U.S. patent application number 10/734500 was filed with the patent office on 2004-07-08 for articulating stone basket.
Invention is credited to Bagley, Demetrius, Bimbo, Frank, Butcher, Ken, Mercereau, Steve, VanDusseldorp, Gregg A..
Application Number | 20040133213 10/734500 |
Document ID | / |
Family ID | 21800328 |
Filed Date | 2004-07-08 |
United States Patent
Application |
20040133213 |
Kind Code |
A1 |
Bagley, Demetrius ; et
al. |
July 8, 2004 |
Articulating stone basket
Abstract
A medical retrieval device includes a handle, two gear racks
movably mounted to the handle for longitudinal movement, and a
pinion rotatably mounted to the handle so as to engage the two gear
racks. Rotation of the pinion moves the gear racks in opposite
directions. A basket has at least three legs, an adjacent two of
the legs being connected to one of the gear racks, and the
remainder of the legs being connected to the other gear rack such
that rotation of the pinion displaces the two legs in a first
direction and displaces the remainder of the legs in a second
direction. Thus rotation of the pinion articulates the basket.
Inventors: |
Bagley, Demetrius;
(Philadelphia, PA) ; Bimbo, Frank; (Lawrenceville,
GA) ; Butcher, Ken; (Conyers, GA) ; Mercereau,
Steve; (Conyers, GA) ; VanDusseldorp, Gregg A.;
(Crown Point, IN) |
Correspondence
Address: |
JOHN S. PRATT, ESQ
KILPATRICK STOCKTON, LLP
1100 PEACHTREE STREET
SUITE 2800
ATLANTA
GA
30309
US
|
Family ID: |
21800328 |
Appl. No.: |
10/734500 |
Filed: |
December 12, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10734500 |
Dec 12, 2003 |
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10020749 |
Dec 12, 2001 |
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6676668 |
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Current U.S.
Class: |
606/127 |
Current CPC
Class: |
A61B 17/221 20130101;
A61B 2017/2212 20130101; A61B 2017/2927 20130101; A61B 2017/2923
20130101 |
Class at
Publication: |
606/127 |
International
Class: |
A61B 017/22 |
Claims
What is claimed is:
1. A medical retrieval device comprising: a handle; two gear racks
movably mounted with respect to said handle for longitudinal
movement; a pinion rotatably mounted with respect to said handle so
as to engage said two gear racks such that rotation of said pinion
moves said gear racks in opposite directions; a basket having at
least three legs, an adjacent two of said legs being connected to a
first one of said gear racks, and the remainder of said legs being
connected to a second one of said gear racks such that rotation of
said pinion displaces said two legs in a first direction and
displaces the remainder of said legs in a second direction
different from said first direction.
2. The medical retrieval device of claim 1, further comprising a
slide attached to said handle for longitudinal movement with
respect thereto along a path between a rearward location and a
forward location, wherein said racks and said pinion are mounted
with respect to said handle by said racks and said pinion being
mounted to said slide, which is in turn mounted to said handle.
3. The medical retrieval device of claim 2, further comprising a
hollow sheath extending forward from said handle, said sheath
having a forward end, and said basket being located at a forward
end of said sheath; said basket being operatively associated with
said slide such that said basket is retracted within a forward
portion of said sheath when said slide is in said rearward
location, and said basket is extended forward of said forward end
of said sheath when said slide is in said forward location; whereby
longitudinal movement of said slide extends and retracts said
basket.
4. The medical retrieval device of claim 1, further comprising: a
slide attached to said handle for longitudinal movement with
respect thereto along a path between a rearward location and a
forward location, a hollow sheath mounted to said slide and
extending forward from said handle, said sheath having a forward
end, and said basket being located at a forward end of said sheath,
said sheath being operatively associated with said slide such that
said sheath is retracted to expose said basket when said slide is
in said rearward location, and said sheath is extended forward to
cover said basket when said slide is in said forward location;
whereby longitudinal movement of said slide extends and retracts
said sheath.
5. The medical retrieval device of claim 1, further comprising a
wheel operatively associated with said pinion such that rotation of
said wheel rotates said pinion to displace said basket legs.
