U.S. patent number RE42,757 [Application Number 10/842,057] was granted by the patent office on 2011-09-27 for expandable reamer.
This patent grant is currently assigned to Spineology, Inc.. Invention is credited to Todd Bjork, Joseph E. Gleason, Patricia Kuslich, legal representative, Stephen D. Kuslich, Francis Peterson, Rodney Rogstad.
United States Patent |
RE42,757 |
Kuslich , et al. |
September 27, 2011 |
Expandable reamer
Abstract
An expandable reamer for forming a space within a vertebral disc
includes a pair of opposing blades which have a expanded state and
a retracted state. The blades being pivotally positioned at the
distal end of a shaft assembly. A shaft housing being substantially
disposed about the shaft assembly. The proximal end of the shaft
assembly being operatively engaged by a control device which when
rotated allows the blades to be fully retracted for insertion into
a pre-bored hole and then to be expanded incrementally until the
cavity is bored as desired.
Inventors: |
Kuslich; Stephen D.
(Stillwater, MN), Kuslich, legal representative; Patricia
(Stillwater, MN), Peterson; Francis (Spooner, WI), Bjork;
Todd (River Falls, WI), Gleason; Joseph E. (Eagan,
MN), Rogstad; Rodney (Plymouth, MN) |
Assignee: |
Spineology, Inc. (St. Paul,
MN)
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Family
ID: |
22669228 |
Appl.
No.: |
10/842,057 |
Filed: |
May 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60182610 |
Feb 15, 2000 |
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Reissue of: |
09782176 |
Feb 13, 2001 |
6383188 |
May 7, 2002 |
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Current U.S.
Class: |
606/80;
408/156 |
Current CPC
Class: |
A61B
17/1617 (20130101); A61B 17/1671 (20130101); A61B
2017/00261 (20130101); Y10T 408/8588 (20150115); Y10T
408/85843 (20150115) |
Current International
Class: |
A61B
17/00 (20060101) |
Field of
Search: |
;606/80,79,81,82,84,85,186,86R ;408/157,158,154,147,161,178
;175/282,264 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Philogene; Pedro
Attorney, Agent or Firm: Skaar Ulbrich Macari, P.A.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
The present Utility Patent Application claims priority to
Provisional Application No. 60/182,610 filed Feb. 15, 2000, the
entire contents of which being incorporated herein by reference.
Claims
What is claimed is:
.[.1. An expandable reamer comprising: a) an elongated hollow shaft
having a proximal and a distal end, the distal end being closed and
having a pair of opposing side openings adjacent the closed end; b)
a pair of internal blade members within said hollow shaft; c) a
mechanism for moving said blades from a retracted position within
the shaft to a cutting, extended position through said side
openings..].
.[.2. The expandable reamer of claim 1 wherein said distal closed
end includes an inner, centrally located wedge constructed and
arranged to direct the internal blade members out of said side
openings when pressed distally..].
.[.3. The expandable reamer of claim 2 wherein said internal blade
members each include an elongated shaft having a distal and a
proximal end, said proximal end extending up to said blade moving
mechanism and a cutting blade on a distal end of said elongated
shaft which are completely within said hollow shaft until said
elongated shafts are urged distally by said blade moving
mechanism..].
.[.4. The expandable reamer of claim 3 wherein said blade moving
mechanism is constructed and arranged to engage said proximal end
of said blade member elongated shaft and simultaneously move both
blades distally or proximally in response to operator movement of
said blade moving mechanism..].
.[.5. The expandable reamer of claim 4 wherein said blade moving
mechanism includes an adjusting screw which when rotated causes
said blades to move distally or proximally in said elongated hollow
tube in response to the direction of rotation and degree of
rotation..].
.[.6. The expandable reamer of claim 5 further including an
indicator mechanism toward the proximal end of said reamer which is
visible from the outside of said reamer and shows relative movement
of said blades proximally and distally within said hollow shaft to
indicate position of the cutting blades..].
.[.7. The expandable reamer of claim 6 wherein said reamer includes
a mechanism for applying rotational torque to said hollow shaft
such that said cutting blades rotate and provide a cutting
operation..].
.[.8. The expandable reamer of claim 7 wherein said cutting blades
are constructed and arranged to fully retract within said hollow
shaft until said blade moving mechanism urges them out said side
openings such that said cutting blades are not in a cutting
position until desired..].
