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Claims  |
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What is claimed is:
1. A microsurgical instrument comprising: an outer shaft having a proximal
end, a distal end, and an axial lumen therebetween;
an inner shaft slidably disposed in the axial lumen and having a proximal
end and a distal end;
an end effector coupled to the distal end of the inner shaft and movable
relative to the outer shaft; and
an actuator at the proximal end of the outer shaft, the actuator
comprising:
an actuator body attached to a first shaft selected from the outer shaft
and the inner shaft;
a first arm having a proximal end and a distal end, the proximal end being
pivotally coupled to the actuator body by a pin means, and the distal end
extending distally and outwardly from the actuator body on a first lateral
side of the outer shaft to form an acute angle therewith;
a second arm having a proximal end and a distal end, the proximal end being
pivotally coupled to the actuator body by a pin means, and the distal end
extending distally and outwardly from the actuator body on a second
lateral side of the outer shaft opposite the first lateral side to form an
acute angle therewith;
a first link having an outer end and an inner end, the outer end being
coupled to the first arm at a first pivot point distal to the proximal end
of the first arm, and the inner end being coupled to a second shaft
selected from the outer shaft and the inner shaft; and
a second link having an outer end and an inner end, the outer end being
coupled to the second arm at a second pivot point distal to the proximal
end of the second arm, and the inner end being coupled to the second
shaft;
wherein the first and second arms are symmetrically pivotable to translate
the inner shaft relative to the outer shaft, thereby actuating the
end-effector.
2. The instrument of claim 1 wherein the end-effector is pivotally coupled
to the outer shaft at a first point and pivotally coupled to the inner
shaft at a second point, wherein translation of the inner shaft relative
to the outer shaft moves the end-effector.
3. The instrument of claim 2 wherein the first and second points are
separated by a distance which is less than about 5 mm.
4. The instrument of claim 1 wherein the outer shaft has a diameter of less
than about 5 mm.
5. The instrument of claim 1 further comprising a fixed jaw at the distal
end of the outer shaft, wherein the end-effector comprises a movable jaw
movable between an open position separated from the fixed jaw and a closed
position in engagement with the fixed jaw.
6. The instrument of claim 5 wherein the movable jaw has a gripping surface
disposed in opposition to a gripping surface on the fixed jaw.
7. The instrument of claim 5 wherein the movable jaw has a cutting edge
movable in a shearing relationship with the fixed jaw.
8. The instrument of claim 1 wherein the first and second links are
arranged such that a transverse force exerted through the first link on
the second shaft is opposed by a transverse force exerted through the
second link on the second shaft.
9. The instrument of claim 8 wherein the inner ends of the first and second
links are equidistant from the proximal end of the second shaft.
10. The instrument of claim 1 wherein the first and second arms are each
coupled to the actuator body by a hinge pin.
11. The instrument of claim 10 wherein the first and second arms are rigid.
12. The instrument of claim 10 further comprising spring means for
outwardly biasing the first and second arms such that the distal ends
thereof are spaced apart from the outer shaft.
13. The instrument of claim 12 wherein the the spring means comprises a
flat spring disposed at the proximal ends of the first and second arms, a
first end of the flat spring engaging the first arm and a second end of
the flat spring engaging the second arm.
14. The instrument of claim 1 wherein the inner ends of the first and
second links are distal to the outer ends of the first and second links.
15. The instrument of claim 1 wherein the inner ends of the first and
second links are proximal to the outer ends of the first and second links.
16. The instrument of claim 1 wherein the first pivot point is closer to
the proximal end of the first arm than to the distal end of the first arm,
and the second pivot point is closer to the proximal end of the second arm
than to the distal end of the second arm.
17. The instrument of claim 1 further comprising means for locking the
first and second arms in a closed position.
18. The instrument of claim 1 wherein the first and second arms have outer
longitudinal surfaces configured to be engaged by a finger and a thumb of
a user.
19. The instrument of claim 18 wherein the outer longitudinal surfaces
include finger grips for contacting tips of the finger and thumb.
20. The instrument of claim 19 wherein the finger grips include textural
features for improving grip.
