U.S. patent number RE44,896 [Application Number 13/873,360] was granted by the patent office on 2014-05-13 for dissecting high speed burr for spinal surgery.
This patent grant is currently assigned to Spinascope, Inc.. The grantee listed for this patent is Charles W. Cha. Invention is credited to Charles W. Cha.
United States Patent |
RE44,896 |
Cha |
May 13, 2014 |
Dissecting high speed burr for spinal surgery
Abstract
A rotatable surgical burr (100, 200, 300, 500) having a
protective hood (120, 220, 320, 520, 620, 720) with a dissecting
foot plate (119, 219, 319, 519, 619, 719) is provided to improve
and enable various spinal decompression procedures. The surgical
burr's protective hood has a dissecting foot plate that may be
shaped to resemble a curette, a Woodson, or other appropriate
dissecting tools to allow insertion of the tool between the spinal
nerve and the compressing bone. The protective hood surrounds the
burr bit (130, 230, 530) exposing only a portion of the burr bit
for burring of the offending bone and protects the nerve from the
burr tip. The instrument may also be configured with a soft tissue
resecting tip (330) for soft tissue resection.
Inventors: |
Cha; Charles W. (Marietta,
GA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Cha; Charles W. |
Marietta |
GA |
US |
|
|
Assignee: |
Spinascope, Inc. (Cartersville,
GA)
|
Family
ID: |
34738628 |
Appl.
No.: |
13/873,360 |
Filed: |
April 30, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
60531209 |
Dec 19, 2003 |
|
|
|
Reissue of: |
11017150 |
Dec 20, 2004 |
7585300 |
Sep 8, 2009 |
|
|
Current U.S.
Class: |
606/80 |
Current CPC
Class: |
A61B
17/1671 (20130101); A61B 17/1633 (20130101); A61B
2090/08021 (20160201); A61B 17/1631 (20130101) |
Current International
Class: |
A61B
17/32 (20060101) |
Field of
Search: |
;606/79,80,84,85,159,167,170,180 ;433/116 ;451/451 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Philogene; Pedro
Assistant Examiner: Comstock; David
Attorney, Agent or Firm: Duane Morris LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application
No. 60/531,209 filed on Dec. 19, 2003, the contents of which is
incorporated herein by reference.
Claims
What is claimed is:
1. A surgical instrument comprising: a hand piece having a distal
end and a proximal end; a shaft portion extending from the distal
end of the hand piece and having a distal end and a proximal end; a
drive shaft disposed for rotation within the shaft portion, the
drive shaft having a distal end and a proximal end thereof; a
surgical tool bit connected to the distal end of the drive shaft; a
protective hood including a dissecting foot plate portion connected
to the distal end of the shaft portion, wherein the surgical tool
bit resides within the protective hood, partially exposed, and the
protective hood is rotatable relative to the surgical tool bit
exposing a different portion of the surgical tool bit; .[.and.]. a
rotatable member provided in the hand piece, said rotatable member
operably connected to the proximal end of the shaft portion and
manipulation of the rotatable member controls the rotation of the
protective hood relative to the hand piece and the drive shaft via
the shaft portion.Iadd.; and a flexible neck portion connecting the
protective hood to the distal end of the shaft portion, wherein the
drive shaft comprises a flexible drive shaft portion at the distal
end thereof and extending through the flexible neck portion to
connect to the surgical tool bit, wherein the flexible neck portion
is communicatingly connected to the hand piece and the flexible
neck portion's flexing motion is actuated and controlled from the
hand piece.Iaddend..
2. The surgical instrument of claim 1, wherein the dissecting foot
plate portion has a length of about 1 to 8 mm.
.[.3. The surgical instrument of claim 1, further comprising a
flexible neck portion connecting the protective hood to the distal
end of the shaft portion, wherein the drive shaft comprises a
flexible drive shaft portion at the distal end thereof and
extending through the flexible neck portion to connect to the
surgical tool bit..].
.[.4. The surgical instrument of claim 3, wherein the flexible neck
portion is communicatingly connected to the hand piece and the
flexible neck portion's flexing motion is actuated and controlled
from the hand piece..].
5. The surgical instrument of claim .[.3.]. .Iadd.1.Iaddend.,
wherein the flexible drive shaft portion is made of Nitinol
alloy.
6. The surgical instrument of claim 1, wherein the shaft portion is
a rigid member.
7. The surgical instrument of claim 1, wherein the surgical tool
bit is a bone removing bit.
8. The surgical instrument of claim 1, wherein the surgical tool
bit is a soft tissue resecting bit.
9. The surgical instrument of claim 1, wherein the rotatable member
is a thumb wheel.
10. A surgical instrument comprising: a hand piece having a distal
end and a proximal end; a power drive mechanism provided within the
hand piece; a shaft portion extending from the distal end of the
hand piece and having a distal end and a proximal end; a drive
shaft disposed for rotation within the shaft portion, the drive
shaft having a distal end and a proximal end thereof, wherein the
proximal end is connected to the power drive mechanism; a surgical
tool bit connected to the distal end of the drive shaft; a
protective hood including a dissecting foot plate portion attached
to the distal end of the shaft portion, wherein the surgical tool
bit resides within the protective hood, partially exposed, and the
protective hood is rotatable relative to the surgical tool bit
exposing a different portion of the surgical tool bit; and a
rotatable member provided in the hand piece, said rotatable member
operably connected to the proximal end of the shaft portion and
manipulation of the rotatable member controls the rotation of the
protective hood relative to the hand piece and the drive shaft via
the shaft portion.Iadd.; and a flexible neck portion connecting the
protective hood to the distal end of the shaft portion, wherein the
drive shaft comprises a flexible drive shaft portion at the distal
end thereof and extending through the flexible neck portion to
connect to the surgical tool bit, wherein the flexible neck portion
is communicatingly connected to the hand piece and the flexible
neck portion's flexing motion is actuated and controlled from the
hand piece.Iaddend..
.[.11. The surgical instrument of claim 10, further comprising a
flexible neck portion connecting the protective hood to the distal
end of the shaft portion, wherein the drive shaft comprises a
flexible drive shaft portion at the distal end thereof and
extending through the flexible neck portion to connect to the
surgical tool bit..].
.[.12. The surgical instrument of claim 11, wherein the flexible
neck portion is communicatingly connected to the hand piece and the
flexible neck portion's flexing motion is actuated and controlled
from the hand piece..].
13. The surgical instrument of claim .[.11.]. .Iadd.10.Iaddend.,
wherein the flexible drive shaft portion is made of Nitinol
alloy.
14. The surgical instrument of claim 10, wherein the shaft portion
is a rigid member.
