Micro-catheter

Other snare devices that potentially can be used for embolectomy include (1) the Alligator Retrieval Device, which is a retriever with grasping jaws attached to the tip of a flexible wire designed to be used in conjunction with 0.21-inch micro-catheter " and (2) the EnSnare device, which has a tulip-shaped, three-loop design that opens distally. These devices, which are approved for foreign body removal/coil retrieval, have not been reported in embolectomy for stroke treatment. 

TAE is achieved by using co-axial micro-catheters in order to be able to achieve selective embolization. Most radiologists will use either coils (permanent) or gelfoam (temporary) to embolize vessels. The... 

Deep and diffuse penetration can cause ischemia or even infarction of neighboring tissue. The use of an overly diluted solution can result in delayed polymerization with risk of distal artery or draining vein occlusion. A drip of glue can be attached to the micro catheter which can eventually he emholized to a non-targeted location during retraction of the catheter. 

Stainless steel or platinum coils and detachable balloons are rarely used as aprimaryembolicagentinbron-chial artery embolization. Although these can be used to occlude a pathologic bronchial artery efficiently, use of coils predudes repeat embolization, which is often needed as patients are prone to distal collateralization (Fig. 16.21) [43,44]. The primary indication for use of coils is in patients with a bronchial artery aneurysm. Secondly, in cases where a superselective position of a (micro) catheter cannot be reached, coils can be used to protect a normal distal vascular territory against inadvertent embolization [25]. 

Nanodrug Delivery for Tumor Treatment, Fig. 2 Computational Medical Management Program (CMMP) for implementing direct drug targeting with an optimally positioned smart micro-catheter (SMC)... 

Figure 3 illustrates the approximate nanoparticle release map without the micro-catheter presence as well as the initial injection positions for targeting (a) D1 and (b) D3. While the initial map did a sufficient job of predicting the D3 injection position, the D1 position had to be adjusted due to the effects of the catheter. 

Chandy, T., Van Hee, J., Nettekoven, W. Johnson, J. (2009) Long-term in vitro stability assessment of polycarbonate urethane micro catheters Resistance to oxidation and stress cracking. Journal of Biomedical Materials Research Part B—Applied Biorruiterials, 89B, 314-324. 

Cauda equine syndrome is associated with intrathecal micro-catheters delivering a high concentration of lidocaine (and perhaps the preservatives). It consists of prolonged neural injury with motor weakness, significant pain and other sensory changes. These catheters are no longer in use. 

Figure 6.4 Prototype model of a microcatheter system with active guide wire using IPMC (ICPF) actuator (Reprinted with permission from Guo, S., Fukuda, T., Kosuge, K. et al. Micro catheter system with active guide wire-structure, experimental results and characteristic evaluation of active guide wire catheter using ICPF actuator. Proceedings of the IEEE 5th International Symposium on Micro Machine and Human Science, 191-8. Copyright (2004) IEEE).

Gue, S., Fukunda, T., Kosuge, K., et al. (1995) Micro Catheter System with Active Guide Wire, Proceedings of the IEEE International Conference on Robotic and Automation, Nagoya, Aichi, Japan, 1, 79-84. 

The celiac trunk and hepatic artery are usually catheterized by 4-F or 5-F catheters (cobra or sidewinder configuration), while the tumor-bearing target vessels should be approached by 2.7- to 3-F coaxial micro-catheters. The advantages of a microcatheter system are the increased injection resistance, which reduces the risk of microsphere reflux, and the smaller likelihood of vascular spasms. 

IPMC actuators are soft, flexible, and low drive voltage. Henee, they are very safe for humans. In addition, they are easy to deform in any shape and to miniaturize. Thanks to these advantages, many researchers have tried to apply them to many biomedical applications. In this section, applications of IPMC actuators to biomedical applications such as micro-catheter, micro-pump, and human-affinity tactile devices such as Braille displays are reviewed. 

The motion of the tube to all directions can be controlled with combined signals applied to four electrodes around the tube. For toe practical usage of the tip of toe micro-active catoeter for intravascular neurosurgery as shown in Fig. 1, the tubular actuator of external diameter of 0.8 mm in the swollen state was attached to the end of catheter. The actuator is 2 cm and the total length of the catheter is 1.5 m. The tip of toe active catoeter can be controlled from outside of the human body with a small joystick bent more than 90 within 10 s in physiological saline without gas evolution. Intravascular in vivo tests of the micro-catheter with an animal were also carried out... 

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