21. The instrument of claim 19 wherein the finger grips are disposed in a
distal portion of the arms.
22. The instrument of claim 18 wherein the outer longitudinal surfaces are
generally flat.
23. The instrument of claim 1 wherein the actuator body has an open
interior, the inner ends of the links being coupled to the second shaft
within the interior of the actuator body.
24. A microsurgical instrument comprising:
an outer shaft having a proximal end, a distal end, and an axial lumen
therebetween;
an inner shaft slidably disposed in the axial lumen and having a proximal
end and a distal end;
a fixed jaw at the distal end of the outer shaft;
a movable jaw coupled to the distal end of the inner shaft and movable
relative to the fixed jaw; and
an actuator at the proximal end of the outer shaft, the actuator
comprising:
a first arm having a proximal end and a distal end, the proximal end being
pivotally coupled to a first shaft selected from the outer shaft and the
inner shaft, and the distal end being disposed on a first lateral side of
the outer shaft and biased outwardly to form an acute angle therewith;
a second arm having a proximal end and a distal end, the proximal end being
pivotally coupled to the first shaft, and the distal end being disposed on
a second lateral side of the outer shaft opposite the first lateral side
and biased outwardly to form an acute angle therewith;
a first link having an outer end and an inner end, the outer end being
coupled to the first arm at a first pivot point, and the inner end being
coupled to a second shaft selected from the outer shaft and the inner
shaft; and
a second link having an outer end and an inner end, the outer end being
coupled to the second arm at a second pivot point, and the inner end being
coupled to the second shaft, the first pivot point being closer to the
proximal end of the first arm than to the distal end of the first arm, and
the second pivot point being closer to the proximal end of the second arm
than to the distal end of the second arm;
wherein the first and second arms are symmetrically pivotable such that the
first and the second links exert symmetrical forces on the inner shaft to
move the movable jaw relative to the fixed jaw.
25. The instrument of claim 24 wherein the proximal end of the first shaft
is attached to an actuator body, and the first and second arms are
pivotally coupled to the actuator body.
26. The instrument of claim 25 wherein the actuator body has an open
interior, and the inner ends of the first and second links are coupled to
the second shaft within the interior of the actuator body.
27. The instrument of claim 25 wherein each of the first and second arms is
coupled to the actuator body by a hinge pin about which the arm is
pivotable.
28. The instrument of claim 24 further comprising spring means engaging the
first and second arms for biasing the arms into an outward position.
29. The instrument of claim 28 wherein the spring means comprises a flat
spring having a first end for engaging the proximal end of the first arm
and a second end for engaging the proximal end of the second arm.
30. The instrument of claim 24 wherein the first and second pivot points
are less than about 6 cm from the proximal ends of the first and second
arms, respectively.
31. The instrument of claim 24 wherein the movable jaw is pivotably coupled
to the outer shaft, whereby translation of the inner shaft pivots the
movable jaw relative to the fixed jaw.
32. A method of endoscopic manipulation of a body structure within a body
cavity, the method comprising:
providing an instrument having a shaft with a distal end and a proximal
end, a pair of jaws at the distal end movable relative to each other, an
actuator body at the proximal end, and a pair of arms pivotally coupled to
the actuator body, each arm having a proximal end coupled by pin means to
the actuator body and a distal end extending distally and outwardly
therefrom forming an acute angle with the shaft;
introducing the distal end of the shaft through a percutaneous penetration
into the body cavity;
viewing the body cavity through a percutaneous penetration; and
pressing inwardly on outer surfaces on a distal portion of the arms to
symmetrically pivot both arms toward the shaft, thereby closing the jaws
on the body structure.
33. The method of claim 32 wherein the arms are each coupled to a proximal
end of a rod arranged coaxially with the shaft and movable axially
relative thereto, at least a first of the jaws being coupled to a distal
end of the rod, wherein the first jaw is moved by translation of the rod.
34. The method of claim 33 wherein pressing inwardly on the arms exerts
axial and transverse forces on the rod, wherein a first transverse force
exerted on the rod by a first arm is opposed by a second transverse force
exerted on the rod by a second arm.