15. The surgical instrument of claim 10, wherein the surgical tool
bit is a bone removing bit.
16. The surgical instrument of claim 10, wherein the surgical tool
bit is a soft tissue resecting bit.
17. The surgical instrument of claim 10, wherein the rotatable
member is a thumb wheel.
Description
FIELD OF THE INVENTION
This invention relates to a surgical instrument and more
particularly to a surgical high-speed burr for use in spinal
surgical procedures.
BACKGROUND OF THE INVENTION
Spinal stenosis is a degenerative condition of the spine that
afflicts primarily the elderly population. Patients with lumbar
spinal stenosis suffer from severe radiating pain, which limits
their ability to ambulate and can cause weakness and numbness in
the legs and in severe cases, loss of bowel and bladder control may
occur. It is the development of hypertrophic bone spurs off the
facet joints, protrusions of the disc annulus, as well as
hypertrophy of the ligamentum flavum that combine to narrow the
space available for the nerves in the spinal canal.
The standard surgical procedure to treat lumbar spinal stenosis is
known as the lumbar laminectomy and foraminotomy. During this
procedure, the surgeon removes the spinous processes, the
interspinous ligaments and the central portion of the spinal lamina
to gain a line of sight into the lateral recess and into the
foramen so that the nerve compression can be relieved in these
areas. The current standard tools for performing this procedure are
the Kerrison punch and angled curettes and in severe instances,
osteotomes. To remove the offending bone using these instruments, a
surgeon places the instrument into the interval between the
compressing bone and the underlying nerve that is being compressed
and the bone is then removed from the dorsal aspect of the nerve
where it is impinged, thereby relieving compression exerted on the
spinal nerve. In situations where the compression on the nerve is
not very severe, one can safely insert the Kerrison footplate or
the curette into the interval between the nerve root and the
surrounding bone to perform the necessary bone removal.
However, when there is a severe amount of compression at the neural
foramen or the lateral recess, the interval between the nerve root
and the encroaching bone may not be sufficient to safely conduct
the neural decompression using the conventional tools, such as a
Kerrison punch or a curette. Insertion of a Kerrison footplate or a
curette into a severely stenotic interval may cause compressive
injury to an already compressed nerve root. In these situations,
the only conventionally available method of successfully
decompressing the neural compression, especially in the foramen,
has been to pass a small curved osteotome in the plane that is
superior to the nerve root and osteotomize the bone that is
encroaching on the nerve root from above. This maneuver, however,
poses risk to the nerve root because there is a possibility that
the osteotome will slip or advance too deep, thereby damaging the
exiting nerve. Thus, there is a need for an improved instrument
that would allow a safer, more controlled method of foraminal
lateral recess decompression that minimizes risks to the nerve
roots, especially in severely stenotic situations.
Additionally, the need to remove the interspinous ligament, the
spinous processes and the central portion of the lamina in open
lumbar laminectomy is only to allow the surgeon to have a line of
sight into the lateral recess and foramen to remove pressure on the
compressed nerve. In surgery, the surgeon works from the opposite
side of the table to get the appropriate line of sight and angle of
attack at the encroaching bone and soft tissue in the lateral
recess in the foramen. Working from the contralateral side of the
table is necessary in order to be able to undercut the facet joints
and thereby preserve spinal stability with these procedures. This
line of attack is necessary because of the shape of the current
standard instruments, such as a Kerrison punch, curette or
osteotome, and the necessary vector of applied force that is
required using those instruments. There is therefore an additional
need for an instrument that would allow for ipsilateral
decompression of the lateral recess and the foramen. This
instrument would need to allow for undercutting of the facet joints
and removal of compressive bone and soft tissue in the lateral
recess and the foramen on the ipsilateral side of the patient
(decompression on the same side of the table as opposed to working
across the spinal canal from the contralateral side of the table).
Such an instrument would also allow for the application of
minimally invasive techniques to perform lumbar decompressions and
would allow for the maximal preservation of bone and ligaments
thereby preserving spinal stability.
One tool that is available to a spine surgeon to remove bone, in a
controlled fashion, is a high speed burr. The burr is used from the
dorsal surface of the bone heading towards the neural elements and
the bone is thinned down until it is wafer thin and can be picked
away with curettes. If one is too aggressive with the burr, then
neural injury can occur by penetrating the dura or wrapping the
neural elements in the burr bit. Because the risk of catching the
neural elements with the conventional high speed burr bit is too
high, the use of conventional high speed burrs to perform the
lateral recess and foraminal decompression has not been
practicable. Thus, an improved novel high speed burr for removing
bone in such tight spaces is desired.
SUMMARY
A surgical instrument according to an embodiment of the invention
comprises a hand piece, a rigid shaft portion extending from the
hand piece and having a distal end and a proximal end, and a drive
shaft disposed for rotation within the shaft portion. The drive
shaft has a distal end and a proximal end thereof and a surgical
tool bit is connected to the distal end of the drive shaft. A
protective hood including a dissecting foot plate portion is
connected to the distal end of the shaft portion. And the surgical
tool bit resides within the protective hood, partially exposed, and
the protective hood is rotatable relative to the surgical tool bit
along the longitudinal axis of the surgical tool bit, exposing a
different portion of the surgical tool bit.
A surgical instrument according to another embodiment comprises a
hand piece, a power drive mechanism provided within the hand piece,
a rigid shaft portion extending from the hand piece and having a
distal end and a proximal end, and a drive shaft disposed for
rotation within the shaft portion. The drive shaft has a distal end
and a proximal end thereof, and the proximal end is connected to
the power drive mechanism. A surgical tool bit is connected to the
distal end of the drive shaft and a protective hood including a
dissecting foot plate portion is attached to the distal end of the
shaft portion. The surgical tool bit resides within the protective
hood, partially exposed, and the protective hood is rotatable
relative to the surgical tool bit along the longitudinal axis of
the tool bit, exposing a different portion of the surgical tool
bit.
The dissecting soft tissue resector embodiment could also be used,
with an extended kind of a Woodson type tip, to get in between
compressive tissue and the nerve root that is sometimes found in
the foramen that can continue to cause residual compression on the
nerve, even after a dorsal bony decompression has been performed.
The dissecting soft tissue resector may be used to debride annulus,
ligamentum flavum, disc and or cartilage that are encroaching the
nerve root in the axilla or in the foramen.
In addition to allowing a safer foraminal decompression in the open
setting, the dissecting burr according to an embodiment of the
invention is also suited for performing lumbar decompression in
minimally invasive surgical settings while sparing bone and
ligament that are in close proximity to the surgical site.
