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Description  |
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FIELD OF THE INVENTION
This invention relates generally to instruments and techniques for
performing less-invasive surgical procedures, and more specifically, to
less-invasive instruments and techniques for retracting tissue structures
within body cavities such as the abdomen or thorax.
BACKGROUND OF THE INVENTION
Various types of surgical procedures are currently performed to
investigate, diagnose, and treat diseases of the heart and the great
vessels of the thorax. Such procedures include repair and replacement of
mitral, aortic, and other heart valves, repair of atrial and ventricular
septal defects, pulmonary thrombectomy, treatment of aneurysms,
electrophysiological mapping and ablation of the myocardium, and other
procedures in which interventional devices are introduced into the
interior of the heart or a great vessel.
Using current techniques, many of these procedures require a gross
thoracotomy, usually in the form of a median sternotomy, to gain access
into the patient's thoracic cavity. A saw or other cutting instrument is
used to cut the sternum longitudinally, allowing two opposing halves of
the anterior or ventral portion of the rib cage to be spread apart. A
large opening into the thoracic cavity is thus created, through which the
surgical team may directly visualize and operate upon the heart and other
thoracic contents.
Surgical intervention within the heart generally requires isolation of the
heart and coronary blood vessels from the remainder of the arterial
system, and arrest of cardiac function. Usually, the heart is isolated
from the arterial system by introducing an external aortic crossclamp
through a sternotomy and applying it to the aorta between the
brachiocephalic artery and the coronary ostia. Cardioplegic fluid is then
injected into the coronary arteries, either directly into the coronary
ostia or through a puncture in the aortic root, so as to arrest cardiac
function. In some cases, cardioplegic fluid is injected into the coronary
sinus for retrograde perfusion of the myocardium. The patient is placed on
cardiopulmonary bypass to maintain peripheral circulation of oxygenated
blood.
Of particular interest to the present invention are intracardiac procedures
for surgical treatment of heart valves, especially the mitral and aortic
valves. According to recent estimates, more than 79,000 patients are
diagnosed with aortic and mitral valve disease in U.S. hospitals each
year. More than 49,000 mitral valve or aortic valve replacement procedures
are performed annually in the U.S., along with a significant number of
heart valve repair procedures.
Various surgical techniques may be used to repair a diseased or damaged
valve, including annuloplasty (contracting the valve annulus),
quadrangular resection (narrowing the valve leaflets), commissurotomy
(cutting the valve commissures to separate the valve leaflets), shortening
mitral or tricuspid valve chordae tendonae, reattachment of severed mitral
or tricuspid valve chordae tendonae or papillary muscle tissue, and
decalcification of valve and annulus tissue. Alternatively, the valve may
be replaced, by excising the valve leaflets of the natural valve, and
securing a replacement valve in the valve position, usually by suturing
the replacement valve to the natural valve annulus. Various types of
replacement valves are in current use, including mechanical and biological
prostheses, homografts, and allografts, as described in Bodnar and Frater,
Replacement Cardiac Valves 1-357 (1991), which is incorporated herein by
reference. A comprehensive discussion of heart valve diseases and the
surgical treatment thereof is found in Kirklin and Barratt-Boyes, Cardiac
Surgery 323-459 (1986), the complete disclosure of which is incorporated
herein by reference.
The mitral valve, located between the left atrium and left ventricle of the
heart, is most easily reached through the wall of the left atrium, which
normally resides on the posterior side of the heart, opposite the side of
the heart that is exposed by a median sternotomy. Therefore, to access the
mitral valve via a sternotomy, the heart is rotated to bring the left
atrium into an anterior position accessible through the sternotomy. An
opening, or atriotomy, is then made in the right side of the left atrium,
anterior to the right pulmonary veins. The atriotomy is retracted by means
of sutures or retraction devices, exposing the mitral valve directly
posterior to the atriotomy. One of the aforementioned techniques may then
be used to repair or replace the valve.
An alternative technique for mitral valve access may be used when a median
sternotomy and/or rotational manipulation of the heart are undesirable. In
this technique, a large incision is made in the right lateral side of the
chest, usually in the region of the fourth intercostal space. One or more
ribs may be removed from the patient, and other ribs near the incision are
retracted outward to create a large opening into the thoracic cavity. The
left atrium is then exposed on the posterior side of the heart, and an
atriotomy is formed in the wall of the left atrium, through which the
mitral valve may be accessed for repair or replacement.
