U.S. patent number RE46,979 [Application Number 14/850,660] was granted by the patent office on 2018-08-07 for electric motor driven tool for orthopedic impacting.
This patent grant is currently assigned to Medical Enterprises, LLC. The grantee listed for this patent is Medical Enterprises, LLC. Invention is credited to Christopher Pedicini.
United States Patent |
RE46,979 |
Pedicini |
August 7, 2018 |
Electric motor driven tool for orthopedic impacting
Abstract
An orthopedic impacting tool comprises a motor, an energy
storage chamber, a striker, and an anvil. The motor stores energy
in the energy storage chamber and then releases it, causing the
striker to apply a controlled force on an adapter to create a
precise impact for use in a surgical setting. The tool may further
comprise a combination anvil and adapter. The tool further allows
forward or backward impacting for expanding the size or volume of
the opening or for facilitating removal of a broach, implant, or
other surgical implement from the opening. An energy adjustment
control of the tool allows a surgeon to increase or decrease the
impact energy. A light source and hand grips improve ease of
operation of the tool.
Inventors: |
Pedicini; Christopher
(Franklin, TN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Medical Enterprises, LLC |
Nashville |
TN |
US |
|
|
Assignee: |
Medical Enterprises, LLC
(Nashville, TN)
|
Family
ID: |
73651880 |
Appl.
No.: |
14/850,660 |
Filed: |
September 10, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
13759813 |
Feb 5, 2013 |
|
|
|
|
12980329 |
Dec 29, 2010 |
8695726 |
|
|
|
13466870 |
May 8, 2012 |
8393409 |
|
|
|
12980329 |
Dec 29, 2010 |
8695726 |
|
|
|
13466870 |
May 8, 2012 |
8393409 |
|
|
|
13337075 |
Dec 24, 2011 |
|
|
|
|
12980329 |
Dec 29, 2010 |
8695726 |
|
|
|
61603320 |
Feb 26, 2012 |
|
|
|
|
61682915 |
Aug 14, 2012 |
|
|
|
|
61734539 |
Dec 7, 2012 |
|
|
|
Reissue of: |
13790870 |
Mar 8, 2013 |
8602124 |
Dec 10, 2013 |
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25D
17/00 (20130101); A61B 17/1659 (20130101); A61B
17/92 (20130101); A61B 17/1604 (20130101); A61B
17/1659 (20130101); B25D 11/005 (20130101); B25D
11/12 (20130101); B25D 11/125 (20130101); B25D
17/00 (20130101); A61B 17/92 (20130101); A61B
17/16 (20130101); B25D 17/06 (20130101); A61F
2/4603 (20130101); A61B 2017/922 (20130101); A61B
17/1626 (20130101); B25D 2250/221 (20130101); A61B
17/1628 (20130101); A61B 17/1668 (20130101); B25D
2250/195 (20130101); A61B 2090/309 (20160201); A61B
2017/924 (20130101); A61B 2017/00734 (20130101); A61B
17/1626 (20130101); A61B 2017/922 (20130101); A61B
2017/00544 (20130101); A61B 17/1628 (20130101); A61B
17/1668 (20130101); A61B 2090/309 (20160201) |
Current International
Class: |
B25D
17/00 (20060101); A61B 17/92 (20060101); A61B
90/30 (20160101); A61B 17/16 (20060101) |
Field of
Search: |
;173/2,48,104,109,114,132,176,201,217 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
103 19 350 |
|
Nov 2004 |
|
DE |
|
0 617 926 |
|
Aug 1998 |
|
EP |
|
2 455 006 |
|
May 2012 |
|
EP |
|
EP 2 455 006 |
|
May 2012 |
|
FR |
|
6-283217 |
|
Oct 1994 |
|
JP |
|
7-226230 |
|
Aug 1995 |
|
JP |
|
2006-218228 |
|
Aug 2006 |
|
JP |
|
Other References
International Search Report and Written Opinion dated Nov. 2, 2016
in International Application No. PCT/US2016/015380. cited by
applicant.
|
Primary Examiner: Williams; Catherine S
Attorney, Agent or Firm: Gardella Grace P.A.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
.Iadd.It is noted that more than one application for reissue of
U.S. Pat. No. 8,602,124 has been filed. Each of copending U.S.
patent application Ser. Nos. 14/850,588, 14/850,620, 14/850,639,
14/850,660, 14/850,674, and 14/850,695 were filed on Sep. 10, 2015
for reissue of U.S. Pat. No. 8,602,124. .Iaddend.
The present application is a .Iadd.reissue of U.S. Pat. No.
8,602,124, issued Dec. 10, 2013 from U.S. patent application Ser.
No. 13/790,870, filed on Mar. 8, 2013, U.S. patent application Ser.
No. 13,790,870 is a .Iaddend.continuation of and claims priority
under 35 .[.U.S.C. .sctn.120 on the pending.]. .Iadd.U.S.C .sctn.