BRIEF DESCRIPTION OF THE DRAWING
The drawings are schematic and the like reference numerals used in
the figures denote like parts throughout the various figures.
FIG. 1a is a side elevational view of a dissecting burr according
to an embodiment of the invention.
FIG. 1b is a detailed side elevational view of region A in FIG.
1a.
FIG. 1c is a front elevational view of the region A in FIG. 1a.
FIG. 1d is a front elevational view of the dissecting burr of FIG.
1c with an alternative shape for the dissecting foot plate
according to another embodiment of the invention.
FIG. 1e is an illustration of a dissecting foot plate of a
dissecting burr according to another embodiment.
FIG. 2a is a side elevational view of the distal end of another
dissecting burr according to another embodiment of the
invention.
FIG. 2b is a front elevational view of the dissecting burr of FIG.
2a.
FIG. 2c is a front elevational view of the dissecting burr of FIG.
2b with an alternative shape for the dissecting foot plate
according to another embodiment of the invention.
FIG. 3a is a side elevational view of a dissecting soft tissue
resector according to another embodiment of the invention.
FIG. 3b is a front elevational view of the dissecting soft tissue
resector of FIG. 3a.
FIG. 3c is a front elevational view of the dissecting soft tissue
resector of FIG. 3a having an alternative shaped dissecting foot
plate according to another embodiment of the invention.
FIG. 4a is a side elevational view of an inner shaft member of the
dissecting burr of FIG. 1.
FIG. 4b is a cross-sectional schematic illustration of the inner
shaft member of FIG. 4a;
FIG. 5a is a cross-sectional schematic illustration of a protective
hood of the dissecting burr of FIG. 1;
FIG. 5b is a cross-sectional schematic illustration of the
protective hood of FIG. 5a with the inner shaft member of FIG. 4a
disposed therein.
FIG. 5c is a cross-sectional schematic illustration of region B in
FIG. 5a.
FIG. 6A is an isometric view of a dissecting burr according to an
embodiment of the invention.
FIG. 6B is a plan view illustration of the dissecting burr of FIG.
6A.
FIG. 7A is a more detailed view of the distal end of the dissecting
burr of FIG. 6A.
FIG. 7B is a longitudinal sectional view of the distal end of the
dissecting burr of FIG. 6A.
FIG. 8 is a longitudinal sectional view of the proximal end of the
dissecting burr of FIG. 6A.
FIGS. 9A-9F are various illustrations of the flexible neck portion
of the distal end of the dissecting burr of FIG. 6A.
FIGS. 10A-10C are detailed illustrations relating to how the
flexible neck portion bends.
FIGS. 11A-11D are detailed illustrations of a burr hood according
to an embodiment of the invention.
FIGS. 12A-12C and 13A-13C are detailed illustrations of a burr hood
according to another embodiment of the invention.
DETAILED DESCRIPTION
Various embodiments of the dissecting high speed burr according to
the invention will now be described in reference to the FIGS. 1
through 5. The embodiments illustrated in these drawings are
presented as examples of various embodiments of the invention only.
These illustrations are not meant to limit the invention to these
examples. The illustrations are not to scale and, thus, the
relative dimensions of some of the aspects of the instrument may be
exaggerated.
Referring to FIGS. 1a-1d, a dissecting burr 100 according to an
embodiment of the invention is disclosed. The dissecting burr 100
comprises a hand piece 114 at its proximal end 112 and a bone
burring surgical tool bit, a burr bit 130, at its distal end 110
housed in a protective hood 120. A generally hollow outer tube 115
connects the hand piece 114 to the protective hood 120.
In an embodiment of the invention, the outer tube 115 may be angled
at a region 117 near the distal end 110 to allow the instrument to
reach into the neural foramen of a patient during a foraminal
decompression. The angled region 117 may be configured and adapted
to have a fixed angle or provided with a hinged or other
articulated flexible joints to allow the angle of the distal end
110 of the instrument to be adjusted as desired.
In another embodiment, the outer tube 115 may be straight without
any angled neck portion 117. Such straight burr instrument may not
be suitable for foraminal decompression but could be used in
situations where the bone spurs are encroaching the foramen from
the posterior lip of the ventral vertebral bodies. The straight
dissecting burr may be used to go in underneath a nerve root and
remove the ventrally encroaching bone. Currently, there are no
tools that allow for the safe removal of bone ventral to the nerve
root in the foramen.
The hand piece 114 functions as a handle for the surgeon to hold
and manipulate the dissecting burr 100 and may house a power drive
mechanism, such as an electrical motor or a pneumatic drive
mechanism, to drive the burr bit 130 of the dissecting burr 100.
The burr bit 130 also may be driven by other suitable driving
means. An elongated outer tube 115 connects the hand piece 114 and
the protective hood 120. The outer tube 115 houses an appropriate
mechanical linkage that connects the power drive mechanism to the
burr bit 130.
The protective housing 120 has an opening 122 exposing one portion
of the burr bit 130. Generally, the superior or dorsally facing
surface of the burr bit 130 is exposed while the undersurface of
the burr bit 130 is protected by a protective hood 120. The
protective hood 120 includes a dissecting foot plate portion 119,
the portion of the protective hood 120 from about the widest
portion to the distal tip 118, that is shaped to enable the distal
end 110 of the dissecting burr 100 to be inserted between the
encroaching bone and the nerve root during a foraminal
decompression procedure, for example. The protective hood 120
enshrouding the burr bit 130 protects the surrounding soft tissue,
such as the nerve root, from being damaged by the burr bit 130
during the bone burring procedure.
The dissecting footplate 119 is shaped like a surgical dissection
tool such as a curette, the Woodson, etc. During surgery, the
distal end 110 of the dissecting burr 100 is placed in the neural
foramen with the exposed burr bit 130 oriented towards the
offending bone. The rest of the burr bit 130 is covered by the
protective hood 120, which rests against the underlying nerve root
thereby protecting the nerve from the burr bit 130.
FIGS. 1b and 1c are detailed side view and a frontal view,
respectively, of the distal end 110 of the dissecting burr 100. The
protective hood 120 may be axially rotatably attached to the outer
tube 115 so that the protective hood 120 is rotatable about a
longitudinal axis 10 of the distal end 110 of the dissecting burr
100. The opening 122 of the protective hood 120 is sized and
configured to expose a desired amount of the burr bit 130
appropriate for the bone removal to be performed with the
instrument. By having an axially rotatable protective hood 120, the
burr bit's exposed cutting portion can be repositioned to
accommodate to the varying geometric relationship of the offending
bone to the compressed nerve. In other words, the protective hood
120 may be axially rotated, changing the angle of attack of the
burr bit 130. The dissecting burr 100 is mechanically configured
such that the rotational motion of the protective hood 120 is
manipulable by the surgeon from the hand piece 114. Thus, the
surgeon can change the direction of the bone resection without
moving the whole instrument, the dissecting burr 100, just by
manipulating the orientation of the protective hood 120 from the
hand piece 114.