6. The medical retrieval device of claim 3, further comprising a
pair of tubes telescopically disposed within said sheath, a first
one of said pair of tubes being connected to said first one of said
gear racks, and a second one of said pair of tubes being connected
to said second one of said gear racks, and wherein said adjacent
two basket legs are connected to said first one of said gear racks
by said adjacent two basket legs being connected to a forward end
of said first tube, and wherein said remainder of said basket legs
are connected to said second one of said gear racks by said
remainder of said basket legs being connected to a forward end of
said second tube.
7. The medical retrieval device of claim 1, wherein said basket
further comprises a tip member, wherein said basket legs each
comprise a forward end, and wherein said forward ends of said
basket legs are connected to said tip member.
8. The medical retrieval device of claim 7, wherein said tip member
comprises a hole formed therein, and wherein said forward ends of
said basket legs are connected to said tip member by inserting said
forward ends of said basket legs into said hole and anchoring said
forward ends of said basket legs within said hole.
9. The medical retrieval device of claim 8, wherein said tip member
is deformable, and wherein said forward ends of said basket legs
are secured within said hole by inserting said forward ends of said
basket legs into said hole and deforming said tip member so as to
clamp said forward ends of said basket legs within said hole.
10. A medical retrieval device comprising: a handle; a gear rack
movably mounted to said handle for longitudinal movement with
respect to said handle; a pinion rotatably mounted with respect to
said handle so as to engage said gear rack such that rotation of
said pinion translates said gear rack; a basket having at least
three legs, at least one of said legs being connected to said gear
rack, and the remainder of said legs being connected to said handle
such that rotation of said pinion translates said gear rack to move
said at least one of said legs relative to the remainder of said
legs.
11. The medical retrieval device of claim 10, further comprising a
slide attached to said handle for longitudinal movement with
respect thereto along a path between a rearward location and a
forward location, wherein said rack and said pinion are mounted
with respect to said handle by said rack and said pinion being
mounted to said slide, which is in turn mounted to said handle; and
wherein the remainder of said legs are connected to said handle
comprises the remainder of said legs being attached to said slide,
which is in turn mounted to said handle.
12. The medical retrieval device of claim 11, further comprising a
hollow sheath extending forward from said handle, said sheath
having a forward end, and said basket being located at a forward
end of said sheath; said basket being operatively associated with
said slide such that said basket is retracted within a forward
portion of said sheath when said slide is in said rearward
location, and said basket being extended forward of said forward
end of said sheath when said slide is in said forward location;
whereby longitudinal movement of said slide extends and retracts
said basket.
13. The medical retrieval device of claim 10, further comprising: a
slide attached to said handle for longitudinal movement with
respect thereto along a path between a rearward location and a
forward location, a hollow sheath mounted to said slide and
extending forward from said handle, said sheath having a forward
end, and said basket being located at a forward end of said sheath,
said sheath being operatively associated with said slide such that
said sheath is retracted to expose said basket when said slide is
in said rearward location, and said sheath being extended forward
to cover said basket when said slide is in said forward location;
whereby longitudinal movement of said slide extends and retracts
said sheath.
14. The medical retrieval device of claim 10, further comprising a
wheel operatively associated with said pinion such that rotation of
said wheel rotates said pinion to displace said gear rack.
15. The medical retrieval device of claim 10, wherein said basket
comprises: a plurality of legs each having a forward end; and a tip
member having a hole formed therein; said forward end of each of
said plurality of legs being received within said hole in said tip
member and secured therewithin.
16. The basket of claim 15, wherein said forward end of each of
said plurality of legs is secured within said hole in said tip
member by said forward end of each of said plurality of legs being
inserted into said hole and said tip member being crimped so as to
capture said forward end of each of said plurality of legs within
said hole.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to surgical
retrieval instruments and relates more specifically to a stone
basket or medical retrieval device in which the basket can be
articulated.
BACKGROUND OF THE INVENTION
[0002] Medical retrieval devices or stone baskets for capturing and
extracting stones from ureters are well known. Such instruments
typically comprise a basket at the forward end of an elongated
sheath. Wires disposed within the sheath connect the basket to a
handle at the opposite end of the sheath. Various mechanisms for
expanding and contracting the basket may be associated with the
handle.
[0003] Today's stone baskets are being used for purposes other than
simply capturing a stone in a ureter. They must also be able to
reach the kidney, capture a stone, reposition it, remove it, or
hold it for adjunctive treatment. Larger baskets can capture larger
stones but perform poorly in capturing smaller stones. Known
medical retrieval devices cannot readily release a stone if
complications arise and there is a need to exit quickly. On
occasion, a physician may actually have to cut the basket wires in
order to release a stone, which presents the obvious complication
of having to extract the basket wires from the patient.
