Surgery – Instruments – Forceps
Reexamination Certificate
1999-10-25
2001-10-23
Recla, Henry J. (Department: 3731)
Surgery
Instruments
Forceps
C606S170000
Reexamination Certificate
active
06306155
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ophthalmic surgical device. More particularly, this invention is a capsulorhexis forceps for performing continuous curvilinear capsulorhexis having a replaceable hub assembly that allows a constant grip of the cornea, and utilizes the forceps as both a forceps and a cystotome.
BACKGROUND OF THE INVENTION
In the medical visual arts, it is well known that development of cataracts, a clouding of the material within the lens capsule of the eye, is a common accompaniment to the aging process. In response to this problem, eye surgeons have developed several techniques for cataract extraction. Generally, cataract extraction involves making an incision through the anterior portion of the lens capsule. A currently known technique called a capsulotomy or more particularly a Continuous Curvilinear Capsulorhexis (hereinafter “CCC”) is done to cut the anterior capsulor bag.
In this procedure, a slit incision is made in the cornea at the beginning of the continuous curvilinear capsulorhexis procedure. After the incision is made, the eye is entered with the cystotome to puncture the capsulor bag. The cystotome will either be used to continue to tear the capsulor bag or forceps will be used, after the cystotome is taken out, to make the capsulor tear. A flap is formed and is peeled off which allows the surgeon to continue with phacoemulsification procedures. At that point, direct access to the cataract lens is allowed. Clouded material is then removed through suction of the lens nucleus emulsion.
CCC is done to cut the anterior capsulor bag. One incision method done uses a cystotome or a pre-formed bent hypodermic syringe needle to enter into the anterior chamber through the pupil to access the capsulor bag. The cystotome is used to cut into the anterior portion of the capsulor bag. The problem with this technique is that there is not a lot of control with the tear of the anterior flap formed and it is not a continuous tear which produces jagged edges on the anterior portion.
Another method for performing CCC is using a cystotome in conjunction with a forceps. The cystotome is used to make a punch in the anterior capsulor bag and the forceps are used to grab the flap that was created. The anterior capsulorhexis bag is then pulled and torn by the forceps. The problems with this procedure is that there is considerable trauma to the cornea when the forceps are open and closed. Opening and closing the forceps are required to reposition the forceps to make a continuous tear in the anterior capsulor bag. By this motion, the initial incision in the eye where the forceps enters can encounter tremendous trauma.
Additionally, these two procedures are a two-step surgical procedure. There have been procedures using one device for this procedure. However, such techniques and devices can cause trauma due to stretching the incision when the forceps are opened and closed for repositioning. Such prior art techniques use one device to make the incision in the anterior capsulorhexis bag and then use it to pull and tear the flap. Such a device can be seen using the Gimbel-modified Kraff Utrata forceps. The problem with this device, like other prior art devices, is that the forceps can cause considerable trauma to the cornea when open and closed due to repositioning of the forceps when a continuous tear is required. In addition, tip damage can occur to the top of the forceps which would require replacement of the entire device. Also, the device lacks flexibility in giving the surgeon a choice of having the forceps open or closed during its initial unactuated or starting position.
Thus, there remains a need for a device that allows opening and closing of the forceps with minimal trauma to the cornea. There is also a need to provide an instrument with a replaceable tip that can cut as well as tear the anterior capsulor bag.
Other problems with current state-of the-art forceps devices for the continuous curvilinear capsulorhexis procedure is that devices can cause trauma due to variable pressure to the forceps. As the surgeon grasps the forceps, different forces on the eye may be applied due to change of grip as the anterior flap is torn. This variable in force applied to the eye could lead to trauma. There is a current need that would allow the surgeon to apply a constant grip or force to the cornea while tearing the anterior membrane. There is also a need for a device that has a replaceable tip that allows changing of the tip if the tip is damaged rather than replacing the instrument. In addition, there is a need for more flexibility in the surgical procedure to allow physicians to choose whether they would have the forceps initially opened or initially closed in the unactivated or initial starting position.
SUMMARY OF THE INVENTION
The present invention avoids the disadvantages of prior art by allowing the tip to be replaced. Replacing the tip gives the surgeon flexibility to start with an open or closed forceps. This replaceability also allows the tip to be replaced if damage to the needle occurs. The surgeon can easily replace the tip instead of discarding the instrument. A second object of this invention is that one device can be used for the surgical procedure which allows the surgeon to use a one-handed technique. This allowance could reduce the incidence of nicking interocculatory tissue. In addition, it decreases the amount of time required for this surgical procedure. Thirdly, the invention allows repositioning of the forceps without stretching the corneal tissue thus decreasing trauma to the initial incision in the eye. This device can be used in a scleral tunnel incision as well as a clear corneal incision. Lastly, the device provides constant pressure or force on the anterior membrane while gripping the anterior membrane independent of manual actuation forces.
Accordingly, there is provided in the present invention a cannula with a wire co-axially disposed within. The device performs both the incision and the forceps procedures. The cannula is attached to a replaceable hub that is attached to a handle assembly. The wire attaches to the handle assembly. The handle assembly includes at least one activation grip, a leaf spring, a shaft and a cup. Depending on whether the wire and cannula are orientated in the front or the back dictates whether the forceps are in the closed or open position initially. A spring can be disposed in the hub which allows the wire to either open or close back in its initial position. When the spring is not used in the hub, a spring in the handle is used to return the wire to its initial position. Manual gripping may be allowed by removal of the spring in the handle.
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“Closed-chamber capsulohrexis for cataract extraction combined with penetrating keratoplasty”, Lee SaBaca, M.D.; Randy J. Epstein, M.D., J Cataract Retract Surg-vol. 24, May 1998, pp. 581-584, pp. 64-65 —Forceps, Asico, p. 62 —Forceps —Katena.
Akorn Ophthalmics, Utrata/Kershner Capsulorhexis Cystotome Forceps in Titanium (4 pages).
Chandler Lamar
Lee Edwin G.
Mc Linden Thomas
Szymanski Aaron
Becton Dickinson and Company
Bui Vy Q.
Fiedler Alan W.
Recla Henry J.
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