This document discusses wound closure, suturing techniques, and suture materials. It provides details on ideal characteristics of suture materials, different suture characteristics like strength and absorbability. It also describes various suturing techniques like simple interrupted, continuous, and mattress sutures. Finally, it discusses alternatives to sutures like skin adhesives, tissue glue, and techniques for laparoscopic wound closure.

1. WoundClosure
Hadi Munib
Oral and Maxillofacial Surgery

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Outline
• Wound Closure
• Ideal Characteristics of Suture Materials
• Suture Characteristics
• Suturing Techniques
• Needle Size
• Alternatives to Sutures
• References
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WoundClosure
• The suturing of any incision or wound needs to take into consideration
• The site and tissues involved
• The technique for closure.
• There is no ideal wound closure technique that would be appropriate for all
situations.
• The correct choice of suture technique and suture material is vital, but will never
compensate for inadequate operative technique
• There must be a good blood supply and no tension on the closure
• Clean uninfected wounds with a good blood supply heal by primary intention and
therefore closure simply requires accurate apposition of the wound edges.
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WoundClosure
• If a wound is left open, it heals by secondary intention through the formation of
granulation tissue, which is tissue composed of capillaries, fibroblasts and
inflammatory cells.
• Wound contraction and epithelialization assist in ultimate healing, but the process
may take several weeks or months.
• Delayed primary closure, or tertiary intention, is utilized when there is a high
probability of the wound being infected.
• The wound is left open for a few days and, provided any infective process has
resolved, the wound is closed to heal by primary intention.
• Skin grafting is another form of tertiary intention healing
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WoundClosure
• When choosing suture materials, there are certain specific requirements depending
on the tissues to be sutured.
• Vascular anastomoses require smooth, non-absorbable, non-elastic material
• Biliary anastomoses require an absorbable material that will not promote tissue
reaction or stone formation.
• When using absorbable material, the time for which wound support is required and
maintained will vary according to the tissues in which it is inserted.
• Certain tissues require wound support for longer than others [muscular aponeuroses
compared with subcutaneous tissues].
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SutureCharacteristics–PhysicalStructure
• Suture material may be monofilament or multifilament.
• Monofilament sutures are smooth and they tend to slide through tissues easily
without any sawing action, but are more difficult to knot effectively and they can be
easily damaged by gripping it and this can lead to fracture of the suture material.
• Multifilament or braided sutures are much easier to knot, but have a surface area of
several thousand times that of monofilament sutures and thus have a capillary
action and interstices where bacteria may lodge and be responsible for persistent
infection or sinuses.
• Certain materials are produced as a braided suture, which is coated with silicone in
order to make it smooth.
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SutureCharacteristics-Strength
• The strength depends upon its constituent material, its thickness and how it is
handled in the tissues.
• Absorbable material and non-absorbable material, such as polypropylene, may differ
in their designations.
• The tensile strength of a suture; the force required to break it when pulling the two
ends apart.
• Only a useful approximation as to its strength in the tissues, because what matters is
the material’s in vivo strength.
• Absorbable sutures show a decay of this strength with the passage of time
• The 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.
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SutureCharacteristics
• Catgut (no longer in use in the UK), have a tensile strength that lasts only about a
week.
• PDS will remain strong in the tissues for several weeks.
• Even non-absorbable sutures do not necessarily maintain their strength indefinitely,
and may degrade 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.
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SutureCharacteristics-Tensilebehaviour
• Suture materials behave differently depending upon their deformability and flexibility.
• Could be ‘elastic; the material will return to its original length once any tension is
released
• Others can be ‘plastic’
• 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.
• Knotting technique also plays a significant role in any suture line’s tensile strength and
it is important to recognize that sutures lose 50% of their strength at the knot.
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SutureCharacteristics-Absorbability
• Suture materials may be non-absorbable or absorbable
• Sutures for use in the biliary or urinary tract need to be absorbable in order to
minimize the risk of stone production.
• Vascular anastomosis requires a non-absorbable material and it is wise to avoid
braided material because platelet adherence may predispose to distal embolization.
• Non-absorbable materials tend to be preferred where persistent strength is required.
• 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.
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SutureCharacteristics–BiologicalBehaviour
• Depends upon the constituent raw material.
• Biological or natural sutures 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 hydrolyzed and their disappearance in the tissues is more
predictable.
• The presence of pus, urine or feces 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.
• Synthetic materials that have a greater predictability and elicit minimal tissue reaction
may have an important non-carcinogenic property.
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Non-AbsorbableSutureMaterials
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AbsorbableSutureMaterials
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Barbedsutures
• Recently, novel suture materials have helped surgeons to reduce or eradicate the
need for knot tying in some situations, such as laparoscopic surgery.
