US Patent 8246575 Flexible hollow spine with locking feature and manipulation structure

An apparatus is disclosed for introducing surgical instruments into a body cavity. The apparatus includes a series of interconnected segments configured to pivot relative to one another allowing an end effector to be steered into position. The apparatus is also capable of achieving a rigidized state wherein the interconnected segments are in high frictional contact with one another providing a stable platform for the manipulation of tissue. Tensile elements are attached to the end effector and a control member such that an operator may use the same control member to both rigidize the instrument and also to thereafter control the end effector.