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Description  |
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The present application is a continuation-in-part application of
International application PCT/DE93/00418 filed May 13, 1993, claiming the
priority of German application P 42 17 202.0 filed May 23, 1992.
BACKGROUND OF THE INVENTION
The invention relates to a suturing instrument for remotely joining the
edges of a wound within the body of a patient.
Such a surgical instrument is known, for example, from U.S. Pat. No.
4,935,027 (Yoon); it is suitable for conventional as well as minimal
invasive (MIC) surgery. It comprises outer and inner tubes which are
movable axially relative to one another and which carry at their distal
ends (remote from the operator and to be inserted into the body of a
patient) two pliers or forceps-like jaws or hooks which are hollow and are
received within the suturing material. This U.S. patent shows an
arrangement wherein both jaws or hooks are movable or One jaw is
stationary and the other is movable. At the proximal end (the end next to
the operator) there is a handle portion which is connected to the inner
tube and to the outer tube for moving the jaws or hooks relative to one
another. Within the inner tube there is the supply passage for the
suturing material.
With this suturing instrument however, only single-knot sutures can be
applied wherein each suture must be secured with a knot movable toward the
tissue. The applying of the knots is complicated and time-consuming.
Furthermore, the tissue is penetrated not only by the suturing material
but also by the hook.
DE 31 41 647 A1 discloses a surgical instrument for the application of
clamps. This instrument includes an elongated body with a handle portion
at the proximal end. At the distal end of the elongated body there is a
stationary support jaw with a recess for locking the clamp. Furthermore
there is at the distal end of the elongated body a movable engagement jaw
with the clamp applicator. The engagement jaw is mounted to the body so as
to be movable back and forth in the direction of the stationary support
jaw. The instrument also includes a drive mechanism for operating the
engagement jaw and the clamp applicator. The movable engagement jaw
includes a channel for feeding a wire thereto and is provided, at the
channel exit, with a cutter which is movable back and forth in a plane
normal to the channel for cutting off wire pieces and which is operatively
connected to the drive mechanism.
However this instrument is relatively large and already because of its size
and design is not suitable for minimally invasive surgery.
Another suturing instrument is known from EP 01 74 843 A2. This suturing
instrument includes a block defining a one-sided open cavity receiving a
suturing material support structure which can be operated by a handle
portion at the proximal end of the elongated instrument. There is further
a channel extending into the cavity which receives a needle with an eye
through which the suturing material passes. The channel is arranged
opposite the suturing material support structure. Furthermore a suction
structure extends into the cavity. The block is placed onto the tissue to
be sutured in such a way that the cavity is closed by the tissue. Then the
cavity is evacuated by the suction structure such that the adjacent tissue
enters the cavity. Then a suture is applied by means of the needle and the
suturing material support structure and finally the application of vacuum
by the suction structure is interrupted so that the tissue returns to its
original location. This suturing instrument however is only suitable for
stitching over closed tissue since only then can it be pulled into the
cavity by the suction structure. Suturing of the edges of wounds is not
possible.
DE 29 27 143 A1 discloses a surgical instrument for the application of
sutures which is designed particularly for the attachment, by stitching,
of heart pace makers. This instrument comprises an instrument shaft with a
proximal end and a distal end to be inserted into the body of a patient.
The instrument shaft includes two channels which receive sections of a
wire-like suturing material. At the distal end these channels are shaped
in such a manner that the suturing material assumes an annular shape. At
the beginning of the operation the electrode of the pace maker is attached
to the distal end of the instrument shaft. A two-piece handle portion is
used to advance the suturing material and to disconnect the electrode. The
instrument has no jaws. It might be utilized for suturing tissue edges but
only under most favorable conditions.
U.S. Pat. No. 1,449,087 discloses a plier-like suturing apparatus with two
curved jaws at its distal end of which each is provided with a clamping
surface. Each jaw includes a curved channel which ends at the clamping
surface. By means of a piston a surgical stitching needle with stitching
material is moved through the curved channels and through the tissue
disposed between the clamping surfaces.
EP-A-0 121 362 discloses a clamping arrangement with opposite clamping jaws
of which one includes a channel receiving a straight piece of stiff
suturing material and the other has a curved channel into which the
suturing material is moved through tissue disposed between the clamping
jaws whereby the suturing material is bent to an annular shape.
