U.S. patent application number 12/752725 was filed with the patent office on 2010-07-29 for instruments and methods for delivering multiple implants in a surgical procedure.
This patent application is currently assigned to WARSAW ORTHOPEDIC, INC.. Invention is credited to W. Alan Rezach.
Application Number | 20100191249 12/752725 |
Document ID | / |
Family ID | 37758809 |
Filed Date | 2010-07-29 |
United States Patent
Application |
20100191249 |
Kind Code |
A1 |
Rezach; W. Alan |
July 29, 2010 |
Instruments and Methods for Delivering Multiple Implants in a
Surgical Procedure
Abstract
Instruments and methods are provided for delivering multiple
implants to locations for implantation in a patient without
requiring a second implant to be loaded onto or engaged to the
delivery instrument after delivery of a first implant.
Inventors: |
Rezach; W. Alan; (Atoka,
TN) |
Correspondence
Address: |
MEDTRONIC;Attn: Noreen Johnson - IP Legal Department
2600 Sofamor Danek Drive
MEMPHIS
TN
38132
US
|
Assignee: |
WARSAW ORTHOPEDIC, INC.
Warsaw
IN
|
Family ID: |
37758809 |
Appl. No.: |
12/752725 |
Filed: |
April 1, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11253880 |
Oct 19, 2005 |
7717921 |
|
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12752725 |
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Current U.S.
Class: |
606/99 |
Current CPC
Class: |
Y10T 279/17811 20150115;
A61B 17/12009 20130101; A61B 17/8695 20130101; A61B 17/8872
20130101 |
Class at
Publication: |
606/99 |
International
Class: |
A61F 2/46 20060101
A61F002/46; A61B 17/58 20060101 A61B017/58 |
Claims
1-18. (canceled)
19. A method for delivering multiple implants in a surgical
procedure, comprising: positioning a distal end of a delivery
instrument at a first implantation location, the delivery
instrument including a first distal-most implant and at least one
second implant proximal the first implant positioned about and
retained on the delivery instrument; distally advancing the first
implant along the delivery instrument for implantation at the
implantation location while simultaneously retaining the at least
one second implant on the delivery instrument with the delivery
instrument; positioning the distal end of the delivery instrument
adjacent a second implantation location; and distally advancing the
at least one second implant along the delivery instrument for
implantation at the second implantation location.
20. The method of claim 19, wherein the implants are biased
distally along the delivery instrument.
21. The method of claim 20, wherein the delivery instrument
includes a retaining mechanism comprising a distal retaining member
and a proximal retaining member, wherein the retaining members have
a first position wherein the distal retaining member projects
outwardly from the delivery instrument and contacts the first
implant and the proximal retaining member is recessed in the
delivery instrument, the retaining members being moveable to a
second position wherein the distal retaining member is recessed
into the delivery instrument to permit the first implant to advance
distally along the delivery instrument for implantation and the
second retaining member projects outwardly from the delivery
instrument to contact the at least one second implant to retain the
at least one second implant on the delivery instrument.
22. The method of claim 21, wherein the delivery instrument
comprises: a mounting member having a proximal end member and an
elongate mounting portion along which the implants are mounted; an
actuator axially movable in the mounting member, the actuator
including a proximal engaging end manipulatable to effect axial
movement of the actuator, the actuator including an elongate shaft
extending from the proximal engaging end through the mounting
member to a distal actuating end adjacent the mounting portion; and
the proximal and distal retaining members are positioned in the
mounting member and are movable relative thereto between their
respective recessed and outwardly projecting positions by contact
with the actuating end of the actuator as the actuator is axially
moved in said mounting member.
23. The method of claim 22, wherein the delivery instrument
includes: a housing having a proximal end secured to the proximal
end member of the mounting member, the housing extending about the
tubular portion of the mounting member to a distal end; and a
piston member within the housing and positioned about the tubular
portion of the mounting member, the piston member being biased
distally along the tubular portion to extend from the housing and
into contact with a proximal-most implant along the mounting
portion.