[0004] Many conventional medical retrieval devices have tips at
their forward ends for joining the legs of the basket. Such
"tipped" medical retrieval devices usually have to be maneuvered
alongside the stone to permit the stone to enter the basket
laterally. Tipped medical retrieval devices thus present special
challenges when a stone is located directly ahead of the basket and
lodged against an obstruction, such as the wall of a kidney, which
prevents the basket from being maneuvered alongside the stone.
SUMMARY OF THE INVENTION
[0005] Stated generally, the present invention comprises a medical
retrieval device. The device includes a handle, two gear racks
movably mounted to the handle for longitudinal movement, and a
pinion rotatably mounted to the handle so as to engage the two gear
racks. Rotation of the pinion moves the gear racks in opposite
directions. A basket has at least three legs, an adjacent two of
the legs being connected to one of the gear racks, and the
remainder of the legs being connected to the other gear rack such
that rotation of the pinion displaces the two legs in a first
direction and displaces the remainder of the legs in a second
direction. Thus rotation of the pinion articulates the basket.
[0006] In one embodiment of the invention a sheath extends from the
front of the handle, and the basket is located at the forward end
of the sheath. A slide is mounted to the handle for longitudinal
movement, and the gear racks and pinion are mounted to the slide.
Movement of the slide extends or retracts the basket with respect
to the sheath.
[0007] In another embodiment of the invention the sheath is coupled
to the slide and extends or retracts as the slide is translated.
The gear racks and pinion are mounted to the handle at a
longitudinally fixed position. Rotation of the pinion articulates
the basket, while translation of the slide moves the sheath to
cover or expose the basket.
[0008] In the disclosed embodiments the slide assembly is moved
along its longitudinal path by the operator applying pressure with
his thumb to a button on the top of the slide assembly. Also in the
disclosed embodiments, a thumb wheel is operatively associated with
the pinion such that rotation of the wheel by the operator's thumb
causes the pinion to rotate to articulate the basket.
[0009] In another aspect the invention relates to a basket for a
medical retrieval device and to a method for manufacturing the
basket. The basket has the forward ends of its legs mounted to a
tip member. In one embodiment the tip member has a hole, the
forward ends of the tip members are inserted into the hole, and the
tip member is crimped to clamp the legs to the tip member.
[0010] A special feature of the disclosed embodiments is the
capability of a tipped basket to articulate to such a degree that
the tip is moved to a location rearward of the forward extent of
the basket. This capability permits the basket to open forwardly to
permit an object directly ahead of the basket to enter the basket
without having to maneuver the basket alongside the stone. Thus
stones which are lodged against an obstruction such as the wall of
a kidney which could normally not be retrieved with a tipped basket
can be retrieved with the medical retrieval device of the disclosed
embodiment.
[0011] Another special feature of the disclosed embodiment is that,
after having grasped a stone, the basket is capable of releasing
it. Thus if a physician begins to withdraw a stone and finds it is
too large to pass through a physiological constriction such as the
intramural ureter, or if complications arise which require rapid
extraction of the medical retrieval device, the physician can
articulate the basket to spread the basket wires, thereby releasing
the stone.
[0012] Other objects, features, and advantages of the present
invention will become apparent upon reading the following
specification, when taken in conjunction with the drawings and the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side view of a medical retrieval device
according to a preferred embodiment of the invention.
[0014] FIG. 2 is a top view of the medical retrieval device of FIG.
1.
[0015] FIG. 3 is a side view of gear racks of the medical retrieval
device of FIG. 1.
[0016] FIG. 4 is a front view of the gear racks of FIG. 3.
[0017] FIG. 5 is a side view of a slide of the medical retrieval
device of FIG. 1.
[0018] FIG. 6 is a front view of the slide of FIG. 5.
[0019] FIG. 7 is a side view of a thumb wheel of the medical
retrieval device of FIG. 1.
[0020] FIG. 8 is a front view of the thumb wheel of FIG. 9.
[0021] FIG. 9 is a cross-sectional view taken along line 9-9 of
FIGS. 7
[0022] FIG. 10 is an exploded perspective view of the handle and
slide assembly of the medical retrieval device of FIG. 1.
