U.S. patent application number 10/359996 was filed with the patent office on 2003-07-24 for devices and methods for percutaneous surgery.
Invention is credited to Clayton, John B., Foley, Kevin Thomas, Moctezuma, Joseph, Smith, Maurice Mell.
Application Number | 20030139648 10/359996 |
Document ID | / |
Family ID | 24488004 |
Filed Date | 2003-07-24 |
United States Patent
Application |
20030139648 |
Kind Code |
A1 |
Foley, Kevin Thomas ; et
al. |
July 24, 2003 |
Devices and methods for percutaneous surgery
Abstract
Devices and methods for performing percutaneous spinal surgery
under direct visualization and through a single cannula are shown.
A device (10) is provided which includes an elongated cannula (20)
having a first inner diameter (D.sub.I) and an outer diameter
(D.sub.O) sized for percutaneous introduction into a patient. The
cannula (20) defines a working channel (25) between its ends (21,
22) which has a second diameter (D.sub.2) equal to the diameter
(D.sub.I) of the cannula sized for receiving a tool therethrough.
An elongated viewing element (50) is engageable to the cannula (20)
adjacent the working channel (25), preferably by a fixture (30).
The fixture (30) includes a housing (31) attachable to the proximal
end (22) of the cannula (20) that defines a working channel opening
(35) which is in communication with the working channel (25). The
housing (31) also defines an optics bore (60) adjacent the working
channel opening (35). In certain embodiments, the fixture (30)
supports the viewing element (50) for translation and/or rotation
within the optics bore (60) along the longitudinal axis of the
bore, and for rotation of the housing (31) relative to the cannula
(20) so that the longitudinal axis of the optics bore (60) will
rotate about the longitudinal axis of the working channel (25).
Methods are also provided for performing spinal surgeries
percutaneously with direct visualization and without the
requirement for a fluid-maintained workspace.
Inventors: |
Foley, Kevin Thomas;
(Germantown, TN) ; Smith, Maurice Mell; (Cordova,
TN) ; Clayton, John B.; (Germantown, TN) ;
Moctezuma, Joseph; (Memphis, TN) |
Correspondence
Address: |
Woodard, Emhardt, Naughton,
Moriarty and McNett LLP
Bank One Center/Tower
111 Monument Circle, Suite 3700
Indianapolis
IN
46204-5137
US
|
Family ID: |
24488004 |
Appl. No.: |
10/359996 |
Filed: |
February 6, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10359996 |
Feb 6, 2003 |
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09449647 |
Nov 30, 1999 |
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6520907 |
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09449647 |
Nov 30, 1999 |
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08920991 |
Aug 29, 1997 |
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6007487 |
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08920991 |
Aug 29, 1997 |
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08620933 |
Mar 22, 1996 |
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5792044 |
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Current U.S.
Class: |
600/114 |
Current CPC
Class: |
A61B 2017/00261
20130101; A61B 2017/0046 20130101; A61B 2090/306 20160201; A61B
2017/0262 20130101; A61B 90/50 20160201; A61M 29/02 20130101; A61B
2017/3445 20130101; A61B 17/02 20130101; A61B 2017/00296 20130101;
A61B 17/3421 20130101; A61B 2090/3614 20160201; A61B 17/3417
20130101; A61B 17/1671 20130101; A61B 2017/00469 20130101; A61B
2090/373 20160201; A61B 2017/347 20130101; A61M 29/00 20130101 |
Class at
Publication: |
600/114 |
International
Class: |
A61B 001/00 |
Claims
What is claimed:
1. A device for use in percutaneous spinal surgery, comprising: an
elongated cannula having a first inner diameter and an outer
diameter sized for percutaneous introduction into a patient, said
cannula further including a distal working end and an opposite
proximal end, said cannula defining a working channel between said
ends having a second diameter equal to said first inner diameter
sized for receiving a tool therethrough; and an elongated viewing
element mounted inside said cannula adjacent said working channel,
said viewing element having a first end connectable to a viewing
apparatus and an opposite second end disposed adjacent said distal
working end of said cannula.
2. The device of claim 1 wherein said second inner diameter is
sized to simultaneously receive a plurality of tools
therethrough.
3. The device of claim 1, wherein said elongated viewing element
includes a lens at said second end and an image transmission
channel extending therefrom.
4. The device of claim 3, wherein said elongated viewing element is
a fiber-optic cable having illumination fibers and image
transmission fibers.
5. The device of claim 1, further comprising a fixture for mounting
said elongated viewing element to said cannula.
6. The device of claim 5, wherein said fixture is configured to
mount said viewing element within said working channel.
7. The device of claim 5, wherein said fixture includes: a housing
attached to the proximal end of the cannula, said housing defining
a working channel opening therethrough in communication with the
working channel, said working channel opening sized to
substantially correspond to said second diameter of said working
channel to receive a tool therethrough; said housing further
defining an optics bore adjacent said working channel opening, said
optics bore sized to receive said elongated viewing element
therethrough.
8. A device for use in percutaneous spinal surgery, comprising: an
elongated cannula sized for percutaneous introduction into a
patient having a distal working end and an opposite proximal end
and defining a working channel between said ends, said working
channel having an inner diameter sized to receive a tool
therethrough; an elongated viewing device having a first end
connectable to a viewing apparatus and a second end including a
lens positionable adjacent said working end of said cannula; and a
fixture connected to said proximal end of said cannula adjacent to
said working channel and defining an optics bore having a
longitudinal axis, said optics bore sized to removably receive said
elongated viewing device therethrough, and said fixture supporting
said viewing device for movement within said optics bore along the
longitudinal axis of said bore to extend or retract said lens
relative to said distal working end of said cannula.
9. The device of claim 8 wherein said elongated viewing element
includes a lens at said second end and an image transmission
channel extending therefrom.
10. The device of claim 9, wherein said lens defines an optical
axis, said optical axis being offset at an angle relative to said
longitudinal axis of said optics bore.
11. The device of claim 9, wherein elongated viewing element is a
fiber-optic cable having illumination fibers and image transmission
fibers.
12. The device of claim 8, wherein said fixture is configured to
support said viewing element within said working channel.
13. The device of claim 8, wherein said fixture includes: a housing
attached to the proximal end of the cannula, said housing defining
a working channel opening therethrough in communication with the
working channel, said working channel opening sized to
substantially correspond to said second diameter of said working
channel to receive a tool therethrough; said housing further
defining said optics bore adjacent said working channel
opening.
14. A device for use in percutaneous spinal surgery, comprising: an
elongated cannula having a distal working end and an opposite
proximal end and defining a working channel between said ends, said
working channel having an inner diameter sized to receive a tool
therethrough; an elongated viewing device having a first end
connectable to a viewing apparatus and a second end including a
lens positionable adjacent said working end of said cannula; and a
fixture connected to said proximal end of said cannula adjacent to
said working channel and defining an optics bore having a
longitudinal axis, said optics bore sized to removably receive said
elongated viewing device therethrough, and said fixture supporting
said viewing device for rotation within said optics bore about the
longitudinal axis of said bore.
15. The device of claim 14 wherein said elongated viewing element
includes a lens at said second end and an image transmission
channel extending therefrom.
16. The device of claim 15, wherein said lens defines an optical
axis, said optical axis being offset at an angle relative to said
longitudinal axis of said optics bore.
17. The device of claim 15, wherein said elongated viewing element
is a fiber-optic cable having illumination fibers and image
transmission fibers.
18. The device of claim 14, wherein said fixture is configured to
support said viewing element within said working channel.
19. The device of claim 14, wherein said fixture includes: a
housing attached to the proximal end of the cannula, said housing
defining a working channel opening therethrough in communication
with the working channel, said working channel opening sized to
substantially correspond to said second diameter of said working
channel to receive a tool therethrough; said housing further
defining said optics bore adjacent said working channel
opening.
20. The device of claim 14, wherein said fixture further supports
said elongated viewing device for movement within said optics bore
along said longitudinal axis of said bore.
21. A device for use in percutaneous spinal surgery comprising: an
elongated cannula having a distal working end and an opposite
proximal end and defining a working channel between said ends, said
working channel having a first longitudinal axis and ana inner
diameter sized to receive a tool therethrough; and a fixture
mounted to said proximal end of said cannula, said fixture
including a housing defining a working channel opening in
communication with said working channel of said cannula and an
optics bore for receiving an elongated viewing device therethrough
in communication with said working channel, said optics bore having
a second longitudinal axis substantially parallel to said first
longitudinal axis, said housing being rotatable relative to said
cannula so that said second longitudinal axis of said optics bore
rotates about said first longitudinal axis of said working
channel.