.[.9. The expandable reamer of claim 8 wherein said elongated
shafts of said blade members are rectangular in cross-section and
abut against each other within said hollow shaft to increase
torsional rigidity..].
.[.10. The expandable reamer of claim 9 wherein the proximal ends
of said elongated shafts of said blade members include notches
which engage with an adjustment slide of said blade moving
mechanism..].
.[.11. The expandable reamer of claim 10 wherein said adjustment
slide is inserted through a side access port which is covered by a
locking cover..].
.[.12. The expandable reamer of claim 11 wherein said blade members
are spring steel and constructed and arranged to have a slip fit
within the hollow shaft such that the blade members may be inserted
into said hollow shaft through said side openings while limiting
movement of said blade members within said shaft..].
13. An expandable reamer comprising: a) an elongated shaft having a
proximal end and a distal end, a pair of blade members pivotally
engaged to the distal end of the elongated shaft, a pair of
elongated blade guides positioned immediately adjacent to the
elongate shaft, the elongate blade guides each having a guide slot,
at least a portion of each of the pair of blade members being
operatively engaged to one of the guide slots; b) an elongate
hollow tube, the elongate hollow tube being disposed substantially
about the elongated shaft and the pair of elongated blade guides,
the elongate hollow tube being longitudinally moveable relative to
the elongated shaft; c) a handle, the handle having a hollow
engagement barrel and at least one griping member extending
therefrom, the hollow engagement barrel having a first end engaged
to the elongate hollow tube, and a second end having a control
knob, the control knob being operatively engaged to the elongate
hollow tube, whereby when the control knob is rotated the elongate
hollow tube is moved longitudinally relative to the elongated shaft
causing the pair of blade members to move between a retracted
position and an extended position.
.[.14. An expandable reamer comprising: a) an elongated shaft
having a proximal end and a distal end, a pair of blade members
being pivotally engaged to the distal end of the elongated shaft,
the distal end of the elongate shaft having a pair of blade slots
constructed and arranged to slidingly and removably receive at
least a portion of one of the blade members: b) an elongate hollow
tube, the elongate hollow tube being disposed substantially about
the elongated shaft, the elongated shaft being longitudinally
moveable relative to the elongate hollow tube; c) a turn wheel, the
turn wheel operatively engaged to the proximal end of the elongated
shaft and positioned proximal to the elongate hollow tube, whereby
when the turn wheel is rotated the elongated shaft is moved
longitudinally relative to the elongate hollow tube causing the
pair of blade members to move between a retracted position and an
extended position..].
.Iadd.15. An expandable reamer for use in bone and related tissue
in a mammal comprising: an elongated hollow body having a proximal
end and a distal end, sized and configured to engage bone and
related tissue in the mammal; an elongated blade carrier having a
proximal end and a distal end, the blade carrier disposed within
the body; a set of blades pivotally attached proximate the distal
end of the blade carriers; the set of blades having at least a
first retracted position relative to the body, the body having a
maximum cross-sectional diameter transverse to a longitudinal axis
of the body that is substantially at least as large as a maximum
cross-sectional diameter of the blades in the first retracted
position, and a second fully expanded position having a diameter
greater than the maximum cross-sectional diameter of the body; and
an manually actuated activation mechanism that moves the set of
blades from the first retracted position to the second fully
expanded position and any expanded position
therebetween..Iaddend.
.Iadd.16. The reamer of claim 15 wherein the body includes a view
port..Iaddend.
.Iadd.17. The reamer of claim 15 wherein the blade carrier is
linearly movable relative to the body and the body includes
indicators that indicate a distance that the blade set is extended
from the distal end of the body..Iaddend.
.Iadd.18. The reamer of claim 15 wherein the set of blades includes
cam arms and the activation mechanism is a moveable cannulated
shaft having linear movement along the body, the moveable
cannulated shaft having cam surfaces that engage the cam arms of
the set of blades such that the linear movement of the moveable
cannulated shaft is translated to pivoting movement of the blade
set thereby driving the blade set to the first expanded
position..Iaddend.
.Iadd.19. The reamer of claim 18 wherein the cam arms are double
sided such that reverse linear movement of the moveable cannulated
shaft retracts the blade set into the first retracted
position..Iaddend.