[0023] FIG. 11 is an exploded cross-sectional view of the handle
and slide assembly taken along line 11-11 of FIG. 1.
[0024] FIG. 12 is a partially exploded cross-sectional view of the
handle and slide assembly taken along line 11-11 of FIG. 1, with
the handle and thumb slide assembled and the thumb wheel
exploded.
[0025] FIG. 13 is a cross-sectional view of the handle and slide
assembly taken along line 11-11 of FIG. 1.
[0026] FIG. 14 is a side view of the assembled handle, slide, and
thumb wheel of FIG. 13.
[0027] FIG. 15 is a sectional view taken along line 15-15 of FIG.
13.
[0028] FIG. 16 is an exploded isometric view showing the assembly
of the basket wires of the device of FIG. 1 onto the tip
member.
[0029] FIG. 17 is an isometric view showing the assembled basket
wires and tip member of FIG. 16.
[0030] FIG. 18 is a side cutaway view of the medical retrieval
device of FIG. 1 with the basket in a retracted position.
[0031] FIG. 19 is a side cutaway view of the medical retrieval
device of FIG. 1 with the basket in an extended position.
[0032] FIG. 20 is a front view of the basket in the extended
position of FIG. 19.
[0033] FIG. 21 is a side cutaway view of the medical retrieval
device of FIG. 1 with the basket extended and articulated
downward.
[0034] FIG. 22 is a front view of the basket in the extended and
articulated position of FIG. 21.
[0035] FIG. 23 is a side cutaway view of the medical retrieval
device of FIG. 1 with the basket extended and articulated
upward.
[0036] FIGS. 24-27 are perspective views showing the use of the
medical retrieval device of FIG. 1 to retrieve a stone from a
lumen, in which:
[0037] FIG. 24 shows the basket in its normal, extended
position;
[0038] FIG. 25 shows the basket in its articulated position, open
and ready to receive a stone;
[0039] FIG. 26 shows the basket in its articulated position
maneuvered to position the basket around the stone; and
[0040] FIG. 27 shows the basket retracted to capture the stone.
[0041] FIG. 28 is a slide assembly of an alternate embodiment of a
medical retrieval device.
[0042] FIG. 29 is a side cutaway view of an alternate embodiment of
a medical retrieval device including the slide assembly of FIG.
28.
[0043] FIG. 30 is a side view of an alternate embodiment of a
medical retrieval device in which the sheath is connected to the
slide for movement with respect to the handle, showing the sheath
in an extended position so as to cover the basket.
[0044] FIG. 31 is a side view of the alternate embodiment of FIG.
30 showing the sheath in a retracted position so as to expose the
basket.
DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENT
[0045] Referring now to the drawings, in which like numerals
indicate like elements throughout the several views, FIGS. 1 and 2
show a medical retrieval device 10. The medical retrieval device 10
includes a handle 12, a sheath 14 attached to the forward end of
the body, a basket 16 extending from the forward end of the sheath
14, and a slide assembly 18 slidably mounted to the body 12. A
longitudinal slot 20 (FIG. 1) is formed in the upper edge of the
handle 12. A channel 22 (FIG. 2) is formed in one lateral face of
the handle, and a second channel 24 (see FIG. 12) is formed in the
opposite lateral face of the handle.
[0046] FIGS. 3 and 4 show upper and lower gear racks 26a, 26b. The
gear racks are identical, with the exception that the upper gear
rack 26a is inverted with respect to the lower gear rack 26b. Each
of the gear racks 26a, 26b includes a vertical member 27 and a
transverse base 28 mounted to one edge of the vertical member. A
plurality of gear teeth 29 are formed in the edge of the vertical
member 27 opposite the base 28. A passage 30 is formed in the front
face 31 of each of the gear racks 26a, 26b.
[0047] FIGS. 5 and 6 show a thumb slide 34 of the slide assembly
18. The thumb slide 34 includes a body portion 35 and a button
member 36 atop the body portion 35 and adapted to receive the thumb
of the operator. The button member 36 includes a ribbed upper
surface 38 to minimize slippage of the operator's thumb on the
button member 36. A narrowed neck portion 39 joins the button
member 36 to the body portion 35. Longitudinally extending recesses
40 are formed between the body portion 35 and the button member 36
along either side of the neck portion 39. At the lower edge of the
body portion 35 is a foot member 41 having a rounded lower surface.