35. The method of claim 33 wherein each arm is coupled to the rod by a
link, each link being coupled at a first end to the proximal end of the
rod and at a second end to a pivot point in a proximal portion of the arm.
36. The method of claim 35 wherein the outer surface of each arm may be
pressed at a point which is separated from the pivot by at least half of
the length of the arm.
37. The method of claim 33 wherein at least a first jaw is pivotally
coupled to the shaft at a first point and pivotally coupled to the rod at
a second point, wherein translation of the rod relative to the outer shaft
pivots the first jaw.
38. The method of claim 32 further comprising positioning an access cannula
in the percutaneous penetration, the access cannula having an inner
passage through which the shaft is introduced into the body cavity.
39. The method of claim 38 wherein the inner passage has a diameter in the
range of 3 mm to 10 mm.
40. The method of claim 32 wherein the body structure comprises a vessel
selected from the group consisting of coronary arteries, internal mammary
arteries, aortas, and saphenous veins.
41. The method of claim 32 wherein closing the jaws on the body structure
engages the body structure between opposing gripping surfaces on the jaws
to grip the body structure therein.
42. The method of claim 41 wherein the body structure comprises an internal
mammary artery, the method further comprising dissecting a portion of the
internal mammary artery from surrounding tissue while gripping the
internal mammary artery between the jaws.
43. The method of claim 32 wherein at least one of the jaws comprises a
cutting edge movable in a shearing relationship with the other jaw,
wherein closing the jaws on the body structure cuts the body structure.
44. The method of claim 43 wherein the body structure comprises a coronary
artery, wherein the jaws are closed on a wall of the coronary artery to
cut an opening therein.
45. The method of claim 44 further comprising attaching a graft vessel to
the coronary artery under visualization by means of the scope such that a
lumen in the graft vessel is in communication with the opening in the
coronary artery.
46. The method of claim 45 wherein the step of attaching comprises suturing
the graft vessel to the coronary artery by means of a suture manipulating
instrument.
47. The method of claim 46 wherein the suture manipulation instrument
comprises a shaft with a distal end and a proximal end, a pair of jaws at
the distal end movable relative to each other, and a pair of arms coupled
to the proximal end, each arm having a proximal end coupled to the
proximal end of the shaft and a distal end biased outwardly from the shaft
forming an acute angle therewith, whereby the arms may be pivoted toward
the shalt to close the jaws on the suture.
48. The method of claim 46 wherein the step of suturing further comprises
holding a portion of the graft vessel with a grasping instrument.
49. The method of claim 48 wherein the grasping instrument comprises a
shaft with a distal end and a proximal end, a pair of jaws at the distal
end movable relative to each other, and a pair of arms coupled to the
proximal end, each arm having a proximal end coupled to the proximal end
of the shaft and a distal end biased outwardly from the shaft forming an
acute angle therewith, whereby the arms may be pivoted toward the shaft to
close the jaws on the graft vessel.
50. The method of claim 46 wherein the suture manipulation instrument is
introduced through a percutaneous intercostal penetration in the patient's
chest.
51. The method of claim 32 wherein the step of pressing comprises engaging
the outer surfaces of the arms with a thumb and a forefinger in a
generally straightened configuration and oriented generally parallel to
the arms. |
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Claims |
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Description |
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FIELD OF THE INVENTION
This invention relates generally to instruments for performing
minimally-invasive surgery, and more specifically, to instruments for
performing extremely small-scale, minimally-invasive microsurgeries such
as coronary artery bypass grafting.
BACKGROUND OF THE INVENTION
Minimally-invasive surgical techniques, such as thoracoscopy, laparoscopy,
pelviscopy, endoscopy, and arthroscopy, minimize patient trauma by
providing access to interior body cavities through very small incisions or
through percutaneous cannulas known as trocar sleeves. To perform a
surgical procedure, elongated, low-profile instruments are introduced into
a body cavity through these incisions or trocar sleeves. Visualization is
facilitated by percutaneous visualization devices known as laparoscopes,
endoscopes, arthroscopes, and the like, which typically consist of a video
camera configured for introduction through a small incision or trocar
sleeve to allow observation of the body cavity on a video monitor. By
obviating the need for a large, open incision to expose the body cavity,
minimally-invasive techniques can significantly reduce the pain, recovery
period, morbidity and mortality rates, and cost of open surgical
procedures without a sacrifice in efficacy.