Using such open-chest techniques, the large opening provided by a median
sternotomy or right thoracotomy enables the surgeon to see the mitral
valve directly through the left atriotomy, and to position his or her
hands within the thoracic cavity in close proximity to the exterior of the
heart for manipulation of surgical instruments, removal of excised tissue,
and/or introduction of a replacement valve through the atriotomy for
attachment within the heart. However, these invasive, open-chest
procedures produce a high degree of trauma, a significant risk of
complications, an extended hospital stay, and a painful recovery period
for the patient. Moreover, while heart valve surgery produces beneficial
results for many patients, numerous others who might benefit from such
surgery are unable or unwilling to undergo the trauma and risks of current
techniques.
In response to the various problems associated with open-chest procedures,
new methods of performing closed-chest surgery on the heart using
minimally invasive thoracoscopic techniques have been recently developed.
In these methods, the patient's heart is arrested by occluding the
patient's aorta between the coronary arteries and the brachiocephalic
artery with an expandable balloon on the distal end of an endovascular
catheter introduced via a femoral artery. Cardioplegic fluid is then
delivered to the patient's myocardium through a lumen in the same catheter
or through a catheter positioned in the coronary sinus via a peripheral
vein. To repair or replace the mitral valve, minimally-invasive cutting
and suturing instruments are then introduced thoracoscopically through a
trocar sleeve in the right lateral portion of the chest. A complete
description of such methods is found in commonly assigned, co-pending
application Ser. No. 08/163,241, filed Dec. 6, 1993, which is incorporated
herein by reference.
This new generation of thoracoscopic methods of performing heart valve
repair has, of course, created many new challenges. One such challenge is
that of retracting the left atrial wall to open the atriotomy so that the
mitral valve can be exposed for the surgical procedure. The heart wall
must be retracted anteriorly to suitably expose the mitral valve and
provide access through the atriotomy for the cutting and suturing
instruments introduced through the right lateral portion of the chest. In
addition, the instruments that retract the heart wall must be introduced
in a minimally-invasive manner through small percutaneous incisions or
cannulae positioned in intercostal spaces in the patient's rib cage.
Introducing an instrument through an intercostal space in the anterior side
of the chest presents additional problems. One such problem is that the
patient's rib cage is typically structured so that the ribs in the
anterior portion of the chest are closer together than in the lateral
portions of the chest. In addition, the tissue layer in the anterior chest
wall contains nerves that could be damaged by a large percutaneous
incision. Therefore, a retraction device introduced from the anterior side
should be as small as possible, preferably on the order of 3-8 mm, to fit
within the smaller anterior intercostal spaces and to avoid unnecessary
trauma to the patient. Another problem is that the part of the retraction
device that engages the heart wall must be wide enough to engage a
sufficient portion of the heart wall to open the atriotomy enough to
expose the mitral valve. It must also be long enough to extend a
sufficient distance into the heart to extend beneath the interatrial
septum and prevent it from sagging or otherwise inhibiting access to the
mitral valve. Introducing an instrument which is large enough to
sufficiently expose the mitral valve through the smaller intercostal
spaces in the anterior portion of the chest is problematic.
What is needed, therefore, are improved systems and methods for
manipulating a tissue structure in a body cavity via a small percutaneous
incision or cannula. Preferably, the systems and methods would be capable
of retracting an incision in a vessel or organ, such as an atriotomy in
the left atrium to expose the mitral valve for repair or replacement. The
system should be configured for introduction through an extremely small
percutaneous penetration, such as a cannula positioned in an anterior
intercosial space. The system should also be large enough to retract the
heart wall sufficiently to expose the mitral valve and to support the
interatrial septum. In addition, the system should be configured to
facilitate retraction of the left atrium from the anterior side of the
chest.
SUMMARY OF THE INVENTION
The invention provides systems and methods for manipulating a tissue
structure in a body cavity through a small percutaneous penetration in a
patient. The system is configured for being introduced through a small
percutaneous penetration into a body cavity and retracting an incision in
the left atrium from the anterior side of the chest. The system is well
suited for engaging the heart wall, making the invention particularly
useful during surgeries such as mitral valve replacement. The system is
wide enough to retract a sufficient portion of the heart wall to expose
the left atrium and long enough to extend into the heart and support the
interatrial septum. While being especially useful for thoracoscopy, the
system and method are also useful in other surgical procedures, such as
laparoscopy and pelviscopy.
