International Guild of Knot Tyers Forum

General => Practical Knots => Topic started by: Nickels on October 18, 2011, 11:33:12 PM

Title: Challenging medical knot tying scenario
Post by: Nickels on October 18, 2011, 11:33:12 PM
Hello,

I'm new to the community and to knot tying, so please bear with my explanation of the situation!  Thanks to the administrators for hosting this very informative forum.

The situation I'm facing is one where a suture has been tied around a wound and secured with a Dines knot.  The wound is deep in the body, and requires tools to access the site (typically you work through a tube).  The dines knot come pre-configured and is used to slide down and approximate the wound.  Unfortunately, even when locked, the Dines knot tends to slide back when the loop is under tension; however, it is useful to close the wound temporarily, prior to backing it up with (perhaps) some additional knots.

I am looking to secure the dines knot with some other knots.  I've tried multiple overhand knots (reverse half-hitches with alternating posts), but that is "finnicky" and not easy to ensure it has been done properly when working in the tube and pushing it down with a tool.  I was hoping that perhaps I could put a stopper knot on the end of each of the post and locker, and somehow slide these stopper knots down to the treatment site.  Is there such a knot?  Are there any other options that I should consider?

Thanks to everyone in advance for your time and consideration with this problem.
Title: Re: Challending medical knot tying scenario
Post by: SS369 on October 19, 2011, 01:06:07 AM
Hello Nickels and welcome to the forum.

A quick search brought a few methods to light and I hope this link gives you some ideas.

http://www.rcsed.ac.uk/fellows/lvanrensburg/classification/approaches/shoulder%20arthroscopy/arthroscopic%20knots/arthroscopic_knot_tying.htm#The%20knots (http://www.rcsed.ac.uk/fellows/lvanrensburg/classification/approaches/shoulder%20arthroscopy/arthroscopic%20knots/arthroscopic_knot_tying.htm#The%20knots)

Another here: http://books.google.com/books?id=OlSZEdgzRKIC&pg=PP8&lpg=PP8&dq=Dines+knot&source=bl&ots=MkfDrzzPWR&sig=pvWapQojCA04FIfweWywUxh7cUg&hl=en&ei=9xGeTt2oEcWviQKWnqDICQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDQQ6AEwAw#v=onepage&q=Dines%20knot&f=false (http://books.google.com/books?id=OlSZEdgzRKIC&pg=PP8&lpg=PP8&dq=Dines+knot&source=bl&ots=MkfDrzzPWR&sig=pvWapQojCA04FIfweWywUxh7cUg&hl=en&ei=9xGeTt2oEcWviQKWnqDICQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDQQ6AEwAw#v=onepage&q=Dines%20knot&f=false)

http://shoulders.md/PDFs/ch07knot.pdf (http://shoulders.md/PDFs/ch07knot.pdf)

A browser search with the term "Arthroscopic knot tying" will yield a slew of results that you will be the better judge of than I.
I hope this helped.

SS
Title: Re: Challending medical knot tying scenario
Post by: roo on October 19, 2011, 03:46:57 AM
Hello,

I'm new to the community and to knot tying, so please bear with my explanation of the situation!  Thanks to the administrators for hosting this very informative forum.

The situation I'm facing is one where a suture has been tied around a wound and secured with a Dines knot.  The wound is deep in the body, and requires tools to access the site (typically you work through a tube).  The dines knot come pre-configured and is used to slide down and approximate the wound.  Unfortunately, even when locked, the Dines knot tends to slide back when the loop is under tension; however, it is useful to close the wound temporarily, prior to backing it up with (perhaps) some additional knots.

I am looking to secure the dines knot with some other knots.  I've tried multiple overhand knots (reverse half-hitches with alternating posts), but that is "finnicky" and not easy to ensure it has been done properly when working in the tube and pushing it down with a tool.  I was hoping that perhaps I could put a stopper knot on the end of each of the post and locker, and somehow slide these stopper knots down to the treatment site.  Is there such a knot?  Are there any other options that I should consider?

Thanks to everyone in advance for your time and consideration with this problem.