120 to .Iaddend.U.S. patent application Ser. No. 13/759,813, filed
on Feb. 5, 2013, .Iadd.now abandoned, .Iaddend.the disclosure of
which is incorporated by reference.[., which '813 application.].
.Iadd.U.S. patent application Ser. No. 13/759,813 .Iaddend.is a
continuation-in-part of and claims priority under 35 U.S.C.
.[..sctn.120 on the pending.]. .Iadd..sctn. 120 to .Iaddend.U.S.
patent application Ser. .[.Nos..]. .Iadd.No. .Iaddend.12/980,329,
filed on Dec. 29, 2010, .[.and.]. .Iadd.now U.S. Pat. No.
8,695,726. U.S. patent application Ser. No. 13/759,813 is also a
continuation of and claims priority under 35 U.S.C. .sctn. 120 to
U.S. patent application Ser. No. .Iaddend.13/466,870.Iadd.,
.Iaddend.filed on May 8, 2012, now U.S. Pat. No. 8,393,409 .[., as
well as.]. .Iadd.. U.S. patent application Ser. No. 13/759,813 also
claims the benefit of priority .Iaddend.under 35 .[.USC .sctn.119
on.]. .Iadd.U.S.C. .sctn. 119 to .Iaddend.U.S. Provisional Patent
Application .Iadd.Ser. Nos. .Iaddend. 61/603,320, filed on Feb. 26,
2012, .Iadd.61/682,915, filed on Aug. 14, 2012, and 61/734,539,
filed on Dec. 7, 2012, .Iaddend.the disclosures of which are
incorporated by reference. .[.The present.]. .Iadd.U.S. patent
.Iaddend.application .Iadd.Ser. No. 13/790,870 .Iaddend.is also a
continuation-in-part of and claims priority under 35 U.S.C.
.[..sctn.120 on the pending.]. .Iadd..sctn. 120 to .Iaddend.U.S.
patent application Ser. Nos. 12/980,329, filed on Dec. 29, 2010,
.Iadd.now U.S. Pat. No. 8,695,726, .Iaddend.and 13/466,870.Iadd.,
.Iaddend.filed on May 8, 2012, now U.S. Pat. No. 8,393,409, the
disclosures of which are incorporated by reference. .Iadd.U.S.
patent application Ser. No. 13/466,870 is also a continuation of
and claims priority under 35 U.S.C. .sctn. 120 to U.S. patent
application Ser. No. 13/337,075, filed on Dec. 24, 2011, now
abandoned, and is a continuation-in-part of and claims priority
under 35 U.S.C. .sctn. 120 to U.S. patent application Ser. No.
12/980,329, filed on Dec. 29, 2010, now U.S. Pat. No. 8,685,726.
.Iaddend.Additionally, the present application claims .Iadd.the
benefit of .Iaddend.priority under 35 .[.USC .sctn.119 for.].
.Iadd.U.S.C. .sctn. 119 to .Iaddend.pending U.S. Provisional Patent
Application Ser. Nos. 61/734,539, filed on Dec. 7, 2012, and
61/682,915, filed on Aug. 14, 2012, the disclosures of which are
incorporated by reference.
Claims
What is claimed is:
.[.1. An orthopedic impacting tool for striking an object, the tool
comprising: a motor; a linear motion converter; an energy storage
means; a detent; a control means; an adapter, said adapter capable
of holding a broach, chisel or other surgical implement; and a
striker, said striker capable of impacting at least two distinct
impact surfaces, wherein a first impact surface moves said adapter
forward and a second impact surface moves said adapter rearward,
wherein said control means directs said motor to store an energy in
said energy storage means and said energy storage means thereafter
releases the energy onto said striker causing said striker to move
from a first position to a second position such that said striker
is capable of imparting a force upon said adapter in a direction
that is dependent at least in part on which surface said striker
impacts..].
.[.2. The tool as claimed in claim 1, wherein said impact surface
being impacted is controlled by a bias that a user puts on the
tool..].
.[.3. The tool as claimed in claim 1, wherein said energy storage
means includes a chamber operating at less than 9 psia or a
pressure in excess of 50 psia at or near the point of peak energy
storage..].
.[.4. The tool as claimed in claim 1, wherein said detent retains
said striker in said first position until said detent is released
or overcome thus allowing said energy storage means to release the
energy onto said striker..].
.[.5. The tool as claimed in claim 1, wherein said energy storage
means further comprises a valve..].
.[.6. The tool as claimed in claim 1, wherein the tool further
comprises an energy control element, said energy control element
used to adjust the impact energy said striker exerts on said
adapter..].
.[.7. The tool as claimed in claim 1, wherein the tool further
comprises a stroke limiter, said stroke limiter limiting a stroke
of said adapter to less than fifty percent of a stroke of said
striker..].