Conversely, the protective hood 120 is positioned to maximally
protect the underlying nerve from the exposed burr face. This
configuration allows the angular orientation of the opening 122 in
the protective hood 120 to be changed about its longitudinal axis
and change the direction of the exposed burr bit.
The burr bit 130, the protective hood 120 and the dissecting foot
plate portion 119 of the dissecting burr 100 may be made in any
desired sizes. In one embodiment, the protective hood 120 and the
dissecting foot plate portion 119 may be provided in the following
dimensions that are useful for foraminal decompression. In this
example, the dissecting foot plate 119 of the instrument is
illustrated with a shape resembling a Woodson tip. In FIGS. 1c and
1d, a dissecting burr instrument having Woodson-type dissecting
foot plate 119 according to an embodiment of the invention is
disclosed. In FIG. 1e, a dissecting burr instrument having a
curette-type dissecting foot plate 119 according to another
embodiment is disclosed.
TABLE-US-00001 TABLE Burr Bit Diameter 2 mm 3 mm 4 mm Protective
Hood Size 3 mm 8 mm 4 mm 9 mm 5 mm 10 mm (diameter at the widest
portion) Dissecting Foot 1 to 8 mm long with taper depending on the
Plate Size width of the protective hood.
The protective hood sizes are the diameter W1 (FIG. 1c) of the hood
measured at the widest portion. In these examples, there are two
sizes of protective hood 120 for each burr bit size. The larger
diameter protective hoods are primarily intended for central
laminectomy whereas the smaller protective hoods are primarily
intended for foraminotomy. This preference is determined by the
amount of protection needed for the nerve tissue depending on the
type of procedure and the location in which the instrument is being
used to remove bony tissues from the patient. Some procedures
require more protection from the burr for the other tissues
surrounding the surgical site.
During surgery, the surgeon inserts the dissecting foot plate
portion 119 of the dissecting burr 100 into the interval between
the nerve root and the overlying compressing bone and continue to
insert the instrument into the interval until the burr is
positioned at a suitable location for removing the encroaching
bone. The dissecting burr 100 is then turned on at high speed and
the burr bit 130 is generally pushed forward into the encroaching
bone. As such the whole width of the dissecting burr 100 is not
forced into the interval between the bone and the nerve root. This
minimizes any additional compression that may be exerted by the
dissecting burr 100 because as the burr is advanced, the overlying
bone is resected. The amount of bone that is removed depends on the
combined girth or the diameter of the burr bit 130 and the
protective hood 120 that is inserted into the interval.
FIG. 2a is a schematic side view illustration of a dissecting burr
200 according to another embodiment of the invention. The
dissecting burr 200 of this embodiment is similar to that
illustrated in FIGS. 1a-1c. The dissecting burr 200 comprises an
axially rotatable protective hood 220 that houses a burr bit 230.
The protective hood 220 is axially rotatably attached to outer tube
215. The diameter of the outer tube 215 and the diameter of the
rotating protective hood 220 are substantially similar throughout
their lengths without the bulged portion 128 of the protective hood
120 in the embodiment of the dissecting burr 100. Such
configuration provides smoother profile that may be beneficial
during a surgical procedure.
FIG. 2b is a schematic frontal view illustration of the dissecting
burr of FIG. 2a. The protective hood 220 has an opening 222
exposing one portion of the burr bit 230. Generally, the superior
or dorsally facing surface of the burr bit 230 is exposed while the
undersurface of the burr bit 230 is protected by a protective hood
220. Again, the shape of the dissecting foot plate portion 219 of
the protective hood 220 may be made in a variety of shapes as
appropriate to meet the variety of dissecting action required in
various spinal decompression procedures or any other bone removing
procedures in which these instruments may be useful. For example,
the dissecting foot plate portion 219 may be shaped like a curette
or a Woodson surgical dissection tool.
The protective hood 220 may be rotatable about the longitudinal
axis 20 of the distal end of the instrument to allow the surgeon to
change the direction of the burring action of the burr bit. The
protective hood 220 will generally be fixed so that it does not
rotate while the dissecting burr 200 is in operation (i.e. the burr
bit is rotating). Adjustments in the orientation of the protective
hood may be made when the instrument is turned off. In FIG. 2c, an
alternative shape for the dissecting foot plate portion 219 is
illustrated, which is a Woodson-type tip.
Referring to FIGS. 3a-3c, a dissecting soft tissue resector 300
according to another embodiment of the invention. The dissecting
soft tissue resector 300 comprises a hand piece 314 and an outer
tube 315 that functions as the shaft of the soft tissue resector
300. In this embodiment, however, the surgical tool disposed within
a rotating protective hood 320 is a soft tissue resector bit 330
rather than a burr bit 130, 230. The protective hood 320 has an
opening 322 exposing a portion of the soft tissue resecting bit
330. The portion of the protective hood 320 between the widest
portion W2 of the protective hood and the distal tip 318 of the
protective hood 320 is a dissecting foot plate portion 319, shaped
to resemble a surgical dissection tool, such as a curette or a
Woodson. The outer tube 315 may be angled to allow the instrument
to reach into the neural foramen or other surgical sites with
ease.
The protective hood 320 may be axially rotatably attached to the
outer tube 315. The protective hood 320 is rotatable about a
longitudinal axis 30 of the distal end 310 of the dissecting soft
tissue resector 300. The opening 322 is sized and configured to
expose a desired amount of the burr bit 330 appropriate for the
bone removal to be performed with the instrument. This rotatable
attachment allows the soft tissue resecting bit's exposed cutting
portion to be repositioned to accommodate the varying geometry at
the surgical site. In other words, the protective hood 320 may be
axially rotated, changing the angle of attack of the soft tissue
resecting bit 330. The side with the exposed soft tissue resecting
bit 330 would generally be the dorsal side of the soft tissue
resector 300. The soft tissue resecting bit 330 is similar to that
of the meniscal debriders that are used in arthroscopic
surgery.
