Miniature Shredding Tools for Use in Medical Applications, Methods for Making, and Procedures for Using

A method of selectively removing target tissue from a body, the method comprising:

• providing a tissue cutting instrument capable of distinguishing between target tissue to be removed and non-target tissue;
• urging the instrument against the target tissue and the non-target tissue;
• and
• allowing the instrument to cut the target tissue while automatically avoiding cutting of non-target tissue.

A medical device for removing tissue from a subject, comprising:

• a distal housing configured with at least one tissue engaging opening;
• an elongate member coupled to the distal housing and configured to introduce the distal housing to a target tissue site of the subject;
• a first rotatable member located at least partially within the distal housing and configured to rotate about a first axis, the first rotatable member comprising a first disc-shaped blade having a series of teeth along an outer circumference of the blade, the first blade lying in a first plane;
• the first rotatable member further comprising a circular first axle portion lying in a second plane that is offset from, parallel and adjacent to the first plane, the first axle portion having an outer circumference that is smaller than that of the first blade, and
• a second rotatable member located at least partially within the distal housing and configured to rotate about a second axis parallel to and radially offset from the first axis, the second rotatable member configured to rotate in a direction opposite of a direction of rotation of the first rotatable member, the second rotatable member comprising a second disc-shaped blade having a series of teeth along an outer circumference of the blade, the second blade lying in the second plane, the second rotatable member further comprising a circular second axle portion lying in the first plane, the second axle portion having an outer circumference that is smaller than that of the second blade,
• wherein the first and second blades are directly adjacent to one another and positioned to partially overlap such that tissue may be sheared between the first and second blades, between the first blade and the second axle portion and between the second blade and the first axle portion, the rotatable members configured to engage tissue from the target tissue site with the teeth of the first and second blades, rotate towards one another and inwardly to direct tissue from the target tissue site through the tissue engaging opening and into an interior portion of the distal housing.

A medical device for removing tissue from a subject, comprising:

• distal housing configured with at least one tissue engaging opening;
• an elongate member coupled to the distal housing and configured to introduce the distal housing to a target tissue site of the subject, the elongate member having a central longitudinal axis;
• a first rotatable member located at least partially within the distal housing and configured to rotate about a singular first axis, the first rotatable member comprising a first cutting blade, the first blade having a first side and a second side opposite the first side;
• a first tissue shearing surface located and configured to cooperate with the first side of the first blade to shear tissue therebetween;
• and
• a second tissue shearing surface located and configured to cooperate with the second side of the first blade to shear tissue therebetween, the first rotatable member configured to engage tissue from the target tissue site, rotate towards the first and second tissue shearing surfaces and inwardly to direct tissue from the target tissue site through the tissue engaging opening and into an interior portion of the distal housing.

A medical device for removing tissue from a subject, comprising:

• a distal housing configured with a tissue cutter assembly;
• an elongate member coupled to the distal housing and configured to introduce the distal housing to a target tissue site of the subject, the elongate member having an outer tube, an inner drive tube rotatably mounted within the outer tube, the inner drive tube having a crown gear located on a distal end thereof and comprising a plurality of gear teeth, wherein the crown gear teeth have opposing side surfaces that taper towards a center point of the inner drive tube, the inner drive tube having an outer diameter no greater than 12 mm and no smaller than 0.5 mm;
• a first rotatable member and a second rotatable member each rotatably mounted to the tissue cutter assembly, the first and the second rotatable members each comprising a plurality of disc shaped blades, wherein each of the plurality of blades of the first rotatable member lies in a plane parallel to and axially offset from a plane of another of the blades of the first rotatable member,
• each of the plurality of blades of the first and the second rotatable members being directly adjacent to at least one parallel surface and positioned to partially overlap the adjacent parallel surface such that tissue may be sheared between the adjacent, overlapping blades and parallel surfaces and such that the first and the second rotatable members are configured to rotate in opposite directions to direct tissue into an interior portion of the distal housing;
• a first drive gear train coupled between the crown gear and the first rotatable member, the first drive gear train comprising a first spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear and a second spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the first spur gear, the first and the second spur gears being configured to rotate about axes that are perpendicular to an axis of rotation of the crown gear, wherein the crown gear teeth and the second spur gear teeth have a convex profile and the first spur gear teeth have a concave profile, wherein the crown gear teeth and the second spur gear teeth have a mid-point base thickness that is greater than a base thickness of the first spur gear teeth;
• and
• a second drive gear train coupled between the crown gear and the second rotatable member, the second drive gear train comprising a third spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear and a fourth spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the third spur gear, the third and the fourth spur gears being configured to rotate about axes that are perpendicular to the axis of rotation of the crown gear, wherein the fourth spur gear teeth have a convex profile and the third spur gear teeth have a concave profile, wherein the crown gear teeth and the fourth spur gear teeth have a mid-point base thickness that is greater than a base thickness of the third spur gear teeth.