.Iadd.8. A hand-held, powered hip replacement device for striking
an object with a repeatable, controlled striking force to impel a
surgical implement of the device in one of at least two opposing
directions, the device comprising: a drive mechanism; a battery
integral with the device configured to power the drive mechanism;
an energy controller configured to control storage and release of
energy output from the drive mechanism to an energy storage
mechanism to produce the repeatable, controlled striking force; an
adapter configured to receive the surgical implement to interface
the object; a surface of a striker operable to impact a first
surface and a different second surface of an anvil, responsive to
the repeatable, controlled striking force delivered thereto, the
impact of the surface of the striker on the first surface impelling
the adapter in a first direction and the impact of the surface of
the striker on the second surface impelling the adapter in a
direction opposite the first direction; and a detent mechanism
configured to retain the striker in position. .Iaddend.
.Iadd.9. The device of claim 8, wherein a selection of a direction
of impact on the first and second surfaces is based upon a user
bias force applied to the device. .Iaddend.
.Iadd.10. The device of claim 9, wherein the user bias force in a
direction of the object causes the surface of the striker to impact
the first surface. .Iaddend.
.Iadd.11. The device of claim 9, wherein the user bias force in a
direction away from the object causes the surface of the striker to
impact the second surface. .Iaddend.
.Iadd.12. The device of claim 8, wherein the energy storage
mechanism includes a chamber operating between 0 and 9 psia for a
portion of a storage cycle. .Iaddend.
.Iadd.13. The device of claim 8, wherein the energy storage
mechanism includes a chamber that is under at least a partial
vacuum when the surface of the striker impacts the first surface to
impel the surgical implement in the first direction. .Iaddend.
.Iadd.14. The device of claim 8, wherein the energy storage
mechanism is a compressed air storage chamber. .Iaddend.
.Iadd.15. The device of claim 8, further comprising: an energy
adjustment mechanism to adjust the striking force the striker
delivers to the adapter in accordance with a patient profile.
.Iaddend.
.Iadd.16. The device of claim 8, further comprising: a linear
motion conversion mechanism to convert an output of the drive
mechanism to a linear motion. .Iaddend.
.Iadd.17. The device of claim 16, further comprising: wherein upon
release of the detent mechanism, a retention force of the detent
mechanism on the striker is reduced by at least fifty percent
within a first thirty percent of a stroke of the striker.
.Iaddend.
.Iadd.18. The device of claim 8, wherein the striker is operably
linked to the adapter by the impact of the surface of the striker
on the first and second surfaces of the anvil. .Iaddend.
.Iadd.19. The device of claim 8, wherein the adapter is configured
to releasably connect to the surgical implement. .Iaddend.
.Iadd.20. The device of claim 8, wherein the striker moves in a
substantially axial direction along a guide portion having openings
therein for venting of air during operation. .Iaddend.
.Iadd.21. The device of claim 16, further comprising: a sensor
operably linked to the energy controller to regulate the linear
motion conversion mechanism to a preferred cyclic operation.
.Iaddend.
.Iadd.22. The device of claim 21, wherein the sensor detects a
position of the linear motion conversion mechanism to limit a
stroke to a percentage less than full power. .Iaddend.
.Iadd.23. A hand-held, powered hip replacement device for striking
an object with a repeatable, controlled striking force to impel a
surgical implement of the device in one of at least two opposing
directions, the device comprising: a drive mechanism configured to
drive the device; a battery integral with the device configured to
power the drive mechanism; an energy controller configured to
control storage and release of energy output from the drive
mechanism to an energy storage device to produce the repeatable,
controlled striking force; an adapter having a mount configured to
receive the surgical implement; a surface of a striker operable to
impact a first surface and a different second surface of an anvil,
responsive to the repeatable, controllable striking force delivered
thereto, the impact of the surface of the striker on the first
surface impelling the adapter in a first direction and the impact
of the surface of the striker on the second surface impelling the
adapter in a direction opposite the first direction; and a detent
mechanism configured to retain the striker in position. .Iaddend.
Description
FIELD OF THE DISCLOSURE
The present disclosure relates to electric tools for impacting in
orthopedic applications, and, more particularly, to an electric
motor driven tool for orthopedic impacting that is capable of
providing controlled impacts to a broach or other end effector.
BACKGROUND
In the field of orthopedics, prosthetic devices, such as artificial
joints, are often implanted or seated in a patient's body by
seating the prosthetic device in a cavity of a bone of the patient.
Typically, the cavity must be created before the prosthesis is
seated or implanted, and traditionally, a physician removes and or
compacts bone to form this cavity. A prosthesis usually includes a
stem or other protrusion that serves as the particular portion of
the prosthesis that is inserted into the cavity.
To create such a cavity, a physician may use a broach, which broach
conforms to the shape of the stem of the prosthesis. Solutions
known in the art include providing a handle with the broach, which
handle the physician may grasp while hammering the broach into the
implant area. Unfortunately, this approach is clumsy and
unpredictable as being subject to the skill of the particular
physician. This approach almost will always inevitably result in
inaccuracies in the location and configuration of the cavity.
