U.S. patent application number 10/287693 was filed with the patent office on 2003-07-03 for spring loaded fixation element insertion device.
Invention is credited to Chen, Michael C., Zwirnmann, Ralph Fritz.
Application Number | 20030125750 10/287693 |
Document ID | / |
Family ID | 26964599 |
Filed Date | 2003-07-03 |
United States Patent
Application |
20030125750 |
Kind Code |
A1 |
Zwirnmann, Ralph Fritz ; et
al. |
July 3, 2003 |
Spring loaded fixation element insertion device
Abstract
The invention relates to a device for attaching fixation
elements to bone, having a longitudinal member with a channel
extending therein adapted for receiving at least one fixation
element. A shaft extends within the channel and is positioned
coaxially within at least a portion of the longitudinal member and
at least a portion of the shaft is retained within the longitudinal
member and a distal end of the shaft is configured and adapted to
contact at least a portion of the fixation element received within
the longitudinal member. A spring is positioned adjacent the shaft
for resiliently biasing the shaft in an axial direction and the
shaft is moveable with respect to the longitudinal member to drive
the fixation element into bone.
Inventors: |
Zwirnmann, Ralph Fritz;
(Roslyn, PA) ; Chen, Michael C.; (King of Prussia,
PA) |
Correspondence
Address: |
PENNIE & EDMONDS LLP
1667 K STREET NW
SUITE 1000
WASHINGTON
DC
20006
|
Family ID: |
26964599 |
Appl. No.: |
10/287693 |
Filed: |
November 5, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60330977 |
Nov 5, 2001 |
|
|
|
Current U.S.
Class: |
606/104 ;
606/295; 606/309; 606/329 |
Current CPC
Class: |
A61B 17/068 20130101;
A61B 17/8875 20130101; B25B 23/04 20130101; B25B 23/065 20130101;
A61B 17/0642 20130101; B25B 15/02 20130101; A61B 2017/0647
20130101; B25B 23/101 20130101; A61B 17/92 20130101; A61B 2017/925
20130101 |
Class at
Publication: |
606/104 ;
606/72 |
International
Class: |
A61B 017/56 |
Claims
What is claimed is:
1. A device for attaching a fixation element to bone, comprising: a
longitudinal member extending along a longitudinal axis from a
proximal end to a distal end and having a channel extending therein
adapted for receiving at least a portion of one fixation element;
and a shaft positioned coaxially within and extending along at
least a portion of the longitudinal member, at least a portion of
the shaft retained within the channel of the longitudinal member
and having a distal end configured and adapted to contact at least
a portion of the fixation element, a spring positioned adjacent the
shaft for resiliently biasing the shaft in an axial direction,
wherein the shaft is moveable with respect to the longitudinal
member to drive the fixation element into bone.
2. The device of claim 1, further comprising an adjustment gauge
for adjusting the bias of the spring.
3. The device of claim 1, wherein the shaft is moveable from a
loaded position to a unloaded position.
4. The device of claim 3, further comprising a locking mechanism
for engaging the shaft, wherein the locking mechanism is moveable
from a first position to a second position, and when the locking
mechanism is in the first position the shaft is locked in the
loaded position and when the shaft is in the second position the
shaft is moveable to the second unloaded position.
5. The device of claim 4, wherein the locking mechanism is
pivotally mounted to the longitudinal member and is resiliently
biased into the locking position.
6. The device of claim 3, further comprising a loading mechanism
for engaging the shaft and moving the shaft from the unloaded to
the loaded position.
7. The device of claim 6, wherein the loading mechanism comprises a
slide member moveably mounted to the longitudinal member that is
operable by a user to manually move the shaft in an axial
direction.
8. The device of claim 7, wherein the slide member is resiliently
biased out of engagement with the shaft.
9. The device of claim 3, wherein the shaft is moveable to the
loaded position by applying force on the distal end of the
device.
