Abstract: A surgical instrument comprising a node rotatably mounted within a restraining structure at the distal end of a shaft. The node can be rotated allowing manipulation and orientation of a surgical tool extending from the node at the distal end of the shaft through control remote from the distal end of the shaft. Cameras may also be located at the distal end of the shaft allowing stereoscopic imaging to be conveyed to an operator. The surgical instrument is well suited for administering biologically active substances to a desired location. The method of administration comprises insertion of a flexible shaft comprising a channel, controlling the location of the distal end of the shaft through control cables within the shaft, and projecting the biologically active substance from the end of the channel at the desired location.