A race 42 is formed in each lateral edge of the foot member 41.
[0048] An "I"-shaped channel 43 extends longitudinally through the
body portion 35 of the thumb slide 34. The "I"-shaped channel 43
includes horizontal upper and lower channel sections configured to
receive the bases 28 of the gear racks 26a, 26b. The upper and
lower horizontal channel sections are joined by a vertical channel
section which is configured to receive the vertical members 27 of
the gear racks 26a, 26b.
[0049] A first transverse bore 44 is formed in one lateral face of
the body portion 35 of the thumb slide 34 and extends into the
I-shaped channel 43. A second transverse bore 45 coaxial with the
first bore 44 and having a smaller diameter than the first bore is
formed in the opposite lateral face of the body portion 35 and
extends into the I-shaped channel 43.
[0050] FIGS. 7-9 depict a thumb wheel 46 of the slide assembly 18.
The thumb wheel 46 has a ribbed periphery 48 adapted to receive the
operator's thumb. A tab 49 is formed at the twelve o'clock position
on the thumb wheel 46 to provide a visual and tactile indicator of
the angular orientation of the wheel.
[0051] The thumb wheel 46 has a concentric, disk-shaped boss 50
formed on its inner surface. A cylindrical axle 51 is formed
concentric with the boss 50 and extends inward from the thumb wheel
46. The axle 51 is dimensioned to fit within the first transverse
bore 44 of the thumb slide 34. A pinion 52 is formed coaxial with
the axle 51 and includes a plurality of teeth adapted to engage the
gear teeth on the upper and lower gear racks 26a, 26b. A
cylindrical extension 53 is formed on the side of the pinion 52
opposite the axle 51 and coaxial therewith. The cylindrical
extension 53 is configured to be received within the second
transverse bore 45 in the thumb slide 34. A threaded bore 54 is
formed in the free end of the extension 53.
[0052] FIG. 10 is an exploded view of the handle 12 and slide
assembly 18. The handle 12 includes mating handle halves 12a, 12b
which are essentially mirror images of one another. One of the
handle halves 12a, 12b includes locator pins (not shown), and the
other handle half includes corresponding locator holes (also not
shown) which receive the pins in the opposite handle half to align
the handle halves. The two handle halves 12a, 12b are then
adhesively bonded together.
[0053] Each of the handle halves 12a, 12b includes a longitudinal
recess 20a, 20b in its upper surface. The outer boundary of each of
the longitudinal recesses 20a, 20b is defined by a slot wall 56.
When the handle halves are assembled, the longitudinal recesses
20a, 20b together form the longitudinal slot 20 (FIG. 1).
[0054] The channel 22 formed in the first handle half 12a is
dimensioned to receive the axle 51 of the thumb wheel 34
therethrough. The channel 24 in the second handle half 12b is
horizontally and longitudinally aligned with the channel 22 in the
opposite handle half 12a and is dimensioned to receive the
cylindrical extension 53 of the thumb wheel 34 therethrough.
[0055] Immediately beneath the channels 22, 24, a longitudinally
extending rib 58 is formed on the inner wall of each handle half
12a, 12b. When the handle halves 12a, 12b are assembled, the ribs
58 extend toward one another, but their ends are spaced apart.
[0056] Assembly of the handle 12 and slide assembly 18 will now be
explained with respect to FIGS. 10-13. Referring first to FIG. 10,
the upper and lower gear racks 26a, 26b are inserted into either
end of the I-shaped channel 43 in the thumb slide 34 and
longitudinally centered with respect to the thumb slide. The handle
halves 12a, 12b are then assembled around the thumb slide 34. As
can be seen in FIGS. 11 and 12, the walls 56 defining the outer
edges of the longitudinal slot 20 fit within the recesses 40 of the
thumb slide 34, and the neck 39 of the thumb slide rides within the
slot 20. Similarly, the ribs 58 on the inner wall of each handle
half 12a, 12b extend into the races 42 on either side of the foot
41 of the thumb slide 34. The walls 56 and ribs 58 guide the thumb
slide 34 for sliding movement along a predetermined path within the
handle 12.