22. The device of claim 21, further comprising an elongated viewing
device disposed within said optics bore, said viewing device having
a first end connectable to a viewing apparatus and a second end
including a lens positionable adjacent said working end of said
elongated cannula.
23. The device of claim 21, wherein: said cannula has an outer
diameter; and said housing defines a receiving bore having an inner
diameter slightly larger than said out diameter of said cannula,
wherein said proximal end of said cannula is received within said
receiver bore so that said housing can rotate about said proximal
end of said cannula.
24. The device of claim 23, wherein said housing further includes
an upper bore contiguous with said working channel opening and in
communication with said receiver bore, said optics bore being
disposed within said upper bore of said housing.
25. The device of claim 21, wherein said optics bore is defined by
a C-shaped clip.
26. The device of claim 25, wherein said C-shaped clip is formed of
a resilient material and said optics bore defined by said clip has
an inner diameter that is slightly less than an outer diameter of
said elongated viewing device so that said viewing device
resiliently deflects said C-shaped clip when said viewing device is
disposed within said optics bore.
27. The device of claim 23, wherein said housing further defines a
number of grooves in said receiver bore.
28. The device of claim 27, further comprising sealing members
disposed in each of said number of grooves, said sealing members
disposed between said housing and said outer diameter of said
cannula.
29. The device of claim 21 wherein said working channel opening has
a diameter substantially equal to said inner diameter of said
working channel.
30. The device of claim 21 wherein said fixture includes engagement
means, disposed between said housing and said cannula when said
fixture is mounted to said proximal end of said cannula, for
providing a gripping engagement between said housing and said
cannula.
31. The device of claim 30, wherein said engagement means includes
a number of resilient rings disposed between said housing and said
cannula.
32. A device for supporting an elongated viewing device within a
cannula defining a working channel, comprising: a fixture mountable
to said proximal end of the cannula, said fixture including a
housing defining a working channel opening arranged to communicate
with the working channel when said fixture is mounted to the
cannula, said working channel opening sized to receive tools
therethrough, and said housing further defining an optics bore for
receiving an elongated viewing device therethrough and arranged so
that the viewing device received within said optics bore will
extend into the working channel of the cannula when said fixture is
mounted to the cannula.
33. The device of claim 32, in which the cannula defines a first
longitudinal axis, wherein said optics bore defines a second
longitudinal axis substantially parallel to the first longitudinal
axis when said fixture is mounted on the cannula, said housing
being rotatable relative to said cannula so that said second
longitudinal axis of said optics bore rotates about the first
longitudinal axis of the cannula.
34. The device of claim 32 in which the cannula has an outer
diameter, wherein said housing defines a receiving bore having an
inner diameter slightly larger than the outer diameter of the
cannula, so that said housing can rotate about the cannula.
35. The device of claim 34, wherein said housing further includes
an upper bore contiguous with said working channel opening and in
communication with said receiving bore, said optics bore being
disposed within said upper bore of said housing.
36. The device of claim 35, wherein said optics bore is defined by
a C-shaped clip.
37. The device of claim 36, wherein said C-shaped clip is formed of
a resilient material and said optics bore defined by said clip has
an inner diameter that is slightly less than an outer diameter of
the elongated viewing device so that the viewing device resiliently
deflects said C-shaped clip when the viewing device is disposed
within said optics bore.
38. The device of claim 34, wherein said housing further defines a
number of grooves in said receiver bore.
39. The device of claim 38, further comprising O-rings disposed in
each of said number of grooves, said O-rings disposed between said
housing and the outer diameter of the cannula when the cannula is
disposed within said receiver bore.
40. A tissue retractor for use in percutaneous surgery through a
cannula having an inner cylindrical surface, said retractor
comprising: a working tip configured to atraumatically displace
tissue as the retractor is manipulated through the tissue; and a
body having a proximal first end and a distal second end, said
second end being integral with said working tip, said body having a
convex surface configured to conform to the inner cylindrical
surface of the cannula when said tissue retractor is disposed
within the cannula, said body sized to be rotatable received within
the cannula and having a length from a said first end to a said
second end sufficient so that said first end and said working tip
can be outside the cannula when said body is within the
cannula.
41. The tissue retractor of claim 40, wherein said working tip has
a blunt curved end.
42. The tissue retractor of claim 40, wherein said body includes a
curved plate defining said convex surface and an opposite concave
surface.
43. The tissue retractor of claim 42, wherein said curved plate
includes opposite edges extending substantially parallel to said
length of said body, said curved plate subtending an arc between
said opposite edges of at least 200 degrees.
44. The tissue retractor of claim 43, wherein said curved plate
subtends an arc between said opposite edges of about 270
degrees.
45. The tissue retractor of claim 40, wherein said body includes: a
first plate portion defining a first convex surface and an opposite
first concave surface and including first opposite edges extending
substantially parallel to said length of said body, said first
plate portion subtending a first arc between said first opposite
edges; and a second plate portion integral with said first plate
portion and disposed between said first plate portion and said
working tip, said second plate portion defining a second convex
surface and an opposite second concave surface and including second
opposite edges extending substantially parallel to said length,
said second plate portion subtending a second arc between said
second opposite edges that is different from said first arc.
46. The tissue retractor of claim 45, wherein said first arc
subtends an angle of less then 180 degrees and said second ar
subtends an angle of more than 180 degrees.
47. The tissue retractor of claim 46, wherein said first arc
subtends an angle of about 90 degrees and said second arc subtends
an angle of about 270 degrees.
48. The tissue retractor of claim 45, wherein said second arc
subtends an angle that decreases along said length toward said
working tip.
49. The tissue retractor of claim 48, wherein said second arc
subtends an angle of about 200 degrees adjacent said first plate
portion decreasing to an angle of less than 10 degrees adjacent
said working tip.
50. The tissue retractor of claim 49, wherein said first arc
subtends an angle of about 200 degrees.
51. The tissue retractor of claim 40, wherein said convex surface
of said body is at a diameter that is greater than the diameter of
the inner cylindrical surface of the cannula, said body being
resiliently deformable to be insertable into the cannula with said
convex surface in contact with the inner cylindrical surface of the
cannula.
52. The tissue retractor of claim 40, further comprising an arm
attached to said proximal first end of said body, said arm having a
gripping surface to facilitate manipulation of said tissue
retractor.
53. The tissue retractor of claim 52, wherein said arm is
substantially perpendicular to said length of said body.
54. A tissue dilator, comprising: a sleeve having a tapered working
end and an opposite end, said working end configured to displace
tissue; and a gripping portion on an outer surface of said sleeve
adjacent said opposite end, said gripping portion defining a
plurality of circumferential grooves configured for manually
gripping the dilator to manipulate the dilator within tissue.
55. A method for performing a surgical procedure at a location in a
patient's body, comprising: inserting a cannula into a patient
through skin and tissue to create a working channel; creating a
working space in communication with the working channel and
adjacent the location in the patient's body; inserting optics
through the working channel to the working space; extending a first
tool through the working channel to the working space; and
manipulating the first tool through the working channel to perform
a surgical procedure on the location in the working space under
direct vision from the optics and without directing irrigation
fluid to the location.
56. The method of claim 55 wherein the tool is a power drill and
the surgical procedure is drilling through bone or tissue at the
location.
57. The method of claim 55, further comprising: extending the
optics through the working channel beyond the end of the working
channel adjacent the working space for direct visualization of the
working space and manipulating the tool.
58. The method of claim 55, further comprising: removably inserting
a second tool through the working channel simultaneous with the
first tool; and manipulating the second tool to perform a function
at the location.
59. The method of claim 58 further comprising: inserting a
guidewire into a patient through skin and tissue to the location;
inserting a cannulated dilator over the guidewire and through the
skin and tissue to the location wherein the inserting the cannula
includes inserting the cannula over the dilator; removing the
guidewire after inserting the dilator; and removing the dilator
after inserting the cannula.
