1. n-butyl α-cyanoacrylate is the most representative product among adhesive liquid embolic materials, and it is widely used all over the world. The liquid NBCA monomer and the nucleophilic group in the blood can be instantly polymerized in the blood to form a sticky, non-degradable solid on the intima of the blood vessel. This process takes 15 to 40 seconds to polymerize in saline, but at 5% Polymerization does not occur in the glucose solution, which brings convenience to the embolization operation. Flushing the microcatheter with 5% glucose solution before and after embolization can prevent its polymerization in the microcatheter and block the microcatheter. At the same time, adding an appropriate amount of tantalum powder can further enhance the developing effect without affecting the polymerization time of the glue. For different AVM lesions, different concentrations of glue can achieve the same embolization effect, but the time of glue polymerization is different. The biggest disadvantage of cyanoacrylate liquid embolic materials represented by NBCA glue is "sticky tube", which is unique to adhesive embolic materials. Due to its adhesiveness, the injection time is limited, and the catheter must be withdrawn immediately after injection, otherwise there will be a risk of the microcatheter adhering to the deformity. This requires the operator to have rich experience in glue injection, master the concentration of glue, grasp the injection speed and injection time, strictly control the reflux, and remove the microcatheter in time.
NBCA glue concentration preparation and injection technology: NBCA glue is an X-ray-permeable permanent liquid embolism material, which coagulates after contact with blood. The coagulation time is related to the concentration of NBCA glue, and it does not coagulate when it contacts with glucose solution and lipiodol. Therefore, according to the arteriovenous circulation time of AVM, it is necessary to add an appropriate amount of iodized oil to achieve the purpose of developing and diluting under fluoroscopy. If the flow rate of AVM is extremely fast, pure NBCA can be added with appropriate amount of tantalum powder. According to the lesion size, blood flow velocity, resistance, blood supply artery thickness, and drainage vein conditions learned by superselective contrast angiography, NBCA glue with different concentrations was prepared with iodized oil. The commonly used concentration is 17%~33%. Flow velocity, dubbed concentration is 50% or 66%. A 1ml syringe is used for injection, and the injection volume is the volume of AVM lesion recorded during superselective angiography. Flush the working area with glucose solution before injection, including repeated perfusion of glucose solution in the microcatheter for about 3 times or more, flushing the syringe and microcatheter connection, as well as all the utensils and materials related to the injection of NBCA glue. Manual injection of NBCA glue under DSA fluoroscopy can clearly show the diffusion of NBCA glue in the AVM lesion. Once the NBCA glue enters the draining vein or backflows into the blood supply artery, the injection is stopped and the microcatheter is quickly withdrawn. The ideal injection technique is that NBCA glue is evenly distributed in the AVM lesion to form a permanent cast. If there are multiple supplying arteries, repeat the above steps for multiple embolizations. If it is a huge AVM, embolization can be performed in stages. Angiography was performed immediately and 15 minutes after the operation to evaluate the embolism, and MRI/MRA examination was performed six months to one year after the operation to evaluate the long-term effect.
2. GLUBRAN-2 glue NBCA-MS is an adhesive liquid embolic material produced by GE Company in Italy. It is also called GLUBRAN-2 glue, commonly known as Italian glue and surgical glue. The polymerization time has been extended from 15 to 40 seconds to 60 to 90 seconds, which provides a valuable time window for sufficient and uniform diffusion of embolized intracranial AVM, thus avoiding the microcatheter sticking due to premature polymerization of embolization glue in the past. Risk of hemorrhage with stuck tube or extubation. Its preparation and injection technology are the same as NBCA glue. It is an adhesive liquid embolism material widely used at home and abroad at present, and it can be said to be an upgraded product of NBCA.
3. The new liquid embolic agent Onyx Onyx is a simple mixture of vinyl alcohol copolymer dissolved in dimethyl sulfoxide, in which micronized tantalum powder is added to make it visible under X-ray. When the polymer comes into contact with blood or any aqueous solution, the solvent DMSO quickly diffuses out, EVOH crystallizes out, and gradually solidifies from the outside to the inside like lava, and its liquid center can still flow, and finally forms a sponge-like solid containing tan powder. As an embolic material for intracranial AVM, compared with other liquid embolic materials, the characteristics of Onyx can be summarized as follows: ① It has good controllability and generally does not flow rapidly with the blood flow like diluted NBCA; Diffusion forward; ③ The diffusion of Onyx in the deformity is under the action of bolus injection force and hemodynamic force, and it diffuses with the pressure gradient from high to low. There are 3 different concentrations of Onyx suitable for AVM or fistula embolization. According to the different ratios of EVOH and DMSO, the three concentrations of Onyx are: Onyx-18 (6% EVOH+94% DMSO), Onyx-20 (6.5% EVOH+93.5% DMSO) and Onyx-34 (8%EVOH+92% DMSO), currently the most commonly used in China is Onyx-18.