The document discusses various knot tying techniques, suture materials, and methods for performing intestinal anastomoses. Key topics include types of knots (square knot, surgeon's knot), suture characteristics (absorbability, strength), intestinal anastomosis techniques (Lembert, Senn), and principles such as adequate exposure and a tension-free anastomosis. Suture materials are typically absorbable polymers mounted on atraumatic needles."

1. Knotting & Anastomosis
Presentor – Dr Thana Ram Patel
Junior resident
Moderator – Dr Amit Jain
Associate professor
SMS medical college & AGH, Jaipur

2. Knotting techniques
• Hand tied knot - are commonly described as one
handed or two handed – slightly confusing
because both techniques involve two hands.
(based on the way that the end is guided through
each knot)
• One handed (pulling technique)
• Two handed (pushing technique)
• Instrument tied knot
• Endoscopic knot tying

3. Square knot
• A square knot is performed on tissues that are not
under tension and is composed of 2 simple knots
• One handed technique- once the first throw is
completed using the index finger technique , a second
throw will be added using the middle finger technique
• Two handed technique – once the first throw is
completed , another simple knot will be added in order
to obtain the square knot
• Square knot with instrument
• Deep tie
• Sliding knot

11. Granny knot

12. Surgeon knot

19. sutures
• Suture characteristics – five
• Physical structure
• Strengh
• Tensile behavior
• Absorbability
• Biological behavior

20. Physical structure
• monofilament or multifilament.
• Monofilament suture material is material can be easily damaged
by gripping it with needle holder or forceps and this can lead to
fracture of the suture material.
• Multifilament or braided sutures have a capillary action and
interstices where bacteria may lodge and be responsible for
persistent infection or sinuses. In order to overcome some of
these problems, certain materials are produced as a braided
suture, which is coated with silicone in order to make it smooth.
monofilament multifilament
knotting difficult easier
Surface area Less (smooth) More (capillary
action &
interstices)

21. strength
• The strength of a suture material depends upon its constituent material, its thickness and
how it is handled in the tissues.
• Suture material thickness is classified according to its diameter in tenths of a millimetre.
• The tensile strength of a suture can be expressed as the force required to break it when
pulling the two ends apart.
• Absorbable sutures show a decay of this strength with the passage of time and although a
material may last in the tissues for the stated period in the manufacturer’s product profile,
its tensile strength cannot be relied on in vivo for this entire period.
• Catgut have a tensile strength that lasts only about a week, PDS will remain strong in the
tissues for several weeks
• non-absorbable sutures do not necessarily maintain their strength indefinitely, and may
degrad with time.
• Those non-absorbable materials of synthetic origin, such as polypropylene, probably retain
their tensile strength indefinitely and do not change in mass in the tissues, although it is
still possible for them to fracture.
• Non-absorbable materials of biological origin, such as silk, will definitely fragment with
time and lose their strength, and such materials should never be used in vascular
anastomoses for fear of late fistula formation.

22. Tensile behavior
• Suture materials behave differently depending upon their deformability
and flexibility.
• Some may be ‘elastic’, where the material will return to its original length
once any tension is released, while others may be ‘plastic’, in which case
this phenomenon does not occur.
• Sutures may be deformable, in that a circular cross-section may be
converted to an oval shape, or they may be more rigid and have the
somewhat irritating capacity to kink and coil.
• Many synthetic materials demonstrate ‘memory’, so that they keep curling
up in the shape they adopted within the packaging. A sharp but gentle pull
on the suture material helps to diminish this memory, but the more
memory a suture material has, the lower is the knot security. Therefore,
knotting technique also plays a significant role in any suture line’s tensile
strength and it is important to recognise that sutures lose 50% of their
strength at the knot

23. Absorbability
• Suture materials may be non-absorbable or absorbable and this
property must be taken into consideration when choosing suture
material for specific wound closures or anastomoses.
• Sutures for use in the biliary or urinary tract need to be absorbable
in order to minimise the risk of stone production.
• a vascular anastomosis requires a non-absorbable material and it is
wise to avoid braided material because platelet adherence may
predispose to distal embolisation.
• Nonabsorbable materials tend to be preferred where persistent
strength is required and, as an artificial graft or prosthesis never
heals fully or integrates into a host artery, persistent monofilament
suture materials, such as polypropylene, are almost universally
used.

24. Biological behavior
• The biological behaviour of suture material within the tissues
depends upon the constituent raw material.
• Biological or natural sutures, such as catgut, are proteolysed, but
this involves a process that is not entirely predictable and can cause
local irritation, and such materials are therefore seldom used.
• Synthetic polymers are hydrolysed and their disappearance in the
tissues is more predictable. However, the presence of pus, urine or
faeces influences the final result and renders the outcome more
unpredictable. There is also some evidence that, in the gut, cancer
cells may accumulate at sites where sutures persist, possibly giving
rise to local recurrence. For this reason, synthetic materials that
have a greater predictability and elicit minimal tissue reaction may
have an important non-carcinogenic property.

