Note: Descriptions are shown in the official language in which they were submitted.
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MULTI-FIBER FLEXIBLE SURGICAL PROBE
The present invention relates to ophthalmic surgical equipment and
more particularly to posterior segment ophthalmic surgical equipment. Even
more particularly, the present invention relates to multi-fiber ophthalmic
probes.
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Background of the Invention
Microsurgical instruments typically are used by surgeons for removal of
tissue from delicate and restricted spaces in the human body, particularly in
surgery on the eye, and more particularly in procedures for removal of the
vitreous body, blood, scar tissue, or the crystalline lens. Such instruments
include a control console and a surgical handpiece with which the surgeon
dissects and removes the tissue. With respect to posterior segment surgery,
the handpiece may be a vitreous cutter probe, a laser probe, an illumination
probe, or an ultrasonic fragmenter for cutting or fragmenting the tissue and
is
connected to the control console by a long air- pressure (pneumatic) line
and/or power cable, optical cable, or flexible tubes for supplying an infusion
fluid to the surgical site and for withdrawing or aspirating fluid and
cut/fragmented tissue from the site. The cutting, infusion, and aspiration
1s functions of the handpiece are controlled by the remote control console
that
not only provides power for the surgical handpiece(s) (e.g., a reciprocating
or
rotating cutting blade or an ultrasonically vibrated needle), but also
controls
the flow of infusion fluid and provides a source of vacuum (relative to
atmosphere) for the aspiration of fluid and cut/fragmented tissue. The
functions of the console are controlled manually by the surgeon, usually by
means of a foot-operated switch or proportional control.
During posterior segment surgery, the surgeon typically uses several
handpieces or instruments during the procedure. This procedure requires
that these instruments be inserted into, and removed out of the incision. This
repeated removal and insertion can cause trauma to the eye at the incision
site. To address this concern, hubbed cannulae were developed at least by
the mid-1980s. These devices consist of a narrow tube with an attached hub.
The tube is inserted into an incision in the eye up to the hub, which acts as
a
stop, preventing the tube from entering the eye completely. Surgical
instruments can be inserted into the eye through the tube, and the tube
protects the incision sidewall from repeated contact by the instruments. In
addition, the surgeon can use the instrument, by manipulating the instrument
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when the instrument is inserted into the eye through the tube, to help
position
the eye during surgery.
Many surgical procedures require access to the sides or forward
portion of the retina. In order to reach these areas, the surgical probes must
be pre-bent or must be bendable intra-operatively. Articulating
laser/illumination probes are known. See for example, USPN 5,281,214
(Wilkins, et al.). The articulation mechanism, however, adds extra complexity
and expense. One flexible laser probe needing no articulation mechanism is
commercially available, but this device uses a relatively large diameter
optical
fiber sheathed in a flexible tube comprising the distal tip, resulting in a
large
bend radius and large distal tip diameter with significant bend stiffness.
These characteristics require that the distal tip contain a non-bent straight
portion for ease of insertion of the bent portion, which must flexibly
straighten
as it passes through the hubbed cannula. The straight portion of the distal
tip
allows the bent portion to flexibly pass through the hubbed cannula before the
distal cannula of the handpiece enters the hubbed cannula, to allow
maximum bending clearance of the flexible portion, thereby minimizing the
bending strain and corresponding frictional insertion forces. Such a large
bend radius, large diameter flexible tube, and straight distal tip cause the
useable portion of the fiber to extend a relatively long distance from the
distal
tip of the probe and limits laser treatment access of the probe.
A further disadvantage in the known art is the flexibility of the distal
cannula, which is a function of the material properties and cross sectional
moment of inertia, as determined by the gauge size of the outside diameter of
the cannula to fit within the hubbed cannula, and the inside diameter of the
cannula to accept the flexible tube. For any given material, the outer and
inner diameters of the cannula determine the flexibility of the cannula. This
flexibility limits the surgeon's ability to use the instrument to manipulate
the
position of the eye during surgery.