60. A method for performing a surgical procedure at a location on
the spine, comprising: inserting a cannula into a patient through
skin and tissue to create a working channel; creating a working
space in communication with the working channel and adjacent the
location on the spine; extending a tool through the working channel
beyond the end of the working channel and manipulating the tool in
the working space; and extending optics through the working channel
beyond the end of the working channel adjacent the working space to
directly visualize the working space and manipulation of the
tool.
61. A method for performing a surgical procedure at a location on
the spine, comprising: inserting a cannula into a patient through
skin and tissue to create a working channel; creating a working
space in communication with the working channel and adjacent the
location on the spine; removably inserting a first tool through the
working channel; manipulating the first tool to perform a function
at the location; removably inserting a second tool through the
working channel simultaneous with the first tool; and manipulating
the second tool to perform a function at the location.
62. The method of claim 61 wherein: the first tool is a tissue
retractor; and the step of manipulating the first tool includes
manipulating the tissue retractor to retract tissue to maintain the
working space.
63. A method for performing a discectomy at a subject vertebral
level on the spine, comprising: creating an incision in the skin
substantially directly posterior to the subject vertebral level;
creating a bore through the lamina at a posterior medial position
on the spine; mounting a cannula through the incision at the bore
in the lamina to create a working channel; inserting optics through
the cannula to directly visualize the location on the spine
underneath the working channel; extending a retractor through the
working channel to retract tissue to create a path to the spinal
disc; extending the optics through the working channel an d path to
the spinal disc; and extending and manipulating discectomy
instruments through the working channel to the disc to perform a
discectomy under direct vision by the optics.
64. The method of claim 63 wherein the creating a bore includes
conducting a laminectomy comprising the steps of: inserting a
cannula into the incision and through tissue to the lamina to
define a working channel; extending optics through the working
channel to directly visualize the lamina; and extending a bone
cutting tool through the working channel and manipulating the tool
to perform a laminectomy under direct vision from the optics.
65. A method for performing a laminectomy, comprising: creating an
incision in the skin substantially directly posterior to the
subject vertebral level; inserting a cannula into the incision and
through tissue to the lamina to define a working channel; extending
optics through the working channel to directly visualize the
lamina; and extending a bone cutting tool through the working
channel and manipulating the tool to perform a laminectomy under
direct vision from the optics.
66. A method for implanting a vertebral fixation element,
comprising: making an incision in the skin to provide access to the
location on the vertebra at which the fixation element is to be
implanted; inserting a cannula into the incision and through tissue
to the location to define a working channel; inserting optics
through the cannula to directly visualize the location; extending
an insertion tool supporting the vertebral fixation element through
the working channel to the location under direct vision; and
manipulating the insertion tool to implant the fixation element at
the location under direct vision from the optics.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to devices, instruments and
methods for performing percutaneous surgeries, particularly at
locations deep within the body. One specific application of the
invention concern devices, instruments and techniques for
percutaneous, minimally invasive spinal surgery. In another aspect
of the invention, the percutaneous surgery is performed under
direct vision at any location in the body.
BACKGROUND OF THE INVENTION
[0002] Traditional surgical procedures for pathologies located deep
within the body can cause significant trauma to the intervening
tissues. These open procedures often require a long incision,
extensive muscle stripping, prolonged retraction of tissues,
denervation and devascularization of tissue. Most of these
surgeries require a recovery room time of several hours and several
weeks of post-operative recovery time due to the use of general
anesthesia and the destruction of tissue during the surgical
procedure. In some cases, these invasive procedures lead to
permanent scarring and pain that can be more severe than the pain
leading to the surgical intervention.
[0003] Minimally invasive alternatives such as arthroscopic
techniques reduce pain, post-operative recovery time and the
destruction of healthy tissue. Orthopedic surgical patients have
particularly benefitted from minimally invasive surgical
techniques. The site of pathology is accessed through portals
rather than through a significant incision thus preserving the
integrity of the intervening tissues. These minimally invasive
techniques also often require only local anesthesia. The avoidance
of general anesthesia reduces post-operative recovery time and the
risk of complications.
[0004] Minimally invasive surgical techniques are particularly
desirable for spinal and neurosurgical applications because of the
need for access to locations deep within the body and the danger of
damage to vital intervening tissues. For example, a common open
procedure for disc herniation, laminectomy followed by discectomy
requires stripping or dissection of the major muscles of the back
to expose the spine. In a posterior approach, tissue including
spinal nerves and blood vessels around the dural sac, ligaments and
muscle must be retracted to clear a channel from the skin to the
disc. These procedures normally take at least one-two hours to
perform under general anesthesia and require post-operative
recovery periods of at least several weeks. In addition to the long
recovery time, the destruction of tissue is a major disadvantage of
open spinal procedures. This aspect of open procedures is even more
invasive when the discectomy is accompanied by fusion of the
adjacent vertebrae. Many patients are reluctant to seek surgery as
a solution to pain caused by herniated discs and other spinal
conditions because of the severe pain sometimes associated with the
muscle dissection.
[0005] In order to reduce the post-operative recovery time and pain
associated with spinal and other procedures, micro-surgical
techniques have been developed. For example, in micro-surgical
discectomies, the disc is accessed by cutting a channel from the
surface of the patient's back to the disc through a small incision.
An operating microscope or loupes is used to visualize the surgical
field. Small diameter micro-surgical instruments are passed through
the small incision and between two laminae and into the disc. The
intervening tissues are disrupted less because the incision is
smaller. Although these micro-surgical procedures are less
invasive, they still involve some of the same complications
associated with open procedures, such as injury to the nerve root
and dural sac, perineural scar formation, reherniation at the
surgical site and instability due to excess bone removal.
[0006] Other attempts have been made for minimally invasive
procedures to correct symptomatic spinal conditions. One example is
chemonucleolysis which involved the injection of an enzyme into the
disc to partially dissolve the nucleus to alleviate disc
herniation. Unfortunately, the enzyme, chymopapain, has been
plagued by concerns about both its effectiveness and complications
such as severe spasms, post-operative pain and sensitivity
reactions including anaphylactic shock.
[0007] The development of percutaneous spinal procedures has
yielded a major improvement in reducing recovery time and
post-operative pain because they require minimal, if any, muscle
dissection and they can be performed under local anesthesia. For
example, U.S. Pat. No. 4,545,374 to Jacobson discloses a
percutaneous lumbar discectomy using a lateral approach, preferably
under fluoroscopic X-ray. This procedure is limited because it does
not provide direct visualization of the discectomy site.
[0008] Other procedures have been developed which include
arthroscopic visualization of the spine and intervening structures.
U.S. Pat. Nos. 4,573,448 and 5,395,317 to Kambin disclose
percutaneous decompression of herniated discs with a posterolateral
approach. Fragments of the herniated disc are evacuated through a
cannula positioned against the annulus. The '317 Kambin patent
discloses a biportal procedure which involves percutaneously
placing both a working cannula and a visualization cannula for an
endoscope. This procedure allows simultaneous visualization and
suction, irrigation and resection in disc procedures.
[0009] Unfortunately, disadvantages remain with these procedures
and the accompanying tools because they are limited to a specific
application or approach. For example, Jacobson, Kambin and other
references require a lateral or a posterolateral approach for
percutaneous discectomy. These approaches seek to avoid damage to
soft tissue structures and the need for bone removal because it was
thought to be impractical to cut and remove bone through a channel.
However, these approaches do not address other spinal conditions
which may require a mid-line approach, removal of bone or
implants.
[0010] U.S. Pat. No. 5,439,464 to Shapiro discloses a method and
instruments for performing arthroscopic spinal surgeries such as
laminectomies and fusions with a mid-line or medial posterior
approach using three cannulas. Each of the cannulas requires a
separate incision. While Shapiro discloses an improvement over
prior procedures which were limited to a posterolateral or lateral
approach for disc work, Shapiro's procedure still suffers from many
of the disadvantages of known prior percutaneous spinal surgery
techniques and tools. One disadvantage of the Shapiro procedure is
its requirement of a fluid working space. Another significant
detriment is that the procedure requires multiple portals into the
patient.
[0011] Fluid is required in these prior procedures to maintain the
working space for proper function of optics fixed within a prior
art cannula and inserted percutaneously. Irrigation, or the
introduction of fluid into the working space, can often be
logistically disadvantageous and even dangerous to the patient for
several reasons. The introduction of fluid into the working space
makes hemostasis more difficult and may damage surrounding tissue.