24. The method of claim 23, wherein the actuator is rotatable about
a longitudinal axis thereof in the mounting member to a loading
orientation, wherein in the loading orientation the actuating end
of the actuator is structured relative to the mounting portion and
the proximal and distal retaining members to recess both the
proximal and distal retaining members in the mounting member.
25. The method of claim 19, wherein the implants are washers.
Description
BACKGROUND
[0001] Various types of devices and systems have been used for
positioning implants into a patient in surgical procedures. Spinal
stabilization systems have employed plating systems, rods, anchors,
fusions devices, artificial discs, and other implants along or in
the spinal column for rigid, dynamic, and semi-rigid spinal
stabilization procedures. Such systems often include multiple
implant members that must be engaged for the system to be properly
installed. There remains a need for instruments and methods for
delivering multiple implants to the implantation location while
minimizing the time and complexity associated with handling and
positioning such implants during surgery.
SUMMARY
[0002] According to one aspect, an instrument for delivering
multiple implants to at least one surgical location in a patient
includes a mounting member, a retaining mechanism housed in the
mounting member, and an actuator coupled to the mounting member.
The mounting member includes an elongate tubular portion extending
between a distal mounting portion for receiving multiple implants
therealong and a proximal end member. The retaining mechanism is
movable between a retaining position for retaining the implants
along the mounting portion and a dispensing position allowing a
distal-most implant on the mounting portion to move distally along
the mounting portion for delivery to the at least one surgical
location. The actuator includes a proximal engaging end adjacent
the proximal end member of the mounting member. The actuator
extends from the proximal engaging end through the tubular portion
to an actuating end along the mounting portion. The actuator
includes a first axial position with the actuating end positioning
the retaining mechanism in the retaining position. The actuator is
movable in the mounting member to a second axial position with the
actuating end positioning the retaining mechanism in the dispensing
position.
[0003] According to another aspect, an instrument for delivering
multiple implants to at least one surgical location in a patient
includes a mounting member, an actuator in the mounting member, and
distal and proximal retaining members in the mounting member in
contact with the actuator. The mounting member includes an elongate
tubular portion extending between a distal mounting portion for
receiving multiple implants therealong and a proximal end member.
The actuator includes a distal actuating end in the tubular portion
of the mounting member and a proximal engaging end received in the
end member of the mounting member. The actuator has a first
rotational alignment relative to the mounting member wherein the
actuator is axially movable in the mounting member between a
retaining position and a dispensing position. In the retaining
position the distal retaining member projects outwardly from the
mounting portion and contacts a distal-most implant to axially
retain the multiple implants on the mounting portion and the
proximal retaining member is recessed in the mounting portion. In
the dispensing position the distal retaining member is recessed
into the mounting portion to permit the distal-most implant to
advance distally along the mounting portion for implantation and
the proximal retaining member projects outwardly from the mounting
portion to contact a second implant proximal of the distal-most
implant to axially retain the second implant on the mounting
portion.
[0004] In another aspect, a surgical system includes a delivery
instrument and multiple implants along the delivery instrument. The
delivery instrument includes an elongated mounting member having a
distal mounting portion and a proximal end member, an actuator in
the mounting member including an actuating end in the mounting
portion and a proximal engaging end extending proximally from the
proximal end member of the mounting member, and a retaining
mechanism in the mounting member movable upon axial displacement of
the actuator in the mounting member between a retaining position
and a dispensing position. The plurality of implants positioned
about the mounting portion include a distal-most implant in contact
with the retaining mechanism in the retaining position and a
proximal most implant in contact with a biasing member biasing the
multiple implants distally into contact with the retaining
mechanism.
