Abstract: The present invention provides a surgical retractor system in which first and second retractor blades are maintained in spaced relationship by a third retractor blade engaged with the first and second retractor blades. The first and second retractor blades are moveable between a first position in which they are nearer one another and a second position in which they are further from one another. The third retractor blade is engageable with the first and second retractor blades in the second position to maintain the first and second retractor blades in the second position. The first, second, and third retractor blades define an open space between them in which a minimally invasive surgical procedure may be carried out.

Abstract: The present invention relates to a shunt, and a method for treating catheters, more particularly shunts, wherein the catheter is made of a biocompatible material and adapted at least for insertion into the brain of a living organism and enzymes are impregnated, either directly or through a matrix forming system, into the interior of the lumen of the catheter. The enzymes impregnated have at least one of the following characteristics: (1) they require a confirmational form and either completely or substantially lose their activity upon dislocation from the interior of the lumen; (2) they require the presence of co-factors for activation which co-factors are also present in the interior of the lumen but are not otherwise present in the biological system in sufficient quantity to excite activation of the impregnated enzymes.