Excess fluid nay dangerously dilute the sodium concentration of the
patient's blood supply which can cause seizures or worse. The fluid
environment can also make drilling difficult due to cavitation. The
requirement for a fluid environment generally increases expenses
associated with the surgery and adds to the complexity of the
surgery, due in part to the relatively high volume of fluid
required.
[0012] A need has remained for devices and methods that provide for
percutaneous minimally invasive surgery for all applications and
approaches. A need has also remained for percutaneous methods and
devices which do not require a fluid-filled working space, but that
can be adapted to a fluid environment is necessary.
[0013] A signficant need is present in this field for techniques
and instruments that permit surgical procedures in the working
space under direct vision. Procedures that reduce the number of
entries into the patient are also highly desirable. The fields of
spinal and neuro surgery have particularly sought devices and
techniques that minimize the invasion into the patient and that are
streamlined and concise in their application.
SUMMARY OF THE INVENTION
[0014] Briefly describing one aspect of the invention, there is
provided devices and method for performing percutaneous procedures
under direct visualization, even at locations deep within a
patient. In one embodiment, a device for use in percutaneous
surgery includes an elongated cannula having a first inner diameter
and an outer diameter sized for percutaneous introduction into a
patient. The cannula further includes a distal working end and an
opposite proximal end and defines a working channel between the
ends having a second diameter which is equal to the first inner
diameter. The working channel is sized to receive a tool
therethrough. The device also includes an elongated viewing element
mounted inside the cannula adjacent the working channel. The
viewing element has a first end connectable to a viewing apparatus
and an opposite second end disposed adjacent the distal working end
of the cannula.
[0015] In another aspect, a fixture is provided for mounting the
elongated viewing element to the cannula. The fixture includes a
housing attachable to the proximal end of the cannula. The housing
defines a working channel opening therethrough in communication
with the working channel. The working channel opening is sized to
substantially correspond to the second diameter of the working
channel. The housing also defines an optics bore adjacent the
working channel opening. The optics bore is sized to receive the
elongated viewing element therethrough.
[0016] In some embodiments, the fixture supports the viewing device
for movement within the optics bore along the longitudinal axis of
the bore to extend or retract the lens relative to the distal
working end of the cannula. In other embodiments, the fixture
supports the viewing device for rotation within the optics bore
about the longitudinal axis of the bore. In some embodiments, the
housing is rotatable relative to the cannula so that the
longitudinal axis of the optics bore is rotatable about the
longitudinal axis of the working channel.
[0017] Novel tools are also provided which are insertable into the
working channel of the cannula. A tissue retractor in one
embodiment includes a body and an integral working tip configured
to atraumatically displace tissue as the retractor is manipulated
through tissue. The body has a convex surface configured to conform
to the inner cylindrical surface of the cannula and an opposite
concave surface which does not obstruct the working channel or
visualization of the working space. Cannulated tissue dilators are
also provided which are insertable over a guidewire or another
dilator as well as insertable into the working channel. In some
embodiments, the tissue dilators include a tapered working end to
displace tissue and a gripping portion having a number of
circumferential grooves to enhance gripping and manipulation of the
dilator.
[0018] According to the methods of this invention, spinal and other
surgeries can be performed percutaneously with direct visualization
without the requirement for a fluid-maintained working space. In
another aspect of the inventive surgical techniques, all steps of a
surgical procedure are conducted under direct vision through a
single working channel cannula. An optical scope or viewing device
is moved within the working channel and throughout the working
space from a variety of angles and orientations to provide a clear
view of the operative steps.
[0019] The techniques of the present invention also encompass
passing multiple tools and instruments through the single working
channel cannula and manipulating the instruments and tools within
the working space. In one specific embodiment, a tissue retractor
is provided that extends through the working channel without
significantly reducing the dimensions of the channel.
[0020] It is an object of the invention to provide devices and
methods for percutaneous spinal surgery for all applications and
approaches. One advantage of this invention is that percutaneous
procedures can be accomplished in a dry environment because a fluid
working space is not required for the proper function of the
optics. One benefit of this invention is that it provides
instruments and methods which reduce the cost, risk, pain and
recovery time associated with surgery. These and other objects,
advantages and features are accomplished according to the devices
and methods of the present invention.
DESCRIPTION OF THE FIGURES
[0021] FIG. 1 is a side elevational view of a device according to
this invention.
[0022] FIG. 2 is a top elevational view of a fixture for supporting
a viewing device within a cannula according to this invention.
[0023] FIG. 3 is a side cross-sectional view of the fixture shown
in FIG. 2.
[0024] FIG. 4 is a side elevational view of a retractor according
to one embodiment of this invention.
[0025] FIG. 4A is an end cross-sectional view of the retractor of
FIG. 4 taken along lines A-A.
[0026] FIG. 5 is a top elevational view of the retractor shown in
FIG. 4.
[0027] FIG. 6 is an end elevational view of the retractor shown in
FIGS. 4 and 5.
[0028] FIG. 7 is a side elevational view of a retractor according
to another embodiment of this invention.
[0029] FIG. 7A is an end cross-sectional view of the retractor of
FIG. 7 taken along lines A-A.
[0030] FIG. 7B is an end cross-sectional view of the retractor of
FIG. 7 taken along lines B-B.
[0031] FIG. 8 is a top elevational view of the retractor shown in
FIG. 7.
[0032] FIG. 9 is a side elevational view of a dilator according to
this invention.
[0033] FIG. 10 (a)-(i) depicts the steps of a method according to
this invention.
[0034] FIG. 11 is a side cross-sectional view of a device according
to one embodiment of this invention.
[0035] FIG. 12 is a side cross-sectional view of an aspiration cap
as shown in FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
embodiments illustrated in the drawings and specific language will
be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended, such alterations and further modifications in the
illustrated devices and described methods, and such further
applications of the principles of the invention as illustrated
therein being contemplated as would normally occur to one skilled
in the art to which the invention relates.
[0037] The present invention provides instruments and methods for
performing percutaneous surgery, including spinal applications such
as laminotomy, laminectomy, foramenotomy, facetectomy or
discectomy, with a single working channel endoscope. The present
inventors have discovered that many percutaneous surgeries may be
performed without a fluid workspace through the use of optics which
move independently of the cannula. The present invention
contemplates techniques and instruments that can be implemented
with or without a fluid environment.
[0038] This invention also brings the advantages of percutaneous
procedures to applications that previously required open surgery.
One advantage is based upon the further discovery that bone work
can be performed percutaneously through a large working channel.
Another advantage is realized in the use of a single portal within
the patient to perform a wide range of simultaneous procedures.
[0039] According to one embodiment of the present invention, as
depicted in FIG. 1, a device 10 is provided for use in percutaneous
surgery which includes an elongated cannula 20 having a first inner
diameter D.sub.I and an outer diameter D.sub.O sized for
percutaneous introduction into a patient. The cannula 20
also-includes a distal working end 21 and an opposite proximal end
22. The cannula defines a working channel 25 between the ends 21,
22 having a second diameter d.sub.2 equal to the first inner
diameter D.sub.I sized for receiving a tool therethrough. The
cannula has a length along its longitudinal axis L that is sized to
pass through the patient from the skin to an operative site or
working space. In some cases, the working space may be adjacent a
vertebra or disc, or in the spinal canal.
[0040] An elongated viewing element 50 is mountable inside cannula
20 adjacent the working channel 25. The viewing element 50 has a
first end 51 connectable to a viewing apparatus, such as an
eyepiece or camera, and an opposite second end 52 disposed or
positionable adjacent the distal working end 21 of the cannula 20.
The particular elongated viewing element 50 is not critical to the
invention. Any suitable viewing element is contemplated that
creates an optical or image transmission channel. In one
embodiment, the elongated viewing element 50 includes a fiber optic
scope 54 and a lens 55 at the second end 52. Preferably, the fiber
optic scope includes illumination fibers and image transmission
fibers (not shown). Alternatively, the viewing element may be a
rigid endoscope or an endoscope having a steerable or bendable
tip.
[0041] One advantage of this invention is that it provides optics
which are movable relative to the cannula 20. Because the optics
are movable, it is not necessary to provide a fluid-maintained work
space. The optics can be removed, cleaned and replaced while the
cannula is percutaneously positioned within the patient over the
working space. Any configuration which allows the optics to be
movably supported adjacent the working channel 25 is contemplated.
In one embodiment, shown in FIGS. 1-3, a fixture 30 is provided for
mounting the elongated viewing element 50 to the cannula 20.