In one aspect of the invention, the system comprises a tissue supporting
member positionable through a first percutaneous penetration into a body
cavity. The tissue supporting member has a contact surface configured for
supporting at least a portion of the tissue structure. A shaft has a
proximal end, a distal end configured for introduction through a second
percutaneous penetration and a diameter less than the width and length of
the contact surface. A connection means is coupled to the distal end of
the shaft for releasably holding the tissue supporting member such that
the contact surface is arranged transversely to the longitudinal axis of
the shaft. With this configuration, the shaft and tissue supporting member
can be introduced through two separate percutaneous penetrations and
connected together within a body cavity. This allows the shaft to be
introduced through a small intercosial space in the anterior side of the
chest from the direction in which retraction will occur, while the tissue
supporting member is introduced through a larger intercosial space in the
lateral side of the chest.
In one embodiment, the tissue supporting member includes a support plate
having an arcuate upper surface configured for supporting the tissue
structure. Preferably, the arcuate upper surface has a curvature selected
to conform to an opening in the tissue structure. The upper surface is
long enough to extend relatively deep beneath the tissue structure to
support a relatively thick outer wall of a vessel or organ. The upper
surface is also wide enough to allow the surgeon to substantially enlarge
the opening so that an inner cavity of the tissue structure is exposed.
The support plate may also include means for retaining the tissue wall on
the contact surface. Preferably, the retaining means comprises a lip that
projects upwards from the upper surface on at least one end of the tissue
supporting member. The lip prevents the tissue wall from sliding along the
upper surface and off of the support plate. The upper surface may also
include grooves for frictionally engaging the tissue wall.
In a second embodiment, the tissue supporting member includes a pair of
arms extending transversely from the distal end of the shaft. The arms are
disposed apart from each other and preferably form a "V" shape to allow
the surgeon to retract a substantial portion of the tissue wall. Each arm
has an upper surface configured to extend relatively deep beneath the
tissue structure to engage the outer tissue wall. The arms may further
include distal tips that curve upwards to prevent the tissue wall from
sliding off the upper surfaces.
In a third embodiment, the tissue supporting member includes an expandable
member coupled to the distal end of the shaft. Preferably, the expandable
member is a balloon that is movable into an expanded configuration for
supporting the tissue structure. In the expanded configuration, the
balloon is large enough to substantially enlarge the opening in the tissue
structure and to extend beneath the tissue structure to support the outer
wall. To expand the balloon, the shaft further includes a lumen fluidly
coupling the balloon with an inflation means at the proximal end of the
shaft.
In a preferred embodiment, the connections means includes a hook slidably
coupled to the distal end of the shaft. The tissue supporting member has
an opening configured for receiving the hook so that the shaft holds the
tissue supporting member with the contact surface arranged transversely to
the longitudinal axis of the shaft. Preferably, the contact surface is
disposed at an angle of at most 110.degree., usually less than 90.degree.,
relative to the longitudinal axis of the shaft so that it can easily
support the tissue wall. The connection means rigidly holds the contact
surface so that the contact surface will be maintained at this angle
relative to the shaft. In this manner, the surgeon may apply a force to
the shaft to manipulate the tissue structure with the contact surface.
In one embodiment, the hook includes a U-shaped distal tip to ensure that
the hook remains engaged with the opening in the tissue supporting member.
In a second embodiment, the hook includes an L-shaped distal tip to
facilitate the surgeon's engagement of the tip with the opening.
The invention may further include actuator means at the proximal end of the
shaft for moving the shaft with respect to the hook between a first
position, where the tissue supporting member is locked to the shaft, and a
second position, where the tissue supporting member is releasable from the
shaft. Preferably, the shaft is biased into the second position by biasing
means such as a spring. The actuator means may further include a locking
mechanism to maintain the shaft in the first position and means to release
the locking mechanism so that the biasing means can move the shaft into
the second position.
In a preferred embodiment, the invention includes a clamping means for
fixing the shaft in a longitudinal position with respect to the second
percutaneous penetration. The clamping means may include a collar slidably
coupled to the shaft and means such as a set screw or clamping ring for
locking the collar at a particular longitudinal position along the shaft.