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A further disadvantage in the known art is that it does not offer a non-
articulating flexible-tip probe providing both laser and illumination delivery
through separate paths optimized for each delivery function. Current surgical
procedures require unique delivery patterns for laser and illumination: a
narrow beam pattern for laser delivery, and a wide angle pattern for
illumination. The optical parameters needed to deliver these two unique
patterns differ to the extent that a single delivery path requires either
separate
instruments or compromised performance of the laser delivery pattern and/or
the illumination pattern.
Accordingly, a need continues to exist for a non-articulating flexible-tip
probe that does not require a straight portion of flexible tube at the distal
tip,
and which thus provides a more compact useable tip length, thereby allowing
greater laser treatment access to internal posterior structures of the eye
is without compromising insertion forces. The need also continues to exist for
a
flexible-tip probe which provides increased rigidity of the distal cannula to
facilitate manipulation of the eye position during surgery. In addition, the
need exists for a flexible-tip probe which provides both laser and
illumination
delivery through separate paths optimized for each delivery function.
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Brief Summary of the Invention
The present invention improves upon prior art by providing a probe
having a flexible, small diameter fiber within a flexible tube, comprising the
s non-articulating distal tip of the probe. The small diameter fiber and tube
combination allow the fiber to be bent in a tight radius comprising the major
portion of the length of the exposed portion of the fiber, minimizing the need
for a straight portion to reduce insertion forces. Such a tight radius and
compact length allow the fiber greater access to the internal posterior
structures of the eye; thus increasing the laser treatment area of the probe,
without compromising insertion forces.
Accordingly, an objective of the present invention is to provide a laser
probe having a flexible, small diameter non-articulating fiber/tube comprising
the distal tip of the probe.
Another objective of the present invention is to provide a laser probe
having a flexible, small diameter fiber/tube comprising the distal tip of the
probe that is bent in a tight radius comprising the major portion of the
length
of the exposed portion of the fiber.
A further objective of the present invention is to provide a laser probe
that allows greater access to the internal posterior structures of the eye.
A further objective of the present invention is to provide increased
rigidity of the distal cannula to facilitate manipulation of the eye position
during surgery.
A further objective of the present invention is to provide a flexible-tip
laser probe able to deliver both laser and illumination through separate,
optimized fiber optic paths.
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Other objectives, features and advantages of the present invention will
become apparent with reference to the drawings, and the following
description of the drawings and claims.
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Brief Description of the Drawings
FIG. 1 is a perspective view of the probe of the present invention.
FIG. 2 is an elevational view of the probe of the present invention.
FIG. 3 is a cross-sectional view of the probe of the present invention.
FIG. 4 is a cross-sectional view of an alternate embodiment of the
io present invention, having separate laser and illumination fiber optic
delivery paths.
FIG. 5 is a cross-sectional magnified view of distal end of an
embodiment of the present invention shown in FIG. 4.
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Detailed Description of the Invention
Embodiments of the probe of the present invention provide for a
flexible illuminated laser probe with separate, optimized fibers for laser and
illumination in a single instrument designed for minimally invasive Trocar-
entry surgical systems, unlike the prior art which does not provide for
separate fibers to deliver laser and illumination light and that can be used
in
minimally invasive Trocar-entry surgical systems. The embodiments of this
invention thus can provide a probe having optimal illumination intensity, ease
to of insertion to a surgical site, and a compact tip for broad treatment
access.
Some of the advantages that can be provided by the embodiments of this
invention are: minimally invasive retinal photo-coagulation with directed,
optimized illumination of a treatment area; laser and illumination in a single
instrument, allowing a surgeon to perform self-scleral depression; compact
curved tip and short active length provide broad access to peripheral retina;
reduces or eliminates the possibility of elliptical burn associated with
straight
tipped laser probes; help to avoid lens contact when treating a surgical site
opposite to entry port; and facilitate treatment posterior to the sclera
buckle.
As best seen in the FIGS. 1-5, probe 10 of the present invention generally
consists of handle or body 12, containing or encasing a laser fiber optic 16
and/or an illumination fiber optic 22, flexible tube 21, distal cannula 18,
and
fiber optic sheath 14. Body 12 is generally hollow and can be made from any
suitable material such as stainless steel, titanium or thermoplastic. Cannula
18 may be made from any suitable material such as titanium or stainless steel
and held within body 12 by any conventional method, such as adhesive or
crimping. Fiber optic sheath 14 may be any suitable tubing such as
thermoplastic or silicone. In some embodiments, the probe can comprise a
plurality of fiber optic cables, each having one or more optical fibers (e.g.,
fiber optics such as laser fiber optic 16 and illumination fiber optic 22).
