A medical device for guiding through anatomy, such as a catheter or guidewire, with a tubular body that has been slotted to enhance bending flexibility, and a polymer liner with an anti-collapsing structure, and a method of making a medical device with a kink-resistant corrugated tubular member and an anti-collapsing structure. Anti-collapsing structures may be helical or annular, and may be wire, such as ribbon wire, grooves in the liner, corrugations, or a braid. Liners may be bonded to the anti-collapsing structure, or may have two layers, with the anti-collapsing structure between the layers. Corrugations may be formed between sections of the anti-collapsing structure with heat, pressure, stretching, compression, a mold, or a combination thereof, and may extend inward or outward. Shape or wall thickness may vary along the length to provide a varying bending stiffness. Slots may be formed in groups of two, three, or more, and adjacent groups may be rotated about the axis forming a helical pattern.
