Surgery – Means for introducing or removing material from body for... – With means for cutting – scarifying – or vibrating tissue
Reexamination Certificate
2000-01-24
2001-07-10
Mendez, Manuel (Department: 3763)
Surgery
Means for introducing or removing material from body for...
With means for cutting, scarifying, or vibrating tissue
C604S027000, C604S289000
Reexamination Certificate
active
06258053
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a phacoemulsification apparatus that is used to control fluid flow transfer within a surgical site of an eye. The apparatus includes a needle whose outer surface converges and inner channel narrows.
2. Discussion of Related Art
A wide array of fluid-irrigated, ultrasonically-operated cutting devices have been developed for ophthalmological surgical techniques such as phacoemulsification—a method for removing a cataract through a surgical incision in the eye.
Heretofore, phacoemulsification involved the use of a dual chambered handpiece consisting of a hollow metallic needle surrounded by a tubular sleeve. The needle is vibrated ultrasonically at selected frequencies and amplitudes to fracture the cataract to be removed and replaced by an intraocular lens. The fractured cataract tissue is aspirated through the needle interior through the use of a suction force. A fluid is infused into the eye through the tubular sleeve to irrigate the eye. The tubular sleeve has been made heretofore preferably of a soft material such as silicone or less desirably of a rigid composition such as metal or teflon.
Phacoemulsification needles come in many different configurations. Some are straight yet their inner channel narrows in diameter in a direction heading away from the open tip and spaced therefrom. Some of these also have an outer surface that converges from the tip, with the inner channel narrowing in diameter for the length of this convergence. Still others are angulated and have an inner channel that is of constant diameter.
U.S. Pat. No. 5,084,009 ('009 patent), entitled FLUID INFUSION SLEEVE FOR USE DURING EYE SURGERY, which issued to Richard Mackool on Jan. 28, 1992, whose contents are incorporated herein by reference, discloses a silicone sleeve and discusses the problems that arise from the incision compressing the non-rigid, pliable silicone sleeve. Such problems include the sleeve collapsing on the vibrating needle so that the needle, which is being vibrated at ultrahigh frequencies, rubs against the sleeve and the irrigation flow path between the needle and the sleeve becoming constricted due to the collapsed sleeve.
The sleeve through which irrigation takes place, i.e., delivering fluid to the eye, should be made of soft material that can deform to match the contour of the eye incision and thereby prevent leakage. To prevent the sleeve from collapsing on the vibrating needle, the '009 patent suggests surrounding the needle with a rigid sleeve that is interposed between the needle and the outer, soft, silicone sleeve. Thus, a collapse of the outer, soft, silicone sleeve will be onto the rigid sleeve rather than in rubbing contact with the vibrating needle.
U.S. Pat. No. 5,505,693 ('693 Patent), entitled “Method and Apparatus For Reducing Friction and Heat Generation By an Ultrasonic Device During Surgery”, which issued to Richard Mackool on Apr. 9, 1996 and whose contents are incorporated herein by reference, discloses a soft outer sleeve having a rigid lining, thereby obviating the need for a separate rigid sleeve between the outer sleeve and the needle.
The experience of the applicant, who has performed literally thousands of cataract eye operations, has found that during the course of an eye surgical operation, the tubes that lead to the handpiece of the phacoemulsification instrument from a surgical console are susceptible to unintentional kinking by medical personnel if the tubes are made from soft, pliable material that may elastically expand under pressure. These tubes include the infusion tube from the fluid supply to the handpiece and the discharge tube from the handpiece to the drainage receptacle or suction. There is no vibratory needle within these tubes so there is no risk of making unwanted rubbing contact as would prompt the solution of interposing a rigid sleeve to surround the needle as taught in the '009 patent.
Kinking may lead to severe consequences. If the infusion tube becomes kinked, a pressure loss downstream may lead to deflation of the eye. Such deflation could lead to collapse of certain eye tissues upon each other or upon the surgical instrument which extends into the eye. Either way, the tissues which are most likely to be damaged from such deflation are the cornea, the iris and the lens capsule, all surrounding the cataract. Fragile cells which line the inside of the cornea are known as corneal endothelium and they cannot be regenerated by the eye. Damage to the corneal endothelium can cause permanent damage to the cornea, resulting in a corneal clouding and decreased vision. A corneal transplant may then be necessary.
If the discharge tube becomes inadvertently kinked or, as commonly occurs, blocked by fractured tissue, the eye will still be pressurized, but the surgical operation will cease until the kink or blockage is eliminated. At the time of the kinking or blocking, however, the pressure falls downstream so that upon removal of the kink or blockage, a sudden surge in the outflow rate arises as the downstream vacuum acts to drain the eye due to loss of upstream pressure. This sudden drop in upstream pressure is felt by the eye, tending to create some deflation until normal flow is restored. It would be desirable to avoid such deflation by allowing the infusion tube to expand to hold more fluid and develop elastic energy which upon release can cause increase of flow into the eye and thereby counter the abrupt surge in the outflow upon removal of the kink or blockage. Soft material, such as silicone, elastically expands under pressure build-up and so its use is preferable.
Upon release of the blockage or kinking, the expanded, soft infusion tube contracts back to its unexpanded state and thereby provides a temporarily greater volume of fluid flow per second than was being supplied to the eye before the kinking or blocking arose. Thus, the volumetric loss of fluid during the sudden surge in outflow upon removal of the kink or blockage is better compensated by the larger volume of fluid readily available under pressure in the expanded, soft infusion tube.
U.S. Pat. No. 5,685,841 (the '841 patent) issued to Richard Mackool on Nov. 11, 1997, whose contents are incorporated herein by reference, offers a solution to the kinking problem.
The infusion sleeve may be circular or ellipsoidal in cross-section and is made of a soft, pliable material. Preferably, a rigid, noncompressible sleeve is surrounded by this infusion sleeve and acts as a barrier between the infusion sleeve and the needle in the event the infusion sleeve collapses, thereby preventing undesirable rubbing contact.
The '841 patent reveals a conventional phacoemulsification handpiece arranged to irrigate fluid into the eye and aspirate fluid and tissue from the eye continuously throughout an eye surgery operation. A concentric relationship exists between the needle, the rigid, noncompressible sleeve and the infusion sleeve. The forward end of the infusion sleeve is tapered. There is a vibratory drive in the handpiece for imparting vibratory motion on the hollow needle. The infusion sleeve defines a chamber between its inner wall and the outside of the vibrating hollow needle. Irrigation into the eye is provided normally through this chamber and aspiration from the eye is through the needle.
The irrigation is provided from a gravity fed fluid supply and through an infusion tube to the handpiece. Aspiration is provided through a discharge tube from the handpiece to a drain receptacle. In a known manner, a gate valve is provided to permit flow through the infusion tube to occur. The fluid supply is at a higher elevation than the eye. A pumping mechanism may be present and, when activated, suctions fluid from the eye and through discharge tube.
The tubes may be susceptible to unintentional kinking by medical personnel unless they are made from an incompressible material. If the kinking arises in the discharge tube, the surgical procedure stops but the eye remains inflated under pressur
Alcon Universal Ltd.
Cobrin & Gittes
Mendez Manuel
LandOfFree
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