10. The device of claim 6, further comprising at least one pin
member rigidly mounted tot he shaft and extending radially
therefrom, and wherein the loading mechanism comprises a cam
mechanism that has an internal ramp for engaging the pin and moving
the shaft in the axial direction.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Priority of Provisional Application No. 60/330,977, filed on
Nov. 5, 2001 is claimed under 35 U.S.C. .sctn.119 and priority of
U.S. patent application Ser. No. 09/866,841, filed on May 30, 2001
and PCT Application No. PCT/US02/16656, filed on May 28, 2002 is
claimed under 35 U.S.C. .sctn.120, the entire contents of which are
incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a device for the storage
and dispensing of osteosynthetic fixation elements, and in
particular to a device for attaching fixation elements to bone.
BACKGROUND OF INVENTION
[0003] In the surgical treatment of fractures in the maxillofacial
area, as well as fractures of the foot and hand, a trend toward
preferring ever-smaller implants can clearly be noted. The reason
for this is the generally increased understanding of the
biomechanical bases of osteosynthesis. In the field of treating
maxillofacial fractures, more attention can be paid to the cosmetic
results of osteosynthesis, thanks to the miniaturization of
implants. In the field of hand surgery, restrictions on movement in
the area of the fingers can be avoided. In this regard, smaller
osteosynthetic implants in the fingers can be placed under the
tendons. In the case of an implant with a large cross-section, the
tendons need no longer be extended to their full length.
[0004] The dimensions of some smaller implants (screws, plates and
tacks) are in the range of about 0.8 mm to about 2.0 mm. Problems
in the area of packaging, storage and manipulation during surgery
arise due to this miniaturization. Handling in the operating room,
particularly in the maxillofacial area, has proved difficult.
Depending on the degree of severity of the fracture or correction,
up to 40 bone fixation elements, such as tacks or screws, may be
required. These screws must be taken individually by the operating
room nurse from a so-called screw rack, checked for length, placed
on a screwdriver and given to the surgeon. The surgeon must, in
turn, insert them through the osteosynthesis plate into pre-drilled
screw holes. During the transfer of the screw and the attempted
insertion of the screw, it often falls off the screwdriver, into
the wound or onto the operating room floor. The attempt to find a
lost screw is often excessively time-consuming, given their
dimensions and extends the time spent in surgery. The frequent loss
of screws in the operating room, and during packing and
sterilization, causes unnecessary costs for the hospital. Thus, it
is desirable to have a simple device that can be operated with one
hand, thereby freeing the operator's other hand to align the
fixation element or perform other tasks
[0005] An additional problem in dealing with mini-screws arises
during their implantation. After the surgeon has selected the
osteosynthesis plate proper for the fracture in question, a plate
is positioned over the fracture. A hole is then drilled for the
screw (0.5-1.5 mm diameter) through one of the plate holes.
Commonly, problems arise in controlling the amount of force applied
during the insertion of the screw and or tack. For example, if a
surgeon is required to insert a screw or tack with manual force,
the manula force could be transmitted to the surrounding bone,
which could bend thin and/or flexible bone in young patients.
[0006] Also, problems such as surgical gloves tearing or hand
pinching can arise if the insertion device has parts that move
externally during the firing of the device. Thus, a need exists for
an insertion device that minimizes the manual force exertion
required and to minimize the gross forces applied to the
surrounding bone during insertion.
SUMMARY OF INVENTION
[0007] The present invention relates to a device for attaching
fixation elements to bone, including a longitudinal member
extending along a longitudinal axis from a proximal end to a distal
end and having a channel extending therein adapted for receiving at
least one fixation element. A shaft extends within the channel and
is positioned coaxially within at least a portion of the
longitudinal member and at least a portion of the shaft is retained
within the longitudinal member and a distal end configured and
adapted to contact at least a portion of the fixation element
received within the longitudinal member. A spring is positioned
adjacent the shaft for resiliently biasing the shaft in an axial
direction and the shaft is moveable with respect to the
longitudinal member to drive the fixation element into bone.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a partially transparent elevated view of one
embodiment of an insertion device according to the present
invention;
[0009] FIG. 2 is an elevated view of a fixation element for use
with the insertion device of FIG. 1;
[0010] FIGS. 3-4 illustrate the placement of a fixation element
within a pre-drilled hole in bone;
[0011] FIG. 5 is a partially transparent elevated view of another
embodiment of an insertion device;
[0012] FIG. 6 a partial elevated view of the device of FIG. 5;
[0013] FIG. 7 is a partially transparent elevated view of another
embodiment of an insertion device;
[0014] FIG. 8 is a cross-sectional view of the embodiment of FIG.
