High quality permanent cannula pairs are
available in a wide variety of lengths and sizes.
Since the the inner cannula is ensheathed within a
slotted outer cannula, the tip of the inner cannula does not
impact upon the subcutaneous tissues with every advancement while
suctioning. As the effect is similar to that of the screen overlying the
blades of an electric razor, the patient is spared the battering
ram effect of the inner cannula with every stroke.