Medical instrument for directed placement of a knot

A medical instrument for placement of a knot, in particular, for operating within closed spaces. With the use of such instrument, the thread can be held, guided and/or manipulated at least on one side of the knot and adjacent thereto by an instrument head in such a way that the knot can be pushed into the vicinity of a target point and placed exactly in the target point by spreading at least one free end of the thread.

BACKGROUND OF THE INVENTION 
a) Field of the Invention 
The invention is directed to a medical instrument for the directed 
placement of a knot formed by two free ends of a surgical thread of like 
suture material accompanied by formation of a continuous loop. 
b) Description of the Related Art 
In medical practice, tissue, organs and the like are frequently joined by 
means of surgical thread by passing the thread through the tissue or 
looping it around the organ and then tightening the loop by means of a 
knot until the tissue or organ is held in the desired position. Often, an 
additional knot is then tied on the first knot in order to secure this 
position. Placing the knot is very difficult in particular when the suture 
line is poorly accessible. Placing the knot is especially problematic when 
operating within a closed space. For this purpose, after the loop is 
placed through the tissue or organ, the two free ends must be guided out 
of the body via a trocar and then knotted. An instrument is then used to 
move the knot through the trocar to the suture line while the free ends of 
the thread remain outside the trocar. Known instruments for sliding the 
knot have a long shaft having a holder or the like for the knot arranged 
at one end. The holder is guided to the knot between the two free ends of 
the thread until the knot is received therein or held in some other 
manner. The knot is then slid, first within the trocar and then within the 
body cavity, until reaching the suture line. Handling of the knot and the 
free ends of the thread is not always exact. Sometimes the knot or the 
ends of the thread cannot be held securely by the instrument and are lost 
so that the ends must be knotted again and the sliding of the knot must be 
repeated. A particular drawback consists in that the knot can, at best, be 
slid, but not placed and tightened in an exact manner. 
OBJECT AND SUMMARY OF THE INVENTION 
The primary object of the present invention is to provide a medical 
instrument of the type mentioned above which facilitates reliable handling 
of the knot and ends of the thread and enables an exact placement of the 
knot in poorly accessible suture lines. 
According to the invention, this object is met in that the thread can be 
guided and handled so as to be held by an instrument head adjacent to the 
knot at least on one side of the knot so that the knot and the adjacent 
thread portions can be held securely, slid into the vicinity of a target 
point and then placed, i.e., tightened, in the target point in an exact 
manner by spreading out at least one free end of the thread. In this way, 
very precise, secure knots can be placed reliably and economically even in 
locations with extremely limited access. 
In a special development, the instrument head is provided with at least one 
profile for separately holding, guiding or handling the free ends of the 
thread and/or the knot and the looped portions adjacent thereto so as to 
assist precise placement of the knot. 
The profile of the instrument head advantageously has a peripheral region 
for the free ends of the thread. In addition, it is provided with a 
central region serving to receive the knot and the adjacent loop portions. 
The two regions are connected via a recess. The peripheral region permits 
the free ends of the thread to be manipulated separately and accordingly 
allows exact guidance of the knot on the instrument head. On the other 
hand, the recess makes it possible to move the knot sliding in the 
peripheral region into the central region in a continuous manner. 
The recess penetrates the instrument head roughly vertically to its center 
line and preferably has an acute-angled cross section so that the knot and 
one of the free ends of the thread can be guided in a directed manner and 
separately by an open branch of the recess and separately by the other 
dead-end branch, respectively. 
In a further development of the invention, the instrument head is divided 
into two halves which are movable relative to one another so that the free 
ends of the thread which are held by the respective halves are movable 
relative to one another. 
It is provided in a special development that the halves are constructed in 
the manner of shears and are swivelable around an axis. The free ends can 
accordingly be spread apart from one another in such a way that the knot 
can creep toward the target point and be tightened and placed to a certain 
extent in this location. 
Further features of the invention and their advantages are indicated in the 
patent claims and the description. The invention is explained more fully 
in the following with reference to an embodiment example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A medical instrument 10 (FIG. 1) for directed placement of a knot 11 has a 
base body 12. One side of the base body 12 is formed by a guide sleeve 13 
and the other side is formed by a support 14. 
