Apparatus and methods for advancing surgical knots

A knot pusher comprises a shaft having a fitting at its distal end. The fitting includes a radial slot for receiving a suture length therein. A mechanism is provided for closing the slot so that the suture can be contained within the slot as a knot is advanced over the contained suture length.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to surgical devices and methods. 
More particularly, the present invention relates to the construction and 
use of devices for advancing surgical knots, commonly referred to as "knot 
pushers." 
The closing of incisions and wounds using sutures is a preferred technique 
of surgeons and many other physicians. While other techniques are now 
available, such as stapling, the use of "tissue glues," and the use of 
collagen for closing vascular puncture, the use of suture is often 
preferred since it provides a reliable and tight closure of any wound 
where the suture can be properly placed, tied, and tightened. 
While suturing is relatively straightforward in most open surgical 
procedures, placement and tying of sutures in laparoscopic and other 
minimally invasive procedures can be problematic. In order to provide for 
suturing under such circumstances, a variety of devices have been 
developed for the remote placement and tying of suture through cannulas 
under video observation. Usually, a sliding knot will be formed in a 
suture loop, and it will be necessary to use a tool, usually referred to 
as a "knot pusher," for cinching the slidable knot over the loop. 
Such knot pushing devices may also be used in recently developed techniques 
for the remote suturing of vascular punctures. Punctures are formed in the 
femoral and other arteries to provide vascular access for performing 
angioplasty and other vascular procedures. Such techniques are described 
in Ser. Nos. 07/989,611 (now U.S. Pat. No. 5,417,699), 08/148,809 (now 
U.S. Pat. No. 5,527,322), and PCT/US93/11864. Such methods result in 
placement of a suture loop through tissue on opposites sides of the 
vascular puncture. Two free ends of the suture loop are brought out 
through a tissue tract leading to the puncture, and the loops may be 
externally tied by the treating physician. It is then necessary to use a 
tool to advance the knot back through the tissue tract so that it lies 
directly over the adventitial wall of the blood vessel. 
Heretofore, knot pushers have been relatively cumbersome and awkward to 
employ. Frequently, one or both free ends of the suture must be threaded 
through an aperture or slot on the knot pusher prior to advancing the 
knot. The need to thread suture during the surgical procedures can be 
problematic and time consuming. Moreover, the suture can sometimes be lost 
from the open slots which are employed in many of the presently available 
knot pushers. 
For these reasons, it would be desirable to provide improved devices and 
methods for advancing surgical knots where the suture can be readily 
loaded onto the devices and the knot advanced with a reduced chance of 
losing the suture. The methods and devices should be suitable for use in 
laparoscopic and other minimally invasive procedures, in newly developed 
vascular suturing protocols, as well as in open surgical and other less 
demanding circumstances. 
2. Description of the Background Art 
Knot pushers, appliers, and related suturing devices are described in U.S. 
Pat. Nos. 5,250,054; 5,201,744; 5,176,691; 4,803,984; 2,595,086; 
2,131,321; 1,940,361; and 1,574,362. 
Application Ser. Nos. 07/989,611 and 08/148,809, and PCT/US93/11864, 
describe methods and apparatus for suturing vascular punctures. 
SUMMARY OF THE INVENTION 
According to the present invention, an improved knot pusher device 
comprises a shaft having a proximal end and a distal end, wherein the 
distal end is configured to advance a slidable knot in a suture loop to 
close the loop. The distal end is usually a flat or slightly convex or 
concave surface having a slot for receiving a free end of a suture 
proximate to the knot, wherein the slot is large enough to slidably 
receive the free suture end but small enough to engage the knot and "push" 
the knot by advancing the device relative to the free suture end. The 
improvement comprises a capture mechanism on the distal end of the shaft 
to maintain the suture within the distal end while still allowing free 
axial travel of the suture within the slot. The slot is preferably 
configured to allow easy capture of the suture, even while the device is 
being manipulated through an access sleeve or trocar, and the capture 
mechanism assures that the suture will not be inadvertently lost from the 
slot as the knot is advanced. 