Additionally, the surgeon suffers from fatigue in this approach due
to the constant hammering. Finally, this approach carries with it
the risk that the physician will damage bone structure in
unintended areas.
Another technique for creating the prosthetic cavity is to drive
the broach pneumatically, that is, by compressed air. This approach
is disadvantageous in that it prevents portability of an impacting
tool, for instance, because of the presence of a tethering air
line, air being exhausted from a tool into the sterile operating
field and fatigue of the physician operating the tool. Further,
this approach, as exemplified in U.S. Pat. No. 5,057,112, does not
allow for precise control of the impact force or frequency and
instead functions very much like a jackhammer when actuated. Again,
this lack of any measure of precise control makes accurate
broaching of the cavity more difficult.
A third technique relies on computer-controlled robotic arms for
creating the cavity. While this approach overcomes the fatiguing
and accuracy issues, it suffers from having a very high capital
cost and additionally removes the tactile feedback that a surgeon
can get from a manual approach.
A fourth technique relies on the author's own prior disclosures to
use a linear compressor to compress air on a single stroke basis
and then, after a sufficient pressure is created, to release the
air through a valve and onto a striker. This then forces the
striker to travel down a guide tube and impact an anvil, which
holds the broach and or other surgical tool. This invention works
quite well, but, in the process of testing it, does not allow for a
simple method to reverse the broach should it become stuck in the
soft tissue. Further, the pressure of the air results in large
forces in the gear train and linear motion converter components,
which large forces lead to premature wear on components.
Consequently, there exists a need for an impacting tool that
overcomes the various disadvantages of the prior art.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages of the prior art, an
electric motor-driven orthopedic impacting tool configured to
include all the advantages of the prior art and to overcome the
drawbacks inherent therein is provided. The tool may be used by
orthopedic surgeons for orthopedic impacting in hips, knees,
shoulders and the like. The tool is capable of holding a broach,
chisel, or other end effector and gently tapping the broach, chisel
or other end effector into the cavity with controlled percussive
impacts, resulting in a better fit for the prosthesis or the
implant. Further, the control afforded by such an electrically
manipulated broach, chisel, or other end effector allows adjustment
of the impact settings according to a particular bone type or other
profile of a patient. The tool additionally enables proper seating
or removal of the prosthesis or the implant into or out of an
implant cavity and advantageously augments the existing surgeon's
skill in guiding the instrument.
In an embodiment, an electric motor-driven orthopedic impacting
tool comprises a power source (such as a battery), a motor, a
control means, a housing, a method for converting the rotary motion
of the motor to a linear motion (hereafter referred to as a linear
motion converter), at least one reducing gear, a striker, a detent
and an energy storage means, which energy storage means can include
either compressed air or a vacuum. The tool may further include an
LED, a handle portion with at least one handgrip for the
comfortable gripping of the tool, an adapter configured to accept a
surgical tool, a battery and at least one sensor. At least some of
the various components are preferably contained within the housing.
The tool is capable of applying cyclic impact forces on a broach,
chisel, or other end effector, or an implant and of finely tuning
an impact force to a plurality of levels.
In a further embodiment, the handle may be repositionable or
foldable back to the tool to present an inline tool wherein the
surgeon pushes or pulls on the tool co-linearly with the direction
of the broach. This has the advantage of limiting the amount of
torque the surgeon may put on the tool while it is in operation. In
a further refinement of the hand grip, there may be an additional
hand grip for guiding the surgical instrument and providing
increased stability during the impacting operation.
In a further embodiment, the broach, chisel or other end effector
can be rotated to a number of positions while still maintaining
axial alignment. This facilitates the use of the broach for various
anatomical presentations during surgery.
In a further embodiment, the energy storage means comprises a
chamber, which is under at least a partial vacuum during a portion
of an impact cycle.
In a further embodiment the linear motion converter uses one of a
slider crank, linkage mechanism, cam, screw, rack and pinion,
friction drive or belt and pulley.
In an embodiment, the linear motion converter and rotary motor may
be replaced by a linear motor, solenoid or voice coil motor.
In an embodiment, the tool further comprises a control means, which
control means includes an energy adjustment element, and which
energy adjustment element may control the impact force of the tool
and reduce or avoid damage caused by uncontrolled impacts. The
energy may be regulated electronically or mechanically.
Furthermore, the energy adjustment element may be analog or have
fixed settings. This control means allows for the precise control
of the broach machining operation.