The dissecting soft tissue resector 300 may preferably have a
suction means attached to it to remove the resected tissue debris
from the surgical site. Vacuum may be drawn through the outer tube
315 and to the soft tissue resecting bit 330. Preferably, the
tissue resecting bit's cutting teeth 333 are spaced apart to
provide sufficiently large open spaces 335 between the cutting
teeth 333, allowing removal of the resected tissue debris through
those open spaces by the vacuum. The soft tissue resector 300 may
be configured with channel(s) or passage(s) within the instrument
so that vacuum may be applied through the instrument, the open
spaces between the cutting teeth 333 of the soft tissue resector
bit 330 functioning as the intake opening.
The dissecting soft tissue resector 300 embodiment could also be
used, with an extended kind of a Woodson-type foot plate portion
319 as shown in FIGS. 3b and 3c, to get in between compressive
tissue and the nerve root that is sometimes found in the foramen
that can continue to cause residual compression on the nerve, even
after a dorsal bony decompression has been performed. The
dissecting soft tissue resector may be used to debride annulus,
ligamentum flavum, disc and or cartilage that are encroaching the
nerve root in the axilla or in the foramen.
FIG. 4a is a schematic illustration of an inner shaft 140 of a
dissecting burr 100 according to an embodiment of the invention
with a burr bit 130 provided at its distal end. FIG. 4b is a
cross-sectional schematic illustration of an inner shaft 140 and a
burr bit 130 showing an example of how they may be joined together.
In this example, the burr bit 130 has a base portion 137 that is
inserted into the inner shaft and secured. The base portion 137 and
the inner shaft 140 may be secured together by any appropriate
methods such as press fitting, welding, ultrasonic welding.
Alternatively the burr bit 130 may be secured to the inner shaft
140 using an adhesive. The burr bit 130 has helical cutting or
abrading edges 131 on the head portion and a base portion 137 for
attaching the burr bit 130 to the inner shaft 140. The inner shaft
140 is shown as a hollow tube in this example, but it may also be a
flexible solid shaft made from such elastic material as Nitinol
metal alloy.
The soft tissue resector 300 discussed in reference to FIG. 3 may
also utilize a similar inner shaft. In that embodiment, a soft
tissue resector bit 330 would be disposed at the distal end of the
inner shaft. And to enable the vacuum tissue removal feature of the
soft tissue resector 300, the inner shaft in this embodiment would
have a tubular structure (as the inner shaft illustrated in FIG.
4b) with one or more channels therein. The soft tissue resector bit
330 may be provided with one or more channels or pathways through
its base portion so that the open spaces 335 between the tissue
cutting teeth 333 of the tissue resector bit 330 are
communicatively connected to the one or more channels of the inner
shaft. A vacuum drawn through the inner shaft of the instrument can
then remove soft tissue debris from the surgical site using the
open spaces 335 between the tissue cutting teeth 333 as the intake
openings.
Referring to FIGS. 5a-5c, exemplary detailed views of the rotatable
protective hood 120 and the burr bit 130 assembly will be
discussed. FIG. 5a is a cross-sectional schematic illustration of
the outer tube 115 and the rotating protective hood 120 of the
dissecting burr 100 of FIG. 1. The rotating protective hood 120 is
rotatably attached to the distal end of the outer tube 115. The
distal end of the protective hood is the dissecting foot plate 119.
The protective hood 120 has an open space 121 in which the burr bit
130 (or a soft tissue resector bit 330 in the dissecting soft
tissue resector embodiment 300) attached to the inner shaft 140 may
be disposed.
FIG. 5b is a schematic illustration of the protective hood 120 of
FIG. 5a with the inner shaft 140 and the burr bit 130 disposed
therein occupying the open space 121 inside the protective hood
120. The inner shaft 140 is disposed inside the protective hood 120
and the outer tube 115 in such manner so that the inner shaft 140
can rotate about the longitudinal axis 10. The inner surface of the
outer tube 115 comprises a first inner cylindrical side wall 123
having a first diameter and a second inner cylindrical side wall
124 having a second diameter that is smaller than the first
diameter. This second inner cylindrical side wall surface 124
provides a bearing means 151 that comes in contact with the inner
shaft 140 allowing the inner shaft 140 to rotate about the
longitudinal axis 10 with low friction. A portion of the burr bit
130 is shown exposed by the opening 122 in the protective hood
120.
FIG. 5c is a detailed schematic illustration of region B in FIG.
5a. This illustration is one example of the rotational engagement
between the protective hood 120 and the outer tube 115. The
proximal end of the protective hood 120 may form an outer sleeve
126 and the distal end of the outer tube may form an inner sleeve
116 that mate with one another and a suitable bearing means 152 is
disposed between the mating sleeve surfaces to allow the protective
hood to rotate about the longitudinal axis 10 of the distal end of
the instrument. The rotatable joint between the outer tube 115 and
the protective hood 120 may be formed in a variety of other
configurations that are well known in the art.
The power drive mechanism for rotating the inner shaft/burr bit
assembly may be any one of the known mechanisms known in the art.
Many examples can be found in many conventional high speed surgical
burrs, abraders, and other hand held power surgical instruments.
Electrical motors or pneumatic power driven driving mechanisms
commonly found in such instruments may be used to power the
instrument of the invention.
As illustrated in FIGS. 1a, 2a and 3a, the outer tube 115, 215, 315
of the instruments of the invention may preferably include an
angled neck portion 117, 217, 317 whose angle may be variably
controlled. The power drive mechanism utilized in those embodiments
would have to accommodate the angled neck. Many known flexible
coupling mechanisms may be utilized here to transmit the rotational
motion of the power drive mechanism, usually housed in the hand
piece 114, 214, 314, to the burr bit 130, 230 or the soft tissue
resector bit 330. Such flexible coupling mechanism may be, for
example, multiple hinged linkages used to drive socket wrenches or
helical coil flexible connectors often used with hand held drills.
In another embodiment, the flexible neck portion 117, 217, 317 of
the instrument may be hollow structures and a solid shaft made of
elastic materials such as Nitinol metal alloy provided therethrough
may connect the power drive mechanism to the tool bits 130, 230,
330 for actually driving the tool bits. One example of a flexible
coupling mechanism is disclosed in U.S. Pat. No. 5,411,514 (Fucci
et al.), the disclosure of which is incorporated herein by
reference.
Referring to FIGS. 6A and 6B, a dissecting burr 500 according to
another embodiment of the invention is disclosed. The dissecting
burr 500 is well suited for the surgical operations discussed
herein. The dissecting burr 500 has an elongated shape with a
dissecting burr tool at the distal end 510 and a hand piece 514 at
the proximal end. Connecting the hand piece 514 and the distal end
510 of the dissecting burr 500 is a shaft portion 515. The
dimensions of the shaft portion 515 and the distal end 510 of the
dissecting burr 500 are such that they can be inserted through a
cannula to reach the surgical site percutaneously. Provided at the
distal end 510 is a burr bit partially enclosed by a protective
hood 520. The protective hood 520 and the burr bit are connected to
the shaft portion 515 by a flexible neck portion 517. The flexible
neck portion 517 is controllably bendable in dorsal direction
marked by an arrow U in FIG. 6A. The hand piece 514 may be provided
with thumb wheels 610 and 620, one for controlling the rotational
position of the protective hood 520 and the latter for controlling
the bending angle of the flexible neck portion 517. The hand piece
514 may house a power drive mechanism for driving the burr bit.