[0005] In yet another aspect, a method for delivering multiple
implants to an implantation location comprises: positioning a
distal end of a delivery instrument at a first implantation
location, the delivery instrument including a first distal-most
implant and at least one second implant proximal the first implant
positioned about and retained on the delivery instrument; distally
advancing the first implant along the delivery instrument for
implantation at the implantation location while simultaneously
retaining the at least one second implant on the delivery
instrument with the delivery instrument; positioning the distal end
of the delivery instrument adjacent a second implantation location;
and distally advancing the at least one second implant along the
delivery instrument for implantation at the second implantation
location.
[0006] These and other aspects will also be apparent from the
following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an elevation view of a delivery instrument for
delivering multiple implants in a surgical implantation
location.
[0008] FIG. 2 is an elevation view of the delivery instrument of
FIG. 1 rotated 90 degrees about its longitudinal axis from its FIG.
1 positioning.
[0009] FIG. 3 is an exploded view of the delivery instrument of
FIG. 1.
[0010] FIG. 4 is a section view along line 4-4 of FIG. 3.
[0011] FIG. 5A is a perspective view of a proximal end of the
delivery instrument in a dispensing orientation.
[0012] FIG. 5B is a sectional view of a distal portion of the
delivery instrument with the delivery instrument in the dispensing
orientation and the actuator and retaining mechanism in a retaining
position.
[0013] FIG. 5C is a sectional view of the distal portion of the
delivery instrument of FIG. 5B with the delivery instrument in the
dispensing orientation and the actuator and retaining mechanism in
a dispense position.
[0014] FIG. 6A is a perspective view of the proximal end of the
delivery instrument in a loading orientation.
[0015] FIG. 6B is a sectional view of the distal portion of the
delivery instrument with the actuator and retaining mechanism in
the loading orientation.
[0016] FIG. 7 is a longitudinal section view of a mounting member
of the delivery instrument of FIG. 1.
[0017] FIG. 8 is an elevation view of an actuator of the delivery
instrument of FIG. 1.
[0018] FIG. 9 is an elevation view of the actuator of FIG. 8
rotated 90 degrees about its longitudinal axis from its FIG. 8
orientation.
[0019] FIG. 10 is an enlarged view of a distal portion of the
actuator of FIG. 9.
[0020] FIG. 11 is a longitudinal section view of a housing of the
delivery instrument of FIG. 1.
[0021] FIG. 12 is a longitudinal section view of a piston member of
the delivery instrument of FIG. 1.
[0022] FIG. 13 is a perspective view of an alignment pin of the
delivery instrument of FIG. 1.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0023] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
embodiments illustrated in the drawings and specific language will
be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended. Any such alterations and further modifications in the
illustrated devices, and such further applications of the
principles of the invention as illustrated herein are contemplated
as would normally occur to one skilled in the art to which the
invention relates.
[0024] Positioning of multiple implants during a surgical procedure
without withdrawing or re-loading the delivery instrument with an
implant is facilitated by a delivery instrument that includes a
mounting member with multiple implants positioned axially
therealong. The multiple implants are axially retained on the
mounting portion until positioned adjacent an implantation
location. The instrument can be actuated to deliver the distal-most
implant from the distal end of the delivery instrument to the
implantation location while the next most distal implant is axially
retained on the mounting portion. The delivery instrument can then
be re-positioned, or maintained in the same position, for delivery
of the second implant from the distal end by actuating the delivery
instrument. The process can be repeated until all required implants
have been delivered or until it is necessary to re-load the
delivery instrument with additional implants.
[0025] The delivery instrument can include an actuator that is
operable at the proximal end of the delivery instrument to effect
delivery and retention of the implants along the distal mounting
portion of the delivery instrument. In one embodiment, the actuator
includes a dispensing orientation that provides a push-button type
control to dispense the implants from the delivery instrument. The
actuator is moveable to a loading orientation that allows multiple
implants to be loaded about the mounting portion from the distal
end of the instrument. After loading of the implants, the actuator
is movable to the dispensing orientation where the implants are
retained on the mounting portion until the actuator is depressed by
the user to deliver the distal-most implant.