It is the object of the present invention to provide a suturing instrument
without the disadvantages of the known instruments, with jaws which do not
penetrate the tissue and which permits the application of several sutures
with a single operating procedure. The instrument should permit suturing
of wound edges in conventional surgery as well as in minimally invasive
surgery. It should therefore be slim enough to be movable and operable
through an access sleeve (Trokar sleeve).
SUMMARY OF THE INVENTION
In a suturing instrument for remote suturing of the edges of tissue wherein
a stationary and a pivotal jaw are arranged at the distal end of an
instrument shaft and a suturing wire guide channel extends through the
instrument shaft for supplying a suturing wire from the instrument's
proximal end to the stationary jaw and wherein an outer tube is movably
disposed on the instrument shaft for engaging the pivotal jaw to move it
toward and from the stationary jaw and hold the jaws in an operating
position in which they are arranged parallel to one another, the jaws have
spaced wire guide grooves with groove bases defining in the operating
position of the jaws, a screw line which is followed by the suturing wire
when it is advanced by advancing means operated by a handle disposed at
the proximal end of the suturing instrument.
With the suturing instrument according to the invention, tissue edges can
be fixed after lacerations or incisions. For that purpose the two tissue
edges to be connected are placed onto one another by means of grasping
pincers or a special arrangement of the suturing instrument according to
the invention to be described below in greater detail such that the two
surfaces of the tissue adjacent the wound edges are in contact with each
other. The sutures are applied while portions of the adjacent tissue are
held together in a kind of tissue fold projecting essentially
perpendicularly from the surface of the rest of the tissue.
With the jaws of the suturing instrument according to the invention, the
edges of the tissue are engaged such that they are disposed closely
together. The jaws will assume a position in which they are disposed
essentially parallel to one another at a distance which corresponds about
to twice the thickness of the tissue to be sutured together. This position
will be designated as the operating position in the following description.
Depending on the grasping depth single or double row sutures can be
applied in the operating position.
Both jaws have formed in their opposite faces, that is, in the movable as
well as in the stationary jaw, several spaced grooves which extend from
the suturing wire supply channel and whose base surfaces are disposed
along a screw line.
When the suturing wire is advanced in the channel it is moved out of the
end of the channel in the stationary jaw such that it penetrates the two
tissue ends held together by the jaws and then enters the first groove in
the movable jaw where it is bent around and (if the grasping depth of the
jaws is large enough) again penetrates the tissue ends. Then the tip of
the suturing wire enters the first groove in the stationary jaw where the
suturing wire is further guided along a screw line.
When the suturing wire has passed all the grooves in the jaws it has a
screw-like or spiral shape. The axis of the suturing wire coil is parallel
to the tissue edges. Depending on the grasping depth of the jaws the coil
penetrates the tissue once or twice with each turn so that a single or
double row suture is formed. After completion of the suture the suturing
wire is cut and secured to prevent it from sliding out of engagement with
the tissue. The procedure is repeated until the tissue edges are sutured
over their full length.
Preferably the suturing wire is moved within the channel by suitable design
means in a stepwise fashion by means of the handle portion, from the
proximal toward the distal end. The length of the advancing steps depends
on the strength of the suturing wire utilized. Preferably a thin metal
wire of stainless steel, tantalum, etc. is used. Metal wires of this type
are sufficiently stiff so that they do not tend to cant or bend; they also
are able to penetrate the tissue without any auxiliary means. However the
instrument according to the invention may utilize also other types of
suturing materials as long as they are sufficiently stiff. The advancing
steps should be selected--in accordance with the mechanical strength of
the suturing material utilized--such that they are sufficiently short to
prevent canting of the suturing material within the supply channel and
that it penetrates the tissue without bending; but they should be as long
as possible under the given conditions to keep the time necessary for the
distal advancing of the suturing material during an operation within
reasonable limits. If the suturing material is a stainless steel wire with
a diameter of 0.25 mm the single advancing steps may have a length of 3
mm.
Preferably the channel is provided with a locking structure which .engages
the suturing wire to prevent the suturing wire from sliding back and which
releases the suturing wire for the advancing movement. It is particularly
preferred if the locking structure can be controlled by the operator from
the operating handle so that the locking mechanism can be operated to
release the suturing wire, for example, for replacement of the suturing
wire.