[0057] With the handle halves 12a, 12b assembled around the thumb
slide 34, the cylindrical extension 53 of the thumb wheel 46 is
inserted through the channel 22 in the handle half 12a and advanced
to the position shown in FIG. 13. The extension 53 is located
within the bore 45 of the thumb slide, the pinion 52 is engaged
with the upper and lower gear racks 26a, 26b, and the axle 51 of
the thumb slide is disposed within the transverse bore 44 of the
thumb slide. With the pinion 52 thus engaged with the gear racks
26a, 26b, the outer end of the cylindrical extension 53 of the
thumb wheel 46 rides within the channel 24 of the handle 12, the
inner portion of the axle 51 rides within the channel 22 of the
handle, and the boss 50 of the thumb wheel bears against the wall
surrounding the channel 22 of the handle to space the thumb wheel
from the surface of the handle.
[0058] Referring further to FIG. 13, to retain the thumb wheel 46
in position, a screw 60 having a threaded shank 62 and an enlarged
head portion 63 is inserted into the threaded bore 54 in the end of
the cylindrical extension 53 of the thumb wheel 46. The enlarged
head portion 63 of the screw is larger than the slot 24 in the
handle 12 and thus prevents the thumb wheel 46 from becoming
laterally disengaged from the thumb slide 34 and handle.
[0059] Referring now to FIGS. 14 and 15, when the handle 12 and
slide assembly 18 are assembled as explained above, the teeth of
the pinion 52 engage the teeth 29 of the gear racks 26a, 26b.
[0060] FIGS. 16 and 17 depict details of the basket 16. The basket
16 comprises four legs 70a-70d having forward ends 71a-71d
respectively. A tip member 72 is made from a stainless steel ball
having a hole 73 drilled therein. The forward ends 71a-71d of the
wires 70a-70d are inserted into the hole 73 in the tip member 72.
The tip member 72 is then crimped in a collet to capture the wires
within the hole 73, in much the same way that a sinker is attached
to a fishing line. The resulting structure provides a rounded tip
that minimizes the chance of causing any laceration or puncture
during use.
[0061] FIGS. 18-21 illustrate further details of the medical
retrieval device 10. Two elongated tubes 64, 66 are telescopically
disposed within the sheath 14 of the medical retrieval device 10.
The basket 16 is mounted to the forward ends of the tubes 64, 66.
More specifically, the rearward ends 75a, 75b of the upper two
basket legs 70a, 70b are mounted to the upper tube 64, and the
rearward ends 77a, 77b of the lower two basket legs 70c, 70d are
mounted to the lower tube 66. (note: basket leg 70a is directly
behind basket leg 70b in FIGS. 18-21, and basket leg 70c is
directly behind basket leg 70d). The basket legs 70a-70d of the
disclosed embodiment are secured to the tubes 64, 66 by inserting
the rearward ends 75a, 75b, 77a, 77b of the legs into their
respective tubes and then crimping the tube ends. However, it will
be appreciated that other means for mounting the basket legs to the
tubes may be employed, including adhesives, welding, and the
like.
[0062] As will be appreciated from the foregoing explanation, an
advantage of the tip member 72 is that the forward ends 71a-71d of
the basket legs 70a-70d can be joined to the tip member after the
ends rearward ends 75a, 75b, 77a, 77b of the loops have been
attached to their respective tubes 64, 66, thus facilitating
assembly.
[0063] The rearward ends of the tubes 64, 66 are operatively
connected to the slide assembly 18 by inserting the tube ends
directly into the passages 30 in the front faces 31 of the upper
and lower gear racks 26a, 26b. The tubes 64, 66 are anchored to the
gear racks 26a, 26b by adhering, welding, clamping, or otherwise
bonding the tube ends within the passages. In the alternative, a
short length of cable can be used to couple each tube to its
associated gear rack. The forward end of the cable is connected to
the rearward end of a tube by crimping, adhering, welding, or
otherwise bonding the cable to the tube. The rearward end of the
cable is inserted into the passages 30 in the front faces 31 of the
upper and lower gear racks 26a, 26b and secured by adhering,
welding, clamping, or otherwise bonding the tube ends within the
passages. In the latter arrangement, the cable should be
sufficiently stiff that an axial compressive force applied to the
cable will be transferred to the opposite end of the cable without
causing the cable to buckle.