An axle pin 16 is arranged at an end region 15 of the guide sleeve 13, the 
two halves 17, 18 of a divided instrument head 19 being held so as to be 
swivelable relative to one another around this axle pin 16. The swiveling 
movement is effected by means of an actuating device 20 whose connecting 
rod 21 is held in the guide sleeve 13 so as to be displaceable axially. An 
end portion or side of the connecting rod 21, neither of which is shown in 
the drawing, is connected with each half 17, 18 of the instrument head 19 
in each instance via a lever (not shown) somewhat in the manner of a 
folding lattice grate so that the swiveling movement of the halves 17, 18 
is produced by the axial displacement of the connecting rod 21 within the 
guide sleeve 13. 
A scissor-like grip member 23 with two grip halves 24, 25 which are 
swivelable relative to one another are associated with the support 14 of 
the base body 12 for handling the instrument 10 as a whole and for 
carrying out the axial displacement of the connecting rod 21 and 
accordingly the swiveling movement of the halves 17, 18 of the instrument 
head 19. A drive mechanism 26 constructed in the manner of a folding 
lattice grate is associated with the grip halves 24, 25 for the axial 
displacement of the connecting rod 21. This drive mechanism 26 is 
connected with the connecting rod 21 in such a way that a swiveling 
movement of the grip halves 24, 25 causes an axial displacement of the 
connecting rod 21. 
The instrument head 19 has a substantially cylindrical shape. Its diameter 
corresponds approximately to that of the guide sleeve 13 and is 
dimensioned in such a way that the instrument head 19 and guide sleeve 13 
are displaceable in a trocar so that there is sufficient room in an inner 
gap between the trocar and guide sleeve 13 for two free ends 27 of a 
surgical thread. 
The instrument head 19 is provided with a profile (FIG. 2) having a 
peripheral region 28 for holding, guiding and handling the free ends 27 of 
the thread in particular and a central region 29 for holding a knot 31 
made with the two free ends 27 so as to form a continuous loop 30. The 
peripheral and central regions 28, 29 are connected via a recess 32 
penetrating the instrument head 19 roughly vertically to its center line 
34. The recess has the shape and cross section of an acute angle. A 
dead-end branch 33 extends parallel to the center line 34 of the 
instrument head 19 approximately in the plane of the center line 34 until 
a front part 35 of the instrument head 19. The inner diameter or clear 
width of this branch 33 is so dimensioned that a free end 27 of the thread 
can be received and guided therein. 
An open branch 36 of the recess 32 extends at an acute angle from an end 
region of branch 33 near the front part in the direction away from the 
front part 35 and exits from the instrument head 19. This branch 36 has a 
clear width allowing the knot 31 to pass through. 
The peripheral region of the profile is provided with a bevel 37 which 
extends from the outer circumference of the instrument head 19 in the 
direction of the front part 35 at an inclination to the center line 34. 
The bevel 37 comprises roughly half of the instrument head 19 
circumferentially and is curved in a uniform manner. It ends in the recess 
32 on the side facing the front part approximately at the point where the 
branches 33, 36 merge. 
A clearance grinding 38 with a cross section shaped like the segment of a 
circle is associated with the bevel 37 approximately symmetrically 
opposite the latter between its outlet at the circumference of the 
instrument head 19 and the location where it ends in the recess 32. This 
clearance grinding 38, which opens into the dead-end branch 33 of the 
recess 32 in the region of its base 39, extends from the base 39 to the 
center line 34 at a slight inclination facing away from the front part 35. 
A pin 40 extends from the base 39 parallel to the clearance grinding 38 so 
as to form a narrow slit 41 between the pin 40 and the clearance grinding 
38, this slit 41 being open at the top. The length of the pin 40 is so 
dimensioned that it extends beyond the clearance grinding 38 and the bevel 
37. However, the bevel 37 is dimensioned in such a way that the pins 40 do 
not project beyond the instrument head 19 in its radial direction so that 
the instrument head 19 can be displaced axially within a trocar without 
hindrance. 
The central region 29 of the profile is formed by a bore hole 42 which is 
disposed coaxially to the instrument head 19, opens into the recess 32 and 
completely penetrates the branch 33 centrally (FIG. 4). The diameter of 
the bore hole 42 is greater than the clear width of branch 33 so that the 
bore hole 42 also has a lateral guide 45 in the region of branch 33 which 
securely holds the knot 31 in the bore hole 42. Further, the dimensions of 
the diameter of the bore hole 42 somewhat exceed those of the knot 31 in 
the radial direction of the instrument head 19. 
