Note: Descriptions are shown in the official language in which they were submitted.
113Sl~Z
1 Background of the Invention
This invention relates to suture forming surgical
apparatus and more particularly to a surgical tool for suturing
an epicardial pacer electrode to heart tissue.
~ eretofore, a pacer electrode was attached to a heart
by either conventional suture techniques that require a thora-
cotomy to expose the heart or by constructing the electrode to
provide its own means of attachment and usually directing it to
the heart through a vein. Both of these approaches, however,
have disadvantages. A thoracotomy requires a large incision in
the chest or thorax and carries with it the high risks associated
with any such drastic surgery. Electrodes with their own means
of attachment, for example the corkscrew-like device described
in U.S. Patent No. 4,000,745, traumatize the heart at the point
of electrical stimulation. Trauma, in turn, causes scar tissue
to form. Because scar tissue is a poor electrical conduction
medium, more current is needed to properly stimulate the heart
and the current requirements may vary with time. U.S. Patent
No. 4,066,085 to Hess describes a resilient epicardial eIectrode
with prong-like attachment hooks separate from an electrical
stimulating coil. While this device minimizes the trauma at
the point of electrical stimulation, it must be inserted directly
using forceps or the like. This requires drastic surgery to
provide access for the implantation. U.S. Patent Nos. 3,754,555;
3,902,501 and 3,814,104 describe known pervenous, endocardlal
electrodes where manipulation of the electrode after it is
positioned in the heart releases hooks, tines or prongs to secure
the electrode.
More broadly, various surgical tools have been devised
to facilitate the suturing of tissue in hard to reach locations.
1- ~
;~
il3~ Z
1 U.S. Patent No. 1,822,330, for example, describes a tool that
sutures tissue within the oraI cavity druing a tonsilectomy.
The tool is inserted through a natural body opening and guided
visually. Other suturing devices join easily accessible tissue
by means of preformed metal clips or staples as described in
U.S. Patent Nos. 715,612; 2,881,762 and 3,098,232. None of these
known suturing devices, however, can suture tissue that cannot
be reached or viewed through a natural body opening or directly
after exposing the tissue through surgery. Also, none of these
known devices are adapted to support, position and suture an
electrode on the heart, particularly where the suture is a closed
loop and is removed from the point of electrical stimulation. -
It is therefore a principal object of this invention
to provide a surgical tool for suturing an epicardial pacer
electrode to the heart without a thoracotomy and with a minimum
degree of trauma to the heart tissue at the point of electrical
contact.
Another object is to provide a surgical tool that can
form sutures in generally inaccessible tissue that is not direct-
ly visible.
Yet another object is to provide a surgical tool with
the foregoing advantages that can form multiple sutures at the
same time.
A further object is to provide a pacer electrode sutur-
ing tool that guides the electrode and its lead to the implanta-
t~on site and selectively detaches both the electrode and its
lead after the suture is formed.
A still further object is to provide a suturing tool
which is reliable, convenient to use, and of relatively simple
and inexpensive construction.
--2--
~135~Z
1 Summary of the Invention
A surgical tool for forming at least one generally
circular suture within normally inaccessible tissue has an
elongated body with a grip and plunger actuator at one end. In
a preferred form the other or distal end is adapted to releasa-
bly hold an epicardial pacer electrode. The body supports at
least one tubular die member with an inner bore shaped for close-
ly guiding an associated, formable suture element. The end of
the die member adjacent the electrode is curved to deflect the
suture element beyond its elastic limit, thereby imparting a
curvature of an essentially predetermined radius to the suture
element. The plunger and a push wire carried in the die member
drive the suture element through the bore and past its curved
deflecting end. This action ejects the suture element along a
curving path to form a substantially closed-loop, circular
suture. The suture or sutures thus formed pass through the heart
tissue adjacent the electrode and securely hold the epicardial
pacer electrode in electrical connection ~ith the heart tissue.