[0064] Operation of the medical retrieval device 10 will now be
described with respect to FIGS. 18-23. In FIG. 18, the slide
assembly 18 is in a rearward position with respect to the handle
12, and the basket 16 is retracted within the forward end of the
sheath 14. In FIG. 18 the tip member 72 is shown retracted within
the forward end of the sheath 14. To make the sheath 14 as small a
diameter as possible to facilitate introduction into the patient,
while still providing a tip assembly 72 sufficiently large to make
assembly of the basket 16 expedient, the tip member 72 may have a
larger outer diameter than the inner diameter of the sheath 14. In
this case the legs 70a-70d will be retracted within the forward end
of the sheath, but the tip member 72 will abut the forward end of
the sheath and remain at least partially exposed outside the
sheath. For purposes of this application, the basket 70 will be
considered retracted within the forward end of the sheath 14 if a
major portion of the legs 70a-70d is retracted within the forward
end of the sheath, even if the tip member 72 remains outside the
sheath.
[0065] When the slide assembly 18 is advanced in the direction of
the arrow 80, as shown in FIG. 19, the tubes 64, 66 are
telescopically advanced within the sheath 14, extending the basket
legs 70a-70d from the forward end of the sheath. The basket legs 70
are preferably formed from a shape memory metal such as nitinol,
such that the legs, once freed from the confines of the sheath 14,
spring outward into their predetermined configurations. As can be
seen in FIG. 20, when the basket 16 has expanded to its
predetermined configuration, the basket legs 70a-70d essentially
form an "X" configuration as viewed along the longitudinal axis of
the device.
[0066] In FIG. 21 the thumb wheel 46 is rotated forward. This
action rotates the pinion 52 in a counterclockwise direction, as
shown by the arrow 82 in FIG. 21. The upper gear rack 26a is
displaced forward, and the lower gear rack 26b is displaced
rearward. The rearward motion of the lower gear rack 26b retracts
the lower tube 66. Simultaneously the forward motion of the upper
gear rack 26a advances the upper tube 64. Thus the tubes 64, 66
move in reciprocal directions. This extension of the upper tube 64
and retraction of the lower tube 66 causes the upper basket legs
70a, 70b to extend and the lower basket legs 70c, 70d to retract,
thus articulating the basket 16 downward.
[0067] Referring to FIGS. 21 and 22, articulation of the basket 16
causes several advantageous effects. First, as can be seen in FIG.
21, the tip member 72 is displaced rearward of a plane 92 defined
by the forward edge of the basket. Thus if a stone is lodged
against a wall perpendicular to the longitudinal axis of the device
10, the tip member 72 does not prevent the basket 16 from being
advanced right up against the wall to capture the stone. Second, as
can be seen in FIG. 22, articulation of the basket 16 causes the
two upper legs 70a, 70b to spread apart, thus making it easier to
maneuver the basket around a stone.
[0068] In FIG. 23, the thumb wheel 46 is rotated rearward. The
turning of the thumb wheel rotates the pinion 52 in a clockwise
direction, as indicated by the arrow 84 in FIG. 23. This rotation
of the pinion 52 drives the upper gear rack 26a rearward and
simultaneously drives the lower gear rack 26b forward. This
reciprocal motion of the gear racks 26a, 26b retracts the upper
tube 64 and advances the lower tube 66. Thus the lower basket legs
70c, 70d are extended, and the upper basket legs 70a, 70b are
retracted. This causes the basket 16 to articulate upward.
[0069] Use of the device 10 to capture a stone from the body of a
patient will now be explained with reference to FIGS. 24-27. With
the basket 16 retracted within the sheath 14, the forward end of
the device is inserted into the patient to a location adjacent the
target site. For purposes of example, the target location is a
point within a duct 100 such as a ureter. As the forward end of the
device nears a stone 102, the basket 16 is opened. As shown in FIG.
24, the four basket wires 70a-70d expand. In this expanded but
unarticulated configuration, the tip assembly 72 is the forwardmost
element of the device.
[0070] The device is then actuated to articulate the basket 16, as
shown in FIG. 25. The upper two legs 70a, 70b extend, and the lower
two legs 70c, 70d retract. This articulation causes the tip
assembly 72 to be displaced downward and rearward, such that the
tip assembly is no longer the forwardmost point of the device. In
addition, articulation causes the upper two legs 70a, 70b to spread
apart, thereby creating a larger opening to facilitate maneuvering
the basket 16 around the stone 102.
[0071] The device is now maneuvered to the position shown in FIG.