Preferably, the fixture 30 includes a housing 31 attachable to the
proximal end 22 of the cannula 20. The working channel opening 35
is sized to substantially correspond to the second diameter d.sub.2
of the working channel 25 to receive tools. The fixture 30 includes
a housing 31 which defines a working channel opening 35 arranged to
communicate with the working channel 25 when the fixture 30 is
mounted to the cannula 20. The working channel opening 35 is sized
to receive tools therethrough for passage through the working
channel 25. In the embodiments shown in FIGS. 1-3, the fixture 30
is configured to mount the viewing element 50 within the working
channel 25.
[0042] The housing 31 also defines an optics bore 60 adjacent the
working channel opening 35. The optics bore 60 has a longitudinal
axis l that is preferably substantially parallel to the axis L of
the cannula and working channel. The optics bore 60 is preferably
sized to removably receive the elongated viewing element 50
therethrough. The fixture 30 preferably supports the viewing
element 50 for movement within the optics bore 60 along the
longitudinal axis l of the bore 60 to extend or retract the lens 55
relative to the distal working end 21 of the cannula 20. The
retractable/extendable feature of the optics of this invention
provides an advantage over prior endoscopes because it eliminates
the requirement for a fluid workspace. While the device 10 and its
viewing element 50 can be easily used in a fluid environment, the
fluid is not essential for the system to operate, contrary to prior
systems. Furthermore, many of the prior endoscopes were not suited
to access certain areas because of their large diameters. For
example, prior endoscopes could not access the spinal canal.
However, with this invention, access to the spinal canal is not
limited by the diameter of the channel or cannula. The cannula 20
can be left behind in the soft tissue or supported by the lamina
while the second end 52 of the elongated viewing element 50 can be
advanced into the spinal canal along with any spinal instruments
which have been inserted into the working channel 25.
[0043] Preferably the fixture 30 also supports the viewing element
50 for rotation within the optics bore 60 about the longitudinal
axis l of the bore 60. The lens 55 of the viewing element 50
defines an optical axis A.sub.O. As in many endoscopes, the optical
axis A.sub.O can be offset at an angle relative to the longitudinal
axis l of the optics bore 60. This feature allows the optical axis
A.sub.o of the lens to be swept through a conical field of view F
for greater visibility of the working space. The fixture 30 can
further be configured so that the viewing element 50 is rotatable
relative to the cannula 20. In this embodiment, the housing 31 is
rotatable relative to the cannula 20 so that the second
longitudinal axis l of the optics bore 60 rotates about the
longitudinal axis L of the working channel 25. The rotatable
features of this invention allows visualization of the entire
working space. This feature also aids in simplifying the surgical
procedure because the optics 50 and accompanying fittings can be
moved out of the way of the surgeon's hands and tools passing
through the working channel.
[0044] In one embodiment depicted in FIG. 3, the housing 31 defines
a receiver bore 40 having an inner diameter d.sub.I slightly larger
than the outer diameter D.sub.O of the cannula 20. In this
configuration, the proximal end 22 of the cannula 20 can be
received within the receiver bore 40 so that the housing 31 can
rotate about the proximal end 22 of the cannula 20. As shown in
FIG. 3, the housing 31 also includes an upper bore 41 which is
contiguous with the working channel opening 35 and the receiver
bore 40. In one embodiment, the optics bore 60 is disposed within
the upper bore 41 of the housing 31.
[0045] In a preferred embodiment depicted in FIG. 2, the optics
bore 60 is defined by a C-shaped clip 61 disposed within the upper
bore 41. Preferably, the C-shaped clip 61 is formed of a resilient
material and the optics bore 60 defined by the clip 61 has an inner
diameter D.sub.i that is slightly less than the outer diameter of
the elongated viewing element 50. When the viewing element 50 is
pushed into the optics bore 60 it resiliently deflects the C-shaped
clip 61. The resilience of the clip 61 provides a gripping force on
the element 50 to hold it in the desired position, while still
allowing the element 50 to be repositioned.
[0046] Alternatively, the optics bore 60 can have an inner diameter
larger than the outer diameter of the viewing element. In this
instance, the viewing element 50 can be supported outside the
device 20, either manually or by a separate support fixture.
[0047] Preferably the device 10 provides engagement means for
securely yet rotatably engaging the fixture 30 to the cannula 20.
Most preferably, the fixture 30 is configured to engage a standard
cannula 20. Engagement means can be disposed between the housing 31
and the cannula 20 when the fixture 30 is mounted to the proximal
end 22 of the cannula 20 for providing gripping engagement between
the housing 31 and the cannula 20. In one embodiment depicted in
FIG. 3 the engagement means includes a number of grooves 32 within
the receiver bore 40 and a resilient sealing member, such as an
O-ring (see FIG. 11) disposed in each groove 32. The sealing
members, or O-rings, disposed between the housing 31 and the outer
diameter D.sub.O of the cannula 20 rotatably secure the fixture 30
to the cannula 20. The O-rings provide sufficient resistance to
movement to hold the fixture 30 in a selectable position on the
cannula. In another embodiment, the housing 31 defines a receiver
bore 40 which has an inner diameter d.sub.I which is only slightly
larger than the outer diameter D.sub.O of the cannula 20 so that
the housing 31 can rotate freely about the cannula 20.
[0048] The working channel 25 and the working channel opening 35
are both sized to receive a tool or instrument therethrough.
Preferably, the working channel opening 35 of the housing 31 has a
diameter Dw which is substantially equal to the inner diameter
d.sub.2 of the working channel 25 so that the effective diameter of
the working channel is not reduced by the fixture 30. This
configuration provides a maximum amount of space for the insertion
of tools into the working channel 25. The present invention is
advantageous because standard micro-surgical spinal tools can be
inserted into the working channel and manipulated to perform a
surgical procedure. The present invention is particularly
advantageous because the working channel 25 will simultaneously
accept a plurality of movable instruments. No other known prior art
device has a working channel that accepts more than one movable
instrument at a time through a single port. Therefore, according to
this invention, an entire percutaneous surgical procedure can be
performed through the working channel 25 of the device 10 under
direct visualization using the viewing element 50 disposed within
the optics bore 60.
[0049] Although standard micro-surgical instruments may be used
with the present invention, this invention also contemplates
certain novel tools which capitalize on and enhance the advantages
of this invention.
[0050] According to one preferred embodiment of the invention, a
tissue retractor 70 is provided as depicted in FIGS. 4-6. The
retractor 70 is removably and rotatably insertable through the
working channel 25 and the working channel opening 35 of the device
10. The tissue retractor 70 includes a working tip 75 configured to
atraumatically displace tissue as the retractor 70 is manipulated
through the tissue and a body 76 having a proximal first end 77 and
a distal second end 78. The second end 78 can be integral with the
working tip 75 which preferably has a blunt curved end 82. In
addition, the working tip 75 is also preferably bent or curved away
from the body 76, as shown in FIG. 7. The body 76 is sized to be
rotatably received within the cannula 20 and has a length B from
the first end 77 to the second end 78 sufficient so that the first
end 77 and the working tip 75 can both extend outside the cannula
20 when the body 76 is within the cannula 20.
[0051] This invention contemplates any suitable retractor for use
through the working channel 25. However, retractors such as the
retractor 70 depicted in FIGS. 4-6 are preferred in which the body
76 includes a curved plate 84 that is configured to conform to the
inner cylindrical surface 26 of the cannula without substantially
blocking the working channel 25. The curved plate 84 has a convex
surface 80 and an opposite concave surface 81. In one embodiment,
the curved plate 84 includes a first plate portion 85 defining a
first convex surface 80 and an opposite first concave surface 81. A
second plate portion 86 is integral with the first plate portion 85
and is disposed between the first plate portion 85 and the working
tip 75. The second plate portion 86 defines a second convex surface
(not shown) and an opposite second concave surface 81'. Both the
first plate portion 85 and the second plate portion 86 include
opposite edges 90 extending substantially parallel to the length B
of the body 76.
[0052] Preferably, the curved plate 84 subtends an arc A.sub.1
between the opposite edges 90 of at least 200 degrees, and most
preferably 270 degrees. In a specific embodiment, the second plate
portion 86 and specifically the second concave surface 81' subtends
an angle that decreases along the length of the retractor. Thus, in
an embodiment, the second concave surface 81' subtends an angle of
about 200 degrees adjacent the first plate portion 85, decreasing
to an angle of less than about 10 degrees at end 78.