Looking up this Dines Slider Knot, I noticed it is a loop based on this knot form (sometimes called a Japanese Knot):

(http://t0.gstatic.com/images?q=tbn:ANd9GcSL7LdpjUlVYPGQwD1W96xBZkXOj-GAWq7fixG7nInv8Q-saEi5)

I'm a little surprised that such a high-complexity knot is used.  It seem to do OK in monofilament once locked, only slipping at higher loads.  Perhaps your material is more difficult to deal with, and it makes me wonder if add-ons like half hitches and stopper knots wouldn't just spring out.  A simple overhand stopper can be "slid" to the knot as an add-on by inserting a needle in the center of the knot to force it to roll where the needle pulls it.

The Dines Slider Knot has a slide-locking-when-the-free-end-is-pulled mechanism that is similar to a Sailor's Hitch that is tied around its own standing part to form a loop.  I don't think it will surpass the performance of the knot you are using, but it would be less complex:

http://notableknotindex.webs.com/sailorhitches.html
(see first footnote)

Does the knot need to slide and then lock?
Title: Re: Challending medical knot tying scenario
Post by: Nickels on October 19, 2011, 05:12:31 PM
Thansk roo and SS369 for your quick feedback!

SS369: The issue with standard arthroscopic techniques is generally that they require quite a bit of training - the doctors performing the procedure I'm working on won't have that type of training (they know overhand knots/square knots but that's about it).  I'm stuck in that sense - can't use very complicated knots yet somehow need good security.  That being said, the Google book link you provided is interesting and I'll dig into that a litter bit more.  The Dines knot is something that we can provide beforehand, and it seems to be the best in terms of temporarily securing the loop.

roo: I'm really interested in the idea of a double overhand knot; however, whenever I tighten the knot it tightens "towards" me, and away from the dines knot.  This gap between the two knots ends up as a loss in tension in the loop.  Is there a way to tighten an overhand stopper fully whilst only pushing from one side?  To answer your other question, the backup knot doesn't necessarily need to "slide" and "lock" as used in knot terminology, but does need to be made outside the tube and then pushed down using an instrument.

Thank you both for your help!
Title: Re: Challending medical knot tying scenario
Post by: roo on October 20, 2011, 04:35:27 PM
Thank you both for your help!

I've been playing with various knots that are supposed to shrink and lock, but the devil is in the details.  Once you get the loop shrunk down and binding something, the tension caused by this binding often interferes with the intended change of geometry that is supposed to cause locking in order to prevent backsliding.

I am assuming that your task is a compact binding task (applying or holding tension around an object or group of objects).  Correct me if I am mistaken.
Title: Re: Challending medical knot tying scenario
Post by: Nickels on October 20, 2011, 08:47:57 PM
roo:  That's exactly right - we're trying to hold tension around an object with a very small suture (about 0.3 mm).  The locking of a knot, plus ensuring that the back up knot is close behind is very tricky!  Thanks again for looking into this.
Title: Re: Challending medical knot tying scenario
Post by: Sweeney on October 20, 2011, 09:16:48 PM
The overhand locking knot should work (I've tried it in fine monofilament) but you cannot tighten it by pulling on the standing part. Using a needle or fine forceps the knot has to "roll" down to the Dines knot and be held there while the standing end is finally tightened. This is probably best practised with some cord first to understand the mechanics but it should be possible in a .3mm suture.

Barry
Title: Re: Challending medical knot tying scenario
Post by: Dan_Lehman on October 20, 2011, 09:36:52 PM
... where a suture has been tied around a wound and secured with a Dines knot.
...

It would be best to include an image of the knot of interest,
either directly --by your own camera, say-- or with a URLink
to some clear image (and not to some paper which might have
an image somewhere buried ... --I'm now still digging, trying
to find this; which is a waste of each responder's time (reinventing
the wheel), compared to the OP providing the information needed!).
So, far, I've reached the frustrating dead ends of finding image-LESS
astracts, full articles (w/image(s)?) for a fee --no thanks.

Having been consulted by a doctor some ages ago (who provided
materials to me, for *play*), I'm guessing that your material
is rather flexible?


