Vacuum assisted biopsy device

1. A biopsy device, comprising:

a stylet having a lumen with an open proximal end and a tissue receiving opening near a distal end thereof;

an outer cannula slidably disposed over the stylet, the outer cannula having an open distal end with a cutting edge formed thereon; and

a vacuum chamber in fluid communication with the lumen of the stylet,

wherein the outer cannula is configured to be actuated so as to causes a vacuum to be delivered to the tissue receiving opening through the lumen of the stylet before the outer cannula advances distally over the tissue receiving opening, and

wherein the outer cannula is mechanically connected to the vacuum chamber such that advancement of the outer cannula over the stylet causes movement of a wall of the vacuum chamber, thereby expanding the vacuum chamber.

2. The biopsy device of claim 1 , wherein stylet is configured to be advanced distally before the outer cannula is advanced distally.

3. The biopsy device of claim 1 , further comprising an actuation lever that is configured to selectively position the stylet and the outer cannula into a cocked position, wherein the actuation lever is configured to be actuated in a multi-step sequence to place the stylet and outer cannula in the cocked position, wherein a first actuation of the actuation lever is configured to collapse the vacuum chamber, wherein a second actuation of the actuation lever is configured a second time to retract the outer cannula, and wherein a third actuation of the actuation lever is configured to retract the stylet.

4. The biopsy device of claim 1 , wherein actuating the outer cannula partially expands the vacuum chamber that is fluidly connected to the lumen of the stylet.

5. The biopsy device of claim 4 , wherein the vacuum chamber comprises first and second seal members and a cylinder, wherein the first seal member is moveably mounted with respect to the second seal member, and wherein the second seal member is fixedly connected to the stylet.

6. The biopsy device of claim 5 , further comprising a one-way valve member attached to the proximal end of inner cannula.

7. The biopsy device of claim 1 , wherein the stylet extends through the vacuum chamber and further comprising a vacuum opening formed through the sidewall of the stylet and in communication with the lumen, wherein the vacuum opening is positioned within the vacuum chamber.

8. The biopsy device of claim 7 , further comprising a vacuum valve that is positioned over the vacuum opening, wherein the vacuum valve is configured to selectively open when the vacuum chamber is expanded so as to deliver vacuum to the lumen.

9. A biopsy device, comprising:

a stylet and an outer cannula movably mounted to a handpiece,

the stylet having a lumen with an open proximal end and a tissue receiving opening disposed adjacent a distal end thereof and in communication with the lumen;

an outer cannula slidably mounted over the stylet, the outer cannula having an open distal end with a cutting edge formed thereon; and

a vacuum chamber in fluid communication with the lumen of the stylet,

wherein the stylet is configured to be advanced distally with respect to the handpiece and the outer cannula to expose the tissue receiving opening,

the outer cannula is configured to be actuated so as to cause a vacuum to be delivered to the tissue receiving opening through the lumen of the stylet before the outer cannula advances distally over the tissue receiving opening, and

the outer cannula is mechanically connected to the vacuum chamber such that advancement of the outer cannula over the stylet causes movement of a wall of the vacuum chamber, thereby expanding the vacuum chamber.