In an embodiment, an anvil of the tool includes at least one of two
points of impact and a guide that constrains the striker to move in
a substantially axial direction. In operation, the movement of the
striker along the guide continues in the forward direction. A
reversing mechanism can be used to change the point of impact of
the striker and the resulting force on the surgical tool. Use of
such a reversing mechanism results in either a forward or a
rearward force being exerted on the anvil and/or the broach or
other surgical attachment. As used in this context, "forward
direction" connotes movement of the striker toward a broach, chisel
or patient, and "rearward direction" connotes movement of the
striker away from the broach, chisel or patient. The selectivity of
either bidirectional or unidirectional impacting provides
flexibility to a surgeon in either cutting or compressing material
within the implant cavity in that the choice of material removal or
material compaction is often a critical decision in a surgical
procedure. Furthermore, it was discovered in the use of the
author's prior disclosure that the tool would often get stuck
during the procedure and that the method of reversal in that tool
was insufficient to dislodge the surgical implement. This new
embodiment overcomes these limitations. In an embodiment the impact
points to communicate either a forward or rearward force are at
least two separate and distinct points.
In an embodiment the anvil and the adapter comprise a single
element, or one may be integral to the other.
In an embodiment the tool is further capable of regulating the
frequency of the striker's impacting movement. By regulating the
frequency of the striker, the tool may, for example, impart a
greater total time-weighted percussive impact, while maintaining
the same impact magnitude. This allows for the surgeon to control
the cutting speed of the broach or chisel. For example, the surgeon
may choose cutting at a faster rate (higher frequency impacting)
during the bulk of the broach or chisel movement and then slow the
cutting rate as the broach or chisel approaches a desired depth. In
typical impactors, as shown in U.S. Pat. No. 6,938,705, as used in
demolition work, varying the speed varies the impact force, making
it impossible to maintain constant (defined as +/-20%) impact
energy in variable speed operation.
In an embodiment the direction of impacting is controlled by the
biasing force placed by a user on the tool. For example, biasing
the tool in the forward direction gives forward impacting and
biasing the tool in the rearward direction gives rear
impacting.
In an embodiment the tool may have a lighting element to illuminate
a work area and accurately position the broach, chisel, or other
end effector on a desired location on the prosthesis or the
implant.
In an embodiment the tool may also include a feedback system that
warns the user when a bending or off-line orientation beyond a
certain magnitude is detected at a broach, chisel, or other end
effector or implant interface.
In an embodiment the tool may also include a detent that retains
the striker and which may be activated by a mechanical or
electrical means such that the energy per impact from the tool to
the surgical end effector is increased. In an embodiment, the
characteristics of this detent are such that within 30% of striker
movement, the retention force exerted by the detent on the striker
is reduced by 50%.
These together with other aspects of the present disclosure, along
with the various features of novelty that characterize the present
disclosure, are pointed out with particularity in the claims
annexed hereto and form a part of the present disclosure. For a
better understanding of the present disclosure, its operating
advantages, and the specific objects attained by its uses,
reference should be made to the accompanying drawings and detailed
description in which there are illustrated and described exemplary
embodiments of the present disclosure.
DESCRIPTION OF THE DRAWINGS
The advantages and features of the present invention will become
better understood with reference to the following detailed
description and claims taken in conjunction with the accompanying
drawings, wherein like elements are identified with like symbols,
and in which:
FIG. 1 shows a perspective view of an orthopedic impacting tool in
accordance with an exemplary embodiment of the present disclosure
in which a motor, linear motion converter, and vacuum as energy
storage means are used;
FIG. 2 shows an exemplary position of the piston wherein the vacuum
has been created;
FIG. 3 shows the striker being released and the striker moving
towards impacting the anvil in a forward direction;
FIG. 4 shows the striker being released and the striker moving such
that the anvil will be impacted in a reverse direction;
FIG. 5 shows the vacuum piston moving back towards a first position
and resetting the striker;
FIG. 6 shows an exemplary embodiment of a tool in which a
compression chamber is used to create an impacting force;
FIG. 7 shows an exemplary embodiment of a tool in which a valve is
used to adjust the energy of the impact of the striker;
FIG. 8 shows an exemplary embodiment of a tool in which the striker
imparts a surface imparting a rearward force on the anvil;
FIG. 9 shows an exemplary embodiment of a tool in which the striker
imparts a forward acting force on the anvil; and
FIG. 10 shows a comparison of the force vs. time curve between a
sharp impact and a modified impact using a compliance mechanism in
accordance with an exemplary embodiment of the present
disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
The best mode for carrying out the present disclosure is presented
in terms of its preferred embodiments, herein depicted in the
accompanying figures. The preferred embodiments described herein
detail for illustrative purposes are subject to many variations. It
is understood that various omissions and substitutions of
equivalents are contemplated as circumstances may suggest or render
expedient, but are intended to cover the application or
implementation without departing from the spirit or scope of the
present disclosure.
The terms "a" and "an" herein do not denote a limitation of
quantity, but rather denote the presence of at least one of the
referenced items.
The present disclosure provides an electric motor-driven orthopedic
impacting tool with controlled percussive impacts. The tool
includes the capability to perform single and multiple impacts as
well as impacting of variable and varying directions, forces and
frequencies. In an embodiment the impact force is adjustable. In
another embodiment a detent may be provided, which detent
facilitates the generation of a higher energy impact. In yet
another embodiment the impact is transferred to a broach, chisel,
or other end effector connected to the tool.