.Iadd.20. The reamer of claim 18 wherein the activation mechanism
is a blade control knob constrained within the proximal end of the
body, the blade control knob having rotational motion that actuates
the moveable cannulated shaft such that the linear movement of the
moveable cannulated shaft is translated to pivoting movement of the
blade set thereby driving the blade set to the expanded
position..Iaddend.
.Iadd.21. The reamer of claim 15 wherein the blades extend beyond
the distal end of the hollow body..Iaddend.
.Iadd.22. The reamer of claim 15 wherein the blades are pivotally
attached at a single pivot point..Iaddend.
.Iadd.23. The reamer of claim 15 wherein each of the blades
includes a cutting portion arranged such that substantially all of
the cutting portion is outside the maximum cross-sectional diameter
of the body when the blades are in the second fully expanded
position..Iaddend.
.Iadd.24. An expandable reamer for use in bone and related tissue
in a mammal comprising: an elongated hollow body having a proximal
end and a distal end including means for engaging bone and related
tissue in the mammal, an elongated blade carrier having a proximal
end and a distal end, the blade carrier disposed within the body; a
set of blades pivotally attached proximate the distal end of the
blade carrier, the set of blades having at least a first retracted
position relative to the body, the body having a maximum
cross-sectional diameter transverse to a longitudinal axis of the
body that is substantially at least as large as a maximum
cross-sectional diameter of the blades in the first retracted
position, and a second fully expanded position having a diameter
greater than the maximum cross-sectional diameter of the body; and
n means for manually moving the set of blades from the first
retracted position to the second fully expanded position and any
expanded position therebetween..Iaddend.
.Iadd.25. The reamer of claim 24 wherein the body includes a view
port..Iaddend.
.Iadd.26. The reamer of claim 24 wherein the blade carrier is
linearly movable relative to the back and the body includes
indicators that indicate a distance that the blade set is extended
from the distal end of the body..Iaddend.
.Iadd.27. The reamer of claim 24 wherein the set of blades includes
cam arms and the means for moving the set of blades is a moveable
cannulated shaft having linear movement along the body, the
moveable cannulated shaft having cam surfaces that engage the cam
arms of the set of blades such that the linear movement of the
moveable cannulated shaft is translated to pivoting movement of the
blade set thereby driving the blade set to the expanded
position..Iaddend.
.Iadd.28. The reamer of claim 27 wherein the cam arms are double
sided such that reverse linear movement of the moveable cannulated
shaft retracts the blade set into the first retracted
position..Iaddend.
.Iadd.29. The reamer of claim 27 wherein the means for moving the
blade set is a blade control knob constrained within the proximal
end of the body, the blade control knob having rotational motion
that actuates the moveable cannulated shaft such that the linear
movement of the moveable cannulated shaft is translated to pivoting
movement of the blade set thereby driving the blade set to the
expanded position..Iaddend.
.Iadd.30. The reamer of claim 24 wherein the blades extend beyond
the distal end of the hollow body..Iaddend.
.Iadd.31. The reamer of claim 24 wherein the blades are pivotally
attached at a single pivot point..Iaddend.
.Iadd.32. The reamer of claim 24 wherein each of the blades
includes a cutting portion arranged such that substantially all of
the cutting portion is outside the maximum cross-sectional diameter
of the body when the blades are in the second fully expanded
position..Iaddend.
.Iadd.33. A method for creating a cavity in bone comprising:
drilling a bore in bone, inserting an expandable reamer into the
bore, manually actuating an activation mechanism of the reamer that
engages a blade carrier within the reamer such that linear motion
of the blade carrier drives a blade set pivotally attached to the
blade carrier from a first retracted position relative to the body,
the body having a maximum cross-sectional diameter transverse to a
longitudinal axis of the body that is substantially at least as
large as a maximum cross-sectional diameter of the blades in the
retracted position to a second fully expanded position having a
diameter greater than the maximum cross-sectional diameter of the
body and any expanded position therebetween; contacting the bone
with the blade set in the any expanded position; and rotating the
expandable reamer such that the blade set cuts into the
bone..Iaddend.
.Iadd.34. The method of claim 33 wherein the blades extend beyond
the distal end of the hollow body..Iaddend.