Such power drive mechanism may be any suitable source that can
rotate the burr bit at high speeds, such as an electric motor or a
pneumatic drive mechanism.
More detailed views of the distal end 510 of the dissecting burr
500 are illustrated in side elevational view FIG. 7A and a
longitudinal sectional view FIG. 7B. The protective hood 520
includes a dissecting foot plate portion 519 which partially covers
the burr bit 530 leaving the burr bit 530 partially exposed in one
direction for removing bone material. The protective hood 520 is
rotatable about the longitudinal axis L of the burr bit 530 (which
is also the longitudinal axis of the dissecting burr 500. The
protective hood 520 has a base portion 525 that is connected to the
tubular shaft 515 via a flexible sleeve 518, which in turn is
connected to the thumb wheel 610. The user can turn or rotate the
protective hood 520 by turning the thumb wheel 610 to adjust the
exposure direction or the angle of attack for the burr bit 530 as
desired during a surgical procedure.
As illustrated in the sectional view of FIG. 7B, the connection
between the base portion 525 of the protective hood 520 and the
flexible sleeve 518 may be achieved by a friction fit. In FIGS. 7A
and 7B, the flexible sleeve 518, which is a helical coil type in
this exemplary embodiment, is only shown at the two ends so that
the internal structures of the flexible neck 517 can be better
illustrated. The proximal end of the flexible sleeve 518 is affixed
to the tubular shaft 515. Again, this connection may be a friction
fit connection.
FIG. 8 is a sectional view of the hand piece 514 and the
arrangement of the thumb wheels 610 and 620 is illustrated. The
tubular shaft 515 is affixed to the first thumb wheel 610 so that
turning the thumb wheel 610 also turns the tubular shaft 515 which,
in turn, turns the flexible sleeve 518, which then turns the
protective hood 520. The flexible sleeve 518 may be a helical coil
type as illustrated in FIGS. 7A and 7B. The thumb wheel 610, the
tubular shaft 515, the flexible sleeve 518, and the protective hood
520, all share a common rotational axis, which is the longitudinal
axis L of the dissecting burr 500. The thumb wheel 610 may be
provided with an appropriate mechanism (not shown) to lock the
thumb wheel 610 from rotating in order to lock the orientation of
the protective hood 520 after being adjusted. A variety of locking
mechanism may be used for such purpose and it would be obvious to
one of ordinary skill in the art to employ such mechanisms.
Nested inside the tubular shaft 515 is a first inner tube 712
(FIGS. 7B and 7C). The first inner tube 712 at the proximal end
extends into the hand piece 514 and is friction fitted or affixed
by other appropriate means to the hand piece 514 to prevent it from
turning about the longitudinal axis L. At its distal end, the first
inner tube 712 is connected to a series of outer links 710 which
extend through the flexible sleeve 518 and hingeably connects to a
burr drive spindle housing 536 (FIG. 7B). As illustrated in FIG.
7A, the outer links 710 are hingeably linked to each other by a
hinge 711. Because the first inner tube 712 is non-rotatably
affixed to the hand piece 514, the outer links 710 also are not
rotatable about the longitudinal axis L. The linkage formed by the
outer links 710 are, however, bendable in one direction, the dorsal
direction U, marked in FIG. 6A. This is because the outer links 710
are lined up so that the rotational axis M (FIG. 9A) through their
hinges 711 are orthogonal to the dorsal direction U.
As illustrated in FIG. 7B, nested inside the first inner tube 712
is a second inner tube 722. The second inner tube 722 at its
proximal end extends into the hand piece 514 and it is friction
fitted or affixed by other appropriate means to the second thumb
wheel 620. At its distal end, the second inner tube 722 is
connected to a series of inner links 720 which extend through the
outer links 710, with the last inner link 720' stopping at the end
of the flexible neck portion 517. Thus, the inner links 720 are not
connected to anything at the distal end. The inner links 720 are
hingeably linked to each other by hinge pins 737 (FIG. 9B). As will
be further discussed below in more detail, turning the second thumb
wheel 620 rotates the inner links 720 and causes the assembly
formed by the outer links 710 to bend up or down in the dorsal
direction U.
As shown in FIG. 7B, nested inside the second inner tube 722 is a
drive shaft 542. The drive shaft 542 may be a rigid shaft and at
its proximal end it extends into the hand piece 514 and is affixed
to a drive linkage 544 which connects the drive shaft 542 to a
power drive unit 550. The power drive unit 550 may be an electric
motor, a pneumatic drive unit, or any other suitable mechanism that
can turn the drive shaft 542 at desired speeds. The drive shaft 542
at its distal end is affixed to a second drive shaft 540 that is
flexible. The second drive shaft 540 may be made of strong and
elastic material such as Nitinol alloy. The second drive shaft 540
extends through the inner links 710 and at the distal end is
affixed to a burr drive spindle 535. The burr drive spindle 535 is,
in turn, connected to a burr bit 530. Alternatively, the second
drive shaft 540 may be directly connected to the burr bit 530
without the intermediate structure such as the spindle 535.
Alternatively, the flexible second drive shaft 540 may extend all
the way to the drive linkage 544 in the hand piece 514 so that a
single piece drive shaft extends from the drive linkage 544 to the
burr bit 530 or the burr bit spindle 535. The interface between the
spindle 535 and the spindle housing 536 is provided with a suitable
lubricant or bearing arrangement so that the spindle 535 may rotate
with minimal frictional interference. Similarly, the interface
between the spindle housing 536 and the base portion 525 of the
protective hood 520 is also provided with a suitable lubricant or
bearing arrangement.