26, where the basket 16 surrounds the stone 102. The basket is then
articulated back to its original position, and the device actuated
to partially retract the basket 16, causing the basket legs 70a-70d
to tighten around the stone 102, as shown in FIG. 27. With the
stone 102 thus snared, the device is withdrawn to remove the stone
from the duct 100.
[0072] If the physician begins to withdraw the stone 102 and finds
it is too large to pass through a physiological constriction such
as the intramural ureter, or if complications arise which require
rapid extraction of the device 10, the physician can rotate the
wheel 46 to articulate the basket 16 to spread the basket wires
70a-d. Thus the stone can be quickly released.
[0073] If the location of the stone 102 makes it necessary to
articulate the basket 16 left and right, rather than up and down,
the physician simply rotates the handle 12 by 90.degree.. The
sheath 14 has sufficient torsional stiffness to rotate along with
the handle 12, such that rotation of the thumb wheel 46 will effect
left or right steering of the basket 16.
[0074] The arrangement by which movement of one of the tubes 64, 66
causes an equal-but-opposite movement of the other tube provides
the advantage that rotation of the thumb wheel 46 by a given amount
results in twice the effective "throw." Thus less movement of the
thumb wheel 46 is required to effect the same range of articulation
than when only one tube is moved and the remaining tubes held
stationary.
[0075] As will be appreciated, in the embodiment 10 described
above, the motion of the basket legs is dependent, that is,
movement of one basket leg is necessarily accompanied by movement
of all of the other legs, either in the same direction or in an
opposite direction. Stated differently, in the embodiment 10 it is
not possible to move any leg of the basket independently of the
other legs. FIGS. 28 and 29 illustrate an alternate embodiment 110
which permits independent movement of one or more legs relative to
the other legs. In the embodiment 110 the slide assembly 118
comprises only a single gear rack 26a engaging the pinion 52, and
in which only one of the tubes is translated to articulate the
basket 16. The upper tube 64 is mounted to the gear rack 26a in the
same manner as previously described. However, the lower tube 166 is
fixedly mounted to the thumb slide 134. Rotation of the thumb wheel
46 in a forward direction advances the upper tube 64 while the
lower tube 166 is held steady, articulating the basket 16 downward.
Rotation of the thumb wheel 46 in a rearward direction retracts the
upper tube 64 while the lower tube 166 is held steady, articulating
the basket 16 upward.
[0076] FIGS. 30 and 31 depict a second alternate embodiment in
which, rather than the basket 16 being extended and retracted with
respect to a fixed sheath, the basket 16 is fixed with respect to
the handle while the sheath is extensible and retractable.
[0077] While the foregoing embodiment employs a pair of tubes 64,
66 telescopically disposed within the sheath 14 to facilitate
coupling the basket legs 70a-70d to the gear racks 26a, 26b of the
slide assembly 18, it will be appreciated that more than two tubes
can be used to couple the basket legs 70a-70d to the gear racks
26a, 26b of the slide assembly 18. For example, each leg 70a-70d
can be attached to its own tube, with more than one tube attached
to a given gear rack.
[0078] Further, while the foregoing embodiment 10 provides a thumb
wheel 46 which the operator turns to rotate the pinion 52 to
articulate the basket 16, it will be appreciated that the thumb
wheel is not essential to the operation of the device. For example,
a lever coupled to the pinion 52 could be used in lieu of the thumb
wheel, or an electric motor could be arranged to rotate the pinion
when actuated. Similarly, while the slide assembly 18 of the
embodiment 10 is manually advanced and retracted along its path of
movement on the handle 12 by the operator's finger, it will be
appreciated that alternate arrangements for longitudinally
displacing the slide assembly with respect to the handle may be
used, including an electric motor.
[0079] The basket 16 of the disclosed embodiment 10 comprises a tip
member 72 having a hole 73 within which the forward ends 71a-71d of
the basket legs 70a-70d are inserted and the tip member then
crimped to clamp the basket legs to the tip member. However, it
will be understood that the actuation device of the disclosed
embodiment can also be used with a basket of conventional
construction. In the alternative, the basket legs 70a-70d can be
secured within the hole 73 of the tip member 72 by other means,
such as adhesive or welding.
[0080] Finally, it will be understood that the preferred embodiment
has been disclosed by way of example, and that other modifications
may occur to those skilled in the art without departing from the
scope and spirit of the appended claims.
* * * * *