The movable jaw should be movable from an operating position toward the
stationary jaw and away therefrom. In operating position both jaws are
about parallel to one another. Their operating distance is predetermined
by design and is determined essentially by the thickness of the tissue,
that is, it is essentially twice the thickness of the tissue to be
sutured.
The position of the movable jaw in which it is pivoted away from the
stationary jaw will be called in the following description the rest
position of the jaws. By movement of the movable jaw from the operating
position to the rest position and back the tissue layers to be sutured can
be grasped and also released.
The possibility to move the movable jaw from the operating position toward
the stationary jaw is advantageous for the following reasons:
During the distal advance of the suturing wire while the suturing procedure
is in progress, the suturing wire is brought into a screw or spiral shape
since, during suturing, the suturing wire which leaves the guide channel
terminates within the stationary jaw in which the suturing wire is guided
and shaped by the grooves formed in the two jaws. Then, as mentioned, the
tissue to be sutured is penetrated either once when the suturing wire
front tip passes from the stationary jaw to the movable jaw or also (with
sufficient grasping depth) upon passing over of the material front tip
from the movable jaw to the stationary jaw. Guiding and shaping the
suturing wire and also piercing of the tissue results in friction forces
which can become quite large with an increasing number of screw lines or
spiral passes.
The friction forces can be greatly reduced by movement of the movable jaw
from the operating position toward the stationary jaw. The distance by
which the movable jaw is moved for this purpose is preferably only a few
tenths of a millimeter. This movement has the result that the diameter of
the spiral of the suturing wire is slightly reduced. For this reason the
movable jaw is moved slightly toward the stationary jaw at the end of each
advancing step by means of the operating handle. In the operating position
of the jaws the suturing wire is then not engaged in the grooves too
tightly so that, during the following advancing step, the friction is
reduced. The friction may also be reduced during advancement of the
suturing wire by the application of a suitable lubricant. Such lubricants,
for example, silicon oil, are known and are utilized with other suturing
instruments presently in use.
By movement of the movable jaw toward the stationary jaw, the finished
suture can be position-locked. After completion of the suturing procedure
and after cutting the suturing wire the movable jaw is pivoted back to its
rest position whereby the tissue and the suture are released. Then the
spiral of the suturing wire is grasped with the front ends of the jaws and
is compressed wherein the movable jaw is moved toward the stationary jaw
until it reaches its operating position. In this manner, release of the
suture is prevented.
To facilitate this step an embodiment is preferred wherein the distal ends
of the jaws are profiled at their opposite sides in front of the guide
grooves. A preferred profile structure consists of closely adjacent
recesses which extend parallel to the grooves, that is, which are arranged
at the same angle with respect to the axis of the outer tube and at a
distance from one another which is 1/n of the distances between the
grooves; wherein n is an integral number. With such recesses the completed
spiral structure of the suturing wire can be grasped especially securely
since the windings of the spiral are received in these recesses and are
supported therein so that the spiral is safely held and can be deformed in
a controlled manner.
Depending on the embodiment chosen for the suturing instrument according to
the invention it may be advantageous to provide the outer tube at its
distal end with two opposite recesses. These recesses are arranged in such
a way that, upon distal axial movement relative to the instrument shaft
and consequently to the jaws with the tissue engaged thereby, the outer
tube will not come into contact with the tissue and therefore will not
damage the tissue. Such recesses are preferably arranged symmetrically
with respect to a plane which extends parallel to the side of the
stationary jaw which is disposed opposite the movable jaw. The shape of
the recesses may greatly vary depending on the shape of the suturing
instrument. The outer tube may, for example, by chamfered at its distal
end in such a way that the stationary jaw is not fully surrounded thereby.
Furthermore the distal end of the outer tube and the edges of the recesses
can be rounded in order to further reduce the chances of damaging the
tissue.
Advancement of the suturing wire during suturing is facilitated if the ends
of the grooves which are first reached by the suturing wire are widened in
a funnel-like fashion. This prevents canting of the suturing wire and
guides the suturing wire into the grooves.
After completion of a suture the suturing wire can be severed by means of a
slide with a cutting edge which is arranged in the stationary jaw and
which can be operated from the proximal end of the instrument by way of a
lever.