--dl*
====
Title: Re: Challending medical knot tying scenario
Post by: DDK on October 20, 2011, 11:50:27 PM
I have found this reference to the the Dines Slider.  The free sampling of this book did help to clarify a few things for me.

http://books.google.com/books?id=OlSZEdgzRKIC&pg=PP8&lpg=PP8&dq=Dines+knot&source=bl&ots=MkfDrzzPWR&sig=pvWapQojCA04FIfweWywUxh7cUg&hl=en&ei=9xGeTt2oEcWviQKWnqDICQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDQQ6AEwAw#v=onepage&q=Dines%20knot&f=false (http://books.google.com/books?id=OlSZEdgzRKIC&pg=PP8&lpg=PP8&dq=Dines+knot&source=bl&ots=MkfDrzzPWR&sig=pvWapQojCA04FIfweWywUxh7cUg&hl=en&ei=9xGeTt2oEcWviQKWnqDICQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CDQQ6AEwAw#v=onepage&q=Dines%20knot&f=false)

DDK
Title: Re: Challenging medical knot tying scenario
Post by: Nickels on October 21, 2011, 02:02:20 PM
Thanks again everyone for your replies!  This has helped quite a bit already.

Sweeney: Thanks for the tips.  I'm working with rolling the double overhand knot.  As far as I can tell, when you "hold" the loops down just before tightening, there will always be some length of the suture between the dines knot and the first turn in the overhand knot which ends up as slack when finally tightening the overhand knot.  I'll try some more to see if I can get that last little bit out.

Dan_Lehman: Sorry Dan!  Here's a link to the dines knot: (http://img263.imageshack.us/img263/8385/dinesknot.jpg) (http://imageshack.us/photo/my-images/263/dinesknot.jpg/)
The material is flexible - a multi-filament suture.  It's quite strong, but also very slippery which is making holding a knot very difficult.
Here's a picture of the application: (http://img846.imageshack.us/img846/8923/igkt.jpg) (http://imageshack.us/photo/my-images/846/igkt.jpg/)
Because the dines knot (or any sliding/locking knot) can slip back, I'm trying to secure that with some additional knots.

DDK: Thanks for providing the link!

Again, many apologies if I'm not providing the right information or if I should be more clear.  Appreciate the help of everyone on this board.
Title: Re: Challenging medical knot tying scenario
Post by: Dan_Lehman on October 22, 2011, 06:10:14 AM
DDK, that URLink --lengthy though it be-- didn't work for me
(or not yet) : claimed it was either NA or I'd seen too much.
Maybe ..., BUT I'm thankful for the book reference, as it seems
one that could be added to a great many knotters' libraries,
for something quite different from the usual (and maybe better
done)!

Nickles, you still didn't clearly indicate the disposition of the
knot, but I think I've got it (two chances :o) --those squiggly,
cut-off indicators are towards the bound object, upper, as in
the schematic you followed the knot with.  --and that works,
anyway.

Which brings back old memories, for I discovered this as my
"#56''' " qua eyeknot (not to be drawn up so tightly as your
binder (for ring-loading).  --and then followed my notes
with recognition to Eastern sources, though via Brion Toss's
Rigger's Apprentice (pp. xviii/0 [i.e, between "xvii" & "1"], 331, & 381),
it comes out Chinese, not Japanese.  (Sounds like a myth ... .)

Now, to the problem at hand.  Nickles complains ... :

Quote
Unfortunately, even when locked, the Dines knot tends to slide back when the loop is under tension; however, it is useful to close the wound temporarily, prior to backing it up with (perhaps) some additional knots

I don't think that this is an accurate analysis of the failure.
(Btw, in some abstract of a related medical-knotting article,
it was stated that a failure was slippage of 2mm (!).)
What I see happening is that the bight/turn around the
in-tension-until-locking part simply doesn't get tensioned
and drawn snug by tightening via the 2nd end, and so
constitutes slack awaiting expansion of the bound object,
which then pulls it tight with the egress of material.
.:.  I'm skeptical at trying to redress this w/back-up knotting.
Or at least I want to try to find a direct solution, if possible.

