A containing catheter for facilitating sequential treatment operations therethrough, is provided. The containing catheter comprises a median portion comprising an elongated, substantially tubular member, and a distal portion, comprising a distal stiff member. A catheterization apparatus is provided, comprising the containing catheter and an elongated inner catheter insertable into the containing catheter. A method of catheterization is provided, comprising providing the containing catheter, stiffening a portion of the containing catheter and inserting the stiffened containing catheter into a body conduit of a patient.