7;
[0015] FIG. 9 is a partial cross-sectional view of a portion A of
the device of FIG. 8;
[0016] FIG. 10 is an elevated view of another embodiment of an
insertion device; and
[0017] FIG.11 is an elevated view of a cam member of the device of
FIG. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Referring to FIG. 1, a preferred fixation element insertion
device 10 according to the present invention generally includes a
longitudinal member extending along a longitudinal axis 12 from a
proximal end 14 to a distal end 16 and having a channel 18
extending therein. The insertion device is preferably used to drive
an osteosynthetic fixation element, such as a resorbable tack, into
bone tissue. Channel 18 is configured and dimensioned to receive at
least one fixation element for storage, transport, dispensing, and
or insertion into bone.
[0019] Referring to FIG. 2, one preferred fixation element
compatible with insertion device 10 comprises a tack 20 having a
shaft 22 integral with a head 24 at a proximal end thereof. The
distal end of shaft 22 has a conical nose 26 to facilitate the
insertion of tack 20 into bone tissue. A plurality of circular ribs
28 extend radially from the exterior of shaft 22 to prevent the
removal of the tack from the bone tissue after it has been
inserted. Head 24 has an outer diameter greater than the diameter
of shaft 22 and contacts or rests against the bone or bone plate
when the tack is inserted into bone tissue. In the preferred
embodiment, the tack is made from a resorbable material so that it
remains in the bone tissue temporarily and is absorbed by the body.
In alternate embodiments, tack 20 can have numerously different
configurations and dimensions. Also, different types of fixation
elements altogether can be used with insertion device 10. For
example, biocompatible screws, nails, anchors, rivets, or other
similar implants can also be inserted using insertion device
10.
[0020] Referring again to FIG. 1, insertion device 10 has a handle
30 at the proximal end that is configured to conform to the shape
of a person's hand or palm for easily gripping the device and an
applicator extension 32 for holding and dispensing the fixation
element. A central channel 70 extends within handle 30 and through
extension 32 and is in communication with channel 18 at distal end
16. Channel 18 generally comprises a socket defined at the distal
end 16 and an elongate applicator extension 32 extends between
distal end 16 and handle 30. Extension 32 can be a unitary
extension or can include multiple parts. Socket or channel 18 fits
about the proximal end of fixation element 20 to hold element 20 in
insertion device 10 by an interference or friction fit. In the
embodiment of FIG. 1, an individual tack 20 can be held at distal
end 16 and head 24 of tack 20 is preferably held within the socket
or channel 18 while the shaft 22 of tack 20 projects outside
thereof, as shown in FIG. 3. At the distal end of extension 32 is a
pronged tip 34 for retaining a fixation element. Pronged tip 34 is
generally flexible and when the distal end of extension 32 is
pressed, the prongs 34 of sleeve 32 flex around the head of a
fixation element to pick up and retain the element. In this way, it
is possible to pick up a relatively small fixation element in a
simple, single action.
[0021] A shaft member 36 and a firing spring 38 are housed within
central channel 40. Shaft member 36 extends longitudinally within
handle 30 and extension 32 and is preferably moveable along axis 12
with respect to handle 30 and extension 32. Firing spring 38 is
positioned at the proximal end of handle 30 and is compressible
between a force adjustment dial 39 at proximal end 14 and a
proximal end of shaft member 36, biasing shaft member 36 in the
distal direction. Shaft 36 is generally cylindrical and includes a
base portion 42 that slidingly engages the interior of channel 40
within handle 30, a mid-section 44 having a smaller diameter than
base portion 42, and a tip portion 46 having a smaller diameter
than mid-section 44. A first shoulder 43 is positioned at the
transition of base portion 42 and mid-section 44 and a second
shoulder 45 is positioned at the transition of mid-section 44 and
tip portion 46.
