible to control reflux of preparation into embolised afferent, increase efficacy of embolisation of cerebral arteriovenous malformations and reduce quantity of embolisation steps, which improves treatment results and patients' life quality.

2 cl, 2 ex, 7 dwg

Description

The invention relates to medicine, namely to the section of neurosurgery.

Arteriovenous malformations (AVMs) of the brain account for a significant share in the structure of vascular pathology, the treatment of which is currently using the endovascular method. The main pathophysiological factor in this pathology is the presence of an arteriovenous shunt. In the treatment of this vascular malformation, three main methods of treatment are used, as well as their combinations:

direct surgical method (excision of arteriovenous malformations), endovascular method (turning off the arteriovenous shunt by various types of embolization and occlusion) and methods of radiological exposure (radiosurgery and radiotherapy). Each of the above methods has its advantages and disadvantages. Microsurgery is characterized by high radicalism, but this technique is the most traumatic, which causes significant limitations in determining indications for removal of deep AVM and AVM located in functionally significant zones. Radiation surgery is indicated only for AVMs less than 3 cm in diameter, and the irradiation effect is prolonged, therefore, the risk of hemorrhage remains for 2 years, and in the first 6 months after irradiation, the risk of hemorrhage even increases [1].

Currently, the leading position in the treatment of AVM is held by the endovascular method, in particular, embolization of AVM by adhesive (histoacryl, NbCA) and non-adhesive (ONYX) compositions [2, 3].

Particular attention in the literature is given to embolization techniques. So, the occlusion of afferents previously used by various types of emboli does not lead to the shutdown of the AVM, but only accelerates the formation of collaterals; on the contrary, intranidal embolization directly of the body of malformations leads to its complete obliteration.

In this regard, it should be noted that the use of the composition ONYX has several advantages. When using ONYX, the AVM embolization process is more manageable, it is possible to control the distribution of the embolizate over the body of malformations to a large extent, preventing its migration to intact arteries and drainage veins, which reduces the risk of both ischemic and hemorrhagic complications and significantly more radical with other embolizates [4].

Despite the above, ONYX embolization has a drawback - it is an inevitable reflux to the afferent through which embolization is performed. Reflux can lead to fixation of the tip of the microcatheter in the vessel and, accordingly, to displacement of both the afferent vessel and the body of the AVM when the microcatheter is removed, which can lead to rupture of blood vessels and cause intracerebral or subarachnoid hemorrhage, in some cases hemorrhage can be fatal [5 ].

The problem of “sticking” of the microcatheter was solved with the introduction of microcatheters with a detachable distal part (Sonic, Apollo). Using the above microcatheters, the process of their removal is significantly facilitated due to the fact that the tearing away distal part is not removed, but remains in the afferent, in the thickness of the embolisate, and the process of removing these microcatheters does not lead to a significant displacement of the afferent and, moreover, the AVM body itself [6] . The use of microcatheters with a detachable distal part made it possible to exclude the possibility of hemorrhage associated with their removal, to expand indications for ONYX endovascular embolization and to somewhat increase the radicalness of AVM treatment.

However, malformations with AVM with “wide” afferents present the greatest difficulty for embolization of ONYX, since in most cases when catheterizing a large afferent, whose dimensions are significantly larger than the sizes of intranidal vessels, it is not possible to achieve intranidal penetration of the embolizate, since retrograde is moving retrograde along the path of least resistance ONYX forms critical reflux and the microcatheter must be removed.

Known methods that contribute to the intranidal penetration of ONYX and limit reflux.

The first method consists in periodically introducing DMSO into the microcatheter through which embolization is performed, which leads to a certain decrease in the density of the embolizate and its penetration into the stroma of malformation [7].

This method has significant disadvantages. DMSO is a toxic drug that can cause vascular necrosis and its use in embolization is significantly limited. DMSO does not contrast with angioscopy, which leads to poor visualization and uncontrolled penetration into the bloodstream, which is unacceptable when using a toxic and potentially dangerous drug.

The second method is the use of compositions of various concentrations. ONYX 35 is used to create reflux, and then ONYX 18 is injected, which is distributed intranidally. The disadvantage of this method is the technical difficulty of using a high concentration composition, since the administration of a high viscosity drug is associated with a potential risk of microcatheter rupture and it is rather difficult to determine the dose of the drug necessary to create adequate reflux [8].

Another method involves the preliminary embolization of the afferent with detachable microcoils followed by the introduction of Onyx into the inter-turn space, thereby reducing the blood flow velocity in the afferent and creating the basis for the embolizate.

The disadvantage of this method is the impossibility of prolonged administration of the drug through the microspiral frame and thereby the difficulty of intranidal penetration of the embolizate [9].

The aim of the invention is to increase the radicalism of endovascular embolization of AVMs with wide afferents against the background of a small-vascular racemose network and high-speed direct AV fistulas, controlling the reflux of the drug into the embolized afferent by the combined simultaneous use of microcatheters with a detachable distal portion for the administration of non-adhesive 18-arm D-conjugated DMSO micromyloid composition afferent occlusions with microcoils

The method is as follows.