In recent years, minimally-invasive techniques have been developed to
facilitate the performance of a variety of surgical procedures on organs
and ducts of the abdominal and pelvic cavities. Well-known examples of
such procedures include laparoscopic cholecystectomy, laparoscopic
appendectomy, laparoscopic hysterectomy, and laparoscopic hernia repair.
A particularly important milestone in minimally-invasive surgery has been
attained with the development of thoracoscopic techniques for surgery of
the heart and great vessels. Such techniques are described in co-pending,
commonly-assigned U.S. patent application Ser. No. 08/023,778, filed Feb.
22, 1993, the complete disclosure of which is hereby incorporated herein
by reference. In that application, thoracoscopic techniques for performing
coronary artery bypass grafting (CABG) are described which eliminate the
need for the sternotomy or other tom of gross thoracotomy required by
conventional, open surgical techniques. In thoracoscopic CABG, an arterial
blood source such as the internal mammary artery (IMA) is dissected from
its native location, transected, and prepared for attachment to an
anastomosis site on a target coronary artery, commonly the left anterior
descending coronary artery (LAD). A portion of the target coronary artery
containing the anastomosis site is then dissected away from the
epicardium, and a small incision is made in the arterial wall. The distal
end of the arterial blood source (e.g. IMA) is then anastomosed over the
incision in the target coronary artery, usually by suturing. Each of these
steps is performed by means of instruments introduced through small
incisions or trocar sleeves positioned within intercosial spaces of the
rib cage, under visualization by means of an endoscope or other
percutaneous visualization device.
Because the CABG procedure requires complex microsurgery to be carded out
on extremely small body structures, surgical instruments designed for
laparoscopic and other minimally-invasive applications are not generally
suitable for performing thoracoscopic CABG. Most laparoscopic procedures,
for example, target body structures which are quite large in comparison to
the coronary vessels, and do not require the high degree of precision
required by microsurgeries such as CABG. Accordingly, laparoscopic
instruments generally have relatively large end-effectors with relatively
large ranges of movement, making such instruments ill-suited for use on
very small structures like the coronary vessels. In addition, such
instruments commonly have finger loops or pistol-type actuators gripped in
the user's palm or between the user's thumb and forefinger, limiting the
sensitivity and precision with which such instruments can be manipulated
and actuated. Such finger loops or pistol-type grips also are limited to a
single orientation in the user's hand and cannot be repositioned in the
hand to allow better access to a body structure or to change the
orientation of the end-effector.
The advent of thoracoscopic CABG and other minimally-invasive microsurgical
procedures therefore demands a new generation of microsurgical instruments
specifically designed to meet the unique needs of such procedures. These
instruments must have a small profile for introduction through small
incisions or trocar sleeves, and a length sufficient to reach the heart
and other thoracic organs and vessels from various percutaneous access
points. The instruments must have end-effectors adapted to perform
delicate, high-precision microsurgery on very small vessels, including
end-effectors having very small dimensions and very short ranges of
motion. The instruments must have actuators that facilitate ergonomic,
one-handed actuation with sensitivity and precision, preferably having a
stroke which is large enough for comfortable actuation by the fingers and
which is reduced to a very short range of motion at the end-effector.
Desirably, the actuators will have a configuration which is analogous to
surgical forceps or to other types of microsurgical instruments commonly
utilized in open surgical procedures, shortening the learning curve
required for adoption of minimally-invasive microsurgical techniques.
