Obturator with internal tip protector

• US 5,618,297 A
• Filed: 10/13/1994
• Issued: 04/08/1997
• Est. Priority Date: 10/13/1994
• Status: Expired due to Term

• Current Assignee: Applied Medical Resources Corporation (Applied Medical Corporation)
• Original Assignee: Applied Medical Resources Corporation (Applied Medical Corporation)
• Inventors: Hilal, Nabil, Hart, Charles C., Tangherlini, Vincent C.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): RASCHE, PATRICK WILLIAM
• Application Number:
  US08/322,698
• Time in Patent Office: 908 Days
• Field of Search: 604/164, 604/264, 604/272, 606/167, 606/181, 606/182, 606/183, 606/184, 606/185, 30/340, 30/342, 30/366, 30/60, 30/162, 30/71
• US Class Current: 606/185
• CPC Class Codes: A61B 17/3417 Details of tips or shafts, e.g. grooves, expandable, bendable; Multiple coaxial sliding cannulas, e.g. for dilating syringe needles A61M5/32; dilators A61M29/00
• CPC Class Codes: A61B 17/3496 Protecting sleeves or inner probes; Retractable tips for protecting body piercing guide needles A61M25/0612

Abstract

An obturator adapted for use in penetrating a body wall of a patient includes an elongate shaft having an axis extending between a proximal end and a distal end. A handle is disposed at the proximal end and an arcuate cutting edge is formed at the distal end of the shaft. The shaft may include a plurality of inner walls and passages, with a shield mechanism movable within the passages from a retracted cutting position to an advanced position. A system of flanges and walls can be used to maintain the shield elements in close proximity to and sliding engagement with the associated inner walls. In an associated method of manufacture, the shaft of the obturator can be extruded.

Claims

1. An obturator adapted for use in penetrating a body wall of a patient, including:

an elongate tube having a wall with an outer surface, an inner surface, and an axis extending between a proximal end and a distal end;

a handle disposed at the proximal end of the elongate tube;

a cutting section included in the cutting tip;

a mounting section included in the cutting tip, the mounting section being disposed proximally of the cutting section; and

at least two mounting members included in the mounting section of the tip each extending outwardly of the axis of the tube to frictionally engage the inner surface of the tube at least one of the mounting members extending outwardly of the axis of the tube to an outer edge; and

means disposed at the outer edge of the at least one mounting member for enhancing the frictional relationship between the at least one mounting member and the inner surface of the elongate tube, said means including a multiplicity of serrations each forming a point extending distally of the tube for engaging the wall of the tube and facilitating insertion of the tip into the tube while inhibiting removal of the tip from the tube.

2. The obturator recited in claim 1 wherein at least one of the two mounting members extends radially outwardly of the axis of the tube between the axis of the tube and the inner surface of the tube.

3. The obturator recited in claim 1 further comprising:

a least two blades included in the cutting section, each blade extending in a generally planar relationship with an associated one of the mounting members of the mounting section.

4. An obturator, comprising:

a longitudinal wall structure having an axis extending between a distal end and a proximal end, and at least one wall extending from the axis outwardly to a particular radius, the wall defining at least one longitudinal passage along the wall structure;

a cutting edge formed on the wall at the distal end of the wall structure, the cutting edge, extending between the axis and the particular radius of the wall;

at least one shield disposed in the passage and slidable axially along the passage in close proximity to the wall and between a retracted position wherein the cutting edge is sufficiently exposed to facilitate cutting and an advanced position wherein the cutting edge is sufficiently covered to inhibit cutting; and

means having a fixed relationship with the wall structure for maintaining the shield in close proximity to the at least one wall, the maintaining means being disposed a distance from the axis which is not greater than the particular axis of the wall, and including

portions of the wall defining an axial keyway, and

a key extending from the shield into the keyway of the wall to permit axial movement of the key within the keyway while maintaining the shield in sliding engagement with the wall.