Referring to FIGS. 9A-9F and 10A-10C, the controllably bending
mechanism of the flexible neck portion 517 achieved by the outer
links 710 and the inner links 720 in this exemplary dissecting burr
500 will be described. As mentioned above, the outer links 710 form
a non-rotating assembly that is bendable in one direction. The
bending enabled by the hinges 711 connecting each outer links. Each
of the outer links 710 have center hole 714 so that the outer links
710 form a bendable tube-like structure within which sits the
structure formed by the inner links 720. The inner links are
hingeably connected to each other by the hinge pins 737. Each of
the inner links 720 also have center hole 724 (FIG. 9F). Each inner
link 720 has a pair of lower ears 720b and a pair of upper ears
720a, transversely oriented from the lower ears 720b. The hingeable
links between the inner links 720 are formed by a cross-shaped pin
subassembly 730 (FIG. 9D). The pin subassembly 730 comprises a pair
of short hinge pins 737. The hinge pins 737 mate with the lower
ears 720b of the inner links 720 thereby hingeably connecting them.
The pin subassembly 730 also comprises a pair of long camming pins
735 whose longitudinal axis Y is oriented transverse to the
longitudinal axis X of the short hinge pins 737. The pin
subassembly 730 is assembled in between two inner links 720 so that
the camming pins 735 extend through the upper ears 720a of the
inner links 720 and into camming spaces S formed between the outer
links 710. The pin subassembly 730 is provided with center hole 734
that aligns with the center hole 724 of the inner links 724.
Referring to FIG. 10A, each outer link 710 has a first surface 716
that is flat and a second surface 717 that is specifically
contoured. The second surface 717 forms the camming surface for the
camming pins 735 which extends into the camming space S formed
between the outer links 710. The camming surface 717 is contoured
so that as the camming pins 735 rotates in the camming space S, the
two adjacent outer links 710 are forced to bend about the hinge 711
in the dorsal direction U and back to the straight configuration.
The camming surface 717 of the outer link 710 is contoured to have
at least 6 regions marked as A, B, C, D, E, and F in FIG. 10A. FIG.
10B illustrates the configuration where two adjacent outer links
710 and 710' are in a straight arrangement. Thus, this represents
the configuration where the flexible neck 517 of the dissecting
burr 500 is, in turn, straight. The inner links 720 have been
rotated so that one end of their camming pin 735 is positioned in
the camming space S. The camming pin 735 is at the region A of the
camming surface 717. The opposite end (not shown) of the camming
pin 735 is on the opposite side at the region C of the camming
surface 717. This position of the camming pin 735 will be referred
to as the A-C position. Illustrated in FIG. 10C is the
configuration in which the outer links 710 and 710' are at their
maximum bending angle .theta.. The camming pin 735 is now at the
regions D and B of the camming surface 717. This position of the
camming pin 735 will be referred to as the B-D position. As
illustrated in FIGS. 10B and 10C, the thickness T1 of the outer
link 710 at camming region A is thinner than the thickness T2 of
the outer link 710 at the camming region D. Correspondingly, the
camming space S1 is larger than the camming space S2. Thus, as the
camming pin 735 transitions from the A-C position to the B-D
position, the camming pin 735 pushes the outer links 710 and 710'
apart at the S2 side and causing the outer links to pivot relative
to each other about the hinge 711. By rotating the inner links 720
and moving the camming pin 735 back to the A-C position, the
camming pin 735 now pushes the outer links 710 and 710' apart at
the S1 side pivoting the outer links back to the straight
configuration shown in FIG. 10B. FIG. 9A illustrates the outer link
assembly in a position where the camming pins 735 are somewhat
close to the A-C position and FIG. 9E illustrates the outer link
assembly in a position where the camming pins 735 are somewhat
closer to the B-D position. It should be noted that the maximum
range for the amount of bending that may be manipulated for a given
dissecting burr 500 can be varied as desired by changing the
contour of the camming surface 717 of the outer links and the
number of outer links used to form the flexible neck portion
517.
FIGS. 11A-11D are more detailed illustrations of the protective
hood 520 of the dissecting burr 500 of FIG. 6A. The side view, FIG.
11A, and the sectional view FIG. 11B, show that the dissecting foot
plate portion 519 of the protective hood 520 partially enclose the
burr bit 530. The dissecting foot plate portion 519 in this
exemplary embodiment is similarly shaped to the Woodson dissecting
tool, with the dissecting foot plate 519 extending from the widest
portion W of the protective hood 520 towards the distal tip 518
beyond the burr bit 530 providing a space 521. The burr bit end of
the dissecting burr 500 can be inserted into a surgical site, such
as the interval between the nerve root and the encroaching bone in
a neural foramen without the need for a separate dissecting tool
and without the risk of damaging the surrounding soft tissue such
as the nerve root. The surgeon would rotate the protective hood 520
so that the foot plate portion 519 is positioned to be between the
burr bit 530 and the nerve root as the surgeon inserts the burr bit
end of the instrument into the surgical site.
FIGS. 12A-12C are illustrations of another protective hood 820 for
the dissecting burr 500 having another dissecting foot plate 619
having a pointed or tapered distal tip 618 according to another
embodiment. As mentioned above, the dissecting foot plate portion
may be configured and adapted to have many different shapes that
are appropriate for a particular application but all for providing
a dissecting function.
FIGS. 13A-13C are illustrations of another protective hood 720 for
the dissecting burr 500 having a curette-type dissecting foot plate
719 according to another embodiment. The curette-type dissecting
foot plate 719 of this embodiment does not extend out beyond the
burr bit 530 as much as the Woodson-type dissecting foot plates
519, 619. The curette-type dissecting foot plate 719 has a short
curved shape.
The dissecting foot plate portions 519, 619 and 719 have length Z
of about 7.5 mm and a diameter at the widest portion W of about 4.5
mm. For surgical applications involving lumbar decompression
surgical procedures such as lumbar laminectomy and foraminotomy,
the dissecting foot plate portion may have a length of about 1 mm
(currette-like tip) to about 8 mm (Woodson-like tip). The diameter
of the foot plate portion at the widest portion W may be about 2 mm
to 10 mm depending on the burr bit size.
With current minimally invasive lumbar decompression techniques, a
retracting cannula is placed at the interspace percutaneously via
sequential dilators. This technique works well for disc herniations
where the pathology can be accessed at the interspace. The draw
back to this technique with lumbar decompressions is that the
ipsilateral lateral recess and foramen are extremely difficult to
decompress because the line of sight afforded by the cannula does
not allow the surgeon to get a direct view into the recess or the
foramen on the ipsilateral side. Therefore, some surgeons have
modified the technique and taken the cannula and directed it
contralaterally to afford a view at the contralateral lateral
recess and foramen. The drawback of this technique is that you
disrupt the interspinous ligament and reaching across the dural
space risks tearing the dura. In addition, attempting a foraminal
decompression and lateral recess decompression in this fashion is
technically extremely demanding because of the limited view and the
limited maneuverability afforded by the small working diameter of
the cannula. The cannulas typically have a diameter of about 2
centimeters. This could be made even more technically demanding in
a patient with an extremely stenotic lateral recess and
foramen.