.Iadd.35. An expandable reamer for use in bone and related tissue
in a mammal comprising: an elongated hollow body having a proximal
end and a distal end sized and configured to engage bone and
related tissue in the mammal; at least one shaft operably arranged
in a coaxial relation with the hollow body along a longitudinal
axis and having a proximal and a distal end; a set of blades
pivotally attached proximate the distal end of the shaft, the set
of blades having at least a first retracted position relative to
the body, the body having a maximum cross-sectional diameter
transverse to a longitudinal axis of the body that is substantially
at least as large as a maximum cross-sectional diameter of the
blades in the first retracted position, and a second fully expanded
position having a diameter greater than the maximum cross-sectional
diameter of the body; and an manually actuated activation mechanism
that moves the set of blades from the first retracted position to
the second fully expanded position and any expanded position
therebetween..Iaddend.
.Iadd.36. The reamer of claim 35 wherein the body includes a view
port..Iaddend.
.Iadd.37. The reamer of claim 35 wherein the body includes
indicators that indicate a distance that the blade set is extended
from the distal end of the body..Iaddend.
.Iadd.38. The reamer of claim 35 wherein the set of blades includes
cam arms and the activation mechanism is one of a pair of shafts
having linear movement along the body, the shaft having cam
surfaces that engage the cam arms of the set of blades such that
the linear movement of the shaft is translated to pivoting movement
of the blade set thereby driving the blade set to the expanded
position..Iaddend.
.Iadd.39. The reamer of claim 38 wherein the cam arms are double
sided such that reverse linear movement of the shaft retracts the
blade set into the first retracted position..Iaddend.
.Iadd.40. The reamer of claim 38 wherein the activation mechanism
is a blade control knob constrained within the proximal end of the
body, the blade control knob having rotational motion that actuates
one of the pair of shafts such that the linear movement of the
shaft is translated to pivoting movement of the blade set thereby
driving the blade set to the expanded position..Iaddend.
.Iadd.41. The reamer of claim 35 wherein the blades extend beyond
the distal end of the hollow body..Iaddend.
.Iadd.42. The reamer of claim 35 wherein the blades are pivotally
attached at a single pivot point..Iaddend.
.Iadd.43. The reamer of claim 35 wherein each of the blades
includes a cutting portion arranged such that substantially all of
the cutting portion is outside the maximum cross-sectional diameter
of the body when the blades are in the second fully expanded
position..Iaddend.
Description
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an expandable reamer for use in surgery,
particularly in orthopedic applications.
2. Description of the Related Art
U.S. Pat. No. 5,445,639 to Kuslich et al., describes an
intervertebral reamer which is used to ream out the interior of a
degenerated disc to clean the interbody space. U.S. Pat. Nos.
5,549,679 and 5,571,189 to Kuslich describes a device and method
for stabilizing the spinal segment with an expandable, porous
fabric implant for insertion into the interior of a reamed out disc
which is packed with material to facilitate bony fusion.
U.S. Pat. No. 5,928,239 to Mirza discloses a reamer which has a
shaft and a cutting tip attached through a free rotating hinge such
that high speed rotation allows the tip to be deflected outwardly
to form a cavity. U.S. Pat. No. 5,591,170 to Spievack et al
discloses a powered bone saw which inserts its cutting blade
through a bored intramedullary canal.
The reamer of U.S. Pat. No. 5,445,639 is better suited to make a
cylindrical bore than a spherical bore as is needed for the methods
and apparatus of U.S. Pat. Nos. 5,549,679 and 5,571,189, the
disclosure of all of which are incorporated herein by reference.
There exists, therefore, a need for an instrument which will
simplify the surgeon's task of forming a chamber within the
interbody space.
The art described in this section is not intended to constitute an
admission that any patent, publication or other information
referred to herein is "prior art" with respect to this invention,
unless specifically designated as such. In addition, this section
should not be construed to mean that a search has been made or that
no other pertinent information as defined in 37 C.F.R. .sctn.
1.56(a) exists.
SUMMARY OF THE INVENTION
The invention provides a surgical tool is for forming hollow
chambers within bone that are larger in diameter than the external
opening into the chamber. The tool has a distal end with external
dimensions sized to be passed through the patient's anatomy to a
point of entry into the bone. Retractable cutting blades are
provided on the cutting end. The blades can be extended to cut a
cavity greater than the diameter of the surgical tool.
