A minimally invasive surgical system includes a surgical instrument having an elongate body portion and an oversleeve, through which the elongate body portion of the surgical instrument is extendable. A valve assembly is associated with one of the oversleeve or the surgical instrument. Mating structure is associated with two or more of the oversleeve, the surgical instrument and the valve assembly, the mating structure is operable to limit or prevent relative movement between the oversleeve and the surgical instrument.