The collar is configured to rest against an outer surface of the patient's
body or a proximal end of a trocar sleeve so that the shaft will not move
in the distal direction. In this manner, the surgeon can exert traction on
the shaft to manipulate the tissue structure into a desired position and
then fix the shaft so that the tissue structure will remain in a
stationary position without being held by the surgeon.
The invention may further include an introducer for introducing the tissue
supporting member into the body cavity. The introducer includes a second
shaft with proximal and distal ends and a longitudinal axis therebetween.
The distal end is preferably configured for introduction through an
intercostal space. The introducer includes means at the distal end for
releasably holding the tissue supporting member. Preferably, the holding
means holds the tissue supporting member such that the contact surface is
generally parallel to the longitudinal axis of the second shaft. This
minimizes the cross-sectional profile of the tissue supporting member and
the introducer to facilitate delivery of the tissue supporting member
through the intercostal space. In addition, the tissue supporting member
is suitably positioned for connection to the first shaft within the body
cavity.
In a preferred embodiment, the holding means of the introducer is a hook
slidably coupled to the distal end of the shaft such that the shaft can
move relative to the hook. The tissue supporting member has a second
opening configured for receiving the hook. Preferably, the opening is
disposed on an opposite end from the first opening such that the first
shaft and the introducer can simultaneously hold the tissue supporting
member. In this configuration, the introducer will be generally
perpendicular to the first shaft, allowing the introducer to be positioned
in a lateral side of the chest while the first shaft is positioned in the
anterior side of the chest. The tissue supporting member may further
include a third opening disposed proximate to the first opening so that
the first shaft and the introducer can engage the tissue supporting member
on the same side, if desired.
The invention is particularly useful for retracting and supporting the
walls of the heart during a cardiac procedure such as repairing or
replacing the mitral valve. In this procedure, the patient's heart is
placed under cardioplegic arrest and the patient is supported on
cardiopulmonary bypass. A first access cannula is positioned in a first
percutaneous intercostal penetration in the right lateral side of the
patient's chest and a second access cannula is positioned in a second,
much smaller percutaneous intercostal penetration in the anterior side of
the patient's chest. A viewing scope is introduced through another right
anterior percutaneous intercostal penetration. A cutting tool is
introduced through the first access cannula in the right lateral chest to
form an incision or atriotomy in the wall of the left atrium.
To enlarge the atriotomy in the left atrium and expose the mitral valve in
a line of sight from the first access cannula in the right chest, the
first shaft is introduced through the second access cannula. The tissue
supporting member, releasably connected to the introducer, is then guided
through the first access cannula and positioned within the thoracic cavity
adjacent the first shaft. The first shaft is manipulated to engage the
first opening of the tissue supporting member with the hook, and the first
shaft is moved in the distal direction with respect to the hook so that
the tissue supporting member is locked to the first shaft with the contact
surface arranged transversely to the longitudinal axis of the first shaft.
Once the tissue supporting member has been connected to the first shaft,
the introducer is disengaged from the tissue supporting member and
withdrawn from the patient. The tissue supporting member is then
positioned in the atriotomy such that the heart wall is adjacent to the
contact surface. To enlarge the atriotomy, the surgeon moves the shaft and
the hook in the proximal direction to pull upwards on the tissue
supporting member thereby retracting the heart wall anteriorly. The tissue
supporting member sufficiently enlarges the atriotomy to expose the mitral
valve and supports the interatrial septum so that it does not inhibit
access to the mitral valve. The surgeon then moves the collar into the
locked position around the shaft to prevent the shaft from moving in the
distal direction. This ensures that the heart wall will remain retracted
during the operation.
After the heart wall has been retracted to expose the mitral valve, a
cutting tool may be introduced through the first access cannula to remove
all or part of the mitral valve. A replacement valve can then be
introduced through the first access cannula and fastened within the heart,
usually by suturing the replacement valve to an annulus at the natural
valve position in the heart. Once the mitral valve has been replaced, the
collar is moved into the open position to release the first shaft,
allowing the first shaft to move distally to close the atriotomy. The
tissue supporting member is removed from the atriotomy, and the introducer
is reintroduced through the first access cannula to engage the tissue
supporting member. The tissue supporting member is then released from the
first shaft by moving the first shaft in a proximal direction relative to
the hook The introducer and the tissue supporting member may then be
withdrawn from the patient through the access cannula.