In a preferred embodiment, two tubular die members are
employed, arranged on opposite sides of the electrical connection
element of the electrode, and each carrying at its distal end
one suture element. The distal end of the tool body has an
interior recess adapted to receive a resiliently deformable plug
on the rear face of the electrode. ~hen the plug is seated in
the recess, the suturing tool can direct the electrode to an im-
plantation site on the heart muscle. The distal end of the body
and the attached electrode are preferably slanted with respect
to the longitudinal axis of the body to facilitate placement and
implantation of the electrode. The body also has a generally
low cross-sectional height to facilitate its passage under the
113514Z
-~
1 rib cage of a patient.
A slot in the underside of the suturing tool receives
and grips an electrical lead from the pacer electrode to the
pacer electronics. This immobilizes the lead and prevents it
from interferring with the insertion or implantation procedures.
When the pacer electrode is properly positioned on the heart, a
forward movement of the plunger over a fixst portion of its
travel ejects the two suture elements which penetrate the heart
- tissue to secure the electrode to the heart. A further forward
0 movement of the plunger and an axially slideable separating rod
pushes the resilient electrode plug out of the tool recess to
detach the pacer electrode from the tool. The forward movement
of the separating rod also cams the electrode leads from the
~ slot in the underside of the tool. Preferably a portion of the
-~ sIot is formed by a recess in the separating rod and the cam is
an inclined rear surface of the recess.
~ These and other features and objects will become appar-
ent to those skilled in the art from the following detailed
- description which should be read in light of the accompanying
drawings.
Brief Descri~tion of the Drawinqs
;~ Fig. 1 is a top plan view of a suturing tool according
to thi~ invention adapted to secure an epicardial pacer eIectrode
to a heart;
Fig. 2 is a view in side elevation of the tool and
electrode shown in Fig. l;
Fig. 3 is an enlarged view in section taken along the
line 3-3 in Fig. l;
Fig. 4 is a bottom plan view with portions broken away
corresponding to Fig. 3 and showing a slot in the underside of
~ ~13514Z
1 the tool for releasably securing the electrode lead;
Fig. 5 is a view in section taken along the line 5-5
of Fig. 2;
Fig. 6 is a detail view in section and partially in
elevation of the electrode and the adjacent portions of the tool
taken along the line 6-6 of Fig. l;
Fig. 7 is a view in section taken along the line 7-7
in Fig. 6;
Fig. 8 is a view in end elevation corresponding to Fig.
7 of the suturing tool;
Fig. 9 is a view in section taken along the line 9-9
in Fig. 6;
Fig. 10 is a detail view in side elevation of one die -~
member;
Fig. 11 is a top plan view of the electrode; and
Fig. 12 is a view in front elevation of the electrode
shown in Fig. 11.
Detailed Description of;the Preferred Embodiments
Figs. 1 and 2 show a surgical suturing tool 12 con-
structed according to the invention and particularly adapted to
suture an epicardial pacer electrode 18 to a heart. The tool 12has a generally elongated body 14 preferably formed of a rigid
molded plastic such as polycarbonate. One end 12a of the tool
has a pistol-like handle 16 that allows a surgeon to grip the
tool comfortably, guide it accurately and operate it easily dur-
ing the suturing procedure. The other distal end or head 12b of
the tool is adapted to hold the epicardial pacer electrode 18
and guide it to the desired attachment point on the heart. A
hand operated plunger 20 slides axially in a recess 22 within
handle 16. The plunger travels between a retracted position and
--5--
113~i14Z
1 a full forward position. During a first portion of its forward
travel (to the right as shown) the plunger sutures the electrode
to the heart. During a second portion of its forward travel,
the plunger detaches the electrode and its electrical lead 40
from the tool 12.
