Method and a system for performing cataract surgery

Details Method and a system for performing cataract surgery Method and a system for performing cataract surgery

1998-09-18

2001-12-11

Dawson, Glenn K. (Department: 3761)

Surgery

Instruments

Means for removing, inserting or aiding in the removal or...

C606S180000, C606S167000, C604S022000

Reexamination Certificate

active

06328747

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to the field of devices for eye surgery in general and to the field of devices for cataract surgery in particular.
BACKGROUND OF THE INVENTION
Surgical removal of cataract is well known in the art. In cataract surgery, the content of the eye lens is completely removed leaving only the posterior lens capsule, in which an artificial lens may be subsequently installed. It is appreciated that one of the main risks in cataract surgery is a potential damage, e.g. rupture, of the lens capsule. In the past, it was common practice to “freeze” the entire lens using appropriate means and then, to remove the lens in its entirety via a large opening which is formed in the cornea, specifically, along the Cornea Limbus. This procedure resulted in damage to the lens capsule and to the vitreous body and is, therefore, no longer in use.
Presently, there are a number of known methods for removing cataract.
FIG. 1
schematically illustrates a cross-sectional view of a human eye
10
during cataract surgery in accordance with one, commonly used, prior art method. A surgical instrument
12
and, optionally, a manipulation device
14
, are inserted into eye lens
20
via cornea
16
, a preferably dilated pupil
18
and an opening formed in the anterior capsule of lens
20
. As is known in the art, lens
20
includes a core
28
, known as the nucleus, which is formed of a relatively hard tissue. Core
28
is surrounded by a layer
26
of relatively soft, jell-like tissue, known as the cortex, which fills lens capsule
24
.
The soft tissue in cortex layer
26
is typically removed gradually using a vacuum suction device and/or a “scooping” device (not shown in the drawings). To remove nucleus
28
, the hard tissue is typically, first, broken into small fragments and/or dissolved using appropriate instruments and/or solutions and, then, removed gradually by suction and/or “scooping” as described above. Alternatively, the entire nucleus can be removed in one piece, however, this requires cutting a large opening in the cornea.
FIG. 1
illustrates one method of breaking nucleus
28
using directional ultrasonic transmission. According to this method, instrument
12
includes a device
25
, generally known as a Phacoemulsifier (Hereinafter: “Phaco”), which transmits intense ultrasonic energy into nucleus
28
. The crushing effect of the ultrasonic transmission of Phaco device
25
is typically enhanced by a stream of liquid
22
supplied from an external sleeve
23
of instrument
12
, which liquid typically includes a dissolving agent. It is appreciated that, during surgery, a constant supply of liquids is generally required to compensate for escape of intraocular liquids and/or to assist in dissolving the content of lens
20
. In the example shown in
FIG. 1
, the supply of liquid
22
via sleeve
3
is utilized both as a dissolving agent and as a compensatory liquid supply. However, it is appreciated that a separate liquid supply may additionally or alternatively be used.
Manipulation device
14
typically includes a thin, pointed instrument. For example, The thin pointed instrument can be a needle or a spatula, which provide partial counter-support to the operation of instrument
12
on nucleus
28
. Such a device enables the surgeon to manipulate nucleus
28
by pushing it to a desired position and to temporarily support the nucleus at the desired position. However, it should be noted that the ability of the surgeon to manipulate and control nucleus
28
using device
14
is limited, due to various physical parameters. For example, the “angle of the attack” of device
14
on the traction between device
14
and the surface of nucleus
28
can be manipulated, using device
14
, only by pushing and not by pulling.
Medical follow up studies reveal that the quality of the post-operative optical results depends on the size of the incision made during surgery, where smaller incisions are usually associated with better post-operative results.
An additional development favoring the reduction of the incision size is the availability of foldable artificial lenses which can be introduced into the eye and inserted into the capsula while folded inside a needle-like device of relatively small diameter.
Unfortunately, ultrasonic systems such as the Phacoemulsifier are relatively expensive. Moreover, during the operation, the surgeon cannot observe a clearly defined border of the crushing action of the Phaco device
25
. Thus, the inexperienced surgeon might inadvertently damage the posterior capsule of the lens, resulting in poorer post-operative results.
Additionally, the geometry of the crushing zone around the tip of the Phaco device
25
is not constant and varies for different sonication intensities, while having no visible cue which the surgeon can use to determine the precise crushing range from the tip of the Phaco device
25
.
Consequently, there is a steep learning curve for the surgeon, requiring a relatively long training period and resulting in lower quality of the post-operative results during the training period.
Furthermore, in certain cataract cases, the degree of hardening of the cataract nucleus
28
is such that the Phaco device
25
cannot crush it, thus, requiring the surgeon to broaden the small incision in order to remove the whole cataract nucleus.
SUMMARY OF THE INVENTION
The present invention seeks to provide an improved device for manipulating tissue during surgery. The manipulation device of the present invention is particularly useful in intraocular surgery, particularly in cataract removal surgery.
The present invention provides a device, hereinafter referred to as cryomanipulator, having a selectively activated cryogenic tip designed to be inserted into a surgical site, e.g., into an eye lens, and to contact a tissue to be manipulated, for example the nucleus of an eye lens. In response to the selective activation thereof, the cryogenic tip selectively adheres to a portion of the tissue, die to the freezing of the tissue adjacent the tip. This adherence of the cryogenic tip to the manipulated tissue, at the region of contact therebetween, will be hereinafter referred to as a “freeze-grip”. As long as the cryogenic tip is active, i.e., as long as the freeze-grip is active, the tissue can be securely and conveniently manipulated in any direction, e.g., pushed pulled, twisted, etc., by appropriate movement of the cryomanipulator. When the cryogenic tip is deactivated, the freeze-grip is released and the tip can be moved to a new position or location vis-a-vis the tissue. Thus, by sequentially positioning, activating, deactivating, repositioning the cryomanipulator, the tissue can be manipulated efficiently, quickly and accurately during surgery.
The cryomanipulator is preferably used in conjunction with a surgical instrument, for example a Phacoemulsifier device or any other means for crushing hard tissue, which operates on the tissue while the tissue is temporarily supported by the cryomanipulator. It should be noted that the freeze-grip between the cryogenic tip and the tissue provides a firm, stable support to the manipulated tissue, allowing convenient operation of the surgical instrument.
In a preferred embodiment of the present invention, the cryomanipulator includes a supply of liquid, preferably an intraocular-compatible liquid, adjacent to or juxtaposed with the cryogenic tip. The supply of liquid expedites the release of the freeze-grip when the cryogenic tip is deactivated, allowing quicker repositioning of the cryomanipulator and, thus, improving the efficiency and accuracy of the cryomanipulator.
In some preferred embodiments of the present invention, the cryomanipulator includes a heating device juxtaposed with the cryogenic tip. The heating device is preferably activated with the cryogenic tip. The heat provided by the heating device maintains a biocompatible temperature along the cryomanipulator's shaft and expedites the release of the freeze-grip, improving the manipulation efficiency of the cryomanipulator and

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