The
plurality of fiber optic cables and fiber optics can have the same or similar
optical properties or can each have unique optical properties suitable for
their
purpose (e.g., illumination or laser light).
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Laser fiber optic 16 and illumination fiber optic 22 can be connected on
a proximal end (not shown) to any suitable laser or illumination source
through a connector of a type well-known in the art and are surrounded by
flexible tube 21 with exposed portion 19. Flexible tube 21 is made from a
shape memory alloy such as Nitinol, and is held within cannula 18 by any
conventional method, such as adhesive or crimping, and encases laser fiber
optic 16 and/or illumination fiber optic 22, which are held to inner diameter
of
flexible tube 21 by any conventional method such as adhesive or crimping.
Laser fiber optic 16, illumination fiber optic 22, and exposed portion 19 of
to flexible tube 21 extend beyond distal end 20 of cannula 18 a distance of
approximately 3 millimeters to 14 millimeters, with approximately 4
millimeters
to 6 millimeters or 11 millimeters to 13 millimeters being most preferred,
respectively for a single fiber optic or a plurality of fiber optics encased
in the
flexible tube 21.
Laser fiber optic 16 and illumination fiber optic 22 may be made of any
fiber optic material suitable for conducting laser or illumination light,
respectively. Preferable for a single laser delivery fiber optic is silica (or
glass) with an outer diameter of between 100pm and 125pm with at least
exposed portion 19 of flexible tube 21 being a 33 gauge (approximately 0.008
inches OD) flexible nitinol tube bent at an angle of approximately 30-45 on a
radius of approximately between 4.5 millimeters and 6 millimeters along
exposed section 19. Importantly, the section of laser fiber optic 16 within
exposed section 19 can be curved or bent beginning at or near distal end 20
of cannula 18, with minimal or no straight section near distal end 20 of
cannula 18. Such a construction improves peripheral laser treatment access
near the point of entry of cannula 18. By virtue of the smaller diameter
flexible tube with significantly reduced cross sectional moment of inertia,
the
simultaneous insertion force of the exposed section 19 with the cannula 18
into a hubbed surgical cannula remains within an optimal range to facilitate
manual insertion and extraction.
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Preferable material for a laser fiber optic with additional illumination
fiber optic, or for a plurality of fiber optics, is silica or plastic or a
combination
thereof, with outer diameter between 100pm and 250pm with at least
exposed portion 19 of flexible tube 21 being a 31 to 28 gauge (approximately
0.010 to 0.015 inches OD) flexible nitinol tube bent at an angle of
approximately 30-45 on a radius of approximately between 7 millimeters and
millimeters along exposed portion 19. Importantly, the section of laser fiber
optic 16 and/or illumination fiber optic 22 within exposed section 19 can be
curved or bent beginning at or near distal end 20 of cannula 18, with minimal
10 or no straight section near distal end 20 of cannula 18. Such a
construction
provides both the laser and illumination functions, as well as improved
peripheral laser treatment access near the point of entry of cannula 18. By
using a minimized flexible tube diameter, bend radius, and straight section,
the insertion force of the exposed section 19 into a hubbed surgical cannula
15 remains within an optimal range to facilitate manual insertion and
extraction,
while providing the additional illumination function. A further reduction of
insertion force may be realized by the use of anti-friction coating 23 on the
exposed section 19 of flexible tube 21.
In use, exposed section 19 encasing laser fiber optic 16 and/or
illumination fiber optic 22 can be straightened so that exposed section 19 can
be inserted into an eye through a 23 gauge or a 25 gauge hubbed cannula.
Once in the eye, the shape memory characteristics of the nitinol tube cause
exposed section 19 to resume its curved configuration.
While certain embodiments of the present invention have been
described above, these descriptions are given for purposes of illustration and
explanation. Variations, changes, modifications and departures from the
systems and methods disclosed above may be adopted without departure
from the scope or spirit of the present invention.