The tool may further include a housing. The housing may securely
cover and hold at least one component of the tool. In an
embodiment, the housing contains a motor, at least one reducing
gear, a linear motion converter, a gas chamber, a striker, a three
adjuster, a control means, an anvil, a forward impact surface and a
different surface for rearward impact.
The tool further may include a handle portion with at least one
hand grip for comfortable and secure holding of the tool while in
use, and an adapter, a battery, a positional sensor, a directional
sensor, and a torsional sensor. The tool may further comprise a
lighting element such as an LED to provide light in the work area
in which a surgeon employs the tool. The anvil may be coupled to a
broach, chisel or other end effector through the use of an adapter,
which adapter may have a quick connect mechanism to facilitate
rapid change of different broaching sizes. The anvil may further
include a locking rotational feature to allow the broach to be
presented to and configured at different anatomical configurations
without changing the orientation of the tool in the surgeon's
hands.
Referring now to FIGS. 1 through 5, in an embodiment, the linear
motion converter 12 comprises a slider crank mechanism, which
slider crank is operatively coupled to the motor 8 and reducing
gears 7. The tool further comprises a vacuum chamber 23 that
accepts a piston 24 which may be actuated by the linear motion
converter 12. It will be apparent that the piston 24 may be
actuated in more than one direction. The vacuum is created in the
vacuum chamber 23 by the movement of piston 24 away from striker
25. The vacuum created in the vacuum chamber 23 is defined as a
pressure of less than 9 psia for at least a portion of the
operational cycle.
In an embodiment, the motor 8 of the tool causes the linear motion
converter 12 to move, which pulls a vacuum on the face of the
striker 25 and creates at least a partial vacuum in the vacuum
chamber 23, as is shown in FIG. 2. The piston 24 continues to move
increasing the size of the vacuum chamber 23 until it hits a
forward portion of the striker 25 (i.e., a portion of the strike
that is proximate to the end effector or patient), which dislodges
the striker 25 from its detent 10 and allows it to rapidly
accelerate towards the end of the tool that is proximate to the end
effector or patient. In an embodiment, the detent may be
mechanical, electrical, or a combination thereof, with the
preferred detent shown in the figures as a magnet. A characteristic
of the detent 10 is that once the detent 10 is released or
overcome, the retention force of the detent 10 on the striker 25
reduces by at least 50% within the first 30% movement of the
striker 25. The impact of the striker 25 on the anvil 14
communicates a force to the adapter 1 and the broach, chisel or
other orthopedic instrument.
In an embodiment, the direction of the force on the anvil is
controlled by the user's (such as a surgeon) force on the tool and
a stroke limiter 13. It has been determined that prior art tools
may occasionally get stuck in a cavity and the impact of the
striker in the aforementioned paragraph may be insufficient to
dislodge the tool. In this present embodiment, when the tool is
being pulled away from the cavity, the striker 25 will not impact
the anvil 14, but will impact an alternate surface and thereby
communicate a rearward force on the anvil 14. This impact surface
is shown in an exemplary embodiment as actuation pin 27. Actuation
pin 27 communicates a force to lever arm 17, which communicates a
rearward force on the anvil 14, and specifically on the anvil
retract impact surface 26. This embodiment has the unexpected
benefit of easily dislodging tools and instruments that have become
stuck in a surgical cavity, while retaining all the benefits of the
existing tool in terms of precision-controlled impacting. Thus, a
further advantage of this tool was discovered as it can be seen
that the surgeon can control the direction of the impacting by a
bias that he or she may place on the tool and, in so doing, can
reduce the likelihood of the broach, chisel or other end effector
from getting stuck in a patient or surgical cavity.
In a further embodiment, an electromagnet may be incorporated as
the detent 10 and released at an appropriate point in the operation
cycle to allow the striker 25 to impact the anvil 14. Once the
striker 25 has been released from the detent 10, the air pressure
on the rearward side of the striker 25, propels it forward to
impact the anvil 14 or other strike surface. The resultant force
may be communicated through an end of the anvil 14 that is
proximate to the anvil forward impact surface 16 and, optionally,
through the adapter 1 to which a broach, chisel, or other end
effector for seating or removing an implant or prosthesis may be
attached.
The striker guide 11 may also have striker guide vent holes 20,
which allow the air in front of the striker 25 to escape, thus
increasing the impact force of the striker 25 on the anvil 14. The
striker guide vent holes 20 may vent within the cavity of the tool
body, thus creating a self-contained air cycle preventing air from
escaping from the tool and allowing for better sealing of the tool.
The position and the size of the striker guide vent holes 20 can
also be used to regulate the impact force. Further, it was
unexpectedly found that adding the striker guide vent holes 20
increases the impact force of the striker 25 on the anvil 14.
