# US 9,750,530 B2 · Epidural space identification device

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- Number: US 9,750,530 B2
- Document ID: US9750530B2
- Status: Granted
- Kind: B2
- Application number: 14/405,075
- Filed: 2014-06-25
- Published: 2016-09-15
- Granted: 2017-09-05
- Earliest claimed: 2013-10-07
- Assignees: Force Engineering Co., Ltd.
- Applicants: Force Engineering Co., Ltd.
- Inventors: Takanori Imai; Hiroshi Hirota
- Web page: https://patentgrep.com/patent/US9750530B2

## CPC

- A61B 17/3401: {Puncturing needles for the peridural or subarachnoid space or the plexus, e.g. for anaesthesia}
- A61B 90/08: {Accessories or related features not otherwise provided for}
- A61M 5/31505: {Integral with the syringe barrel, i.e. connected to the barrel so as to make up a single complete piece or unit}
- A61M 5/46: having means for controlling depth of insertion
- A61M 19/00: Local anaesthesia (syringes therefor A61M5/00); Hypothermia (A61M5/42 takes precedence; cooling blood in a bypass of the arterial system A61M1/36)
- A61B 2090/0807: {Indication means}
- A61M 2205/3344: Measuring or controlling pressure at the body treatment site
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}

## Abstract

An epidural space identification device to identify when a tip of a needle used for epidural anesthesia enters an epidural space that includes a barrel formed in a cylindrical shape and communicatively connected to a needle section, a plunger formed in a cylindrical shape, retractably inserted into the barrel, and having an air hole communicating with an inside of the plunger, and an expansible member having an expansible part provided at a front end part of the plunger and bulging inside of the plunger with a positive pressure generated by pushing the plunger while air discharge from a needle side is regulated.

## Claims

### Claim 1

An epidural space identification device to identify when a tip of a needle used for epidural anesthesia enters an epidural space, comprising:
a barrel formed in a cylindrical shape, and communicatively connected to a needle section,
a plunger formed in a cylindrical shape, retractably inserted into the barrel, and having an air hole communicating with an inside of the plunger, and
an expansible member that has an expansible part and is provided at a front end part of the plunger, wherein:
the expansible part bulges inside of the plunger with a positive pressure generated by pushing the plunger while the tip of the needle is in a blocked state,
the expansible part is provided at the inside of the front end part of the plunger, and
the front end part of the plunger is inserted into the barrel while the plunger is inserted into the barrel.

### Claim 2 (depends on 1)

The epidural space identification device according to claim 1, wherein
the expansible member further comprises:
an outer circumferential part that fits to an outer circumferential surface of the front end part of the plunger and slidably contacts an inner circumferential surface of the barrel,
an engagement protrusion that engages with an engagement groove formed on the outer circumferential surface of the front end part of the plunger, and
a proximal end part of the expansible member that contacts a front end of the plunger,
and the expansible part that bulges inside of the plunger is continuous with the proximal end part of the expansible member.

### Claim 3 (depends on 2)

The epidural space identification device according to claim 2, wherein:
the expansible member further comprises a cylindrical inner part formed at an inner end of the proximal end part of the expansible member so that the cylindrical inner part fits to an inner circumferential surface of the plunger, and
the expansible part is provided on a base end of the cylindrical inner part of the expansible member.

### Claim 4 (depends on 3)

The epidural space identification device according to claim 3, wherein the air hole is formed at a base end surface of the plunger.

### Claim 5 (depends on 2)

The epidural space identification device according to claim 2, wherein the air hole is formed at a base end surface of the plunger.

### Claim 6 (depends on 1)

The epidural space identification device according to claim 1, wherein the air hole is formed at a base end surface of the plunger.