The plunger 20 has two extension arms 24, 24 which
slide axially in die passages 26, 26. The die passages 26, 26
are circular in cross section and extend the full length of the
bsdy 14 from the handle 16 to the end face 12c. They may be
formed of stainless steel hypodermic tubing. These passages
closely guide the extension arms 24, 24 as well as pusher wires
28, 28 and suture elements 30, 30 held in the die passages. The
pusher wires 28, 28 are relatively stiff, preferably formed of
.010 diameter stainless steel. The suture elements 30, 30 are
formed of a suitable malleable material which will retain a set
after being stressed beyond its elastic limit, preferably half-
hard elgiloy. Each extension arm 24 is associated with and
axially aligned with one pusher wire 28 and one suture 30. These
elements are in end-abutting relationship so that a forward ;
movement of the plunger from its retracted position is translated
into a correspond~ng movement of the associated wire and suture
within the surrounding die passage 26.
With particular reference to Figs. 6-10, the distal
ends 26a, 26a of the die passages 26, 26 within the head portion
12b of the tool are curved so that suture elements 30, 30 emerge
from the die passages 26, 26 following an arcuate path 31 whose
curvature is determined;by the curvature of the die passages
ends 26a, 26a. The curvature of the ends 26a, 26a is selected
so that operation of the plunger drives the suture elements to
penetrate heart tissue first at 32 (Fig. 6), then at 34, and
1~35~4Z
1 finally through notches 36 (Figs. 6 and 12) in pacer electrode
18. The lengths of suture elements are sufficient to form
closed-loop circular sutures that reliably secure the electrode
to the heart with a projecting electrical stimulation electrode
38 of the electrode 18 implanted in the heart tissue. The
projecting electrode 38 is of conventional design and includes
a cutting member 38a and a coiled conductor 38b that supports
the cutting member and transmits a heart stimulating electrical
signal from a pacer (not shown) to the heart muscle. An electri-
cal lead 40 transmits the signal from an implanted pacer (not
shown) to the projecting electrode 38. It should be noted that
a significant advantage of this invention is that the trauma -
caused by suturing is isolated from the point of electrical
stimulation. Another significant advantage is that the invention
in its preferred form forms two closed-loop sutures to secure
the electrode to the heart with a high degree of reliability.
The electrode is releasably secured on the inclined
end face 12c of the tool head 12b. The tool 12 is therefore
useful not only in suturing, but also in guiding the electrode
to the proper location on the heart, usually following a path
under the rib cage from an incision in the abdomen where the
pcaer is implanted. The overall geometry o~ the tool 12 is also
so that it facilitates this insertion procedure. The length is
selected so that the handle 16 and the plunger 20 are readily
grasped and manipulated when the electrode is positioned on the
heart. The cross-sectional width of the tool body is greater
than the height ~Figs. 5 and 9) to slide under the rib cage.
The head 12b and the electrode 18 mounted flush against the end
face of the head are tilted downwardly so that the electrode
18 generally abuts the adjacent heart tissue at the implantation
1~35~4Z
1 site. This tilt also slants the electrode lead 40 projecting
from the lower edge of the electrode 18 to facilitate the in-
sertion of the electrode. The handle 16 is horizontally orient-
ed to minimize its interference with the insertion.
With particular reference to Figs. 7 and 11, the
electrode 18 has a resilient protrusion 42 with an enlarged,
generally cylindrical end portion 42a adapted to seat in a
generally cylindrical recess 44 formed in the head 12b of the
tool. The electrode is secured on the tool by pressing the pro-
0 trusion 42 into a narrowed distal end 46a of a central channel
46 in the body 14 until the portion 42a seats in the recess 44.