[0053] An alternate embodiment of a tissue retractor according to
this invention is depicted in FIGS. 8-11. This retractor 100 has a
body 106 which includes a first plate portion 115 defining a first
convex surface 110 and an opposite first concave surface 111 and
includes first opposite edges 120 extending substantially parallel
to the length B of the body 106. The first plate portion 115
subtends a first arc A.sub.2 between the first opposite edges 120.
The retractor body 106 also includes a second plate portion 116
which is integral with the first plate portion 115 and is disposed
between the first plate portion 115 and a working tip 105. The
second plate portion 116 defines a second convex surface 110' and
an opposite second concave surface 111' and includes second
opposite edges 120' extending substantially parallel to the length
B. The second plate portion 116 subtends a second arc A.sub.3
between the second opposite edges 120' that is different from the
first arc A.sub.2 in this embodiment. Preferably, the first arc
A.sub.2 subtends an angle of less than 180 degrees and the second
arc A.sub.3 subtends an angle of more than 180 degrees. Most
preferably, the first arc A.sub.2 subtends an angle of about 90
degrees and the second arc A.sub.3 subtends an angle of about 270
degrees.
[0054] The retractors of this invention may be provided with means
for engaging the retractors 70, 100 within the working channel 25
of the cannula 20. For example, the convex surfaces 80, 110 can be
configured to have a diameter that is greater than the diameter
D.sub.I of the inner cylindrical surface 26 of the cannula 20. In
that case, the body 76, 106 may be formed of a resilient material
that is deformable to be insertable into the cannula 20 so that the
convex surface 80, 110 is in contact with the inner cylindrical
surface 26 of the cannula 20. When the body 76, 106 is deformed, it
exerts an outward force against the surface 26 to frictionally hold
the retractor in its selected position.
[0055] The preferred components provided by this invention are
configured so that multiple tools and instruments can be accepted
and manipulated within the working channel 25 of the cannula 20.
The components are also configured so that more than one surgeon
may manipulate instruments through the working channel 25 of the
cannula 20 at one time. For example, one surgeon may be
manipulating the retractor while another surgeon is drilling into a
bone. The curvature of the body 76, 106 of the retractors 70, 100
provides more working space and increases visibility. Another
feature is that the long axis of the component can be placed in the
working channel 25 while a bend in the handle portion keeps hands
away from the channel 25 so that more than one surgeon can work in
the channel 25 and more tools can be placed in the channel 25. The
retractors shown in FIGS. 4-11 each comprise an arm 71, 101
attached to the proximal first end 77, 107 of the body 76, 106.
Preferably, as shown in FIGS. 4-11, the arm 71, 101 is at an angle
.alpha. which is less than 180 degrees from the longitudinal axis
of the length L of the body 76. Most preferably, the angle .alpha.
is about 90 degrees so that the arm 71, 101 is substantially
perpendicular to the length L of the body 76, 106. Preferably, the
arm 71, 101 has a gripping surface 72, 102 to facilitate
manipulation of the retractor 70, 100.
[0056] The present invention also provides tissue dilators usable
with the device 10. Any dilator which is insertable into the
working channel 25 of the cannula 20 is contemplated; however, a
preferred dilator provided by this invention is depicted in FIG.
12. A dilator 130 preferably includes a hollow sleeve 135 defining
a channel 131. The channel 131 allows the dilator 130 to be placed
over a guidewire (not shown) or other dilators. The hollow sleeve
135 has a working end 136 defining a first opening 132 in
communication with the channel 131 and an opposite end 137 defining
a second opening 133. The working end 136 is tapered to a tapered
tip 138 to atraumatically displace tissue. Preferably, a gripping
portion 140 is provided on the outer surface 141 of the sleeve 135
adjacent the opposite end 137. In one embodiment, the gripping
portion 140 is defined by a plurality of circumferential grooves
142 defined in the outer surface 141. The grooves 142 are
configured for manual gripping of the dilator 130 to manipulate the
dilator 130 through tissue. Preferably, the grooves 142 are
partially cylindrical. In the embodiment shown in FIG. 12, the
gripping portion 140 includes a number of circumferential flats 143
each of the circumferential grooves 142. The grooves 142 have a
first width W.sub.1 along the length of the sleeve 135 and the
flats 143 have a second width W.sub.2 146 along the length.
Preferably, the first and second widths W.sub.1 and W.sub.2 are
substantially equal.
[0057] The present invention has application to a wide range of
surgical procedures, and particularly spinal procedures such as
laminotomy, laminectomy, foramenotomy, facetectomy and discectomy.
Prior surgical techniques for each of these procedures has evolved
from a grossly invasive open surgeries to the minimally invasive
techniques represented by the patents of Kambin and Shapiro.
However, in each of these minimally invasive techniques, multiple
entries into the patient is required. Moreover, most of the prior
minimally invasive techniques are readily adapted only for a
posterolateral approach to the spine. The devices and instruments
of the present invention have application in an inventive surgical
technique that permits each of these several types of surgical
procedures to be performed via a single working channel. This
invention can also be used from any approach and in other regions
besides the spine.
[0058] The steps of a spinal surgical procedure in accordance with
one aspect of the present invention are depicted in FIG. 10. As can
be readily seen from each of the depicted steps (a)-(i), the
present embodiment of the invention permits a substantially
mid-line or medial posterior approach to the spine. Of course, it
is understood that many of the following surgical steps can be
performed from other approaches to the spine, such as
posterolateral and anterior. In a first step of the technique, a
guidewire 150 can be advanced through the skin and tissue into the
laminae M of a vertebral body V. Preferably, a small incision is
made in the skin to facilitate penetration of the guidewire through
the skin. In addition, most preferably the guidewire, which may be
a K-wire, is inserted under radiographic or image guided control to
verify its proper positioning within the laminae L of the vertebra
V. It is, of course, understood that the guidewire 150 can be
positioned at virtually any location in the spine and in any
portion of a vertebra V. The positioning of the guidewire is
dependent upon the surgical procedure to be conducted through the
working channel cannula of the present invention. Preferably, the
guidewire 150 is solidly anchored into the vertebral bone, being
tapped by a mallet if necessary.
[0059] In subsequent steps of the preferred method, a series of
tissue dilators are advanced over the guidewire 150, as depicted in
steps (b)-(d) in FIG. 10. Alternatively, the dilators can be
advanced through the incision without the aid of a guidewire,
followed by blunt dissection of the underlying tissues. In the
specific illustrated embodiment, a series of successively larger
dilators 151, 152 and 153 are concentrically disposed over each
other and over the guidewire 150 and advanced into the body to
sequentially dilate the perispinous soft tissues. Most preferably,
the tissue dilators are of the type shown in FIG. 9 of the present
application. In a specific embodiment, the dilators have
successively larger diameters, ranging from 5 mm, to 9 mm to 12.5
mm for the largest dilator. Other dilator sizes are contemplated
depending upon the anatomical approach and upon the desired size of
the working channel.
[0060] In the next step of the illustrated technique, the working
channel cannula 20 is advanced over the largest dilator 153, as
shown in step (e), and the dilators and guidewire 150 are removed,
as shown in step (f). Preferably, the working channel cannula 20
has an inner diameter D.sub.I of 12.7 mm so that it can be easily
advanced over the 12.5 mm outer diameter of the large dilator 153.
Larger working channel cannulas are contemplated depending upon the
anatomical region and surgical procedure.
[0061] With the cannula 20 in position, a working channel is formed
between the skin of the patient to a working space adjacent the
spine. It is understood that the length of the cannula 20 is
determined by the particular surgical operation being performed and
the anatomy surrounding the working space. For instance, in the
lumbar spine the distance between the laminae M of a vertebra V to
the skin of the patient requires a longer cannula 20 than a similar
procedure performed in the cervical spine where the vertebral body
is closer to the skin. In one specific embodiment in which the
cannula 20 is used in a lumbar discectomy procedure, the cannula
has a length of 87 mm, although generally only about half of the
length of the cannula will be situated within the patient during
the procedure.
[0062] In accordance with the present surgical technique, the
working channel cannula 20 is at least initially only supported by
the soft tissue and skin of the patient. Thus, in one aspect of the
preferred embodiment, the cannula 20 can include a mounting bracket
27 affixed to the outer surface of the cannula (FIG. 10(f), FIG.