BRIEF DESCRIPTION OF THE DRAWINGS
A detailed description of the invention is hereafter described with
specific reference being made to the drawings in which:
FIG. 1 is a perspective view of the reamer of the invention wherein
the blades of the reamer are shown in the retracted position;
FIG. 2 is an exploded view of the reamer of FIG. 1;
FIG. 3 is top down view of an embodiment of the blade advancer
arbor portion of the reamer of FIG. 1;
FIG. 4 is an exploded view of an embodiment of the blade advancer
arbor;
FIG. 5 is a side view of the blade assembly portion of the reamer
of FIG. 1, wherein the blades are shown in the retracted
position;
FIG. 6 is a side view of the blade assembly portion of the reamer
of FIG. 1, wherein the blades are shown in the retracted
position;
FIG. 7 is an exploded view of an embodiment of the blade assembly
and guides;
FIG. 8 is an enlarged view of a portion of the distal end of the
blade assembly with a blade in the retracted position;
FIG. 9 is an enlarged view of a portion of the distal end of the
blade assembly with a blade extended;
FIG. 10 is a perspective view of an alternative embodiment of the
reamer;
FIG. 11 is an exploded view of the reamer of FIG. 10;
FIG. 12 is a close up view of threaded portion and end of the shaft
shown in FIG. 11;
FIG. 13 is a view depicting the assembly of the barrel and turn
wheel of the reamer shown in FIG. 11;
FIG. 14 is a side view of an alternative embodiment of the blade
assembly wherein the blades are retracted;
FIG. 15 is a side view of the blade assembly shown in FIG. 14
wherein the blades are extended;
FIG. 16 is an enlarged view of a portion of the distal end of the
blade assembly of FIG. 14 with a blade in the retracted position;
and
FIG. 17 is an enlarged view of a portion of the distal end of the
blade assembly of FIG. 14 with a blade extended.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference is now directed to FIGS. 1 through 17 in which identical
elements are numbered identically throughout.
In FIGS. 1 and 2 an embodiment of the inventive reamer, indicated
generally by reference numeral 132, is shown. The reamer 132
includes a handle 134, a blade advancing arbor 138 and a main shaft
136. Within the main shaft is an elongate shaft 140 which may
extends distally beyond the distal end of the main shaft 136. As
may be seen, the elongated shaft 140 includes a blade advancing tab
148 at the proximal end and a pair of blades 142, 144 hingedly
mounted to the distal end by a hinge pin 146.
As may best be seen in FIG. 2, main shaft 136 is hollow to allow it
to carry the elongated shaft 140 and the blade guides 150 and 152.
The blade guides 150 and 152 each have a relatively slender shaft
154 a proximal tab 156 and an arcuate guide slot 158 at their
distal ends. The elongated shaft 140 is positioned between the
blade guides 150 and 152.
The diameter of shaft 136 at distal end 172 is sized such that
shaft 136 can be inserted into a patient's body with distal end 172
placed against a diseased disc or other bone without shaft 136
having undue interference with other anatomical organs.
FIG. 4 shows that main shaft 136 is attached to a guide member 182
which defines a guide tab slot 184 for engaging the guide tabs 156.
The blade advancing tab 148 and the associated shaft 140
longitudinally moveable therebetween. The end of the guide member
182 includes a threaded shaft 190 which is received into an opening
192 in blade advancer knob 194. The guide member 182 is inserted
into an opening in blade advancer barrel 138. Blade advancer barrel
138 includes an annular recess 200 to mate with knob lip 202 which
rotatably secures the knob 194 to the barrel 138. The barrel 138
may include a shaped opening 204 designed to engage shaped member
206 on the guide member 182.
In the embodiment shown, the guide member 182 is inserted into
opening 204 with the elongated blade shaft 140 and the blade
advancing tab 148 as well as blade guides 156 fully inserted into
slot 184. The blade advancing tab 148 projects above the guide
member 182 such that a groove 210 may be provided in the blade
advancer barrel 138 to allow the assembly to pass therewithin.