Preferably, the movable jaw is moved from the operating position away from
the stationary jaw in the following manner: Within the outer tube the
movable jaw is provided with a V-shaped structure directed with its
pointed edge toward the stationary jaw. The pointed edge of the V-shaped
structure extends transverse to the axis of the outer tube and is
supported in a recess in the stationary jaw, which also extends laterally
with regard to the axis of the outer tube. At the distal end of the outer
tube a pin is provided on its side opposite the stationary jaw in such a
manner that, by sliding the outer tube toward the operator relative to the
jaws, the distal side surface of the V-shaped structure is moved toward
the operator whereby the pointed edge rotates in the recess and the
movable jaw moves away from the stationary jaw. The outer tube is axially
movable relative to the instrument shaft by means of the handle at the
proximal end.
The movement of the movable jaw toward the stationary jaw is preferably
achieved by sliding the outer tube in the distal direction over the
movable jaw. In this manner, again the operating position, that is,
parallel positioning, of the jaws is achieved. The further movement of the
movable jaw toward the stationary jaw is preferably provided for by a
protrusion on the outer surface of the movable jaw which is engaged by the
outer tube upon further movement thereof in distal direction.
One of the jaws of the suturing instrument according to the invention, for
example, the stationary jaw, may carry on its side opposite the other jaw
a pointed thorn which, in the operating position of the jaws, is received
in a correspondingly shaped cavity in the other jaw.
With an instrument modified in this manner the use of grasping pincers for
grasping the tissue edges during the suturing procedure is not necessary.
In the rest position of the jaws the thorn is placed under the first
tissue edge at a suitable location. For engagement of the tissue by the
thorn the jaws are moved to their operating position whereby the tissue is
perforated by the thorn. Then the movable jaw is again lifted (moved to
its rest position) and the second tissue edge is engaged in the same
manner. If the thorn is arranged at the proximal end of the jaws, for
example, behind the opening of the channel for the suturing wire, only one
additional penetration per suturing procedure is required. If the thorn is
arranged at the distal end at the pointed end of the jaws, better sight
conditions facilitate the grasping of the tissue edges. In this case,
however, another penetration of the tissue is necessary during the final
deformation of the spiral suturing wire.
The invention will be described in greater detail on the basis of figures
in which a particular embodiment of the surgical suturing instrument
according to the invention is shown.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a complete view of the suturing instrument according to the
invention;
FIG. 2 shows the supply channel for the suturing wire with an arrangement
for advancing the suturing wire;
FIG. 3a shows the distal end of the instrument with the jaws and the
locking device;
FIG. 3b is a top view of the stationary jaw with the movable portion of a
severing device;
FIG. 3c shows a locking structure for the suturing wire;
FIG. 4 is a partial sectional view of the grasping head;
FIG. 5 is another view of the grasping head;
FIG. 6 shows the instrument shaft;
FIGS. 6a, 6b and 6c are enlarged cross-sectional views of the shaft at
different locations; and
FIG. 7 shows the severing device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The embodiment of the invention illustrated is designed for a suturing wire
consisting of stainless steel wire with a diameter of 0.25 mm. It
comprises three building groups:
the operating head with the jaws 23, 24 and the severing device 45 for the
suturing material 17,
the handle 1, 2 comprising the handle head 18 with the stationary hand
portion 2 mounted thereon and the movable finger portion 1 which is
movable relative to the stationary hand portion 2, and
the instrument shaft 20 which is mounted on the handle 1, 2 and locked
thereto by a clamping screw 10 and which interconnects the jaws 23, 24 and
the handle portion 2 as well as the outer tube 21 for operating the
movable jaw 24 by means of the finger portion 1.
Further, the following functions are identifiable with various parts for
the mechanical realization which parts are present in all three building
groups:
acknowledgement of the movable jaw 24,
for the embodiment with an additional thorn: engagement and combining of
the tissue edges,
forming of the suturing wire 17 into a spiral 26,
reduction of the diameter of the spiral of the suturing wire 17, for
example, after each advancing step for the reduction of friction between
the suturing wire and the shaping guide grooves 38 in the jaws 23, 24,
repeated clamping and subsequent stepwise advancing of the suturing wire 17
by the advancing structure 14, 28,
self-locking arresting of the suturing wire 17 against retraction of the
wire to its start position in the locking device 57, 58 and during
repositioning of the clamping and advancing arrangement 14, 28,
severing of the suturing wire, taken for example from a roll, at the end of
a suturing procedure by means of a movable severing slide 45,
bending of the suturing wire 17 at the beginning and end of a suture toward
the tissue in order to inhibit retraction of the suturing wire into the
tissue upon opening of the movable jaw 24 to prevent opening of the suture
before its securing;
forming of the suturing wire front end upon severing so that the
penetration forces are minimized and, upon penetration of the tissue, a
guiding force is generated at the front end of the suturing wire which is
directed toward the axis of the spiral,
shaping of the originally circular suturing wire spiral cross-section into
a flat oval shape to prevent opening of the suture,
securing of the severing mechanism 45 against unintended operation, and
modifying the function sequences by various control knobs 15, 16 with
predetermined operation of the handle 1, 2.
