Pushable fibered coil

Controlled Delivery of Pushable Fibered Coils for Large Vessel Embolotherapy... 

Pushable fibered coils have been the material of choice for large vessel occlusion for the past 30 years, since their introduction by [1]. Their simplicity, reliability, and availability have led to their widespread acceptance by interventional radiologists throughout the world. 

Improvements were made to pushable fibered coils, including the introduction of platinum fibered 0.035-0.038 standard and 0.018 in microcoils [8, 9). These later developments, provided a softer and more MRI compatible coil but without the radial force of the original stainless steel coils. In Europe an Inconel coil, with excellent radial force, replaced the stainless steel coils and so high radial force and soft fibered platinum coils for vessel occlusion, became available in Europe. The Inconel, high radial force coil, is not yet available in the USA. 

Cross sectional occlusion of the artery/vein is easily produced when coaxial catheters were used. The elongation of pushable fibered coils is avoided by advancing the coil through the inner 4- or 5-F catheter while holding the outer guide catheter stable in the artery or vein (Fig. 3.3). In this way the soft... 

Fig.3.5. The anchor technique. This technique is very valuable for providing safe and distal occlusion when there is a question about instability of pushable fibered coils. Diagrammatically, the guide catheter is placed in the artery to be occluded and a 5-F inner catheter or microcatheter is advanced into a side branch next to the site requiring occlusion. At least 2 cm of a 14-cm standard Nester or Micronester are advanced into the side branch which is normally sacrificed. The rest of the coil is then deployed just proximal to that side branch and additional coils are packed so that cross-sectional occlusion is obtained...

Integral to using pushable fibered coils to produce cross sectional occlusion is the use of coaxial or tri-axial guide catheter systems. For venous occlusions (varicocele and/or pelvic congestion) or occlusions of PAVMs, we use standard 7/5 combinations (Pulmonary, Cook) or gonadal (Cordis Inc., Miami FL) with inner 5-F endhole catheters (Fig. 3.9). 

Since the development by Gianturco of the first pushable fibered coils over 30 years ago, significant advances in coils and catheters have occurred. It is now possible to deliver pushable fibered standard 0.035 and 0.018 microcoils in a controlled and precise manner. Experience on a day to day basis with high flow fistulas of the lung has enabled us to develop a number of techniques which enable safe deployment and cross sectional occlusion of the vessel. 

Controlled delivery of all pushable fibered Micro coils (Cook, Boston Scientific and Cordis) 0.018 in. is possible by using a coaxial guide (4-6 F) and microcatheters [14]. In order to achieve cross sectional occlusion of the artery or vein, the micro coils must be delivered into a tight coil mass. To achieve this, a 0.016 pusher wire (Boston Scientific or Cordis) is used and the same weaving action is performed during deployment in order to nest/pack the microcoil into a tight coil mass (Fig. 3.3). 

Also, the microcoils are deliverable by the Squirt technique. The Squirt technique is suitable for delivery of all pushable fibered microcoils (0.018 in.) through microcatheters with 0.016- to 0.027-in. end-holes. The microcoil is loaded into the microcatheter and preferably a 3-ml luer lock syringe, filled with saline is attached to the hub of the microcatheter. Under fluoroscopic guidance, the microcoil is delivered with small boluses of saline. Final adjustment of the microcoil is accomplished by moving the microcatheter before final deployment of the coil, if... 

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