An exemplary and preferred knot pusher comprises the shaft having a 
proximal and a distal end. A fitting is mounted on the distal end of the 
shaft and has a radial slot which receives the free end of suture. A 
member is mounted on the shaft and moves between a first position that 
closes the slot and a second position that leaves the slot open. In this 
way, by shifting the member between the two positions, the suture can be 
selectively captured and released as desired. The shaft is usually tubular 
and has a side opening located just proximally of the fitting to permit 
exit of the suture from the fitting. In a first design option, the member 
is a rod which is slidably received in a lumen of the tubular shaft, 
wherein the rod may be advanced to close the slot or retracted in order to 
open the slot. In a second design option, the member is a rotatable rod 
having a distal end which is shaped to close the slot in a first 
rotational position and to open the slot in a second rotational position. 
According to a method of the present invention, a suture loop having two 
free ends and a slidable knot is provided at a target tissue location, 
such as a vascular or other incision that is to be closed and sealed. 
Tension is provided on a first free end of the suture loop, and the 
tensioned end is captured in a slot formed at the distal end of the knot 
pusher shaft. The slot is closed, and the shaft is advanced over the free 
end toward the tissue to advance the knot and close the suture loop. After 
the loop has been closed, the other free end of the suture loop is 
tensioned to tighten the knot. The slot is then opened, and the first free 
end of the suture loop released. The method is particularly convenient for 
closing and tightening suture loops located through or within percutaneous 
tissue punctures, such as vascular punctures to the femoral artery, 
trocars used in laparoscopic and other minimally invasive surgeries, and 
the like.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS 
The knot pusher of the present invention is a manual device which can be 
used by physicians in any of a variety of surgical procedures where a 
suture loop has been formed in tissue to close an incision or wound, or 
for any other purpose. A slidable knot will be formed in the loop, and the 
knot pusher is used to engage and advance the knot over a free end of the 
suture to close the loop. The knot can then be tightened by pulling on the 
other free end of the suture, and optionally additionally throws may be 
tied into the suture ends and advanced using this or another knot pusher. 
The knot pusher preferably comprises an elongate, narrow diameter body or 
shaft suitable for use in remote procedures performed through percutaneous 
tissue punctures, such as vascular closures, laparoscopic and other 
minimally invasive procedures and the like. Thus, the shaft will typically 
have a length in the range from about 5 cm to 40 cm, usually from about 7 
cm to 10 cm. The diameter of the shaft will be sufficiently small to 
facilitate introduction through access sheaths, trocars, and the like, 
typically being below about 10 mm, preferably being in the range from 2 mm 
to 10 mm, and more preferably being in the range from 2 mm to 4 mm. The 
distal end of the shaft will be configured to engage and advance the 
slidable knot, and the proximal end of the shaft will typically have 
handles, gripping surfaces, actuators, or the like, to facilitate manual 
manipulation of the device. Preferably, a slit, cleat, post or other 
anchor is provided at the proximal end of the device to permit a temporary 
attachment of one or both ends of the suture during use. It will be 
appreciated, of course, that while the device may be particularly useful 
for performing remote procedures through access sheaths and trocars, it 
will also find use in open surgical procedures where its ability to 
capture suture and its one-hand operation will also provide advantages. 
In a preferred aspect, a fitting will be provided at the distal end of the 
shaft or body of the knot pusher. The fitting will preferably be formed 
from a relatively hard material to firmly engage the knot and permit 
smooth advancement of the knot. The fitting is typically a cylindrical 
element having a flat (or slightly convex or concave) front face, a 
diameter in the range of 2 mm to 10 mm, and a length in the range from 
about 3 mm to 10 mm. A radial slot is formed in the fitting for receiving 
and capturing the suture. Preferably, the slot is flared open in the 
outward radial direction to facilitate capture of the suture. An opening 
will be provided in the shaft at the proximal end of the fitting, 
preferably immediately proximal to the fitting to permit exit of the 
captured suture from the device. Thus, the device will allow capture of 
the suture within the fitting, with the remaining portions of the suture 
lying outside of the fitting to permit tensioning, as will be described in 
more detail hereinafter. 
The shaft or body of the knot pusher will usually be rigid, typically being 
formed from a medically acceptable metal or plastic material. Suitable 
metals include stainless steel. Suitable plastics include polycarbonate. 
As will be described in more detail hereinafter, the shaft may be formed 
from more than one component, preferably being formed from coaxial tubes 
or a coaxial tube and rod. The various components of the shaft may be 
formed from the same or different materials, but will usually be rigid 
metals and plastics as described above. 