The distal end of the outer tube 21 with the instrument shaft 20 received
within is introduced into the body of a patient through an access sleeve.
For this purpose the movable jaw 24, which, in its rest position, is
pivoted away from the stationary jaw, is pivoted by actuation of the
finger portion 1 of the handle 1, 2 and the resulting translatory movement
of the outer tube 21 to its operating position parallel to the stationary
jaw 23.
Because of an adjustable play in the coupling mechanism all other
instrument functions are not activated by the jaw pivoting step.
The design of the instrument is such that, for facilitating an exact
manipulation in the surgery area, the distance between the hand-held
stationary handle portion 2 and the two jaws 23, 24 remains constant. For
the operation of the movable jaw 24 only the outer tube is moved axially
so that no compensating hand movement by the surgeon is needed for
maintaining the desired spatial location of the jaws 23, 24.
The distal end of the instrument comprises the two jaws 23, 24. The
stationary jaw 23 is made by giving the distal end of the instrument shaft
on appropriate shape (FIGS. 1 and 6, 6a-c).
The design of the jaw 24 and the guide structure for the suturing wire 17
are apparent from FIGS. 3a and 3b.
The pivot bearing portion 61 of the second movable jaw 24 is disposed in a
recess 46 of the instrument shaft 20 behind the stationary jaw 23.
The movable jaw 24 is pivoted open by a pin 35 extending inwardly from the
outer tube 21 which is movable in a slot 39 in the instrument shaft 20 and
it is pivoted to the closed position by sliding the upper distal front
edge of the outer tube 21 over the outer jaw surface. The outer tube 21
has recesses 25 to accommodate tissue received between the jaws during
such movement. The movable jaw 24 is held in position relative to the
stationary jaw 23 only by its shape, that is, its reception in the recess
46 of the instrument shaft and its being held therein by the outer tube
21. No pins or connecting and support bolts were used since, because of
the small dimensions they would be difficult to mount and would be often
overloaded.
As already mentioned the two superimposed tissue edges are engaged by the
jaws 23, 24 in such a manner that
there will be only one penetration row right behind the edges and the
suturing wire passes, on the other side, outside the tissue or that,
with greater depth engagement by the jaws 23, 24, two parallel penetration
rows are generated and the suturing wire is exposed only at the upper and
lower side of the suture.
The screw-like suture spiral is generated in a stepwise fashion by multiple
actuation of the handle 1, 2 (FIG. 1). The circular spiral has, with a
suturing wire cross-section of 0.25 mm, an outer diameter of 4 mm.
By means of a wire engagement and advancing mechanism 14, 28 (see FIG. 2)
to be described below the wire is moved through the guide channel 43 in
the stationary jaw 23 by further operation of the handle 1, 2. The wire is
advanced in a stepwise fashion by 3 mm with each step.
The suturing wire 17 first passes through a slot 55 (FIG. 3b) adapted to
the spiral pitch which slot is disposed in the movable severing slot 45 in
the stationary jaw 23.
In the area of the guide channel 43 which is disposed in the stationary jaw
23 and in the movable severing slide 45 the wire 17 is bent accurately in
a plane parallel to the instrument axis. The radius of the arc is, for
space reasons (the severing slide 45 has to be accommodated in the
stationary jaw 23) somewhat larger than the finished spiral so that final
shaping of the wire 17 is achieved only after the first tissue penetration
within the movable jaw 24.
At the end of each wire advancing and forming step the distal end of the
outer tube 21 is moved onto a projection 37 eccentrically disposed on the
outer surface of the movable jaw 24 whereby the jaws are forced further
together by 0.3 mm. This results in a reduction of the suture spiral
diameter by a corresponding amount.