SUMMARY OF THE INVENTION
This invention provides instruments and methods to facilitate the
performance of minimally-invasive microsurgical procedures, and
particularly, the performance of thoracoscopic CABG and other procedures
on the heart and great vessels. The instruments of the invention
facilitate a variety of surgical activities, including application of
clips or staples, suturing, incision, transection, dissection, retraction,
and manipulation, and are specially adapted for use on extremely small
body structures such as the coronary blood vessels. To allow precise
microsurgery to be performed on a very small scale, the instruments are
adapted to be held in a single hand in a manner analogous to surgical
forceps. The instruments are actuated by a pair of symmetrical,
proximally-hinged, forcep-like arms which can be pivoted by the fingers
for sensitive and precise actuation of an end-effector. The symmetry of
actuation allows each instrument to be rotated or otherwise repositioned
within the user's hand to change the orientation of the end-effector
without compromising the ease of actuation. Moreover, the actuator's
proximal hinge, along with a proximally-disposed linkage mechanism, allow
the distance between the user's hand and the body surface to be minimized
for optimal control of the instrument.
In a preferred embodiment, a microsurgical instrument according to the
invention comprises an outer shaft having an axial lumen, and an inner
shaft slidably disposed in the axial lumen. An end-effector is coupled to
the distal end of the inner shaft and is movable relative to the outer
shaft. An actuator is disposed at the proximal end of the outer shaft for
actuating the end-effector. The actuator includes first and second arms
each coupled at its proximal end to one of either the outer shaft or the
inner shaft, each arm extending distally and biased outwardly so as to
form an acute angle with the outer shaft. A link is coupled to each arm
and to the shaft to which the arms themselves are not coupled. In this
way, the first and second arms are symmetrically pivotable so as to pivot
the links, thereby translating the inner shaft relative to the outer shaft
to actuate the end-effector.
The end-effector of the instrument may have a variety of configurations for
performing a variety of functions. The end-effector may comprise a pair of
jaws which may be adapted for various purposes, including cutting,
grasping, holding a suture needle, and applying a clip or staple. In an
exemplary embodiment, the end-effector comprises a first jaw fixed to the
outer shaft, and a second jaw coupled to the inner shaft, such that
translating the inner shaft relative to the outer shaft moves the second
jaw relative to the first jaw. The second jaw may be pivotable, axially
slidable, rotatable, or deflectable relative to the first jaw. The jaws
may be configured to have opposing gripping surfaces for grasping tissue
or holding a suture needle, or may have sharp cutting edges movable in a
shearing relationship relative to each other for cutting tissue. The jaws
may further be disposed at various angles and orientations relative to the
inner and outer shafts to provide a range of end-effector configurations
to meet a variety of surgical needs.
Alternatively, the end-effector may be adapted for applying a clip or
staple to a body structure. In an exemplary configuration, the
end-effector includes a pair of jaws fixed to the distal end of the inner
shaft and adapted to hold a clip or staple between them. The jaws are
biased away from each other and are deflectable toward one another. Upon
actuation, the outer shaft is configured to slide distally over a proximal
portion of the jaws so as to urge the jaws toward one another, thereby
closing the clip or staple.
Preferably, the instruments of the invention are adapted for extremely
small scale microsurgical procedures such as coronary anastomosis. To
facilitate such procedures, the arms of the actuator are configured to
provide a comfortable range of motion for forcep-like finger actuation, a
range of motion which is reduced to a very small range of motion at the
end-effector, thereby providing sensitive and precise actuation for very
small end-effector movements.
In actuating very small end-effectors through very small ranges of motion,
the minimization of friction is important in providing smooth and precise
actuation. To reduce friction, the links are coupled to the shaft (either
inner or outer) such that the transverse force exerted on the shaft by one
link is opposed by a transverse force exerted on the shaft by the other
link. Usually, this is accomplished by coupling the inner ends of the
links to the shaft at points which are equidistant from the proximal end
of the shaft. In this way, as the arms are pivoted inwardly, the links do
not urge the inner shaft against the outer shaft (or vice versa), which
would produce friction as the shafts move relative to each other.
The arms may be bendable or rigid, and the arms may be coupled to the inner
or outer shaft in various ways, including by pins, by living hinges, by
bar linkages, or by other means. Preferably, however, the arms are hinged
at their proximal ends to the inner or outer shaft. A means for biasing
the arms outward is provided, which in one embodiment comprises a flat
spring coupled to each arm. With a hinge arrangement, the arms may be
rigid, rather than being bendable or resilient, permitting a wide variety
of materials and geometries to be used. In this way, the arms may be
designed for optimum performance and minimum cost.
