Expandable guide sheath with steerable backbone and methods for making and using them

An apparatus for providing access to a body lumen, comprising:

• a tubular member comprising a proximal end, a distal end sized for insertion into a body lumen, and a lumen extending between the proximal and distal ends;
• an elongate member extending from the distal end of the tubular member, the elongate member terminating in a distal tip, the elongate member comprising a distal portion biased to assume a predetermined nonlinear shape;
• and
• an expandable sheath extending along at least a portion of the elongate member, the sheath being expandable from a contracted condition to minimize a profile of the sheath to allow insertion along with the elongate member into a body lumen, and an enlarged condition wherein the sheath at least partially defines a lumen communicating with the tubular member lumen.

A method for accessing a body lumen or cavity using an apparatus including a tubular proximal portion and an expandable distal portion having a size smaller than the proximal portion, the method comprising:

• advancing the distal portion into a patient's body with an expandable sheath thereon in a contracted condition, the proximal portion reaching a first location when the distal portion extends into a body cavity;
• and
• manipulating the distal portion within the body cavity to access a body lumen;
• advancing the distal portion into the body lumen to access a target location;
• and
• advancing an elongate instrument through the proximal portion and the expandable sheath to deliver the instrument to the target location.