In an embodiment, as the piston 24 continues through its stroke it
moves towards the rear direction, which movement brings it in
contact with rear striker face 28 of striker 25 and moves it
towards the rear of the tool. This allows the detent 10 to lock or
retain the striker 25 in position for the next impact. The piston
24 completes its rearward stroke and preferably activates a sensor
22 that signals the motor 8 to stop such that the piston 24 rests
at or near bottom dead center of the vacuum chamber 23. The vacuum
chamber 23 preferably has a relief or check valve 9 or other small
opening, which, in an embodiment, is part of the piston 24. The
valve 9 may also be located at other points in the vacuum chamber
23 and allows for any air which may have accumulated in the vacuum
chamber 23 to be purged out of the vacuum chamber 23 during each
cycle. In a further embodiment this valve effect could be
accomplished with a cup seal instead of an o-ring seal. This
ensures that approximately atmospheric pressure is present in the
vacuum chamber 23 at a starting point in the operational cycle,
thus ensuring that each impact utilizes the same amount of energy,
as is important in orthopedic impacting for at least the reason
that it assures of a substantially consistent force and impact rate
in multi-impact situations. Thus, in one complete cycle, a forward
or a rearward impacting force may be applied on the broach, chisel,
or other end effector, or on the implant or prosthesis.
In a further embodiment, the motor 8 of the tool causes the linear
motion converter 12 to move the piston 24 until the piston 24 moves
a sufficient distance such that the forward portion of the piston
impacts a portion of the striker and overcomes the detent 10 that
retains the striker in the rear position. Once the striker has been
released from the detent 10, the vacuum in the vacuum chamber 23
exerts a force on the striker, which accelerates the striker,
causing the striker to slide axially down a cavity internal to the
tool housing and strike the anvil forward impact surface 16. In
FIG. 3, the anvil forward impact surface 16 causes a forward
movement of the anvil 14 and/or tool holder, and, in FIG. 4, the
anvil retract impact surface 26 causes a rearward movement of the
anvil 14 and/or tool holder. The resultant force is communicated
through an end of the anvil 14 that is proximate to the anvil
forward impact surface 16 and, optionally, through the adapter 1 to
which a broach, chisel, or other end effector for seating or
removing an implant or prosthesis may be attached.
In another embodiment, the impact force may be generated using a
compressed air chamber 5 in conjunction with a piston 6 and striker
4, as shown in FIGS. 6 through 9. In this embodiment, the motor 8
of the tool causes the linear motion converter 12 to move the
piston 6 until sufficient pressure is built within the compressed
air chamber 5 that is disposed between the distal end of the piston
6 and the proximate end of the striker 4 to overcome a detent 10
that otherwise retains the striker 4 in a rearward position and or
the inertia and frictional force that holds the striker 4 in that
rearward position. Once this sufficient pressure is reached, an air
passageway 19 is opened and the air pressure accelerates the
striker 4, which striker 4 slides axially down a cavity and strikes
the anvil 14. The air passageway 19 has a cross sectional area of
preferably less than 50% of the cross sectional area of the striker
4 so as to reduce the amount of retaining force required from
detent 10. The resultant force is communicated through the end of
the anvil 14 that is proximate to the anvil forward impact surface
16 and, optionally, through the adapter 1 to which a broach,
chisel, or other device for seating or removing an implant or
prosthesis may be attached.
As the piston 6 continues through its stroke, it moves towards the
rear direction, pulling a slight vacuum in compressed air chamber
5. This vacuum may be communicated through an air passageway 19 to
the back side of the striker 4, creating a returning force on the
striker 4, which returning force causes the striker 4 to move in a
rear direction, i.e., a direction away from the point of impact of
the striker 4 on the anvil forward impact surface 16. In the event
that an adapter 1 is attached to the anvil 14, a force may be
communicated through the adapter 1 to which the broach, chisel, or
other end effector for seating or removing an implant or prosthesis
is attached.
Further, when the tool is being pulled away from the cavity, the
striker 4 will not impact the anvil 14, but may instead impact an
alternate surface and thereby communicate a rearward force on the
anvil 14. This impact surface is shown in an exemplary embodiment
as actuation pin 27. Actuation pin 27 communicates a force to lever
arm 17, which communicates a rearward force on the anvil 14, and
specifically on the anvil retract impact surface 26.
The tool may further facilitate controlled continuous impacting,
which impacting is dependent on a position of a start switch (which
start switch may be operatively coupled to the power source or
motor, for example.) For such continuous impacting, after the start
switch is activated, and depending on the position of the start
switch, the tool may go through complete cycles at a rate
proportional to the position of the start switch, for example.
Thus, with either single impact or continuous impacting operational
modes, the creation or shaping of the surgical area is easily
controlled by the surgeon.
