A method of installing a cannula assembly within a coaxially-driven tissue aspiration instrument, including (i) a hand-supportable housing having a front portion with a front opening, and a rear portion with a rear opening aligned along a longitudinal axis, and having an interior volume, and a cylindrical guide tube mounted within the interior volume, and a cannula drive mechanism disposed adjacent the guide tube. The hollow cannula base portion is inserted through the front opening and within the guide tube, so that fluid seals provided on the hollow cannula base portion engage with the inner surface of the guide tube. Then a cannula is inserted through the front opening and the cannula is connected to the hollow cannula base portion.