11). This mounting bracket 27 can be fastened to a flexible support
arm 160, which can be of known design. Preferably, the flexible
support arm 160 is engaged to the bracket 27 by way of a bolt and
wing nut 161, as shown in FIG. 10(i) and in more detail in FIG. 11,
although other fasteners are also contemplated. This flexible arm
160 can be mounted on the surgical table and can be readily
adjusted into a fixed position to provide firm support for the
cannula 20. The flexible arm 160 is preferred so that it can be
contoured as required to stay clear of the surgical site and to
allow the surgeons adequate room to manipulate the variety of tools
that would be used throughout the procedure.
[0063] Returning to FIG. 10, once the cannula 20 is seated within
the patient, the fixture 30 can be engaged over the proximal end of
the cannula 20. The fixture 30, as shown in FIGS. 2 and 3 and as
described above, provides an optics bore 60 for supporting an
elongated viewing element, such as element 50 shown in step h. In
accordance with the invention, the viewing element 50 is advanced
into the fixture 30 and supported by the optics bore 60 (FIG. 2).
In one specific embodiment, the element 50 is most preferably a
fiber optic scope, although a rod lens scope or other viewing
scopes may be utilized. In the final step (i) of the procedure
shown in FIG. 10, the flexible arm 160 is mounted to the bracket 27
to support the cannula 20 which in turn supports the optical
viewing element 50. This final position of step (i) in FIG. 10 is
shown in more detail in FIG. 11. The viewing element 50 can be of a
variety of types, including a rigid endoscope or a flexible and
steerable scope.
[0064] With the viewing element or scope 50 supported by the
fixture 30 the surgeon can directly visualize the area beneath the
working channel 25 of the cannula 20. The surgeon can freely
manipulate the viewing element 50 within the working channel 25 or
beyond the distal end of the cannula into the working space. In the
case of a steerable tip scope, the second end 52 of the viewing
element 50, which carries the lens 55, can be manipulated to
different positions, such as shown in FIG. 11. With virtually any
type of viewing element, the manipulation and positioning of the
scope is not limited by the working channel 25, in contrast to
prior systems.
[0065] Preferably, the positioning capability provided by the
fixture 30 is utilized to allow extension of the lens 55 into the
working space or retraction back within the cannula 20, as depicted
by the arrows T in FIG. 1. Also the fixture preferably accommodates
rotation of the element 50 about its own axis (arrows R in FIG. 1)
to vary the viewing angle provided by the angled lens 55, or
rotation of the entire viewing element 50 about the cannula 20 and
around the circumference of the working channel 25, as shown by the
arrows N in FIG. 1. In this manner, the surgeon is provided with a
complete and unrestricted view of the entire working space beneath
the working channel 25. In instances when the fixture 30 is rotated
about the cannula 20, the viewing orientation of the optics (i.e.,
left-right and up-down) is not altered so the surgeon's view of the
procedure and surrounding anatomy is not disturbed.
[0066] Another advantage provided by the single working channel
cannula 20 of the present invention, is that the cannula can be
readily positioned over an appropriate target tissue or bone, to
thereby move the working space as necessary for the surgical
procedure. In other words, since the working channel cannula 20 is
freely situated within the patient's skin and tissue, it can be
manipulated so that the working space beneath the cannula 20 is
more appropriately centered over the target region of the spine.
Repositioning of the cannula 20 can be performed under fluoroscopic
guidance. Alternatively, the cannula may be fitted with position
sensing devices, such as LEDs, to be guided stereotactically. As
the cannula is being repositioned, the surgeon can also directly
visualize the spine through the viewing element 50.
[0067] Once the position of the cannula 20 is established and a
working space is oriented over the proper target tissue, a variety
of tools and instruments can be extended through the working
channel 25 to accomplish the particular surgical procedure to be
performed. For instance, in the case of a laminotomy, laminectomy,
foramenotomy or facetectomy, a variety of rongeurs, curettes, and
trephines can be extended through the working channel opening 35
(see FIG. 2) and through the working channel 25 of the cannula 20
(see FIG. 11) into the working space. It is understood that these
various tools and instruments are designed to fit through the
working channel. For instance, in one specific embodiment, the
working channel 25 through the cannula 20 can have a maximum
diameter d of 12.7 mm. However, with the viewing element 50
extending into the working channel 25, the effective diameter is
about 8 mm in the specific illustrated embodiment, although
adequate space is provided within the working channel 25 around the
viewing element 50 to allow a wide range of movement of the tool or
instrument within the working channel. The present invention is not
limited to particular sizes for the working channel and effective
diameter, since the dimensions of the components will depend upon
the anatomy of the surgical site and the type of procedure being
performed.
[0068] Preferably, each of the tools and instruments used with the
working channel cannula 20 are designed to minimize obstruction of
the surgeon's visualization of and access to the working space at
the distal end of the working channel cannula. Likewise, the
instruments and tools are designed so that their actuating ends
which are manipulated by the surgeon are displaced from the working
channel cannula 20. One such example is the tissue retractor shown
in FIGS. 4-8. With these retractors, the handles that are manually
gripped by the surgeon are offset at about a 90 degree angle
relative to the longitudinal axis of the tool itself.
[0069] In accordance with once aspect of the present invention, the
surgical procedures conducted through the working channel cannula
20 and within the working space at the distal end of the cannula
are performed "dry"--that is, without the use of irrigation fluid.
In prior surgical techniques, the working space at the surgical
site is fluid filled to maintain the working space and to assist in
the use of the visualization optics. However, in these prior
systems the visualization optics were fixed within the endoscope.
In contrast, the device 10 of the present invention allows a wide
range of movement for the viewing element 50 so that the lens 55
can be retracted completely within the working channel 25 of the
cannula 20 to protect it from contact with the perispinous tissue
or blood that may be generated at the surgical site.
[0070] Moreover, since the viewing element 50 is removable and
replaceable, the element 50 can be completely removed from the
fixture 30 so that the lens 55 can be cleaned, after which the
viewing element 50 can be reinserted into the fixture and advanced
back to the working space. Under these circumstances, then, the
need for irrigation is less critical. This feature can be of
particular value when cutting operations are being performed by a
power drill. It has been found in prior surgical procedures that
the use of a power drill in a fluid environment can cause
turbulence or cavitation of the fluid. This turbulence can
completely shroud the surgeon's view of the surgical site at least
while the drill is being operated. With the present invention, the
dry environment allows continuous viewing of the operation of the
power drill so that the surgeon can quickly and efficiently perform
the necessary cutting procedures.
[0071] While the present invention permits the surgeon to conduct
surgical procedures in the working space under a dry environment,
irrigation may be provided separately through the working channel
25. Alternatively, the viewing device 50 itself may include a tube
54 supported by the fitting 53 through which modest amounts of
fluid can be provided to keep the visualization space clear. In
addition, during a discectomy, aspiration of the excised tissue is
preferred, and irrigation will frequently assist in rapid removal
of this tissue. Thus, separate irrigation and aspiration elements
can also be inserted through the working channel 25 as required by
the procedure.
[0072] As necessary, aspiration can be conducted directly through
the working channel 25 of the cannula 20. In one specific
embodiment, an aspiration cap 165 is provided as shown in FIGS. 11
and 12. The cap 165 includes a body 166 which defines a mating bore
167 having an inner diameter d.sub.b larger than the outer diameter
D.sub.h of the housing 31 of fitting 30. A tool opening 168 is
provided in communication with the mating bore 167. When the
aspiration cap 165 is mounted over the housing 31, as shown in FIG.
11, the tool opening 168 communicates directly with the upper bore
41 and provides the same entry capabilities as the working channel
opening 35 of the housing 31. The aspiration cap 165 is also
provided with a tube receiver bore 169 which intersects the mating
bore 167. The receiver bore 169 is configured to receive an
aspiration tube through which a vacuum or suction is applied. In
certain instances, the tool opening 168 may be covered while
suction is applied through the tool receiver bore 169 and mating
bore 167, and ultimately through the working channel 25. Covering
the opening 168 can optimize the aspiration effect through the
working channel.