28. Alternatives to sutures
• Skin adhesive strips For the skin, self-adhesive tapes or steristrips may be
used where there is no tension and not too much moisture, such as after a
wide excision of a breast lump. They may also be used to minimise
‘spreading’ of a scar..
• Tissue glue Tissue glue is also available, based upon a solution of n-butyl-
2-cyanoacrylate monomer. When it is applied to a wound, it polymerises
to form a firm adhesive bond, but the wound does need to be clean, dry,
with near perfect haemostasis and under no tension.
• Tissue glue has been used for hemostasis
• This process has good adhesive properties and has been used for
haemostasis in the liver and spleen, for dural tears, in ear, nose and throat
(ENT) and ophthalmic surgery, to attach skin grafts and also to prevent
haemoserous collections under flaps. Fibrin glues have also been used to
control gastrointestinal haemorrhage endoscopically, but do not work
when the bleeding is brisk.

29. Surgical staplers
• Mechanical stapling devices with linear, side-to-side and end-to-end
stapling devices that can be used both in the open surgery setting
and laparoscopically.
• Linear cutting staplers allow bowel and blood vessels to be sealed
and divided.
• Most of these devices are disposable and relatively expensive, but
their cost is offset by the saving of operative time and the potential
increase in the range of surgery possible.
• For all stapling devices, it is crucial for the surgeon to understand
the principles behind the device and to know intimately the
mechanism and function of the instrument.
• the surgeon must be trained in their safe use and aware of the
principles, including different staple sizes.
• Linear and circular staplers also allow intracorporeal anastomoses
to be performed.

30. Open Surgical staplers
• Linear cutting stapler(55mm,75mm,100mm)-
Gastrointestinal anastomosis staplers/GIA stapler- (side
to side anastomosis ) -simultaneously divide the bowel
or tissue that has been stapled
• Linear non-cutting stapler(30mm,55mm) -Transverse
anastomosis stapler/TA - merely insert the staples and
the bowel has to be divided separately.
• Circular stapler -Circular end to end anastomosis
stapler /CEEA-( end to end anastomosis -
)simultaneously divide the bowel or tissue that has
been stapled

36. Laparoscopic stapler
• LAPAROSCOPIC STAPLING DEVICES. Many of
the intestinal stapling devices are now
adapted to be inserted down trocars during
laparoscopic surgery, and although they look
very different, the principles of function are
identical to their open surgical equivalent.
• endoGastrointestinal anastomosis
staplers/endoGIA stapler

40. • White cartridge – vascular sealing
• Blue cartridge –small intestine sealing &
cutting
• Green cartridge – stomach, rectum

41. Suture techniques
• Interrupted sutures
 Simple interrupted sutures (sutura nodosa)
 Vertical mattress suture (donati)
 Vertical mattress suture (allgower)
 Horizontal mattress suture
• Continuous sutures
 Simple continuous suture
 Locked continuous suture
 Subcuticular continuous suture
 Purse string suture

43. Simple interrupted sutures
• the needle to be inserted at right angles to the incision and then to
pass through both aspects of the suture line and exit again at right
angles.
• It is important for the needle to be rotated through the tissues
rather than to be dragged through for fear of unnecessarily
enlarging the needle hole.
• As a guide, the distance from the entry point of the needle to the
edge of the wound should be approximately the same as the depth
of the tissue being sutured, and each successive suture should be
placed at twice this distance apart
• Each suture should reach into the depths of the wound and be
placed at right angles to the axis of the wound. In linear wounds, it
is sometimes easier to insert the middle suture first and then to
complete the closure by successively inserting sutures, halving the
remaining deficits in the wound length.

44. Mattress sutures
• either vertical or horizontal
• tend to be used to produce either eversion or
inversion of a wound edge.
• The initial suture is inserted as for an interrupted
suture, but then the needle either moves
horizontally or vertically and traverses both edges
of the wound once again.
• Such sutures are very useful in producing
accurate approximation of wound edges,
especially when the edges to be anastomosed are
irregular in depth or disposition.