In a preferred embodiment, the shaft has an outer diameter less than about
5 mm allowing the second intercostal penetration to be of the same or
slightly larger size, e.g. less than about 8 mm. This reduces the trauma
to the patient and avoids the possibility of damaging nerves in the
patient's chest. In addition, the small diameter shaft facilitates
penetrating the tighter intercostal spaces in the anterior side of the
chest.
In an exemplary embodiment, the contact surface has a width and a length
each greater than about 20 mm. The relatively large dimensions of the
contact surface allow the surgeon to retract a substantial portion of the
heart wall to suitably expose the mitral valve for an approach from the
right side of the chest. In addition, the surgeon can insert the contact
surface deeply enough into the left atrium to support the interatrial
septum so that it does not sag or otherwise inhibit access to the mitral
valve.
It should be understood that while the invention is described in the
context of thoracoscopic surgery on the left atrium and mitral valve, the
systems and methods disclosed herein are equally useful on other types of
tissue structures and in other types of surgery, such as laparoscopy and
pelviscopy.
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. dr
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a system for closed-chest mitral valve
replacement constructed in accordance with the principles of the present
invention, showing the use of the system in a patient;
FIG. 2 is a front view of the system of FIG. 1, showing the positioning of
the system in the patient's chest;
FIG. 3 is a front view of a patient's cardiovascular system illustrating
the positioning of a system for arresting the heart and establishing
cardiopulmonary bypass in accordance with the principles of the present
invention;
FIG. 4 is a top view looking into the patient's thoracic cavity through a
passage of an access cannula in the system of FIG. 1, showing the creation
of an atriotomy in the patient's left atrium;
FIG. 5 is a top view looking into the patient's thoracic cavity through a
passage of an access cannula in the system of FIG. 1, showing the removal
of the mitral valve leaflets;
FIG. 6 is a top view looking into the patient's thoracic cavity through a
passage of an access cannula in the system of FIG. 1, showing the
application of sutures to the mitral valve annulus;
FIG. 7 is a perspective view of the system of FIG. 1 positioned in the
patient, showing the application of sutures to a replacement valve;
FIGS. 8A-8B are transverse cross-sectional views of the system and patient
of FIG. 1 taken through the patient's thorax, showing the introduction of
the replacement valve into the left atrium and the tying of knots in the
sutures to secure the prosthesis in the patient's heart;
FIG. 9 is a top view looking into the patient's thoracic cavity through a
passage of an access cannula in the system of FIG. 1, showing pushing the
knots toward the replacement valve and trimming the free ends of the
sutures;
FIG. 10 is a top view looking into the patient's thoracic cavity through a
passage of an access cannula in the system of FIG. 1, showing the closure
of the patient's left atrium;
FIGS. 11A-11C are perspective, front, and top views respectively of the
access cannula in the system of FIG. 1;
FIG. 11D is a partial cut-away view taken along line 11D--11D in FIG. 11C;
FIG. 12A is a side view of angled scissors in the system of FIG. 1;
FIGS. 12B-12D are side views of a distal portion of the scissors of FIG.
12A showing alternative embodiments thereof;
FIG. 13 is a side view of a retractable knife in the system of FIG. 1;
FIGS. 14A-14B are side and top views, respectively, of grasping forceps in
the system of FIG. 1;
FIG. 15 is a perspective view of a left atrial retractor in the system of
FIG. 1;
FIGS. 16A-16B are side and top views, respectively, of needle drivers in
the system of FIG. 1.