• These sutures have unidirectional or bidirectional barbs that secure the suture in the
tissues.
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SuturingTechniques–SimpleInterrupted
• They require 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.
• The needle should be rotated through the tissues rather than to be dragged through,
to avoid unnecessarily enlarging the needle hole.
• 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
• 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.
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SuturingTechniques–ContinuousSuturing
• 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.
• Producing too much tension by using too little suture length is more dangerous than
leaving the suture line too lax.
• Postoperative edema 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.
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SuturingTechniques–MattressSutures
• May be either vertical or horizontal and 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 moves
either 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
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VerticalMattress
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HorizontalMattress
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SuturingTechniques–SubcuticularSuturing
• 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.
• For absorbable sutures are used, the ends may be secured using a buried knot.
• Small bites of the subcuticular tissues are taken on alternate sites of the wound and
then gently pulled together, thus approximating the wound edges without the risk of
the cross-hatched markings of interrupted sutures
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Needles
• The needle has three main parts:
• shank;
• body;
• point.
• The needle should be grasped by the needle holder approximately one-third to one-
half of the way back from the rear of the needle, avoiding both the shank and the
point.
• The closer the needle holder is to the tip of the needle, the greater the accuracy of
suture placement and the less the degree of rotation of the surgeon’s hand required
in suturing.
• The needle should never be grasped nearer than one-third of the way back from the
rear of the needle.
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Needles
• The body of the needle is either round, triangular or flattened.
• Round-bodied needles gradually taper to a point
• Triangular needles have cutting edges along all three sides.
• The actual point of the needle can be round with a tapered end, conventional cutting
which has the cutting edge facing the inside of the needle’s curvature, or reverse
cutting in which the cutting edge is on the outside.
• Round- bodied needles are designed to separate tissue fibers rather than cut through
them and are commonly used in intestinal and cardiovascular surgery.
• Cutting needles are used where tough or dense tissue needs to be sutured, such as
skin and fascia.
• Blunt-ended needles are now being advocated in certain situations, such as closure of
the abdominal wall, in order to diminish the risk of needle-stick injuries in this era of
bloodborne infectious diseases.
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Needles
• The choice of needle shape tends to be dictated by the accessibility of the tissue to be
sutured, and the more confined the operative space, the more curved the needle.
• Hand-held straight needles may be used on skin, although today it is advocated that
needle holders should be used in all cases to reduce the risk of needle-stick injuries.
• Half circle needles are commonly utilized in the gastrointestinal tract
• J-shaped needles are used in special situations as in vagina suturing
• Quarter circle needles are used in special situations as in eye injuries
• Compound curvature needles are used in special situations as in oral cavity.
• The size of the needle tends to correspond with the gauge of the suture material,
although it is possible to get similar sutures with differing needle sizes
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AlternativestoSutures-Skinadhesivestrips
• For the skin, self-adhesive tapes or steristrips may be used where there is no tension
and not too much moisture.
• Wide excision of a breast lump.
• They may also be used to minimize ‘spreading’ of a scar.
• Other adhesive polyurethane films, such as Opsite, Tegaderm or Bioclusive, may
provide a similar benefit, while such transparent dressings also allow wound
inspection and may protect against cross-infection.
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AlternativestoSutures–TissueGlue
• 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.
• Closing a laceration on the forehead of a fractious child in Accident and Emergency,
thus dispensing with local anesthetic and sutures.
• Relatively Expensive
• Quick to use, does not delay wound healing and is associated with an allegedly low
infection rate.
• Other tissue glues involve fibrin and work on the principles of converting fibrinogen
to fibrin by thrombin with crosslinking by factor XIII, and the addition of aprotinin to
slow the breaking up of the fibrin network by plasmin.
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AlternativestoSutures–TissueGlue
• This process has good adhesive properties and has been used for hemostasis 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 hemoserous collections under flaps.
• Fibrin glues have also been used to control gastrointestinal haemorrhage
endoscopically, but do not work when the bleeding is brisk.
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AlternativestoSuturing–LaparoscopicWoundClosure
• Laparoscopic wounds are generally 3–12 mm in length.
• As with all incisions they should be parallel to Langer’s lines where possible.
• Skin closure can be carried out with sutures, using curved or straight needles, or glue,
and can be further secured with adhesive strips.
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AlternativestoSuturing-Stapling
• Mechanical stapling devices were first used successfully by Hümer Hültl in Hungary in
1908 to close the stomach after resection.
• There is a wide range of mechanical devices with linear, side-to-side and end-to-end
stapling devices that can be used both in the open surgery setting and
laparoscopically.
• 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.
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References
• CHAPTER 7 Basic surgical skills and anastomoses
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41. THANKYOU!
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