Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2001-02-01
2003-03-11
Derakshani, Philippe (Department: 3754)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S218000
Reexamination Certificate
active
06530905
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to syringes for medical use. More particularly, the present invention pertains to syringes having a self-sheathing needle. The present invention is particularly, but not exclusively, useful for syringes having a safety sheath that can be releasably locked over the tip of the syringe needle.
BACKGROUND OF THE INVENTION
The American Dental Association (ADA) attributes most needlestick and subsequent infections in dental offices to the handling of sharp instruments and needles which must be handled carefully to prevent injuries and recapped after use. If a patient requires multiple injections from a single syringe, the needle should be recapped between each use to preclude the possibility of needlestick injury. At best, needles may be recapped by placing the cap in a special holder, by using forceps or other appropriate instrument to grasp the cap, or by simply laying the cap on the instrument tray and then manually guiding the needle into the cap until it is completely sealed. The greatest risk of needlestick injury occurs when the cap must be manually placed over the used needle. Almost 90% of needlestick injuries occur either when the operator withdraws the needle from the patient, or between injections. Operators usually do not bother to take the time to re-cap the needle between injections, and leave the bare infected needle uncovered on the tray, and this is precisely when accidents occur.
The lack of passive devices specifically designed for injury prevention has shown itself to be one of the greatest obstacles in preventing operator exposure to infected blood and bodily fluids. According to a clinical report published in the September 1997 issue of JADA, during a 63-month period, in which 423 parenteral exposures to blood and bodily fluids were documented, dental students and dental assistants had the highest rate of exposure; syringe needle injuries were the most common type of exposure; and giving injections, cleaning instruments after procedures and drilling were the activities most frequently associated with exposure. According to a study published in the July 1998 report of the CDC, 17% of all needlestick injuries to New York City healthcare workers occurred among dental workers, and 10%-18% of these latter injuries resulted in HB infection.
In light of the above, it is an object of the present invention to provide devices suitable for the purposes of injecting a medicament in a safe, efficient manner. It is another object of the present invention to provide a syringe having a disposable needle cartridge that remains in a locked guarded configuration until engagement with a syringe body. It is yet another object of the present invention to provide a syringe that passively resheaths and locks after use. It is yet another object of the present invention to provide a self-sheathing needle cartridge that can be used in conjunction with a re-useable syringe body and a standard medicament cartridge. Yet another object of the present invention is to provide a self-sheathing dental needle which is easy to use, relatively simple to manufacture, and comparatively cost effective.
SUMMARY OF THE PREFERRED EMBODIMENTS
The present invention is directed to a self-sheathing dental needle and a method for using a self-sheathing dental needle. For the present invention, the dental needle includes a cylindrically shaped syringe body that surrounds a chamber and defines a cylinder axis. The chamber is open at both its distal and proximal ends and the syringe body is formed with an exterior surface. A first finger grip is permanently affixed to the exterior surface of the syringe body near the proximal end. Further, the chamber is sized to hold a medication cartridge with an adequate amount of fluid medicament. A plunger is provided for insertion into the proximal end of the syringe body and for engagement with the medication cartridge to apply a force upon the fluid medicament in the medication cartridge.
In addition to the first finger grip, a second finger grip is slideably mounted on the exterior surface of the syringe body. Specifically, the second finger grip is oriented to allow the second finger grip to move relative to the syringe body in a direction that is parallel to the cylinder axis. Preferably, the second finger grip includes a curved proximal portion for engagement with a finger, a distal tang, and a substantially straight section connecting the curved portion to the tang. When the second finger grip is fully advanced in the distal direction, the tang is positioned near the distal end of the syringe body. Additionally, a portion of the tang extends outwardly in a radial direction from the cylinder axis. A spring that is mounted on the syringe body biases the second finger grip in the distal direction.
The self-sheathing dental needle of the present invention also includes a needle cartridge that is engageable with the syringe body. Specifically, the needle cartridge includes two parallel offset needle sections with an interconnecting midsection that provides for fluid communication between the sections. A first needle section is formed with an end extending in the distal direction from the midsection, and the second needle section is formed with an end extending in the proximal direction.
The midsection of the needle is encased in a needle holder to rigidly attach the needle to the needle holder. The needle holder includes a cylindrically shaped section positioned over the second section of the needle and centered on the second axis. For the present invention, the cylindrical section of the needle holder extends beyond the second section of the needle in the proximal direction to guard the end of the second section of the needle. Additionally, the diameter of the cylindrical section is sized to fit over the distal end of the syringe body and create a tight seal between the syringe body and the cylindrical section when the needle cartridge is engaged with the syringe body. The needle cartridge further includes a sheath that is disposed over the first section of the needle and slideably mounted on the needle holder. Preferably, the sheath is substantially shaped as an elongated cylinder having a lumen. Specifically, the sheath is centered on the first axis and slideably mounted on the holder to allow the sheath to move relative to the holder and in the direction of the first axis. For this purpose, the sheath is disposed within a hole provided in the holder. A guide can be mounted on the needle and disposed within the lumen of the sheath to maintain the sheath centered on the first axis. The midsection of the needle passes through a slit in the sheath. Preferably, the slit extends axially along the sheath to allow the sheath to move relative to the needle.
The needle cartridge further includes a spring enclosure that is mounted to the needle holder. Preferably, the spring enclosure is substantially cylindrically shaped and mounted on the needle holder proximal to the second section of the needle and centered on the first axis. The distal end of the spring enclosure is open, while the proximal end is closed. As such, a coil spring can be disposed within the spring enclosure for compression between the sheath and the proximal end of the spring enclosure. With this cooperation of structure, the coil spring in the spring enclosure biases the sheath in the distal direction. Preferably, the inner diameter of the spring enclosure is of sufficient size to allow the sheath to travel within the spring enclosure.
An important aspect of the present invention is a lock that forms a part of the cartridge. For the present invention, the lock is formed with a lock body having a distal end for attachment to the proximal end of the sheath, and a proximal end that engages the distal end of the coil spring in the spring enclosure. The lock body is sized relative to the inner diameter of the spring enclosure to allow the lock body to travel within the spring enclosure.
A locking tab extends radially from the lock body to create a
Derakshani Philippe
HBA Medical Group, Inc.
Nydegger & Associates
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