The spinal instruments of the invention provides many advantages
over the conventional instruments in performing minimally invasive
lumbar decompressions. Lateral recess decompression can be
performed on the ipsilateral side and also a foraminotomy can be
performed on the ipsilateral side. Therefore, the interspinal
ligaments can be preserved and all that is necessary to complete a
full decompression is making a midline incision to bring the
cannula to one side of the spinous process and the interspinous
ligaments to perform one side of the lateral decompression. The
cannula is then pulled out and reenter the spine on the
contralateral side, through the same incision, on the other side of
the spinous process and interspinous ligament and perform the
contralateral lumbar lateral recess and foraminal decompression. In
this way the interspinous ligament and the spinous processes are
preserved and that posterior tension band is not violated. In order
to perform the lateral recess decompression, an endoscope must be
placed, similar to the conventional scopes that can be attached to
the retracting cannula, however, it needs to be angled at a 60-70
degree angle so that it has a view directly into the lateral recess
and the foramen.
Because the high speed dissecting burr 100, 200 of the invention
does not require a large amount of force or a large arc of motion
to perform a bone resection, the lateral recess and foraminal
decompression can be performed safely and accurately in minimally
invasive setting. Because of the precision of bone resection
allowed by the high speed dissecting burr 100, 200 of the
invention, the actual amount of bone that is resected can be
minimized just to the bone that is encroaching on to the nerve root
or the dural elements in the lateral recess. Thus, the amount of
bony resection can be minimized to what is necessary to adequately
decompress the neural elements. This maximally preserves the facet
joints, thereby minimizing post-decompression instability.
A number of benefits are realized by the use of the surgical
instruments of the invention described herein. For example, by
performing the bone and ligament sparing lumbar decompression, the
lamina can be preserved. The ligamentum just needs to be removed at
the interspace, which often is the main source of compression, and
the bone encroaching the lateral recess from facet hypertrophy and
the foraminal stenosis can be adequately decompressed using the
high speed dissecting burr and dissecting spinal soft tissue
resector.
Since the amount of facet resection can be minimized and the
posterior spinal ligaments preserved by using the high speed
dissecting burr of the invention, it may be possible to clinically
avoid fusion in patients with mild instability and mild
spondylolisthesis because most of the spinal stability and the
spinal integrity can be preserved. However, in patients where
fusions are deemed to be warranted, the decompressions can be
performed in a minimally invasive setting and since the lamina are
preserved, one can attempt an interlaminar spinal fusion. Also,
because the intertransverse plane is not dissected, there is no
lateral soft tissue stripping that needs to be performed lateral to
the facets and the intertransverse plane, therefore the morbidity
to the patient is significantly minimized and the patient's
postoperative recovery will be enhanced. Thus, there is no
additional soft tissue dissection that is required than is done
with a normal laminectomy.
By using the surgical instruments of the invention, preservation of
bone and interspinal ligaments can be maximized during spinal
decompression procedures. And since a good portion of the spinal
stability is maintained by preserving the bone and interspinal
ligaments, the overall patient satisfaction will be much improved
in the strictly lumbar decompression patients. Furthermore, by
combining the decompression performed with the instruments of the
invention with a minimally invasive interlaminar fusion, possibly
supplemented with minimally invasive pedicle screw system, the
spinal segment fusion can be performed with a higher union rate and
faster recovery times since the intertransverse muscle plane can be
spared.
The surgical instruments of the invention also have applications in
other areas of the spine. In the cervical spine, for example, the
dissecting burr may be used for posterior foraminotomies. In such
procedure, the dorsal surface of the spinal nerve root is first
located and the dissecting burr is inserted overlying the nerve
root under microscopic visualization and a foraminotomy may be
performed that maximally preserves the cervical facet joint.
The dissecting burr of the invention may also enhance anterior
cervical surgery, for example, during anterior cervical
corpectomies. The width of the corpectomy trough is limited by
concerns of the vertebral artery being violated at the lateral
margin. Often the lateral decompression is incomplete because of
fear of violating the vertebral artery, which can be catastrophic.
With the use of the dissecting burr of the invention, the
dissecting portion of the burr can be inserted into the interval
between the vertebral artery and the lateral margins of the
anterior cervical vertebral body and resect the lateral bony edge.
This would allow the surgeon to perform a complete cervical
corpectomy rather than a partial one.
Also, for anterior cervical disc work, the dissecting burr of the
invention can be used to perform anterior cervical foraminotomies
and osteophytectomies by inserting the burr into the interval
between the lateral margin of the uncus and the vertebral artery by
protecting the vertebral artery and allowing complete resection of
the uncovertebral joint and thereby decompressing the foramina
laterally and allowing preservation of the disc space medially and
avoiding cervical fusion.
According to an aspect of the invention, the various embodiments of
the instruments described herein may be configured so that
irrigation fluid may be delivered to the surgical site via the
instrument. There are many examples of surgical instruments known
in the art having such irrigating feature that may be incorporated
into the instruments of the invention. Example of burring or
similar type of instruments with irrigation feature are described
in, for example, U.S. Pat. No. 5,782,795 (Bays); U.S. Pat. No.
6,068,641 (Varsseveld); and U.S. Pat. No. 6,503,263 (Adams), the
disclosures of which are incorporated herein by reference. In both
the dissecting burr and the dissecting soft tissue resector
embodiments of the invention, channels or pathways may be provided
within the instrument for supplying irrigation fluid to the
surgical site. Irrigation fluid would serve to assist in removal of
tissue debris from the surgical site as well as cooling the
surgical tool tip, the burr bits 130, 230 and the soft tissue
resector bit 330, during the surgical procedure. Keeping the tool
tip cool prevents damaging bone, nerve, or surrounding tissues
during the surgical procedure. The irrigation can also help to
collect the bone or other tissue debris for removal from the
surgical site.
The instruments of the invention may also be configured for
removing the tissue debris from the surgical site by vacuum. As
discussed in reference to the soft tissue resector embodiment of
the invention, the surgical tool tip may be configured to have open
spaces between the cutting or abrading teeth sufficiently large for
removal of tissue debris. The protective hood 120, 220, 320 or the
outer tube 115, 215, 315 may also be configured with openings that
may serve as intake ports for removing tissue debris by suction
from in and around the surgical site. Many examples of surgical
burrs and other abraders having such tissue removal features are
known in the industry.
While the foregoing invention has been described with reference to
the above embodiments, various modifications and changes can be
made without departing from the spirit of the invention.
Accordingly, all such modifications and changes are considered to
be within the scope of the appended claims.
* * * * *