# US 9,750,529 B2 · Safety stylet

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- Number: US 9,750,529 B2
- Document ID: US9750529B2
- Status: Granted
- Kind: B2
- Application number: 12/313,661
- Filed: 2008-11-21
- Published: 2009-12-03
- Granted: 2017-09-05
- Earliest claimed: 2007-11-21
- Assignees: Becton, Dickinson and Company
- Applicants: Annica Wayman; Michael Meehan; Christina D'Arrigo; Douglas Tyukody
- Inventors: Annica Wayman; Michael Meehan; Christina D'Arrigo; Douglas Tyukody
- Web page: https://patentgrep.com/patent/US9750529B2

## CPC

- A61B 17/3401: {Puncturing needles for the peridural or subarachnoid space or the plexus, e.g. for anaesthesia}
- A61B 17/3472: {for bones, e.g. intraosseus injections}
- A61B 2017/06085: {having a blunt tip}
- A61B 2017/320044: {Blunt dissectors}
- A61B 2090/0801: {Prevention of accidental cutting or pricking}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A stylet for insertion within a cannula interior of a needle is disclosed. The stylet includes a solid elongated shaft having a proximal end adapted for engagement with a needle hub, and a distal end having a surface modified profile. The surface modified profile increases the penetration force required to penetrate human skin. The ratio of the penetration force of a stylet having an unmodified distal end to the stylet having a surface modified profile is at least 1:1.4, or greater. The surface modified profile may be a roughened surface, a buffed surface and/or a blunted surface. The surface modified profile may include a yieldable material disposed over at least a portion of the distal end. A needle assembly having a stylet having a surface modified profile is also disclosed.

## Claims

### Claim 1

A safety stylet for insertion within a cannula of a needle, comprising a solid elongated stylet shaft having a proximal end adapted for engagement with a needle hub, and a distal end comprising a dull planar contact surface, wherein the contact surface has a surface modified profile, wherein the surface modified profile comprises a roughened surface.

### Claim 2 (depends on 1)

The stylet of claim 1, wherein the surface modified profile further comprises a blunted region.

### Claim 3 (depends on 1)

The stylet of claim 1, wherein the surface modified profile has been obtained through at least one of a sandblasting process, an electrochemical grinding process, a mechanical grinding process, and an etching process.

### Claim 4 (depends on 1)

The stylet of claim 1, wherein at least 0.002 inch of material has been removed from the distal end to form the surface modified profile.

### Claim 5 (depends on 1)

The stylet of claim 1, wherein the surface modified profile further comprises a beveled edge.

### Claim 6 (depends on 5)

The stylet of claim 5, wherein the beveled edge has a tip angle of from about 20° to about 30°.

### Claim 7 (depends on 1)

The stylet of claim 1, wherein the solid elongated shaft is formed of a polymeric material.

### Claim 8 (depends on 1)

The stylet of claim 1, wherein the solid elongated shaft is formed of a metal or metal alloy, the distal end having an increased bevel angle compared to a bevel angle of the needle cannula for increasing the penetration force.

### Claim 9

A safety stylet for insertion within a cannula of a needle, comprising a solid elongated stylet shaft having a proximal end adapted for engagement with a needle hub, and a distal end comprising a dull contact surface, wherein the contact surface has a surface modified profile, wherein the surface modified profile comprises a blunted surface.

### Claim 10 (depends on 9)

The stylet of claim 9, wherein the surface modified profile has been obtained through at least one of a sandblasting process, an electrochemical grinding process, a mechanical grinding process, a buffing process, and an etching process.

### Claim 11 (depends on 9)

The stylet of claim 9, wherein at least 0.002 inch of material has been removed from the distal end to form the surface modified profile.

### Claim 12 (depends on 9)

The stylet of claim 9, wherein the distal end further comprises a beveled edge.

### Claim 13 (depends on 12)

The stylet of claim 12, wherein the beveled edge has a tip angle of from about 20° to about 30°.

### Claim 14 (depends on 9)

The stylet of claim 9, wherein the solid elongated shaft is formed of a polymeric material.

### Claim 15 (depends on 9)

The stylet of claim 9, wherein the solid elongated shaft is formed of a metal or metal alloy, the distal end having an increased bevel angle compared to a bevel angle of the needle cannula for increasing the penetration force.