[0026] The implantation location can be an implant engageable to
bony structure of the patient, such as a spinal plate, a bone
screw, a clamp, an interbody device, or any other construct. In one
specific technique, the implantation location is a proximally
extending post of a bone screw, and the implant is a washer that is
positionable about the post. Multiple implants can be delivered to
the same location, or to multiple locations in the patient. The
washers can facilitate securement of a plate or rod to the bone
screw post in a desired position therewith.
[0027] In FIGS. 1-4 there is shown a delivery instrument 10
extending along a longitudinal axis 11 between a distal mounting
end 16 about which multiple implants can be mounted and a proximal
actuating end 18 to effectuate delivery of the implants from distal
mounting end 16. In the illustrated embodiment delivery instrument
10 includes a housing 20 to which a mounting member 40 is mounted.
Mounting member 40 extends through housing 20 between a proximal
end member 42 proximal of housing 20 and a distal mounting portion
44 distal of housing 20. Multiple implants 14 (FIG. 5) can be
mounted about distal shaft portion 44 and retained thereon with a
retaining mechanism 120. Retaining mechanism 120 is movable with an
actuator 70 between a retaining position to retain the implants on
mounting portion 44 and a dispensing position where the distal-most
implant is movable axially along mounting portion 44 for delivery
from the distal end of delivery instrument 10.
[0028] Actuator 70 extends through mounting member 40 between a
proximal user engaging end 72 and a distal actuating end 74 in
mounting member 40. Engaging end 72 can be manipulated by the user
to selectively move actuator 70 in mounting member 40 so that
actuating end 74 selectively deploys and recesses retaining
mechanism 120 between the retaining position and the dispensing
position.
[0029] Delivery instrument 10 further includes a piston member 30
movably received in housing 20 and about mounting member 40 that is
distally biased along mounting member 40 and into contact with the
implants along mounting portion 44. Piston member 30 is axially
restrained in the distal direction by a distally oriented outer lip
about piston member 30 adjacent its proximal end that contacts with
a proximally oriented inner lip about housing 20 adjacent its
distal end.
[0030] In the dispensing orientation actuator 70 is proximally
biased in mounting member 40 when in a first rotational alignment
therewith so that it is normally in a retaining position. The user
can move actuator 70 axially by pressing engaging end 72 distally
in mounting member 40 to a dispense position. In the dispensing
position actuating end 74 is configured and positioned to
manipulate retaining mechanism 120 so that distal-most implant is
movable distally along mounting portion 44 for delivery therefrom
while the next most distal implant is axially retained on mounting
portion 44 by retaining mechanism 120. The distally directed force
supplied by piston member 30 can assist in advancing the implants
distally along mounting portion 44, although embodiments without
piston member are contemplated where the implants advance solely
due to gravity.
[0031] In the loading orientation, actuator 70 can further be
configured so that when it is in a second rotational alignment with
mounting member 40 the retaining mechanism 120 is positioned to
allow implants to be axially loaded into mounting portion 44. In
this loading position, actuating end 74 is configured and position
relative to retaining mechanism 120 so that it is recessed in
mounting member 40, allowing implants to be loaded about mounting
member 40 without interference from retaining mechanism 120. Piston
member 30 can be manually restrained in a proximal position about
mounting member 40 as the implants are loaded along mounting
portion 44. When actuator 70 is returned to its first rotational
alignment in mounting member 40 in the dispensing orientation,
piston 30 can be released to contact the proximal most implant and
bias the multiple implants distally into contact with retaining
mechanism 120 in its retaining position.