FIGS. 17A-17B are top and side views, respectively, of a replacement valve
in the system of FIG. 1;
FIG. 17C is an end view of the replacement valve of FIGS. 17A-17B
positioned in a passage of an access cannula in the system of FIG. 1;
FIG. 18 is a perspective view of a prosthesis introducer in the system of
FIG. 1;
FIG. 19A is a side view of the prosthesis introducer of FIG. 18;
FIGS. 19B-19C are bottom and side views, respectively, of a distal portion
of the prosthesis introducer of FIG. 18;
FIGS. 19D-19E are top and side views, respectively, of a stationary arm of
the prosthesis introducer of FIG. 18;
FIGS. 19F-19G are top and side views, respectively, of a movable arm of the
prosthesis introducer of FIG. 18;
FIG. 20A is a side partial cut-away view of the prosthesis introducer of
FIG. 18;
FIG. 20B is a top partial cut-away view of a distal portion of the
prosthesis introducer of FIG. 18;
FIG. 21 is a perspective view of a sizing disk in the system of FIG. 1,
positioned on the introducer of FIG. 18;
FIGS. 22, 23A and 23B are top and side views, respectively, of the sizing
disk of FIG. 21;
FIGS. 24A-24C are front, top, and side views, respectively of a suture
organizing ring in the system of FIG. 1;
FIGS. 25A-25B are side and top views, respectively of a knot-pushing device
in the system of FIG. 1;
FIG. 26 is a perspective view of an alternative embodiment of a retractor
suitable for retracting the left atrium according to the invention;
FIGS. 27A-27B are side cross-sectional views of proximal and distal
portions, respectively, of the retractor of FIG. 26 in a locked position
on a tissue supporting member;
FIGS. 27C-27D are side cross-sectional views of proximal and distal
portions, respectively, of the retractor of FIG. 26 in a releasable
position on the tissue supporting member of FIGS. 27A-27B;
FIGS. 28A-28B are transverse cross-sectional views of the retractor of FIG.
26 taken substantially along the plane of the lines 28A and 28B,
respectively, in FIG. 27C.
FIGS. 29A-29B are side and top views, respectively, of the tissue
supporting member of FIGS. 27A-27D;
FIG. 29C is a side view of an alternative embodiment of the tissue
supporting member of FIGS. 27A-27D;
FIG. 30 is a transverse cross-sectional view of the retractor of FIG. 26
with an adjustable collar for clamping the retractor in a longitudinal
position with respect to a percutaneous penetration; and
FIGS. 31A-31D are transverse cross-sectional views of the system and
patient of FIG. 1, taken through the patient's thorax, showing the
introduction of the tissue supporting member of FIGS. 27A-27D through an
access cannula, the connecting of the tissue supporting member to the
retractor of FIG. 26 within the thoracic cavity and the retraction of the
patient's left atrium wall.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
The invention provides methods and devices for performing surgical
interventions within the heart or a great vessel such as the aorta,
superior vena cava, inferior vena cava, pulmonary artery, pulmonary vein,
coronary arteries, and coronary veins, among other vessels. While the
specific embodiments of the invention described herein will refer to
mitral valve repair and replacement, it should be understood that the
invention will be useful in performing a great variety of surgical
procedures, including repair and replacement of aortic, tricuspid, or
pulmonary valves, repair of atrial and ventricular septal defects,
pulmonary thrombectomy, removal of atrial myxoma, patent foramen ovale
closure, treatment of aneurysms, electrophysiological mapping and ablation
of the myocardium, myocardial drilling, coronary artery bypass grafting,
angioplasty, atherectomy, correction of congenital defects, and other
procedures in which interventional devices are introduced into the
interior of the heart, coronary arteries, or great vessels.
Advantageously, the invention facilitates the performance of such
procedures through percutaneous penetrations within intercostal spaces of
the rib cage, obviating the need for a median sternotomy or other form of
gross thoracotomy.
The terms "percutaneous intercostal penetration" and "intercostal
penetration" as used herein refer to a penetration, in the form or a small
cut, incision, hole, cannula, trocar sleeve, or the like, through the
chest wall between two adjacent ribs, wherein the patient's rib cage and
sternum remain substantially intact, without cutting, removing, or
significantly displacing the ribs or sternum. These terms are intended to
distinguish a gross thoracotomy such as a median sternotomy, wherein the
sternum and/or one or more ribs are cut or removed from the rib cage, or
one or more ribs are retracted significantly, to create a large opening
into the thoracic cavity. A "percutaneous intercostal penetration" may
abut or overlap the adjacent ribs between which it is formed, but the
maximum width of the penetration which is available for introduction of
instruments, prostheses and the like into the thoracic cavity will be the
width of the intercostal space, bounded by two adjacent ribs in their
natural, substantially undeflected positions. It should be understood that
one or more ribs may be retracted or deflected a small amount without
departing from the scope of the invention; however, the invention
specifically seeks to avoid the pain, trauma, and complications which
result from the large deflection or cutting of the ribs in conventional,
open-chest techniques.
A first preferred embodiment of a system and method of clo | | |
