An implantable, time-released substance delivery device includes a casing having an exterior surface, and a number of pores disposed on the exterior surface of the casing. The time-released substance delivery device further has an interior chamber disposed within the casing, and a number of excretion tubes disposed within the casing. Each of the excretion tubes fluidly connects the interior chamber to one of the pores.

A prosthesis for insertion into a body passage is disclosed. The prosthesis includes a plastic or polymer base material which is compatible with living tissue and which possesses a memory of a predetermined configuration. The base material further has a glass transition temperature at which the prosthesis can be molded intravascularly from the predetermined configuration to a larger-radius implant configuration, which is sized and shaped to conform to an internal anatomy of the body passage to expand a narrow segment of or to occlude an opening of an out pouch of the body passage. The glass transition temperature is greater than a temperature of the body passage so that the prosthesis after being molded can be allowed to cool to the temperature of the body passage.

An apparatus for positioning instrumentation into a target region of a brain generally includes an attachment member, specifically a disc adapted to be secured to a cranium, and a marker assembly adapted to be connected to a locator device, for example a conventional stereotaxic assembly. The marker assembly includes a detachable cannula, and is further adapted to be secured to the attachment member in order to immobilize the cannula at a precise position in the brain, thus facilitating additional imaging of the patient in order to determine the position of the cannula with respect to the target region.