A sensor 22 coupled operatively to the control means 21 may be
provided to assist in regulating a preferred cyclic operation of
the linear motion converter 12. For example, the sensor 22 may
communicate at least one position to the control means 21, allowing
the linear motion converter 12 to stop at or near a position in
which at least 75% of a full power stroke is available for the next
cycle. This position is referred to as a rest position. This has
been found to be advantageous over existing tools in that it allows
the user to ensure that the tool impacts with the same amount of
energy per cycle. Without this level of control, the repeatability
of single cycle impacting is limited, reducing the confidence the
surgeon has in the tool.
The tool is further capable of tuning the amount of impact energy
per cycle by way of, for example, an energy control element 18. By
controlling the impact energy the tool can avoid damage caused by
uncontrolled impacts or impacts of excessive energy. For example, a
surgeon may reduce the impact setting in the case of an elderly
patent with osteoporosis, or may increase the impact setting for
more resilient or intact athletic bone structures.
In an embodiment, the energy control element 18 preferably
comprises a selectable release setting on the detent 10 that holds
the striker 25. It will be apparent that the striker 25 will impact
the anvil 14 with greater energy in the case where the pressure
needed to dislodge the striker 25 from the detent 10 is increased.
In another embodiment, the detent 10 may comprise an electrically
controlled element. The electrically controlled element can be
released at different points in the cycle, thus limiting the size
of the vacuum chamber 23, which is acting on the striker 25. In an
embodiment, the electrically controlled element is an
electromagnet.
In another embodiment, the vacuum chamber 23 or compressed air
chamber 5 may include an energy control element 18, which takes the
form of an adjustable leak, such as an adjustable valve. The
leakage reduces the amount of energy accelerating the striker 4 or
25, thus reducing the impact energy on the anvil 14. In the case of
the adjustable leak, adjusting the leak to maximum may give the
lowest impact energy from the striker 4 or 25, and adjusting to
shut the leak off (zero leak) may give the highest impact energy
from the striker 4 or 25.
The tool may further comprise a compliance means inserted between
the striker 4 or 25 and the surgical end effector, which purpose is
to spread the impact force out over a longer time period, thus
achieving the same total energy per impact, but at a reduced force.
This can be seen clearly as a result of two load cell tests on the
instrument as shown in FIG. 10. This type of compliance means can
limit the peak force during impact to preclude such peaks from
causing fractures in the patient's bone. In a further embodiment,
this compliance means may be adjustable and in a still further
embodiment the compliance means may be inserted between striker 4
or 25 and the anvil 14 or surgical tool. In this manner and
otherwise, the tool facilitates consistent axial broaching and
implant seating. Preferably, the compliance means increases the
time of impact from the striker to at least 4 milliseconds and
preferable 10 milliseconds. This contrasts to impacting in which a
very high force is generated due to the comparatively high
strengths of the striker 4 or 25 and the anvil 14 (both steel, for
example). Preferably, the compliance means comprises a resilient
material such as urethane, rubber or other elastic material that
recovers well from impact and imparts minimal damping on the total
energy.
In a further embodiment, the adapter 1 may comprise a linkage
arrangement or other adjustment means such that the position of the
broach, chisel or other end effector can be modified without
requiring the surgeon to rotate the tool. In an embodiment, the
adapter 1 may receive a broach for anterior or posterior joint
replacement through either an offset mechanism or by a rotational
or pivotal coupling between the tool and the patient. The adapter 1
may thereby maintain the broach or surgical end effector in an
orientation that is parallel or co-linear to the body of the tool
and the striker 25. The adapter 1 may also comprise clamps, a vice,
or any other fastener that may securely hold the broach, chisel, or
other end effector during operation of the tool.
In use, a surgeon firmly holds the tool by the handle grip or grips
and utilizes light emitted by the LED to illuminate a work area and
accurately position a broach, chisel or other end effector that has
been attached to the tool on a desired location on the prosthesis
or implant. The reciprocating movement imparted by the tool upon
the broach, chisel or other end effector allows for shaping a
cavity and for seating or removal of a prosthesis.
The tool disclosed herein provides various advantages over the
prior art. It facilitates controlled impacting at a surgical site,
which minimizes unnecessary damage to a patient's body and which
allows precise shaping of an implant or prosthesis seat. The tool
also allows the surgeon to modulate the direction, force and
frequency of impacts, which improves the surgeon's ability to
manipulate the tool. The force and compliance control adjustments
of the impact settings allow a surgeon to set the force of impact
according to a particular bone type or other profile of a patient.
The improved efficiency and reduced linear motion converter loads
allow use of smaller batteries and lower cost components. The tool
thereby enables proper seating or removal of the prosthesis or
implant into or out of an implant cavity.
The foregoing descriptions of specific embodiments of the present
disclosure have been presented for purposes of illustration and
description. They are not intended to be exhaustive or to limit the
present disclosure to the precise forms disclosed, and obviously
many modifications and variations are possible in light of the
above teaching. The exemplary embodiment was chosen and described
in order to best explain the principles of the present disclosure
and its practical application, to thereby enable others skilled in
the art to best utilize the disclosure and various embodiments with
various modifications as are suited to the particular use
contemplated.
* * * * *