The guide member 182 may include a pin 212 which passes from the
guide member 182 across the barrel opening 216 to engage the pin
opening 232 of the slide door 214. When properly assembled the tab
148 protrudes through the tab opening 230 of the door 214 such as
may be seen in FIG. 3. This mutually engaging relationship keeps
the elongated blade shaft 140 from moving.
After the guide member 182 is inserted fully into the barrel 138,
the slide door 214 is placed onto blade advancer barrel 138 to
close the access opening 216. The slide door may be held at the
proximal end by engagement of its tabs 220 to slots 222 in the
barrel. The distal end of the door 214 is held in position by a
lock ring 224 that engages with threads 226 or the like on the
distal end of barrel 138 as is shown in FIG. 4.
As stated above, the slide door 214 includes a pair of openings
230, 232. Opening 230 engages with tab 148 to keep the elongated
shaft 140 from moving. Observation of the position of the pin 212
within the confines of opening 232 allows a user to track the
degree of movement that the shaft 136 makes longitudinally in
response to turning knob 194.
As may best be seen in FIG. 4, when knob 194 is turned or rotated,
the shaft 136 is moved inwardly or outwardly within barrel 138. The
movement of the shaft 138 is relative to the elongate shaft 140
which is held stationary by the blade advancing tab 148 within
shaft 138. This functional relationship causes the blades 142 and
144 to pivotally retract or expand relative to shaft 136, such as
may be seen in FIGS. 5 and 6. However, movement of knob 194
actually causes the entire shaft 136, together with blade guides
150 and 152, which forces the blades to move as their engagement
members 160 move within arcuate guide slots 158 of the blade
guides.
As may best be seen in FIG. 7, the blades 142, 144 each include an
engagement member 160 which aligns with arcuate guide slot 158,
defined by the diverter housings 166 and 168 respectively. When the
engagement members 160 are fully within arcuate guide slots 158,
the blades are extended out their maximum extent for cutting with
blade portions 162, such as may best be seen in FIG. 9. As the
engagement members 160 are withdrawn from the guide slots 158, such
as may be seen in FIG. 8, the blades 142 and 144 are retracted for
insertion and/or withdrawal from the patient.
Turning to FIGS. 10-17, an alternative embodiment of the invention
is shown. FIGS. 10-17 are directed to a more compact form of the
reamer of the present invention. As depicted herein, the diameter
of the reamer 90 with closed blades, such as may best be seen in
FIG. 14 may have a diameter of approximately 5 mm or less. The
present reamer 90 may be used to create openings through pedicles,
channels for anterior cruciate ligaments and the like. Rather, an
elongated tube and barrel 100 carry a long rod 92 that attaches at
the proximal end to a turn wheel 96 that moves the blades distally
and proximally. The end of the long rod 92 is attached to two like
blades by a pivot 118 that allows the blades 114 and 116 to change
position. Each of the blades 114 and 116 have a sloping lever side
120 that allows them to move smoothly outwardly. A notch or stop
126 bottoms out against the main tube 100 to prevent further
movement. The handle may have a flat slot 107 milled therein that
allows the user to see whether the rod 92 is in position for
cutting or pushed forward for no cutting. A second slot 106
provides an access space sufficient to allow a user to remove the
retaining clip 108, so that the reamer may be disassembled as
discussed below.
Note that if the blades 114 and 116 were ever stuck in an open
position, the handle 96 could be removed, allowing the tube to be
removed and then the blades 114 and 116 would have nothing to keep
them open. This blade setup allows disassembly if the blades are
stuck open in the bone. Prior reamer designs may be difficult to
disengage in such an event. In this design, the entire device may
be disassembled from the proximal end such that the parts are
released allowing the blades 114 and 116 to pivot freely. In the
embodiment shown in FIG. 11, removal of the retaining clip 108 will
allow the turn wheel 96 to be separated from the barrel 102. The
barrel 102 along with the shaft housing 104 may then be slid off of
the elongate shaft 92. When the shaft 92 is no longer retained by
the housing 104, the blades 114 and 116 will be free to move into
the retracted position by merely pulling the shaft 92 from the bone
or operation site (not shown).