[0032] Further details of operation of actuator 70 to dispense and
load implants about mounting member 40 are shown in FIGS. 5A-6B. In
FIG. 5A, actuator 70 is positioned in the dispensing orientation
relative to mounting member 40. An arrow or other indicator can be
provided on the proximal end of actuator 70 that can align with the
word "DISPENSE" or some other indicator on the side of mounting
member 40 to provide the user an indication that delivery
instrument 10 is rotationally aligned with mounting member 40 in an
orientation that allows actuator 70 to be axially moved from the
retaining position to the dispensing position. When in this first
rotational alignment, the distal actuating end 74 is positioned in
a first axial position relative to retaining members 120a, 120b of
retaining mechanism 120, as shown in FIG. 5B. In this first axial
position, actuating end 74 contacts retaining members 120a, 120b to
maintain retaining members 120a, 120b in the retaining position. In
the illustrated embodiment, retaining members 120a, 120b are
ball-shaped members that are sized relative to detents 44a, 44b to
project therefrom when bottomed out in the respective detents 44a,
44b, but are too large to pass through detents 44a, 44b.
[0033] In the retaining position of FIG. 5B, proximal retaining
member 120b is aligned with a retaining member recess 76 in
actuating end 74 so that it can recess into proximal detent 44b of
mounting portion 44 and not project outwardly from the outer
surface of mounting portion 44. Distal retaining member 120a, on
the other hand, is in contact with a distal actuating shaft portion
75 of actuating end 74 and forced into distal detent 44a so that
distal retaining member 120a projects outwardly from the outer
surface of mounting portion 44. Distal retaining member 120a thus
prevents implants 14a, 14b about mounting portion 44 from sliding
distally along mounting portion 44. Implant 14a can be located
distally of the proximal retaining member 120b. The distal end of
the second most distal implant 14b, however, is located proximally
of proximal retaining member 120b. Piston member 30 pushes against
the proximal-most implant and forces the distal-most implant 14a
into contact with retaining member 120 and the remaining implants
into end-to-end contact with one another along mounting portion
44.
[0034] In the retaining position of FIG. 5B, a distal end member
130 of actuator 70 contacts a distal end wall of mounting member
40, maintaining the proximally biased actuator 70 in the retaining
position. Actuator 70 can be axially moved toward the dispensing
position by axially and distally displacing actuator 70 in mounting
member 40, as shown in FIG. 5C, locating actuating end 74 in a
second axial position relative to mounting portion 44 and spacing
distal end member 130 a distance d from a distally oriented end
wall of mounting member 40. In the dispensing position of FIG. 5C,
distal retaining member 120a is aligned with retaining member
recess 76 in actuating end 74 so that it can recess into distal
detent 44a of mounting portion 44 and not project outwardly from
the outer surface of mounting portion 44. Distal implant 14a can
thus move distally along mounting portion 44 by gravity and/or the
bias of piston member 30 for delivery therefrom. Proximal retaining
member 120b, on the other hand, is in contact with a proximal
actuating shaft portion 77 of actuating end 74 and pushed into
proximal detent 44b sufficiently to project outwardly from the
outer surface of mounting portion 44. Proximal retaining member
120b thus prevents the next most distal implant 14b about mounting
portion 44 from sliding distally along mounting portion 44 when the
distal-most implant is being delivered.
[0035] When the proximal end of actuator 70 is released, it is
spring biased proximally to return actuating end 74 to its first
axial position and to the retaining position shown in FIG. 5B. The
next most distal implant 14b moves distally along mounting portion
44 via gravity and/or the bias from piston member 30 to contact
distal retaining member 120a, while proximal retaining member 120b
recesses into mounting portion 44. The process can be repeated for
each implant 14 to be dispensed from mounting portion 44 of
mounting member 40.
[0036] FIGS. 6A and 6B show actuator 70 positioned in a second
rotational alignment with mounting member 40 in a loading
orientation to permit loading of implants onto mounting portion 44
of mounting member 40. In FIG. 6A, the proximal end of actuator 70
is rotated relative to mounting member 40 180 degrees from its
orientation in FIGS. 5A-5C. Mounting member 40 can be inscribed
with the word "LOAD" or include some other indicator to indicate
that actuator 70 is in the loading orientation when the arrow is
aligned therewith. In one embodiment, actuator 70 is pressed
distally against the proximal bias thereof, and is then rotated to
position an alignment pin 110 in a keyed portion of actuator 70.