[0022] Shaft 36 is moveable from a loaded position (shown in FIG.
1) to an unloaded position for inserting a fixation element into
bone. An activation button 48 extends within channel 40 for
activating the movement of shaft 36 from a loaded position to an
unloaded position. Button 48 is positioned along a portion of
handle 30 and partially extends within channel 40 for engaging
shaft 36. Referring to FIG. 1, when shaft 36 is in the loaded
position ledge 49 at the proximal end of button 48 engages second
shoulder 45 preventing shaft 36 from moving in the distal direction
or to the unloaded position. When button 48 is depressed by an
operator, ledge 49 is moved out of engagement with shoulder 45,
thereby permitting shaft 36 to move in the distal direction under
the force exerted by firing spring 38 on shaft 36. As a result, tip
portion 46 of shaft 36 is advanced in the distal direction to force
fixation element out of extension 32 and shaft 36 is moved to an
unloaded position.
[0023] In a preferred embodiment, button 48 is pivotably positioned
about a pin 47 and the distal portion of button 48 is biased
radially outward by a spring 50 so that ledge 49 at the proximal
portion of button 48 is biased inward toward engagement with
shoulder 82. In this regard, a collar 51 is preferably positioned
within handle 30 for engaging spring 50 in the radial direction and
permitting mid-section 44 of shaft 36 to slide therethrough without
engaging spring 51. When button 48 is depressed, ledge 49 is
pivoted radially outward and out of engagement with shoulder. In
alternate embodiments, different button assemblies or triggering
mechanisms can be used.
[0024] In a preferred embodiment, a thumb slide 52 is positioned
along a portion of handle 30 opposite activation button 48 and is
moveable in the longitudinal direction for moving shaft 36 from an
unloaded to a loaded position. Thumb slide 52 partially extends
within channel 40 for engaging shaft 36 and moving shaft 36 in the
longitudinal direction. In an unloaded position, shoulder 45
engages an inner ledge 53 of thumb slide 52 and when thumb slide 52
is moved in the proximal direction by an operator, shaft 36 is also
retracted. To move shaft 36 to the loaded position, thumb slide 52
is moved in the proximal direction until shoulder 45 slides beyond
ledge 49 of button 48 and ledge 49 engages shoulder 45, thereby
locking shaft 36 in the loaded position. This shaft retraction will
also compress firing spring 38. In a preferred embodiment, a spring
54 is housed within handle 30 and biases thumb slide 52 in the
distal direction and once shaft 36 is in the loaded position, the
thumb slide is released and returns to its resting position. Once
shaft 36 is again in the loaded position, another tack can be
inserted into the extension 32.
[0025] Referring to FIGS. 3-4, once the insertion device is loaded,
the insertion device can be used to fasten a plate 56 or other
device to a bone 57. In operation, a hole 58 is pre-drilled in the
bone tissue at the desired insertion location and the insertion
device 10 is placed adjacent the insertion location and the tack is
aligned with hole 42. The activation button 48 is depressed to
release shaft 36, and shaft 36 is driven in the distal direction by
the force of firing spring 38 thereby driving tack 20 into the bone
tissue. As shown in FIG. 4, once tack 20 is inserted into bone,
insertion device 10 is withdrawn from the insertion location and
tack 20 is separated from channel 18. When the insertion device 10
is withdrawn, the forces holding shaft 22 of tack 20 to bone 57 are
greater than the forces of the interference fit between head 24 and
channel 18 so that head 24 of tack 20 is separated from distal end
16, leaving tack 20 secured to the bone. The device 10 can then be
reloaded by moving the thumb slide in the proximal direction as
explained above and inserting slightly smaller external dimensions
than the internal dimensions of cover 78 so that the proximal end
of sleeve 82 can be inserted into the distal end of cover 78 and
sleeve 82 can move in the axial direction with respect to cover 78.