As shown in FIGS. 10-14, reamer 90 is elegantly simple. It includes
an elongated shaft 92 with a proximal tab 129 which may include a
threaded proximal end 94 which may receive the tab 129 via slot
128. The combined threaded proximal end 94 and elongate shaft 92 is
engaged with the turn wheel 96 thereby providing a the shaft 92
with the ability to be moved up and down within holder 100 as the
wheel 96 is turned.
The holder 100 includes an enlarged barrel 102 into which the turn
wheel 96 may partially descend and a lower hollow cylindrical guide
104. The distal end 110 of shaft 92 includes a narrow tang 111
which has an opening therethrough to allow blades 114, 116 to be
hingedly attached via a hinge pin member 118.
As best shown in FIGS. 14 and 15, the blades 114, 116 include a
ramp portion 120 sized to enter cylindrical tube 104 and a cutting
portion 122. As may be seen in FIGS. 14-17, the cutting portion 122
of the blades 114 and 116 may be serrated. When turn wheel 96 is
turned to pull the shaft 92 up into the cylindrical tube 104, the
ramped portion 120 enters the tube 104 and begins to extend the
blade portion 122 out past the diameter of the tang 111. As shown
in FIG. 15, blades 114, 116 are at their most extended portion as
limited by a stop member 126 which abuts against the cylindrical
tube 104 preventing further extension.
Turn wheel 96 may include depth marking slot 107 which allows the
user to see how far the blades have extended or retracted. In
addition, the portion of the shaft 92 which may be seen through the
slot 107 may have visible markings or surface features to better
provide a visual basis for determining the extent of the blade
retraction or extension based on the relative position of the shaft
92 within the slot 107. In the unlikely event that the reamer
blades 114, 116 cannot be readily retracted within the cavity being
formed, the turn wheel 96 may be removed, allowing the holder 100
to slide away from the shaft 92. In such a case, the blades 114,
116 would freely pivot on hinge pin 118 allowing the remainder of
the reamer 90 to be readily removed.
FIGS. 11-13 show the construction of the barrel 102 and the
interface of the turn wheel 96 to the reamer 90. Turn wheel 96
includes a projection member 97, which may be a threaded nut or
screw which is inserted into the turn wheel 96 and threadingly
engaged to a retaining clip 108. The retaining clip 108 is
fittingly or frictionally engaged to a retaining slot 109
positioned about the proximal end of the barrel 102, the position
of the retaining slot 109 corresponds to the position of the
indentation 98 of member 97 when member 97 is threadingly engaged
to threaded proximal end 94. The slot 109 has a diameter less than
the diameter of the surrounding barrel 102. Barrel 102 includes a
bore which communicates through the cylindrical tube 104.
As may be best understood from viewing FIG. 11, in order for the
turn wheel 96 to be properly engaged to the barrel 102 a variety of
components must initially be assembled with in the wheel 96. A
projecting member 97 is inserted through the turn wheel 96.
Disposed about the projection member 97 is a biasing member such as
a coiled spring 95. The spring 95 is pushed into the wheel 96 along
with the member 97. A retaining ring 93 is fittingly engaged into
the wheel 96 to retain the member 97 and spring 95 therein.
As may best be seen in FIG. 13, at the proximal end of the barrel
102, an opening 124 is formed which conforms to the cross-sectional
shape of the threaded end 94 and tab 129. The indentation 98 of the
projection member 97 engages the retaining clip 108 such that when
threaded end 128 is threaded into opening 130 or the turn wheel 96,
the turn wheel 96 cannot be removed from shaft 92 without
unscrewing the shaft 92 from opening 130 and removing lock pin
108.
In one embodiment of the invention, when the turn wheel 96 is
assembled in the manner described above, the spring 95 (shown in
FIG. 11) is biased between shoulder 99 of member 98 and shoulder
135 of the turn wheel 96. This biasing relationship provides
sufficient tension force to between the member 98 and the wheel 96
to prevent unintentional movement of the turn wheel relative to the
barrel 102. In order to rotate the wheel 96, the wheel 96 must be
pulled longitudinally away from the barrel 102 with sufficient
force to overcome the biasing force of the spring 95. When pulled
in this manner the wheel may be freely rotated.
