Pulsed vacuum and/or flow method and apparatus for tissue removal
A method of controlling a surgical cutting device, the device including a hollow needle with a port for tissue entry and a moveable cutting blade for severing tissue entering the needle through the port, the blade being movable between a first portion enabling tissue entry through the port and a second portion closing the port, the tissue entering the needle being severed as the blade moves between the first and second portions, the method includes the steps: a) providing vacuum to the hollow needle to cause tissue entry into the needle through the port; b) moving the blade from the first portion to the second position to sever the tissue entering the needle; c) evacuating severed tissue from the needle by vacuum; d) reducing vacuum to the needle before moving the blade from the second position to the first position; and repeating steps (a) through (d).
1. A surgical apparatus comprising:
a hollow needle having a port therein for enabling tissue entry into a needle lumen through said port;
a cutter sleeve including a cutting blade disposed within said hollow needle for severing tissue entering the needle lumen through said port;
a driver, connected to said cutting blade, for moving the blade between a first position enabling tissue entry through said port and a second position closing said port, the tissue entering the needle being severed as the blade moves between the first and second positions, said driver comprising a stepper motor and a cable for connecting said cutter sleeve for moving the cutter sleeve in a stroking motion, said cable including an outer stationary cable and an inner cable slidably disposed therein connected to said cutter sleeve;
a vacuum source in communication with said needle lumen for causing tissue entry into the needle lumen through said port and for aspiration of severed tissue through the lumen; and
a controller, including a valve for controlling vacuum communication between said vacuum source and said needle lumen and connected to said driver, for coordinating vacuum and blade movement at rates between one communication and about 1000 communication per minute so that vacuum is provided to said needle lumen when the blade is in the first position and during severing of tissue by the blade and reducing vacuum to said needle lumen before moving the blade from the second position to the first position.