Finally, a longitudinal slit 43 is associated with the bore hole 42, this 
longitudinal slit 43 extending in the front part 35 parallel to the center 
line 34 and symmetrically with respect to the bevel 37 and on the side of 
the latter. The longitudinal slit 43 is wedge-shaped and tapers from the 
circumference of the front part 35 to a narrow gap 44 by which it passes 
into the bore hole 42. In addition, the longitudinal slit 43 widens 
conically in the longitudinal direction of the instrument head 19 toward 
the end face of the front part 35, wherein the longitudinal slit 43 and 
gap 44 as well as the peripheral and central regions 28, 29 of the profile 
are associated in a symmetrical manner with the two halves 17, 18 of the 
instrument head 19. 
The placement of the knot 31 by means of the instrument 10 is described in 
the following. 
After the knot 31 has been tied by means of the free ends 27 of the thread 
while forming a loop 30 passing through the tissue or around an organ, the 
instrument 10 is positioned with respect to the knot 31 in such a way that 
the knot 31 is located on the guide sleeve 13 roughly in the center. The 
two free ends 27 are held laterally approximately around the guide sleeve 
13 so as to be spread apart from one another (FIG. 5). The free ends are 
held under slight tension so that the thread is tightened as a whole. The 
instrument 10 is then guided in such a way that the knot 31 arrives at the 
instrument head 19 and slides down its bevel 37 in the direction of the 
front part 35. In this way, the free ends 27 are engaged by the pins 40 
and guided into the slit 41, while the regions of the loop 30 which are 
adjacent to the knot 31 pass into the longitudinal slit 43, which is 
assisted by the conical shape of the longitudinal slit 43 described above. 
For reliable placement of the free ends 27 in the slit 41, it is advisable 
to wrap the two free ends 27 somewhat further around the instrument head 
19. Thus, the movement of the instrument 10 is effected away from the 
actual suture line until the knot 31 has slid down the bevel 37 until it 
enters the branch 36 of the recess 32, passes through the latter and 
finally arrives in the bore hole 42 of the central region 29 of the 
profile. In so doing, it is constantly held by the two free ends 27 in the 
center with respect to the bevel 37. At approximately the same time, the 
free ends 27, guided by the respective pin 40, reach the base 39 of the 
clearance grinding 38 and enter the recess 32 laterally. Meanwhile, the 
adjacent loop regions slide along the longitudinal slit 43 and the gap 44 
into the bore hole 42. 
When this position is reached, the movement of the instrument 10 is 
reversed in that it is now moved in the direction of the actual suture 
line. In so doing, the knot 31 in the bore hole 42 initially slides along 
the branch 33 and is held by the lateral guide 45 until it reaches the end 
of the bore hole 42. Next, the knot 31 which is reliably fixed in this 
way, is displaced. This displacement continues until the knot 31 arrives 
in the immediate vicinity of the target point, wherein this displacement 
can be effected very easily due to the guidance of the free ends 27 and 
the tightened thread. The actual placement of the knot 31 is then effected 
precisely in the target point in that the two halves 17, 18 of the 
instrument head 19 are swiveled relative to one another around the axle 
pin 16 by means of the actuating device 20 in such a way that the free 
ends 27 held by them are spread apart. The final movement of the knot 31 
toward the target point and the tightening of the knot 31 are completed by 
means of this spreading. The tightening can be further assisted by 
increasing somewhat the tension on the free ends after the halves 17, 18 
have been spread apart. It is essential that the free ends 27 and the knot 
31 are held securely and separately in each phase by the instrument head 
19. 
After the knot 31 has been placed, the halves 17, 18 are brought together 
again by means of the actuating device 20, whereupon the instrument 10 can 
be freely withdrawn or pulled out of the trocar. The free ends 27 slide 
within the respective gap 44, recess 32 and bore hole 39 until exiting 
from the instrument head. Finally, the respective free end 27 can be cut 
at a suitable location. 
While the foregoing description and drawings represent the preferred 
embodiments of the present invention, it will be obvious to those skilled 
in the art that various changes and modifications may be made therein 
without departing from the true spirit and scope of the present invention.