The engagement of alignment pin 110 in the keyed portion of
actuator 70 allows alignment pin 110 to maintain actuator 70 in its
distally displaced position relative to mounting member 40 without
the application of manual pressure at the proximal end of actuator
70 to overcome the proximal bias of actuator 70.
[0037] As shown in FIG. 6B, in the loading position distal end
member 130 is spaced distance d from the distally oriented end wall
of mounting member 40. Actuating end 74 includes an elongated
recess 78 that is aligned with detents 44a, 44b. Elongated recess
78 is configured to permit both retaining members 120a, 120b to
simultaneously recess into mounting member 40, avoiding
interference with the loading of implants 14 about mounting portion
44. Piston member 30 can be grasped and pulled proximally into
housing 20 against the distal bias of piston member 30 to allow the
implants to be positioned along mounting portion 44. After loading
of the implants, actuator 70 is rotated to its first rotational
alignment with mounting member 40, where it automatically returns
toward the position of FIGS. 5A and 5B to retain the loaded
implants on mounting portion 44. Piston member 30 can then be
released to contact the proximal most implant 14 along mounting
portion 44 and force the distal-most implant 14 into contact with
distal retaining member 120a.
[0038] Further details of the components of delivery instrument 10
are shown in FIGS. 7-13. In FIG. 7 mounting member 40 is shown in
longitudinal section view. Mounting member 40 includes proximal end
member 42 defining a cylindrical receptacle 43 for receiving a
proximal portion of actuator 70, as discussed further below. A
number of holes can be provided about end member 42 to facilitate
longitudinal movement of actuator 70 therein without build-up of
resistive air pressure. Mounting member 40 further includes a
threaded collar 46 adjacent end member 42, and an elongated tubular
portion 48 extending distally from collar 46. Tubular portion 48
defines a passage 49 extending therethrough that opens into the
receptacle 43 defined by end member 42 and at the distal end of
tubular portion 48.
[0039] The distal end of mounting member 40 includes a threaded tip
portion 52 for threadingly receiving positioning member 140
thereabout, as shown in FIG. 5B for example. Positioning member 140
includes a proximal internally threaded portion 142 engageable
about tip portion 52 and a distally extending locator tip 144.
Locator tip 144 includes a reduced diameter or size relative to
proximal portion 142 and mounting member 40, and can be positioned
in an implant receptacle or other structure at the surgical site to
assist in positioning delivery instrument 10 in the desired
position and orientation relative to the implantation location. In
one embodiment, locator tip 144 is smaller in size than mounting
portion 44 to assist in placing delivery instrument 10 in
overlapping relation with the implantation location. For example,
locator tip 144 can be placed in a tool recess in a proximal end of
a bone anchor. The implants can be delivered to the bone anchor
without slipping off, fall between or otherwise misaligning with
the bone anchor as the implant slides off positioning member
140.
[0040] Passage 49 can includes a proximal portion 49b and a reduced
size distal portion 49a. Detents 44a, 44b are located through the
wall of tubular portion 48 in communication with distal passage
portion 49a. Actuator 70, shown also in FIGS. 8-10, includes an
elongated proximal shaft portion 80 that is received in proximal
portion 49b of passage 49 and distal actuating end 74 that is
received in distal portion 49a of passage 49. The axial positioning
of recesses 76, 78 and shaft actuating portions 75, 77 relative to
detents 44a, 44b to effect deployment and recessing of retaining
members 120a, 120b is discussed above. Actuating end 74 includes a
threaded distal tip 82 for threadingly engaging end cap 130. End
cap 130 can abuttingly engage the adjacent distally oriented wall
of mounting member 40 to assist in maintaining actuator 70 in the
retaining position shown in FIG. 5B.