My first general plan was to suggest employing a 2nd line,
to tie some gripping hitch to the two ends of the binding line,
which binder-hitch would be slid down into place and then
tightened around the binding line ends; then, tie off those
ends in a usual manner of successive/alternating half-hitches.
So, the binder-hitch would need to serve as a good *choke*
against the ring-loading of the binder, and as a good gripper
of the binder ends temporarily as they were further secured.

But I might have a more "direct" solution, using a ProhGrip
(aka "Blake's hitch") with a modification to enable it to be
locked once set.  As gripping hitches go, the ProhGrip works well
in like diameters (line to itself, in contrast to other such hitches
that are typically used in a smaller line gripping a larger one),
which is what is wanted here.  The modification I see at the
moment is to reeve the knot's tail through final turn and the
gripped line, to enable it to capsize its final turn and bend and
bind the line back against the knot --the bend, u-turn, being
what will prevent slippage.  Further, the angle of incidence
of the gripping knot to the gripped line is good for any wide
angle (relatively large object) --not so much an issue re the
"choke", as it would be for the knot I mused about above.

I don't have any 0.3mm (!!) stuff lying about to play with
--or maybe I do, but don't have my microscopic spectacles
on to see it.  One quick fiddling in 2mm (giant, hawserish!)
very soft-laid PP looks promising, at least.

I ID it : #20111021a00:44  (yes, this is my time, not GMT;
"a" = "sAturday").


QED?!

--dl*
====
Title: Re: Challenging medical knot tying scenario
Post by: roo on October 22, 2011, 07:32:09 AM
Nickels,

I think I may have something, but I'll let you decide.  I've attached a diagram. 

In all of these sliding binders, you have a hitch being tied around the standing part.  Then then standing part is pulled to cause the hitch to travel and bind.

I propose that we may tie this hitch component around the twinned portion of a coil made in the standing part.  I'm only showing the buntline (http://notableknotindex.webs.com/buntlinehitch.html) hitch (which employs a clove hitch) as an example for simplicity and clarity.  Any better friction hitch of your choice would likely be employed.  So in the example, we cause the clove hitch to travel by first pulling on the blue line labeled "1".  Once this mechanism is squeezing the gray object, we pull on the green portion of line labeled "2" to set the line.  I suppose you may use a tube or other tool to hold the knot in place while you set the line.

This approach solves the problem I was having earlier with the tension in the binder preventing the knot form shift to cause locking.

I hope this works for you.  My eyes can't take working with the tiny, nearly invisible monofilament anymore.   ;)
Title: Re: Challenging medical knot tying scenario
Post by: DDK on October 22, 2011, 02:37:00 PM
@ Nickels

I've noticed several suggestions involving the tying of different (better?) knots than the Dines Slider.  It was my impression from the original post that that the solution was limited to those with a starting point of a "preconfigured" Dines Slider (you also mention later that the Dines Knot is provided beforehand to others with possibly little knot-tying expertise).  If this is the case, some clarification (pictures are always a plus) would be helpful on what the structure of a preconfigured Dines Slider might be. 

I had thought that "preconfigured" possibly meant that the post limb of the suture (that which goes through the knot pusher, what we might call the standing part of the knot) was first threaded around/through the object(s) to be tensioned, then reeved through a partially tied Dines Knot structure (which has been "tied" on the loop limb of the suture, what we might call the working end).  I'm wondering if the post limb can be further reeved through this partially tied Dines (prior to the sliding down of the knot) to produce a more secure knot.  This would require one to "roll down" the additional loop produced as one slides the knot.

DDK
Title: Re: Challenging medical knot tying scenario
Post by: roo on October 22, 2011, 04:35:38 PM
... Knot is provided beforehand to others with possibly little knot-tying expertise
In the solution I offered in my previous post (http://igkt.net/sm/index.php?topic=3659.msg21153#msg21153) this can be done.  In the simplified example, a clove hitch can be tied in the air (http://notableknotindex.webs.com/clovehitch.html) first, and then that clove-ring is clamped to maintain form with forceps or clips, etc.  It'd probably be good to point the clamping forceps toward the intended "standing part entry side" of the hitch.  This could be done with whatever friction hitch is chosen (sailor's hitch, etc.).  Just about any friction hitch will be better than clove hitch.