As best seen in FIG. 9, sleeve 82 can include prongs that interlock
with ridges on the interior of cover 78 so that when sleeve 82 is
inserted into cover 78, sleeve 82 is not inadvertently removed from
cover 78 in the distal direction. In a preferred embodiment, sleeve
82 has prongs 84 that are flexible and are collapsible or bendable
into the interior of sleeve 82 so that sleeve 82 can be removed
from cover 78 for cleaning, disassembly, or replacement. Prongs 84
are biased radially outwardly so that sleeve 82 can be easily
reattached by simply pushing the sleeve into the cover in the
proximal direction. The distal end of sleeve 82 preferably has a
pronged tip similar to that described previously for retaining a
fixation element.
[0026] A central channel 90 extends within handle 72 and through
extension 74 and houses a firing spring 91 and a shaft member 92
similar to the embodiment of FIG. 1. Firing spring 91 is biased
between force adjustment dial 93 and the proximal end of shaft 92.
Adjustment dial 93 includes a knob 100 with internal threading that
engages an externally threaded adjustment slider 102 that is
slidably housed within channel 90. When knob 100 is rotated,
adjustment slider 102 slidably moves within channel 90 and
compresses or decompresses spring 91 for adjusting the amount of
force that is exerted on shaft 92 and consequently the tack during
insertion. A pair of knob retaining screws 104 extend radially
inward from the exterior of handle 72 and engage a circular groove
in knob 100 for retaining knob 100 in the proximal end of handle
72. A guide screw 106 extends inward from handle 72 and engage a
longitudinal groove in adjustment slider 102 to prevent the slider
from rotating.
[0027] Shaft 92 extends longitudinally within handle 72 and is
generally identical to shaft 36 described above, moving between a
loaded and an unloaded position. Shaft 92 includes a base portion
94, a mid-section 96 having a smaller diameter than base portion
94, and a tip portion 98 having a smaller diameter than mid-section
96. A first shoulder 95 is positioned at the transition of base
portion 95 and mid-section 96 and a second shoulder 97 is
positioned at the transition of mid-section 96 and tip portion 98.
Device 70 includes an activation button 108 similar to button 48
described above for facilitating movement of shaft 92 from the
loaded to the unloaded position in the same fashion as described
with respect to the embodiment of FIG. 1. To move shaft 92 from the
unloaded to the loaded position, holding sleeve 82 and tip portion
98 of shaft 92 is retracted in the proximal direction until
shoulder 97 of shaft 92 slides beyond button 108 and the button
engages shoulder 97, thereby locking shaft 92 in the loaded
position in a similar fashion to button 48 described above. Also,
insertion device 70 preferably has a spring 80 housed within spring
cover 78 that biases holding sleeve 82 in the distal direction and
once shaft 92 is in the loaded position, the holding sleeve is
released and returns to its resting position. In this way, shaft 92
can be easily moved from the unloaded to the loaded position, by
depressing device 70 in the distal direction against a solid
object, such as a table or a surgeons hand. In all other respects,
the method of operation or use of device 70 is similar to the
method described above with respect to device 10.
[0028] Referring to FIGS. 10-11, another embodiment of an insertion
device 110 is shown that has yet another alternative loading
mechanism. In all other respects, device 110 is similar to device
70 described previously. Insertion device 110 has a cam 112 for
moving shaft 92 from the unloaded to the loaded position. In this
embodiment, shaft 92 has pins 114 extending outwardly therefrom
that engage an internal ramp 116 within cam 112 and when cam 112 is
rotated pins 114 slide along ramp 1116 in the proximal direction
and thereby move shaft 92 in the proximal direction and shaft 92 is
retracted until shoulder 97 of shaft 92 slides beyond button 108
and the button engages shoulder 97, thereby locking shaft 92 in the
loaded position in a similar fashion to button 48 described above.
After shaft 92 is locked into the loaded position, cam 112 is
rotated to provide clearance for pins 114 to move in the distal
direction during the unloading or firing movement of shaft 92.
[0029] While it is apparent that the illustrative embodiments of
the invention herein disclosed fulfill the objectives stated above,
it will be appreciated that numerous modifications and other
embodiments may be devised by those skilled in the art. Therefore,
it will be understood that the appended claims are intended to
cover all such modifications and embodiments which come within the
spirit and scope of the present invention.
* * * * *