Medical instruments with variable bending stiffness profiles

A medical system comprising:

• an elongated member having a length extending between a distal end and a proximal end, the elongated member further comprising n bending stiffness zones arranged along the length of the elongated member, wherein n is greater than or equal to two, wherein each of the n bending stiffness zones comprises a different bending stiffness, and wherein the bending stiffness of each of the n bending stiffness zones is substantially uniform along a length of the bending stiffness zone;
• a sheath having a sheath length extending between a sheath distal end and a sheath proximal end, the sheath comprising an inner channel, the sheath further comprising m bending stiffness zones arranged along the length of the sheath, wherein m is greater than or equal to two, wherein each of the m bending stiffness zones comprises a different bending stiffness, and wherein the bending stiffness of each of the m bending stiffness zones is substantially uniform along a length of the bending stiffness zone;
• a first drive mechanism configured to control movement of the elongated member independent of a movement of the elongated member;
• and
• a second drive mechanism configured to control the movement of the sheath independent of the movement of the elongated member;
• wherein the elongated member is configured to move within the inner channel of the sheath such that the elongated member and the sheath form a compound structure, wherein the compound structure comprises:
• a first bending stiffness profile when the distal end of the elongated member is aligned with the sheath distal end, and
• a second bending stiffness profile different than the first bending stiffness profile when the distal end of the elongated member extends beyond the sheath distal end,
• wherein each of the first and second bending stiffness profiles comprise a plurality of bending stiffness zones;
• and
• wherein the medical system further comprises a processor configured to operate the first drive mechanism and the second drive mechanism to:
• adjust a position of the elongated member within the inner channel of the sheath relative to the sheath to select between the first bending stiffness profile and the second bending stiffness profile based on an intended movement of the compound structure;
• and
• move the compound structure.