This step is necessary in order to prevent locking of the spiral wire
within the guide grooves 38 of the jaws 23, 24 as a result of friction
forces based on the condition
S.sub.2 =S.sub.1 x exp. (.mu..alpha.) (1)
wherein:
S.sub.2 =the advancement force for the wire [N];
S.sub.1 =the friction and resistance force at the front end of the wire
[N];
=the friction coefficient between wire and guide groove [-];
=the contact angle of wire and guide groove [rad]. (The friction of the
wire within the tissue is disregarded in equation (1).)
In order to facilitate the insertion of the front end of the wire into a
guide groove after penetrating the tissue the entrances 50 of the guide
grooves 38 are widened conically (see FIG. 3b).
For a full or partial completion of the spiral suture 26 z operating steps
with the jaws arranged in parallel are required. The number z is a
function of the desired suture length and the desired number of stitches
or windings and the selected step length of the wire advancing steps.
At the end of each partial suture the handle 1, 2 is pulled back to the
stop of the operating area for spiral compression. Then the lever 11 of
the handle head 18 (see FIG. 1) which can be reached by the thumb of an
operator is released for actuation. By pushing this lever 11 down the
movable severing slide 45 is moved in the dovetailed groove 51 of the
stationary jaw 23 in proximal direction whereby the wire 17 is severed in
the severing slot 55 between the cutting edges 41 and 42 and the spiral
end is bent by the rounded upper edge of the slide 45 into the plane of
the inner surfaces 36, 40 of the jaws.
This measure, like a corresponding wire deformation at the front end serves
to secure a completed suture so that the spiral does not turn open after
the movable jaw 24 is pivoted back for repositioning of the jaws 23, 24
for example. Such repositioning is provided for in order to deform the
circular spiral cross-section in the forming area of the front portion of
the jaws to a flat-oval shape such that opening of the suture is
essentially impossible.
Upon severing of the wire 17 at the end of the spiral, the front end of the
wire is, as a result of the shape of the cutting edge 52 in the stationary
jaw (two cutting edges at an angle of 60.degree. relative to one another)
shaped in such a manner that
the penetration resistance of the wire in the tissue is as small as
possible, and
during tissue penetration a force component in the direction toward the
spiral axis is generated, which counteracts radial outward movement of the
wire 17 as a result of the outward bending moment generated by the
penetration resistance forces.
As already described the instrument shaft 20 is disposed within an outer
tube 21 which is movable in axial direction by operation of the handle 1,
2.
In the instrument shaft 20 (see FIG. 6) which, at the distal end, forms a
stationary jaw and is shaped so as to support the movable jaw, there are
provided the longitudinal grooves 51, 53 for receiving and guiding the
movable slide 45 and a connecting rod 56 for operating the slide of the
severing structure and further the longitudinal groove 34 for guiding the
support tube 27 for the suturing wire 17. Further the instrument portion
comprises in the square guide channel 43 for the wire--in advancing
direction closely in front of the stationary jaw--a pocket 48 for the
reception of a spring-loaded locking pad 58 provided with a bore 60 for
engaging the locking pad 58 to move it out of its locking position if the
wire is to be retracted.
Since for space reasons the wire engaging and advancing mechanism 14, 28
(see FIG. 2) is disposed in the handle head 18 of the instrument,
provisions must be made to prevent kinking of the suturing wire (with a
diameter of 0.25 mm) when it is advanced through the instrument shaft 20
up to the end of the guide channel 43 in the stationary jaw 23. For this
reason it is supported during its advancement in a wire support tube 27
(FIGS. 2, 3a) with an outer diameter of 1.5 mm so as to remain free of
kinking. The wire support tube 27 is welded together with the clamping
sleeve 28 of the advancing mechanism and is moved back and forth in the
groove 34 of the instrument shaft 20 in accordance with the selected step
length.
Upon retraction of the support tube 27 the spring-loaded locking pad 58
(FIG. 3a) which then engages the suturing wire prevents the pull-back of
the suturing wire 17 which might otherwise happen because of friction on
the inner wall of the support tube and in the clamping structure 14 (FIGS.
1, 4 or 14.1, 14.2 in FIG. 2).
The surgeon can--for example, for exchanging the suturing wire 17--couple
the locking pad 58 and the outer tube 21 by means of a pin extending
through the bore 60 in the locking pad 58 and a corresponding bore in the
outer tube and he can eliminate the engagement between these two parts by
actuating the operating handle.