Figure 1 shows the sequence of the method with the steps of embolization of the AVM with a wide afferent of the proposed method, where α is afferent of malformation, v is a draining vein.

A microcatheter with a detachable distal part through which ONYX 18 will be inserted is intranidally mounted to the patient (Fig. 1a).

Then, in the same afferent, a second DMSO compatible reinforced microcatheter is inserted proximal, through which microspiral insertion and ONYX injection are possible. The distal mark of the second reinforced microcatheter should be located between the proximal and distal mark of the first microcatheter with a detachable distal part (figb).

Then, the embolisable afferent is covered with several detachable microcoils through a DMSO-compatible reinforced microcatheter, the size of which is selected depending on the size of the afferent (Fig. 1c).

Then, additionally, ONYX 18 is introduced into the inter-turn space through a DMSO-compatible reinforced microcatheter until the afferent is completely occluded, after which this reinforced microcatheter is immediately removed (Fig. 1d).

It is necessary to ensure that the tip of the microcatheter with the detachable distal part through which ONYX is planned to be inserted should be distal to the conglomerate of spirals and ONYX.

After polymerization of ONYX, after 5-10 minutes, ONYX 18 is injected through the microcatheter with a detachable distal portion to the desired volume, performing phased embolization of the AVM (Fig. 1e).

After the introduction of the required amount of embolizate to complete occlusion of the afferent, the microcatheter is removed by separating the distal part according to the standard procedure (Fig. 1f).

It should be noted that with this method there is no danger of the formation of excess reflux and, accordingly, fixation of the microcatheter in the afferent vessel, and it is possible to produce a more “tight” and more total filling of the malformation with embolizate.

Examples of the method.

1. Patient M., 34 years old. Diagnosis: Arteriovenous malformation of the left parietal and occipital lobe.

From the anamnesis it is known that he considers himself a patient from the age of 16, when initially generalized epileptic seizures began with a frequency of 1-2 times a year. At the age of 32 years, in connection with the increase in epileptic seizures, MSCT of the brain was performed, on which were found arteriovenous malformation of the parieto-occipital region on the left, hemodynamic aneurysm of the right internal carotid artery.

The first stage of surgical treatment was performed - endovascular embolization of the flow aneurysm with microcoils, partial embolization of the arteriovenous malformation with the non-adhesive composition Tumor 18. After the operation, epileptic seizures were not repeated due to anticonvulsant therapy. One year later, she was admitted for the second stage of surgical treatment.

On the preliminary selective cerebral angiography (Fig. 2), in the direct (a) and lateral (b) projections, a mixed (fistular and racemose) malformation was revealed, partial knot embolization according to Spetzler-Martin gradation III.

On selective cerebral angiography, arteriovenous malformation of the left parietal and occipital lobes of 71 × 54 × 50 mm in size is determined, the parieto-occipital branches of the left middle cerebral artery are afferents. Malformation includes racemose and fistular components. The shadow of the embolizate, which occupies about 50% of the entire malformation, is determined.

Our method in this case is used to reduce the blood flow velocity in the fistula of the AVM and increase the manageability of Onyx embolization. The stages of embolization are presented in figure 3.

Through a guide catheter inserted into the left internal carotid artery subcranially, the Sonic 1,2F microcatheter super-selectively catheterizes the afferent ABM, which is a branch of the anterior parietal artery, which is a direct arteriovenous fistula (Fig. 3a). Then, the Echelon-10 microcatheter is installed proximal to the same afferent, the distal mark of which is located between the proximal and distal marks of the Sonic 1,2F microcatheter (Fig.3b).

According to the Echelon-10 microcatheter, the afferent is blocked by six microcoils 6 × 15, 7 × 15, 9 × 20, 3 × 8, 3 × 8, 4 × 12 (Fig.3c), followed by the introduction of 0.5 ml ONYX 18 into the inter-turn space. After that, the Echelon microcatheter was brought out proximal and after 10 minutes a gradual embolization of malformation through the Sonic 1,2F microcatheter was started (Fig. 3d).

On the control angiograms (Fig. 4), in the direct (a) and lateral (b) projections, the complete shutdown of the fistular component and the subtotal shutdown of the racemous component of malformation without visualization of embolizate into the vein are visualized.

Subtotal embolization of malformation without reflux and discharge of the embolizate into the draining vein has been achieved. (Figa, b).

Microcat removed without technical difficulties.

2. Patient T., 11 years old. Diagnosis: Arteriovenous malformation of the right temporal lobe.

From the anamnesis it is known that he considers himself ill for 2 years, when a progressively progressive headache appeared. An examination at the place of residence according to brain MRI and cerebral angiography revealed arteriovenous malformation of the right temporal lobe of the fourth grade according to Spetzler-Martin. The first stage of surgical treatment was the partial embolization of arteriovenous malformation with the non-adhesive composition Swelling 18. After the operation, a decrease in cephalgic syndrome is noted. After 4 months, he was admitted for the second stage of surgical treatment.