45. Simple continuous sutures
• the first suture is inserted in an identical manner to an interrupted suture,
but the rest of the sutures are inserted in a continuous manner until the
far end of the wound is reached.
• Each throw of the continuous suture should be inserted at right angles to
the wound and this will mean that the externally observed suture material
will usually lie diagonal to the axis of the wound.
• It is important to have an assistant who will follow the suture, keeping it at
the same tension in order to avoid either purse stringing the wound by too
much tension, or leaving the suture material too slack.
• There is more danger of producing too much tension by using too little
suture length than there is of leaving the suture line too lax. Postoperative
oedema will often take up any slack in the suture material.
• At the far end of the wound, this suture line should be secured either by
using an Aberdeen knot or by tying the free end to the loop of the last
suture to be inserted

46. Subcuticular suture
• This technique is used in skin where a cosmetic
appearance is important and where the skin
edges may be approximated easily.
• The suture material used may be either
absorbable or non-absorbable.
• For non-absorbable sutures, the ends may be
secured by means of a collar and bead, or tied
loosely over the wound.
• When absorbable sutures are used, the ends may
be secured using a buried knot. Small bites of the
subcuticular tissues are

47. anastomosis
• The word anastomosis comes from the Greek
‘ana’, without, and ‘stoma’, a mouth,
reflecting the join of a tubular viscus (bowel)
or vessel (usually arteries) after a resection or
bypass procedure.

48. principles
• Construction of an anastomosis that is at low risk for disruption
requires the following:
 Adequate exposure, gentle handling of tissues, aseptic precaution,
and meticulous, careful dissection
 Adequate mobilization so that the two attached organs have a
tension-free anastomosis
 Correct technical placement of sutures or staples with little variance
 Matching of the lumina of the two organs to be connected, which
can be done by various techniques
 Preservation of the blood supply to the ends of structures to be
anastomosed
 Accurate approximation of two well-vascularized, healthy limbs of
bowel without tension in a normotensive, wellnourished patient
almost always results in a good outcome.

49. Anastomoses heal
• Intestinal anastomoses heal in a series of
overlapping phases:
lag phase (inflammatory)(days 0–4), in which the
acute inflammatory response clears the wound of
debris
phase of fibroplasia(proliferation) (days 3–14), in
which fibroblasts proliferate and immature
collagen is laid down
maturation phase (remodelling)(day 10 onwards),
in which collagen remodels.

51. Bowel anastomoses
• Lembert seromuscular suture technique for bowel
anastomosis
• Senn two-layer technique using silk
• Kocher’s two-layer anastomosis, first a continuous all-layer
suture using catgut, then an inverting continuous (or
interrupted) seromuscular layer suture using silk, which
became the mainstay of bowel anastomoses for many years
• Conell-single layer interrupted,full thickness
• Halsted & Matheson one-layer extramucosal closure - was
felt to cause the least tissue necrosis or luminal narrowing.
This technique has now become widely accepted.

53. • although it is essential that this is not confused with a
seromuscular suture technique. The extramucosal
suture must include the submucosa because this has a
high collagen content and is the most stable suture
layer in all sections of the gastrointestinal tract.
• There are several prospective randomised trials
comparing two-layer and single-layer anastomoses
demonstrating that there is probably little to choose
between these techniques.
• However, catgut and silk have been replaced by
synthetic, usually absorbable, polymers.

54. Bowel preparation
• In the past, great emphasis was placed on good bowel preparation
prior to any anastomosis.
• The rationale was that, with good bowel preparation and an empty
bowel, there was less likelihood of faecal contamination and
therefore it was probably not necessary to apply bowel clamps
(even of the soft occlusion type).
• However, this tradition is now being challenged, and there is
evidence to suggest that conventional bowel preparation provides
little benefit, and indeed at times may prove detrimental to the
outcome.
• In spite of this, many surgeons still use some form of bowel
preparation, especially for colorectal surgery. Furthermore, if there
is any risk of intestinal spillage during anastomosis, when bowel is
unprepared or obstructed for example, atraumatic intestinal

55. • For all intestinal anastomoses, the bowel ends must be brought together without
tension.
• Stay sutures, which avoid the need for tissue forceps, are invaluable for displaying
the bowel ends and help with the accurate alignment of the bowel and the
placement of the sutures.
• If the anastomosis is being undertaken on mobile bowel, the anterior wall layer of
sutures can be inserted, either in a continuous or interrupted manner, and then
the bowel rotated and the posterior wall sutured in an identical manner to the
anterior wall.
• As the mesenteric edge of the bowel is the most difficult, especially when a fatty
mesentery is present, this angle should be dealt with first, with the final sutures
being inserted at the antimesenteric border which is far more accessible and
visible.
• The apposition of bowel edges should be as accurate as possible and the suture
bites should be approximately 3–5 mm deep and 3–5 mm apart, depending on the
thickness of the bowel wall.

56. • The suture materials should be of 2/0–3/0 size and made of an absorbable
polymer, which can be braided (e.g. polyglactin) or monofilament (e.g.
polydioxanone), mounted on an atraumatic round-bodied needle. Braided,
coated sutures are the easiest to handle and knot.
• It is crucial that only bowel of similar diameter is brought together to form
an end-to-end anastomosis.
• In cases of major size discrepancy, a side-to-side or end-to-side
anastomosis may be safer.
• In cases where the size discrepancy is not marked, a Cheatle split (making
a cut into the antimesenteric border) may help to enlarge the lumen of
distal, collapsed bowel and allow an end-to-end anastomosis to be
fashioned.
• After all anastomoses, the mesentery should always be closed to avoid the
later risk of an internal hernia through a persistent mesenteric defect.
Care must be taken during closure of this defect to prevent damage to any
mesenteric vessels running in the edge of the mesentery.