The movable slide 45 and the connecting rod 56 (FIG. 3b, FIG. 7) of the
slide drive are made as one-piece structures from partially hardenable
stainless steel sheets. Because of the geometric conditions in the handle
head 18 a displacement of the connecting rod 56 is provided for which
results in a side switch-over from the upper part of the slide 45 in the
stationary jaw 23 to the slide drive within a pocket 59 of the handle head
18. The relatively long section 63 in the connecting rod 56 (FIG. 7) is of
increased thickness in order to be able to compensate for transverse
moments occurring during loading by small support forces between the guide
cams 47 of this portion and the inner wall of the outer tube 21. The
transverse passage 64 (FIG. 6b) for this increased thickness section is
enlarged in proximal direction by the length of the dovetail groove 51 in
the stationary jaw 23.
The handle 1, 2 (see FIGS. 1, 4 and 5) of the suturing instrument consists
of
the handle head 18,
the finger portion 1 movable relative thereto, and
the hand portion 2 which is rigidly connected to the instrument shaft 20 by
means of the handle head 18.
Both handle portions 1, 2 are spread as usual by leaf springs 3, 4 arranged
therebetween in the usual manner so that, in their rest positions, they
are spread to the maximum extent.
The handle head 18 serves
to pivotally support the finger portion of the handle,
to accommodate the engagement and advancement mechanism 14, 28 for the
suturing wire 17,
for the installation of the slide operating mechanism, and
for the interconnection of the hand portion 2 of the handle with the
instrument shaft 20.
The finger portion of the handle has the usual shape so that it can be
grasped conveniently. The upwardly extending fork 5 is pivotally mounted
to the handle head 18 by a bearing structure with a bearing pin 6. The
upper ends of the fork 5 are further hinged by screws with stepped shafts
to the rectangular flange 22 which is welded to the proximal end of the
outer tube 21. The shafts of the screws 7 slide in elongated passages 8 at
the end of the fork when the outer tube 21 is moved axially. The fork side
adjacent the thumb-operated lever 11 is partially thickened and provided
with a blocking arm 9 which, in the normal operating range of the handle
1, 2, serves as a safety device against unintended operation of the
movable slide 45.
Movement of the rectangular flange 22 (and the outer tube 21) is
transmitted to the engagement and advancement mechanism 14, 28 for the
suturing wire 17 via a coupling bar 19 guided in the handle head 18. By an
exactly adjustable play-length (control knobs 15 and 16) a force is
transmitted to the engagement sleeve jaws 14.1, 14.2 only after the
movable jaw 24 has reached the parallel operating position by a short
initial movement of the outer tube 21.
The engagement and advancement mechanism (see FIG. 2) comprises two main
components:
the outer clamping sleeve 28 with a conical opening and two inwardly bent
driving lugs 29 as well as the wire support tube 27 welded coaxially to
the front end of the clamping sleeve for supporting the wire 17, and
the inner engagement sleeve 14 with the slotted cone 44 forming engagement
jaws 14.1, 14.2 for frictionally engaging the wire 17 and the
longitudinally divided thread portion 65 for applying the advancement
forces.
Both parts are disposed within a stepped bore 66 in the handle head 18 in
axial alignment with the wire guide channel 43, 14 which extends through
the interior of the instrument shaft 21.
On its outside the clamping sleeve 28 is provided with two conical bores
30, 32 which are spaced from one another in longitudinal direction by 3 mm
and between which a triangular groove 31 of lesser depth extends. A pin 49
engaged by a leaf spring 54 engages and firmly locates the clamping sleeve
28 in the handle head 18 in accordance with the conical bores 30, 32 in
the clamping sleeve 28 in which the pin is received. Upon sliding the
clamping sleeve 28 in axial direction, the spring-loaded pin 49 slides
through the groove 31 between the bores 30, 32 thereby preventing rotation
of the clamping sleeve 28 and, consequently, undesirable torsion of the
wire 17. The distance between the bores 30, 32 determines the length of
the wire advancing step. Other control structures with different bore
distances can be provided side-by-side on the sleeve for different step
lengths. Then shorter or longer advancing steps can be provided for simply
by rotating the sleeve so that the pin enters another guide groove in
which the conical bores are differently spaced.
The engagement structure 14 is first divided in an axial plane. After
cutting the prismatic (V-shaped) i | | |