The links may be configured so as to translate the inner shaft either
distally or proximally relative to the outer shaft as the arms are pivoted
inwardly. To provide translation of the inner shaft proximally, the inner
ends of the links are disposed proximal to the outer ends of the links. To
provide translation of the inner shaft distally, the inner ends of the
links are disposed distal to the outer ends of the links.
The instruments of the invention are further advantageous in that they
allow the user to hold and actuate the instrument from a position which is
as close as possible to the surface of the patient's body, optimizing
control of the instrument. The proximally-hinged arms permit the user to
engage the arms near their distal ends, and to introduce the instrument
into the patient's body cavity through an incision or trocar sleeve up to
the distal ends of the arms. In this way, the user may engage and
manipulate the instrument in a position immediately adjacent the surface
of the patient's body. The links are preferably coupled to the arms in a
proximal portion thereof so as not to interfere with or limit introduction
of the instrument. Proximal disposition of the links also maximizes the
mechanical advantage obtained from the forces exerted on the distal ends
of the arms, and allows the stroke of the arms to be amplified relative to
the range of motion of the end-effector.
The invention may further include means for locking the arms in a closed
position. This may be useful to ensure the jaws of the end-effector are
closed for introduction or removal from the body cavity, or to reduce the
risk of inadvertent injury to the patient caused by an open end-effector.
Usually, the instruments of the invention are adapted for endoscopic uses,
wherein the end-effector is introduced through a small incision or trocar
sleeve into the body cavity. To facilitate such introduction, the profile
of the end-effector and outer shaft are preferably minimized. In one
embodiment, the outer shaft has a diameter of less than about 5 mm.
The instruments of the invention may be utilized to perform a variety of
surgical procedures, both conventional, open procedures and
minimally-invasive procedures. In an endoscopic method of treatment
according to the invention, the distal end of the instrument is introduced
through a percutaneous penetration into a body cavity, and, under
visualization by means of a scope introduced through a percutaneous
penetration, a distal portion of at least one arm is pressed inwardly to
symmetrically pivot both arms toward the shaft, thereby closing the jaws
of the end-effector on a body structure in the body cavity. In various
embodiments, the method may be used for cutting, dissecting, transecting,
retracting, or otherwise manipulating a body structure, as well as for
suturing, or for applying clips or staples to a body structure. In a
particularly preferred embodiment, the method is utilized in a
thoracoscopic CABG procedure for dissecting a graft vessel such as the IMA
from its native location, and performing an anastomosis of the graft
vessel to a coronary artery such as the LAD.
A further understanding of the nature and advantages of the invention may
be realized by reference to the remaining portions of the specification
and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A-1B are side and top elevational views, respectively, of a
microsurgical instrument constructed in accordance with the principles of
the invention.
FIG. 1C is an illustration of a patient's chest in partial section
illustrating the use of the instrument of FIGS. 1A-1B through a trocar
sleeve.
FIGS. 2A-2B are side and top cross-sectional views, respectively, of a
first embodiment of an actuator in the microsurgical instrument of FIG. 1.
FIG. 2C is a side cross-sectional view of the actuator of FIG. 2A in a
closed position.
FIGS. 3A-3B are side and top cross-sectional views, respectively, of a
second embodiment of an actuator in the microsurgical instrument of FIG.
1.
FIG. 3C is a side cross-sectional view of the actuator of FIG. 3A in a
closed position.
FIGS. 4A-4B are side partial cross-sectional views of an actuator in the
microsurgical instrument of FIG. 1 showing two alternative embodiments of
an actuator locking mechanism.
FIGS. 5-6 are side, partial cross-sectional views of two alternative
embodiments of an end-effector in the microsurgical instrument of FIG. 1.
FIG. 7A is a side partial cross-section of an alternative embodiment of an
end-effector in the microsurgical instrument of FIG. 1.
FIGS. 7B-10 are side elevational views of various embodiments of an
end-effector in the microsurgical instrument of FIG. 1.
FIG. 11 is a side, partial cross-sectional view of a further embodiment of
a microsurgical instrument constructed in accordance with the p | | |