Then you put the future standing part through once, coil around, and put it through twice.  Then proceed with the binding and setting operation once you release the hitch clips.

I believe that would make it easy for surgeons without an extensive knot tying background.  It would also save time during the operation.
Title: Re: Challenging medical knot tying scenario
Post by: roo on October 22, 2011, 09:26:57 PM
I'd like to offer an extension, pictured below, of my previous solution (http://igkt.net/sm/index.php?topic=3659.msg21153#msg21153).  It may improve holding performance enough to use it with a simple buntline hitch.

Obviously, extra tucks may be made if desired.

As before, the blue portion is pulled first to shrink the loop, and as the knot is held in place, the green portion is pulled second to secure the knot from backsliding.
Title: Re: Challenging medical knot tying scenario
Post by: xarax on October 22, 2011, 11:53:29 PM
I'm working with rolling the double overhand knot. 

   Perhaps one could use a double overhand knot instead of a half hitch.
The adjustable noose / loop based on the double overhand knot, was shown elsewhere (1).  Notice the particular way the second eye leg passes through the knot s nub.
   ( I have not tested this eye knot in the case of very slippery and  elastic materials. )
 
1.   http://igkt.net/sm/index.php?topic=3315   
Title: Re: Challenging medical knot tying scenario
Post by: Dan_Lehman on October 23, 2011, 06:35:09 AM
I've noticed several suggestions involving the tying of different (better?) knots than the Dines Slider.  It was my impression from the original post that that the solution was limited to those with a starting point of a "preconfigured" Dines Slider (you also mention later that the Dines Knot is provided beforehand to others with possibly little knot-tying expertise).  If this is the case, some clarification (pictures are always a plus) would be helpful on what the structure of a preconfigured Dines Slider might be.

Ah, touche' --pull the reins on our flights of fancy!

Well, then my analysis of the problem with that knot
suggest a limited chance of success, at best (i.e., not
a sure, immediate lock).

I like Roo's simplicity to the general idea I tried to
implement --of putting a u-turn into the part that
had formerly been sliding, to lock.  If forceps or some
device holds the knot up snug for the tightening,
it seems that Roo's re-reeved buntline hitch can be
locked; but another thing to consider, though, is at
what angle of incidence/departure the binding parts
have to the knot.  Possibly, something a little more
involved (another turn or two) than the clove structure
will be needed.

(nb:  the fine material isn't monofilament --more flexible.)

--dl*
====
Title: Re: Challenging medical knot tying scenario
Post by: xarax on October 23, 2011, 12:29:37 PM
My first general plan was to suggest employing a 2nd line...

    That is a very good plan ! The simplest way I can think of, that implements this "second line"  idea, is shown in the attached picture. I guess that one might figure out many other knots, that can slide towards the object, and then locked there by pulling the second line.
Title: Re: Challenging medical knot tying scenario
Post by: Dan_Lehman on October 24, 2011, 05:31:56 AM
My first general plan was to suggest employing a 2nd line...

    That is a very good plan ! The simplest way I can think of, that implements this "second line"  idea, is shown in the attached picture. I guess that one might figure out many other knots, that can slide towards the object, and then locked there by pulling the second line.

Xarax, you quite miss the points : (1) what you show
is the OP's technique, roughly, but with another knot;
(2) it is of one "line", which has, yes, two ends.

My "2nd line" means using an UNknotted line in the bight,
binding role, with a 2nd line sliding down some line-binder
as a choking mechanism --for temporary locking--, which
then must be tied off using 1st & 2nd line's ends.