A separating element or rod 48, preferably formed of a rigid
molded plastic, slides axially in the channel 46 which extends
from the recess 22 in the handle 16 to the end face 12c of the
tool lead. As shown in Figs. 1 and 2, one end 48a of the rod is
adapted to engage the plunger 20. The other end 48b is of reduc-
ed width and adapted to engage the resilient protrusion 42 of
the electrode when it is seated in the recess 44. During the
first portion of the travel of the plunger from the fully re-
tracted position, it acts through the extensions 24, 24 and the
pusher wires 28, 28 to drive and eject the circular sutures. At
the end of the second portion of the travel the rod pushes the
protrusion 42 out of the recess 44 and thereby detaches the
electrode 18 from the tool 12. The last portion of the travel
also completes the ejection of the sutures. The initial position
of the rod 48 is shown in solid lines in Fig. 3 and the full
forward position is shown in phantom.
With reference to Figs. 2-4, the rod 48 also operates
to detach the lead 40 which is held in part in a slot 50 defined
by an opening 52 in the bottom wall of the body 14 and a recess
~135142
1 54 formed in the rod 46. When the plunger is fully retracted,
the recess 54 overlies the slot 52. They together receive a
portion 40a (Figs. 2 and 5) of the lead. The side walls 52a,
52a of the opening 52 are upwardly narrowing to promote the in-
sertion of the lead into the slot but block its movement out of
the slot once it is fully inserted as is best seen in Fig. 5.
This immobilizes the lead during insertion and minimizes the
likelihood that it will interfere with the insertion or suturing
operations. When the suturing is completed, the forward sliding
movement of the rod 48 causes a sloped cam surface 56 at the
rear of the recess 54 to engage the lead and driveit out of the
slot 50. The lead is thus released from the tool just before
the electrode is detached.
To prepare the suturing tool 12 for operation, the
plunger 20 is removed and the suture elements 30, 30 are each
inserted into one of the die passages 26, 26 through the handle
recess 22. Next, the pusher wires 28, 28 are inserted into the
passages 26, 26 in the same manner. The separating rod 48 is
inserted into the channel 46 with the recess 54 aligned with the
slot 52 in the tool body. The plunger 20 is replaced in the re-
cess 22. Finally, the pacer electrode is fi~ed on the head 12b
and the lead portion 40a is jammed into the slot 50. The tool
is then ready for use.
Using a small incision below the rib cage, the tool
carrying the electrode is inserted into the body and guides the
electrode to the heart by mediastinoscopy. When the electrode
i8 in the proper location, the plunger is pushed forward. The
first portion of its travel ejects and forms the suture elements
30, 30 into closed~loop circular sutures that permanently attach
the electrode to the heart. In the last portion of its travel,
1~3Sl~Z
1 the separating rod ejects the electrode and its leads from the
suturing tool. The tool is then withdrawn, leaving the pacer
electrode attached to the heart. Prior to actually applying
the electrode to the heart, the tool with the probe can be
utilized for exploring or mapping the heart with regard to
sensitivity. This is advantageous as compared with mapping
initially with a separate probe because of the difficulty of re-
turning exactly to the same spot with a separate electrode.
There has been described a surgical tool that sutures
an epicardial pacer electrode to the heart without the need of
- directly exposing the heart by a thoracotomy which is a sub-
stantially more hazardous procedure than a small incision below
the rib cage. Also, the present invention sutures the pacer
electrode to the heart with the sutures spaced from the point of
electrical contact with heart tissue to minimize trauma. Further-
more, these objects and advantages are achieved by means of a
tool of simple and inexpensive construction.
Although the suture forming tool disclosed herein has
particular utility in attaching an epicardial pacer electrode to
the heart, it should be understood that the tool may be advan-
tageously applied to other medical procedures since the tool
allows the formation of closed loop sutures at remote locations
within the body. A tissue tear may be repaired, for example,
without the necessity of fully exposing the site as would be
required with conventional suturing techniques. Also, while the
invention has been described with reference to a tool for form-
ing a pair of sutures, it can readily be adapted to form only
one or more than two sutures. These and other modifications of
the invention will occure to those skilled in the art from the
forgoing detailed description and the accompanying drawings.
Such modifications are intended to fall within the scope of the
appended claims.
--10--