On preliminary selective cerebral angiography (Fig. 5), in a direct (a) and lateral (b) projections, a partially embolized expressed racemose network of grade IV arteriovenous malformation according to Spetzler-Martin is visualized. Partially embolized arteriovenous malformation of the right temporal lobe, measuring 6.5 × 7.0 × 4.5 cm, is supplied from the branches of the right middle cerebral artery, right posterior cerebral artery, short branches of the right internal carotid artery, and venous drainage into the deep veins and cortical veins (figa, b). The small-vascular nature of the malformation network is noteworthy against the background of wide afferents, which increases the risk of embolizate reflux, in order to reduce which our technology is used in this case.

Figure 6 presents the stages of embolization. A wide terminal type afferent is visualized (M2 branch of the middle cerebral artery) and the small-vascular racemose network of malformation (Fig. 6a).

By a guide catheter inserted into the right internal carotid artery subcranially, the Apollo 1.5 × 30 microcatheter super-selectively catheterized the AVM afferent, which is an M2 branch of the right middle cerebral artery (Fig. 66). Then, the Echelon-10 microcatheter was installed proximal to the same afferent, the distal mark of which is located between the proximal and distal marks of the Apollo 1.5 × 30 microcatheter (Fig.6c).

According to the Echelon-10 microcatheter, the afferent is blocked by three microspirals 7 × 30, 7 × 30, 6 × 20 (Fig. 6d), followed by the introduction of 0.5 ml of the tumor 18 into the inter-turn space (Fig. 6e). The proximal administration of contrast demonstrates the total occlusion of the embolized afferent (Fig. 6f), after which the Echelon-10 microcatheter is removed and after 10 minutes, the gradual embolization of malformation through the Apollo 1.5 × 30 microcatheter begins. Mediobasal malformations are embolized (Fig. 6g, h).

On the control angiography (Fig. 7), a 40% malformation in the mediobasal regions without embolizate reflux is visualized (Fig. 7a, b). Microcat removed without technical difficulties.

Thus, our method of embolization of cerebral arteriovenous malformations with the non-adhesive composition Swell 18 allows us to increase the radicalization of embolization of cerebral arteriovenous malformations and reduce the number of embolization stages, which improves the results of treatment and the quality of life of patients.

Bibliography:

1. M.G. Yasargil, P.J. Teddy, A. Valavanis - Microneurosurgery., Vol. IIIA., Thieme, 1994.

2. Valavanis A, Christoforidis G. Endovascular management of cerebral arteriovenous malformations. Neurointerventionist 1999; 1: 34-40.

3. Spetzler RF, Ponce FA. A 3-tier classification of cerebral arteriovenous malformations. J Neurosurg. 2011; 114 (3): 842-849.

4. Panagiotopoulos V, Gizewski E, Asgari S, Regel J, Forsting M, Wanke I. Embolization of intracranial arteriovenous malformations with ethylene-vinyl alcohol copolymer (Onyx). AJNR Am J Neuroradiol. 2009 Jan; 30 (1): 99-106. Epub 2008 Oct 8.

5. Berenstein A, Lasjaunias P, Ter Brugge KG. Goals and objectives in the management of brain arteriovenous malformations. In: Surgical Neuroangiography. 2nd ed. Berlin, Germany: Springer-Verlag Berlin; 2004; 695-735.

6. Morris, P. Pearse - Practical Neuroangiography, 2nd Edition., Lippincott Williams & Wilkins, 2007.

7. ApSimon HT, Reef H, Phadke RV, Popovic EA. A Population-Based Study of Brain Arteriovenous Malformation: Long-Term Treatment Outcomes: 17th World Congress of Neurology. London, UK: Lippincott Williams and Wilkins; 2001: 2794-800.

8. W.J. van Rooij, M. Sluzewski G.N. Beute Brain AVM Embolization with Onyx. American Journal of Neuroradiology 28: 172-177, January 2007.

9. AK Gupta and AL Periakaruppan Intracranial dural arteriovenous fistulas: A Review Indian J Radiol Imaging. 2009 February; 19 (1): 43-48).

Claims (2)

1. A method for embolization of cerebral arteriovenous malformations, including the use of an ONYX 18 non-adhesive composition and detachable microcoils as a reinforcing material, characterized in that a patient with a wide afferent on the background of a small-vascular racemose network and high-speed direct AV fistulas intranidally establishes a microcatheter with an separate microcatheter for administration 18, then a DMSO compatible reinforced microcatheter is placed in the same afferent, its distal mark is placed between the proximal and the distal microcatheter marks with a detachable distal part, then the embolisable afferent is blocked with several detachable microcoils through a reinforced microcatheter and additionally through the same microcatheter between the turns of the spirals ONYX 18 is introduced in an amount sufficient to completely occlude the afferent, while the microcatheter part is not separated should be included in the conglomerate of microcoils and ONYX, after which the reinforced microcatheter is removed and after polymerization ONYX after 5-10 minutes, the poet complete embolization of the AVM through the microcatheter with a detachable distal part and after the introduction of the required amount of embolisate, the microcatheter is removed by separating the distal part. 2. The method of embolization of cerebral arteriovenous malformations according to claim 1, characterized in that the size of the microcoils is selected depending on the size of the afferent to achieve subtotal occlusion of the afferent.

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