Referring now to FIGS. 1-4, a knot pusher 10 comprises a shaft assembly 12 
having a proximal end 14 and a distal end 16. The shaft assembly 12 
includes an outer tubular member 18 and an inner rod member 20, as best 
illustrated in FIGS. 3 and 4. A fitting 22 is mounted on the distal end 16 
of shaft assembly 12 and is attached to the outer tube member 18. The rod 
member 20 will be axially reciprocatable within the outer tube member 18 
as well as within an opening or receptacle in the proximal end of the 
fitting 22. The distal end of the rod member 20 is shown in its fully 
distally translated position in FIG. 3 and in a partially retracted 
position in FIG. 4. 
Axial reciprocation or translation of the rod member 20 relative to the 
outer tube member 18 and fitting 22 is effected by an actuator assembly 30 
at the proximal end 14 of the shaft assembly 12. The actuator assembly 30 
includes a finger grip 32 attached to the rod member 20, and a thumb 
depressor 34 attached to the outer tube member 18. A spring 36 is 
maintained under compression between the finger grip 32 and thumb 
depressor 34 so that the thumb depressor (in the absence of a depression 
force) remains proximally retracted relative to the rod member 20. The rod 
member 20 can be proximally retracted by depressing the thumb depressor 
34, typically by a user grasping finger grip 32 between the ring and index 
fingers and pressing on the depressor 34 with the thumb. It will be 
appreciated that a wide variety of other actuator mechanisms, such as 
three-ring actuators, pistol grips, thumb sliders, and the like could also 
be utilized in the knot pusher of the present invention. 
The fitting 22 includes a radial slot 40 having a flared entrance region 42 
for receiving a length of suture S as illustrated in FIG. 1. The suture S 
will be captured within a radially inward region 44 of the slot 40, as 
illustrated in FIG. 2. An opening or aperture 50 is formed in the outer 
tubular member 18 so that the lumen of tubular member is open to the 
exterior on the proximal side of the fitting 22. With this structure, it 
will be appreciated that suture will be able to enter the slot 40 through 
the flared opening 42, but will be free to exit from the lumen of tubular 
member 18 through opening 50. A slit 51 is provided at the proximal end of 
the device to permit a temporary attachment of one or both ends of the 
suture during use. 
Capture of suture within the slot 40 is accomplished by depressing thumb 
depressor 34 relative to the finger grip 32 to proximally retract the 
interrupt member 18 and open slot 40. Such capture will, in itself, be 
sufficient to allow the knot pusher 10 to advance a slidable knot in the 
suture loop. The present invention, however, further provides a structure 
and mechanism for containing suture within the slot 40, as will now be 
described in more detail. The distal end of rod member 20 is formed with a 
quarter-round notch 60, as best seen in FIGS. 3 and 4. The notch 60 
provides an opening for the axial passage of suture, even when the member 
60 is fully advanced in the distal direction, as illustrated in FIG. 3. 
Wall 62 of the notch 60 is aligned with the slot 40 so that an axial 
passage remains in region 44. The suture S is thus able to pass through 
the slot 40, past the wall 62, and out through the opening 50, as best 
seen in FIG. 3. The wall 62, however, blocks lateral passage of the suture 
S through the slot 40. Thus, the suture will be maintained in the fitting 
22, but will be able to axially translate through region 44 of the slot 
40. The suture can be released, however, by retracting rod member 20, as 
illustrated in FIG. 4. 
An alternative handle actuator assembly 200 for effecting axial translation 
of rod member 20 relative to outer tube member 18 is illustrated in FIG. 
1A. The distal end of a knot pusher employing the handle actuator assembly 
can be identical to that illustrated in FIGS. 1-4. The handle actuator 
assembly 200 comprises a tubular handle casing 202 having an open interior 
chamber 204 and an axial slot 206 on one side thereof. A slider 208 is 
reciprocatably mounted in the chamber 204, and thumb knob 210 permits a 
user to manually slide the slider between a distally extended position (as 
illustrated) and a proximally retracted position (by drawing proximally on 
the thumb knob). Spring 212 is mounted in the chamber 204 between a 
proximally exposed surface 214 of the slider 208 and an internal surface 
216 of the handle casing 202. The spring 212 is under slight compression 
so that the slider will be maintained in its distally advanced position 
absent proximal force on the thumb knob 210. Thus, the suture-engaging 
distal end of the knot pusher can be shifted between the "closed" 
configuration of FIG. 3 and the "open" configuration of FIG. 4 by manually 
retracting the thumb knob 210. That is, retraction of the thumb knob 210 
is equivalent to depression of thumb depressor 34 in the embodiment of 
FIGS. 1-4. 