--dl*
====
Title: Re: Challenging medical knot tying scenario
Post by: xarax on October 24, 2011, 12:33:10 PM
(1) what you show is the OP's technique, roughly, but with another knot;

   I think that, at the end, it is with the same  knot, is nt it that so ? Is this the technique the same one used by the surgeons ? If yes, then I we can say we know now, how on earth Dines thought of this seemingly complicated knot : It is not complicated at all ! In fact, it is the simplest knot that uses the "second line" idea, to carry a "lock" on the already tightened hitch on the surface of the object.

(2) it is of one "line", which has, yes, two ends
   I interpreted the "second line" idea as a "second bight "idea  :), a bight with a tip going through  the whatever hitch that has been already pushed and tightened on the surface of the object. This loop serves as a vehicle to carry the "lock" to the hitch - you pull the one end, and the other, with the "lock" attached on it, slides towards the hitch. When it reaches the hitch, the two knots bind together, and you have a secure binder. We can think of a number of sliding "locks", but a simple half turn will suffice, I believe. Now, from this idea it is only a small step to figure out how to connect the two bights together, so, at the end, when the "loch" reaches the hitch, you are left with two only ends...
   Why you always believe that I have missed tha point, when I have not, and I always believe you have understood what I mean...when you had not ?  :)
Title: Re: Challenging medical knot tying scenario
Post by: Nickels on October 26, 2011, 04:35:00 PM
Before I provide an update, please accept my most sincere "Thanks!" for all that have contributed to this thread.  It has really opened my eyes to some of the alternate ways of solving this problem.

I'm working through testing the options presented in this thread (including prototyping some tooling).  So far, the data I'm collected suggests that the buntline hitch on its own won't do the trick; however, I'm looking at using the ideology for other knots.  DDK mentioned that the post goes around the object and then pre-tied loops come over it at the end - that's exactly how this system works.

As I collect the data, I'll post back on the performance of each.

Again, many thanks to all for your input.

Title: Re: Challenging medical knot tying scenario
Post by: Dan_Lehman on October 27, 2011, 05:00:28 AM
... the alternate {alternatIVe} ways of solving this problem.

Note that we have two "problems" : the one you defined
really --as pointed out by DDK-- was to secure the extant,
"preconfigured" Dines knot;
but some us *backed-up* to the problem that the Dines knot
was trying to solve, and offered alternatives to that.  (Imagine
an instruction : "First, UNtie the preconfigured knot; THEN ..." ! )  ;D

Quote
So far, the data I'm collected suggests that the buntline hitch on its own won't do the trick;

But please note that what Roo presented was NOT exactly
the buntline hitch,  but was that structure modified by taking
the noose's standing part through the knot a 2nd time.
Are you saying that this revised structure doesn't work?

Quote
DDK mentioned that the post goes around the object and then pre-tied loops come over it at the end - that's exactly how this system works.

Okay, I wanted a more detailed explanation of the knotting
situation.  The provided diagram above shows a relatively
large (green-shaded) "object" for the line, suggesting that
the buntline hitch indeed will have some challenges, with
the ultimately loaded lines pulling it apart --and that perhaps
the two half-hitches orientation of the clove hitch would
better serve, here (with Roo's modification).

And to the question of exactly how this knotting/binding
is effected, let me point out that in some case what we
are facing is some fixed amount of slippage/yield from
the knot, which serves to lengthen-loosen the binding loop;
but were one to make a double loop, the fixed yield
would be divided in half in its loosening effect (half to each
of the two loops.  So, without adjusting any of the knots
--assuming that they do lock and hold, but just yield some
tightness in doing so--, one can halve the effect on the binding.
(in theory)

--dl*
====
Title: Re: Challenging medical knot tying scenario
Post by: roo on October 28, 2011, 02:07:34 AM
  So far, the data I'm collected suggests that the buntline hitch on its own won't do the trick; however, I'm looking at using the ideology
I made a comment earlier about friction hitches being used in place of the buntline's clove structure, but really, you don't have to limit yourself.  Perhaps some common angling nooses like the Uni-Knot (http://www.arkansasstripers.com/images/knot7.gif) might serve as a basis to apply the aforementioned lock (http://igkt.net/sm/index.php?topic=3659.msg21157#msg21157) in place of the buntline hitch example.

The greater number of coils may make up for the slippery line you apparently have.