[0041] Proximal user engaging end 72 of actuator 70 includes a
gripping portion 84 and a cylindrical portion 86 extending from
gripping portion 84 to shaft portion 80. Gripping portion 84 can be
tapered in at least one dimension to narrow proximally and can be
concavely curved to facilitate gripping by the user to apply the
rotational and axial forces to actuator 70. Cylindrical portion 86
is rotatably received in receptacle 43 defined by end member 42 of
mounting member 40. Actuator biasing member 100 (FIGS. 1-4) can be
a spring positioned about shaft portion 80 and into contact with
the distally oriented wall 87 of cylindrical portion 86. Biasing
member 100 also contacts a proximally oriented wall 56 in end
member 42 to normally bias actuator 70 proximally relative to
mounting member 40.
[0042] Alignment pin 110 (shown in FIG. 13) includes an outer
portion 114 engaged in hole 54 of end member 42 and an inner
portion 112 positioned in a keyway in cylindrical portion 86. The
keyway is formed by an axial slot portion 86a and a transverse slot
portion 86b at the proximal end of axial slot portion 86a. Inner
portion 112 is received in axial slot portion 86a when delivery
instrument 10 is rotationally aligned in the dispensing
orientation. With biasing member 100 normally biasing actuator 70
proximally relative to mounting member 40, alignment pin 110
normally resides at the distal end of axial slot 86a, positioning
actuating end 74 and retaining mechanism 120 in mounting member 40
to the retaining position as shown in FIG. 5B.
[0043] To advance actuating member 70 and place actuating end 74
and retaining mechanism 120 in the dispensing position as shown in
FIG. 5C, user engaging end 72 is depressed against the bias of
biasing member 100, and alignment pin 110 moves along axial slot
portion 86a to its proximal end. If it is desired to position
delivery instrument 10 in the loading orientation, then from the
dispensing position gripping portion 84 can be gripped to rotate
actuator 70 in mounting member 40, advancing alignment pin 110 into
transverse slot portion 86b. When alignment pin 110 has been
translated to the end of transverse slot portion 86b opposite axial
slot portion 86a, actuator 70 is maintained in the depressed
condition against the bias of biasing member 100, and actuating end
74 is maintained in the axial and rotational position shown in FIG.
6B to permit loading of implants about mounting portion 44.
[0044] Housing 20 is shown in longitudinal section view in FIG. 11.
Housing 20 includes a longitudinal bore 21 extending between and
opening through a distal end 22 and a proximal end 24. Proximal end
24 includes internal threads 26 to threadingly engage collar 46 of
mounting member 40. Distal end 22 includes an internal lip 28
extending thereabout.
[0045] Piston member 30 is shown in FIG. 12, and includes an
elongated body extending between a distal end 32 and a proximal end
34. Piston member 30 includes a central bore 31 sized for
positioning about tubular portion 48 of mounting member 40. Piston
member 30 can include a number of elongated slots 36 extending
therethrough and spaced radially thereabout to facilitate movement
of piston member 30 between housing 20 and mounting member 40.
Piston biasing member 90 can be in the form of a spring positioned
about tubular portion 48 with a distal end of piston biasing member
90 in contact with proximal end 34 of piston member 30, and a
proximal end of piston biasing member 90 in contact with collar
46.
[0046] Biasing member 90 pushes piston member 30 against the
proximal-most implant 14 and forces the distal-most implant 14 into
contact with retaining mechanism 120. Piston member 30 further
includes an external lip 38 adjacent proximal end 34 that contacts
internal lip 28 of housing 20 adjacent the distal end of housing
20. Contact between the lips 28, 38 retains piston member 30 about
tubular portion 48 of mounting member 40 even when piston member 30
is fully extended distally from housing 20 under the force of
biasing member 90, as shown in FIGS. 1 and 2.
[0047] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only the preferred embodiment has been shown
and described and that all changes and modifications that come
within the spirit of the invention are desired to be protected.
* * * * *