57. Stapler assisted anastomosis
• In certain situations, stapling devices are used
to fashion the anastomosis, but as they are
expensive, many surgeons reserve them for
specific indications, such as oesophageal,
rectal and gastric pouch procedures.
• Several studies have shown them not to be
cost effective in routine small bowel surgery,
although many surgeons still use them for
ease of use and to save time.

58. Transverse anastomoses
• instruments, which come in different sizes, simply
provide two rows of staples for a single transverse
anastomosis.
• They are useful for closing bowel ends, and the larger
sizes have been used to create gastric tubes and gastric
partitioning.
• One technical point of importance is that the bowel
should be divided before the instrument is reopened
after firing, as the instrument is designed with a ridge
along which to pass a scalpel to ensure that the cuff of
bowel that remains adjacent to the staple line is of the
correct length.

59. Intraluminal anastomoses
• These instruments have two limbs which can be
detached.
• Each limb is introduced into a loop of bowel, the
limbs reassembled and the device closed.
• On firing, two rows of staples are inserted either
side of the divided bowel, the division occurring
by means of a built-in blade that is activated at
the same time as the insertion of staples.
• Such an instrument may be used in fashioning a
gastro-jejunostomy or jejuno-jejunostomy and is
used in ileal pouch formation.

60. End to end anastomoses
• Circular stapling devices allow tubes to be joined together, and such
instruments are in common use in the oesophagus and low rectum.
• The detached stapling head/anvil is introduced into one end of the bowel,
usually being secured within it by means of a purse-string suture.
• The body of the device is then inserted into the other end of the bowel,
either via the rectum for a low rectal anastomosis, or via an enterotomy
for an oesophago-jejunostomy, and the shaft is either extended through a
small opening in the bowel wall or secured by a further purse-string
suture.
• The head/anvil is reattached to the shaft and the two ends approximated.
Once the device is fully closed, as indicated by the green indicator in the
window, the device is fired, and, after unwinding, the stapler is gently
withdrawn.
• It is important to assess the integrity of the anastomosis by examining the
‘doughnuts’ of tissue excised for completeness. It is essential that no
extraneous tissue is allowed to become interposed between the two
bowel walls on closing the stapler.

61. Laparoscopic anastomosis
• The same principles apply to laparoscopic anastomosis as to open
anastomosis: good blood supply, the avoidance of tension and gentle
tissue handling.
• Both sutured and stapled anastomoses can be performed using
laparoscopic needle holders and staplers adapted to laparoscopic surgery.
• If the ends of the bowel have been adequately mobilised, and there is a
specimen extraction site (e.g. right hemicolectomy), an extracorporeal
anastomosis can be performed using open surgical techniques.
• If one or both ends of the bowel to be anastomosed cannot be
exteriorised, an intracorporeal anastomosis can be performed.
• In intra-abdominal surgery, enterotomies are performed in the proximal
and distal ends to be anastomosed and a linear stapler is used to join the
two ends. The resulting common enterotomy is then closed with a running
suture.

62. Vascular anastomoses
• Vascular anastomoses require an extremely accurate closure as
they must be immediately watertight at the end of the operation
when the vascular clamps are removed.
• In many cases, some form of prosthetic material or graft may be
used which will never be integrated into the body tissues and so the
integrity of the suture line needs to be permanent.
• For this reason, polypropylene is one of the best sutures because it
is not biodegradable. It is used in its monofilament form, mounted
on an atraumatic, curved, round-bodied needle.
• Knot security is important, and as polypropylene is monofilament
and the anastomosis often depends on one final knot, several
throws (between six and eight) of a well-laid reef knot are required.
• The suture line must be regular and watertight with a smooth
intimal surface to minimise the risk of thrombosis and embolus, as
well as to avoid any leakage.

63. • Suture size depends on vessel calibre:
• 2/0 is suitable for the aorta,
• 4/0 for the femoral artery
• 6/0 for the popliteal to distal arteries.
• Microvascular anastomoses are made using a loupe and an
interrupted suture down to 10/0 size.
• All vessel walls must be treated with great care, avoiding causing
any damage to the intima. If any significant manipulation is
necessary, atraumatic forceps (such as DeBakey’s) are utilised.
• Vascular clamps should be applied with great care, particularly for
calcified vessels, and in some cases encircling rubber loops or
intraluminal balloon catheters may be less traumatic for control.
• Carrel – end to end vascular anastomosis

64. THANK YOU