[0073] Returning again to the surgical technique of one embodiment
of the present invention, once the working channel cannula 20 and
the optics 50 are in position, as depicted in FIG. 10 step (i) and
FIG. 11, the paraspinous tissue can be reflected using instruments
as described above, and a laminectomy performed using various
rongeurs, curettes and drills. As necessary, the cannula 20 can be
angled to allow a greater region of bone removal, which may be
necessary for access to other portions of the spinal anatomy. In
some instances, access to the spinal canal and the posterior medial
aspects of the disc annulus may require cutting a portion of the
vertebral bone that is greater than the inner diameter of the
working channel 25. Thus, some manipulation of the cannula 20 may
be necessary to permit removal of a greater portion of bone. In
other operations, multi-level laminectomies or foramenotomies may
be necessary. In this instance, these multi-level procedures can be
conducted by sequentially inserting the working channel cannula 20
through several small cutaneous incisions along the spinal
mid-line. Alternatively, several working channel cannulas 20 can be
placed at each of the small cutaneous incisions to perform the
multi-level bone removal procedures.
[0074] Again, in accordance with the preferred illustrated surgical
technique, an opening is cut into the laminae M of the vertebra V
providing direct visual access to the spinal canal itself. As
necessary, tissue surrounding the spinal nerve root can be removed
utilizing micro surgical knives and curettes. Once the spinal nerve
root is exposed, a retractor, such as the retractors shown in FIGS.
4-8, can be used to gently move and hold the nerve root outside the
working space. In one important aspect of the two retractors 70,
100, the portion of the retractor passing through the working
channel 25 generally conforms to the inner surface of the cannula
20 so that the working channel 25 is not disrupted by the retractor
tool. Specifically, the effective diameter within the working
channel 25 is reduced only by the thickness of the curved plates
84, 114 of the retractors 70, 100. In one specific embodiment, this
thickness is about 0.3 mm, so it can be seen that the tissue
retractors do not significantly reduce the space available in the
working channel 25 for insertion of other tools and
instruments.
[0075] With the tissue retractor in place within the working
channel 25, bone within the spinal canal, such as may occur in a
burst fracture, can be removed with a curette or a high speed
drill. Alternatively, the fractured bone may be impacted back into
the vertebral body with a bone impactor. At this point, if the
spinal procedure to be performed is the removal of epidural spinal
tumors, the tumors can be resected utilizing various micro-surgical
instruments. In other procedures, the dura may be opened and the
intradural pathology may be approached with micro-surgical
instruments passing through the working channel cannula 20. In
accordance with the specific illustrated technique, with the nerve
root retracted posterior medial disc herniations can be readily
excised directly at the site of the herniation.
[0076] One important feature of the present invention is achieved
by the large diameter of the working channel 25 in the cannula 20.
This large diameter allows the surgeon or surgeons conducting the
surgical procedure to introduce a plurality of instruments or tools
into the working space. For example, as described above, a tissue
retractor and discectomy instruments can be simultaneously extended
through the working channel. In that illustrated embodiment, the
discectomy instruments could include a trephine for boring a hole
through the disc annulus and a powered tissue cutter for excising
the herniated disc nucleus. Likewise, the present invention
contemplates the simultaneous introduction of other types of
instruments or tools as may be dictated by the particular surgical
procedure to be performed. For example, an appropriately sized
curette and a rongeur may be simultaneously extended through the
working channel into the working space. Since all operations being
conducted in the working space are under direct visualization
through the viewing element 50, the surgeon can readily manipulate
each of the instruments to perform tissue removal and bone cutting
operations, without having to remove one tool and insert the other.
In addition, since the surgical procedures can be conducted without
the necessity of irrigation fluid, the surgeon has a clear view
through the working space of the target tissue. Furthermore,
aspects of the invention which permit a wide range of motion to the
viewing element 50 allow the surgeon to clearly visualize the
target tissue and clearly observe the surgical procedures being
conducted in the working space.
[0077] The surgeon can capitalize on the same advantages in
conducting a wide range of procedures at a wide range of locations
in the human body. For example, facetectomies could be conducted
through the working channel by simply orienting the working channel
cannula 20 over the particular facet joints. The insertion of
vertebral fixation elements can also be accomplished through the
device 10. In this type of procedure, an incision can be made in
the skin posterior to the location of the vertebra at which the
fixation element is to be implanted. Implementing the steps shown
in FIG. 10, the cannula 20 can be positioned through the incision
and tissue directly above the particular location on the vertebra
to be instrumented. With the optics extending through the working
channel, an insertion tool holding the vertebral fixation element
can be projected through the cannula 20 and manipulated at the
vertebra. In one specific embodiment, the fixation element can be a
bone screw. The working channel 25 has a diameter that is large
enough to accept most bone screws and their associated insertion
tools. In many instances, the location of the bone screw within the
vertebra is critical, so identification of the position of the
cannula 20 over the bony site is necessary. As mentioned above,
this position can be verified fluoroscopically or using
stereotactic technology.
[0078] In many prior procedures, cannulated bone screws are driven
into the vertebra along K-wires. The present invention eliminates
the need for the K-wire and for a cannulated screw. The working
channel itself can effectively operate as a positioning guide, once
the cannula 20 is properly oriented with respect to the vertebra.
Moreover, the device 10 allows insertion of the bone screw into the
vertebra to be conducted under direct vision. The surgeon can then
readily verify that the screw is passing into the vertebra
properly. This can be particularly important for bone screws being
threaded into the pedicle of a vertebra. The working channel
cannula 20 can be used to directly insert a self-tapping bone screw
into the pedicle, or can accept a variety of tools to prepare a
threaded bore within the pedicle to receive a bone screw.
[0079] The device 10 can also be used to prepare a site for fusion
of two adjacent vertebrae, and for implantation of a fusion device
or material. For example, in one surgical technique, an incision
can be made in the skin posterior to a particular disc space to be
fused. The incision can be made anteriorly, posteriorly or
posterior laterally. If the incision is made anteriorly for
anterior insertion of the working channel, it is anticipated that
care will be taken to retract tissues, muscle and organs that may
follow the path of the incision to the disc space. However, the
device 10 of the present invention allows this tissue retraction to
occur under direct vision so that the surgeon can easily and
accurately guide the cannula 20 to the disc space without fear of
injury to the surrounding tissue. As the tissue beneath the skin is
successively excised or retracted, the working channel cannula 20
can be progressively advanced toward the anticipated working space
adjacent the vertebral disc. Again under direct vision, the disc
space can be prepared for implantation of fusion materials or a
fusion device. Typically, this preparation includes preparing an
opening in the disc annulus, and excising all or part of the disc
nucleus through this opening.
[0080] In subsequent steps, a bore is cut through the disc annulus
and into the endplates of the adjacent vertebrae. A fusion device,
such as a bone dowel, a push-in implant or a threaded implant can
then be advanced through the working channel of device 10 and into
the prepared bore at the subject disc space. In some instances, the
preparatory steps involve preparing the vertebral endplates by
reducing the endplates to bleeding bone. In this instance, some
aspiration and irrigation may be beneficial. All of these
procedures can be conducted by tools and instruments extending
through the working channel cannula 20 and under direct vision from
the viewing element 50.
[0081] In some instances, graft material is simply placed within
the prepared bore. This graft material can also be passed through
the working channel cannula 20 into the disc space location. In
other procedures, graft material or bone chips are positioned
across posterior aspects of the spine. Again, this procedure can be
conducted through the working channel cannula particularly given
the capability of the cannula to be moved to different angles from
a single incision site in the skin.
[0082] The present invention provides instruments and techniques
for conducting a variety of surgical procedures. In the illustrated
embodiments, these procedures are conducted on the spine. However,
the same devices and techniques can be used at other places in the
body. For example, an appropriately sized working channel device 10
can be used to remove lesions in the brain. The present invention
has particular value for percutaneous procedures where minimal
invasion into the patient is desirable and where accurate
manipulation of tools and instruments at the surgical site is
required. While the preferred embodiments illustrated above concern
spinal procedures, the present invention and techniques can be used
throughout the body, such as in the cranial cavity, the pituitary
regions, the gastro-intestinal tract, etc. The ability to
reposition the viewing optics as required to visualize the surgical
site allows for much greater accuracy and control of the surgical
procedure. The present invention allows the use of but a single
entry into the patient which greatly reduces the risk associated
with open surgery or multiple invasions through the patient's
skin.
[0083] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only the preferred embodiment has been shown
and described and that all changes and modifications that come
within the spirit of the invention are desired to be protected.
* * * * *