Other mechanisms for locking the suture within a distal portion of the knot 
pusher may also be utilized. Referring to FIGS. 5, 6, and 6A, an 
alternative embodiment of a knot pusher 100 constructed in accordance with 
the principles of the present invention will be described. Knot pusher 100 
includes a shaft assembly 102 which comprises an outer tubular member 104 
and an inner tubular member 106. The outer tubular member has an opening 
108 near its distal end with a C-shaped hook 110 at its distal tip. The 
hook element 110 defines a fitting for receiving suture through slot 112. 
The inner tubular member 106 also includes an opening or notch 120 at its 
distal end. The notch 120, however, has a semicircular profile along its 
entire length. Thus, when the outer tubular member 104 and inner tubular 
member 106 are rotationally aligned, as illustrated in FIGS. 5 and 6, the 
slot 112 is fully open to receive suture S as illustrated. By rotating the 
inner tubular member 106 by 90.degree., as illustrated in FIG. 6A, the 
slot 112 may be closed while continuing to allow free axial sliding of the 
suture S through the openings 108 and 120. Conveniently, knobs 130 and 140 
may be provided on the proximal ends of outer tube 104 and inner tube 106, 
respectively, to facilitate relative rotation. 
Referring now to FIGS. 7A-7E, use of the knot pusher 10 for advancing a 
knot K in a suture loop L to close a puncture P in a blood vessel BV will 
be described. Methods for placing the suture loop L so that free ends S1 
and S2 of the suture pass through opposite sides of the blood vessel wall 
and into the percutaneous tissue tract are described in application Ser. 
Nos. 07/989,611; 08/148,809; and PCT/US93/11864, the full disclosures of 
which are incorporated herein by reference. After tying the knot K in the 
suture ends S1 and S2, the suture loop L will extend outward through an 
access sheath 150, as illustrated, and it is necessary to advance the knot 
K down through the lumen in sheath 150 to close the loop. The knot K, 
which is a slidable knot or a square knot, can then be tightened by 
pulling on the free ends S1 and S2. 
The method of the present invention begins by capturing a first free end S1 
of the suture in the fitting 22 (FIG. 7A). The suture will be captured 
while the user depresses thumb depressor 34 relative to the finger grip 32 
to proximally retract the inner rod member 18 and open the slot 40 (FIGS. 
1-4). A particular advantage of the present invention is the ease of 
capturing suture through the flared entrance region 42 into slot 40 of 
fitting 22. The suture may simply be placed over the entrance 42 and will 
fall into the slot 40. Capture is completed by releasing the thumb 
depressor 34. After capturing the free suture end S1, the physician can 
use the knot pusher 10 to advance the knot K without having to depress the 
thumb depressor 34 until it is time to release the suture. 
After the first free suture end S1 is captured, as illustrated in FIG. 7B, 
the device 10 is advanced into the lumen of sheath 150 toward the puncture 
P in blood vessel BV, as illustrated in FIG. 7C. The device is further 
advanced until the fitting 22 pushes the knot K directly over the 
adventitial surface of the blood vessel BV, as illustrated in FIG. 7D. The 
knot K can then be tightened, typically by pulling on both free ends S1 
and S2, and the device 10 can then be withdrawn from the sheath 150 and 
released from the suture end S1, as illustrated in FIG. 7E. The free ends 
of the suture can then be trimmed a short distance over the knot, and the 
sheath 150 removed and the percutaneous tissue tract bandaged. Optionally, 
additional knot throws will be tied and advanced over the free suture and 
S1 using the knot pusher 10. 
Although the foregoing invention has been described in some detail by way 
of illustration and example, for purposes of clarity of understanding, it 
will be obvious that certain changes and modifications may be practiced 
within the scope of the appended claims.