5. An obturator adapted for use in penetrating a body wall of a patient, including:

an elongate shaft having an axis extending between a proximal end and a distal end, and an outer wall including

an outer surface defining a maximum outer diameter of the shaft, and

an inner surface defining a maximum inner diameter of the shaft;

a tip section disposed at the distal end of the elongate shaft;

a plurality of inner walls included in the tip section and extending distally of the shaft, the walls being angularly spaced around the axis of the shaft;

the inner walls of the tip section extending to engage the outer wall of the shaft and to form with the outer wall a plurality of passages extending at least partially along the shaft;

at least one of the inner walls being defined by an inclined cutting edge extending along a line from the axis of the shaft to the outer surface of the shaft;

at least one shield disposed in an associated one of the passages of the shaft, the shield including

a rod portion extending from a proximal end to a distal end and having an outer surface slidably engaging the inner surface of the outer wall of the shaft, and

an enlarged protector portion secured to the distal end of the rod, the enlarged protector portion having an outer surface defining a maximum outer diameter of the protector portion which is larger than the maximum inner diameter of the shaft; and

the shield being slidable axially between a retracted position wherein the cutting edge is exposed to facilitate cutting of the body wall and an extended position wherein the cutting edge is covered by the protector portion of the shield to inhibit cutting.

6. The obturator recited in claim 5 further comprising means for locking the shield in the extended position.

7. The obturator recited in claim 5, wherein at least one of the inner walls of the tip section includes a bevel extending along the entire inclined edge between the axis of the shaft and the outer surface of the shaft to provide the inclined edge with a sharp configuration, the bevel having a radial length and a maximum axial length.

8. The obturator recited in claim 7, wherein the extended position of the shield is axially spaced from the retracted position by a distance not greater than about the maximum axial length of the bevel.

9. The obturator recited in claim 5 wherein the outer wall and the inner wall in radial cross section generally form a "T".

10. The obturator recited in claim 5 wherein the wall structure further comprises:

a first inner wall and a second inner wall;

a first outer wall extending transverse to the first inner wall;

a second outer wall extending transverse to the second inner wall; and

the first outer wall and the second outer wall forming a continuous surface between the first inner wall and the second inner wall.

11. An obturator adapted for use in penetrating a body wall of a patient, including:

an elongate shaft having an axis extending between a proximal end and a distal end, and an outer wall including

an outer surface defining a maximum outer diameter of the shaft, and an inner surface defining a maximum inner diameter of the shaft;

a tip section disposed at the distal end of the elongate shaft;

a plurality of inner walls included in the tip section and extending distally of the shaft, the walls being angularly spaced around the axis of the shaft;

the inner walls of the tip section extending to engage the outer wall of the shaft and to form with the outer wall a plurality of passages extending at least partially along the shaft;

a first one of the inner walls defined by a first inclined cutting edge extending along a line from the axis of the shaft to the outer surface of the shaft;

a second one of the inner walls defined by a second inclined cutting edge extending along a line from the axis of the shaft to the outer surface of the shaft;

a first imaginary plane extending between the axis of the shaft and the first cutting edge;

a second imaginary plane extending through at least a first point on the first cutting edge and a second point on the second cutting edge;

the second imaginary plane forming a facet angle with the first imaginary plane at the first point;

a bevel disposed along the first cutting edge and forming a bevel angle with the first imaginary plane at the first point;

the bevel angle being less than the facet angle to sharpen the first cutting edge;

at least one shield disposed in an associated one of the passages of the shaft, the shield including

a rod portion having an outer surface slidably engaging the inner surface of the outer wall of the shaft, and

an enlarged protector portion and having an outer surface defining a maximum outer diameter of the protector portion which is larger than the maximum inner diameter of the shaft; and

the shield being slidable axially between a retracted position wherein the cutting edge is exposed to facilitate cutting of the body wall and an extended position wherein the cutting edge is covered by the protector portion of the shield to inhibit cutting.

12. The obturator recited in claim 11 wherein the first cutting edge has a straight configuration.

13. The obturator recited in claim 11 wherein the first cutting edge has the configuration of an arc and the second imaginary plane is tangential to the arc at the first point.