In an alternative embodiment of the invention, the turn wheel
includes a plurality of engagement pins 131. Each engagement pins
131 is engaged to receiving holes 133. In order to rotate the wheel
96 the wheel 96 is pulled in the manner described above, but
additionally must be pulled a sufficient distance away from the
barrel 102 to disengage the pins 131 from the holes 133. The wheel
96 may then be rotated to a point where the pins 131 may be
reinserted into the holes 133 in an advancing clockwise or
counterclockwise manner.
When the reamer 90 is assembled in the manner described above,
clockwise rotation of the turn wheel 96 causes shaft 92 to be
pulled up tube 104 such that ramp portion 120, such as may be seen
in FIGS. 14-17, enters tube 104 causing the blades 114, 116 to
extend outwardly until the stop 126 abuts with the distal end of
tube 104.
As shown in FIG. 14-17, blades 114 and 116 include a cutting edges
122. In the embodiment shown, the cutting edges 122 may be
serrated, however straight, or curved cutting edges 122 may also be
provided. In the various embodiments described herein, the blades
of the inventive reamer may be constructed from a variety of
materials such as metal, composite materials such as carbon etc.
Where the blades are metal, the metal may be any type of metal
suitable for use in constructing a blade for use in medical
procedures. Such metals may include: stainless steel, spring steel,
titanium, nickel, or any alloys thereof.
As may be seen in FIG. 14, the blades 116 (114 is not shown) are
shown in a mostly retracted position, whereas in FIG. 15 the blades
114 and 116 are depicted in a fully extended position. Any position
between a fully retracted and fully extended position is possible
with the reamer tool 90 of the invention.
In operation, the blades 114 and 116 are fully retracted and the
device 90 is inserted into an opening drilled into the body
material where a cavity is to be formed. Typically a hole is
drilled into the vertebral body or other bone or area that needs to
be reamed to a diameter larger than the outside drill hole. The
hole is drilled in the bone, and then a guide tube may be abutted
against the bone and adjusted to the proper length or depth where
it is desired to ream the hole. The reamer 90 is then inserted
through the optional guide tube with the blades 114 and 116 in the
retracted position, such as is shown in FIG. 14. Once inserted into
the bone to a desired depth, the turn wheel 96 is rotated to begin
expansion of the blades 114 and 116. Rotation of the reamer 92 with
the blades 114 and 116 gradually expanding, provides a cutting
action which reams out a chamber from within the bone.
In use, turning or rotating the turn wheel 96 relative to the
barrel 102 causes the shaft 92 to be moved longitudinally relative
to the shaft housing 104. This action causes the blades 114 and 116
to pivot around the pivot member 118 thereby expanding out from or
retracting into the tapered ramps 119, as seen in FIGS. 16 and 17,
depending on the direction of the turn wheel's rotation. As the
blades 114 and 116 are rotated out of the ramps 119 the entire
reamer 92 may be rotated causing the blades 114 and 116 to cut an
expanding hole in the cavity, which is limited in size to the
maximum expanded state of the blades 114 and 116, such as is shown
in FIG. 15.
Once a reamed cavity is made, the blades 114 and 116 are retracted
by rotating the turn wheel 96 in a direction opposite that which
was used to expand the blades, until the blades 114 and 116 are
fully retracted. However, it should be noted that unlike in the
embodiment shown in FIGS. 1-9, the present embodiment does not rely
on the ramps or slots to retract the blades. Instead, the blades
114 and 116 may be free to retract when pulled from the hole. Thus
when the reamer 90 is withdrawn from the hole the blades 114 and
116 may retract by themselves as a result of engagement with the
drill hole shaft or the guide tube.
The surgeon may visualize the degree the blades 114 and 116 extend
by viewing the position of the shaft 92 relative to the barrel 102,
through view port 107. The shaft 92 may have markings or surface
features to make such position determinations easier. In the
embodiment shown, the surgeon can see how far down the shaft 92
moves as the turning wheel 96 is rotated. The reamer 90 may be
calibrated to show the distance the blades project from the
tool.
While this invention may be embodied in many different forms, there
are shown in the drawings and described in detail herein specific
preferred embodiments of the invention. The present disclosure is
an exemplification of the principles of the invention and is not
intended to limit the invention to the particular embodiments
illustrated.
This completes the description of the preferred and alternate
embodiments of the invention. Those skilled in the art may
recognize other equivalents to the specific embodiment described
herein which equivalents are intended to be encompassed by the
claims attached hereto.
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