Sutures, Needles, Suturing Techniques,

and Knot Tying

Dr. D. W. Daugherty

Department of Surgery

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Goals of Suturing

• Aid in wound healing

• Avoid wound infection

• Assist hemostasis

• Produce aesthetically pleasing scar by approximating skin edges

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Historical Landmarks

• The earliest records of surgical suture date back to 3500 B.C. in Egypt. The script is now known as The Edwin Smith Surgical Papyrus.

• The oldest physical evidence of surgical suture dates to between 500-100 B.C. Evidenced by several mummies who had been sutured which were found in Egypt.

• Hippocrites first used the term ‘suture’ in 400 B.C. The meaning is literally to ‘sew’ or ‘seam’.

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Historical Landmarks• In 100 B.C., Cornelius Celsus, a Roman,

used the word as a noun and a verb – “the suture” and “to suture”.

• The first sutures were fashioned from hair, cotton, tendon, or silk. They were used on needles made of bone, stone, or wood.

• Sutures were originally used to close open wounds, but shortly were adapted to ligate tissue as well. This method was successful but infection rate was extremely high.

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Historical Landmarks• In 1867, Joseph Lister first attempted to sterilize

suture. He used silk suture that was ‘sterilized’ in carbolic acid. The first trials were unsuccessful.

• In 1869, Lister changed to ‘catgut’ suture, which was being widely used in Germany due to its absorbability. The trials showed great reduction in infection rates.

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Historical Landmarks• Inspired by the data from Joseph Lister, Robert

Wood Johnson and his brothers, Edward Mead Johnson and James Wood Johnson, started a small business in 1885 – they named it Johnson & Johnson.

• In 1886, Johnson & Johnson was the first company to mass produce Joseph Lister’s sterile catgut suture.

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Historical Landmarks

• Johnson & Johnson, off of its success from sterile suture and sterile dressing sales, became incorporated in 1887.

• In 1906, Iodine was first produced in Germany by the B. Braun Company.

• In 1956, Johnson & Johnson created an independent division for its suture production and sales – it was named Ethicon.

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Wound healing

• Phases of wound healing– Coagulation begins immediately following injury

– Epithelialization of the surgical repair should occur within 48 hours of suturing• New blood vessel growth peaks at 4 days

– Collagen reformation starts at 48 hours, peaks at 1 week and continues for 12 months

– Wound contraction starts 3-4 days and can last up to 2 years after the injury / repair

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Factors limiting wound healing

• Steroids• Sepsis• Malnutrition• Diabetes• Obesity• Smoking• Chemotherapy and Radiation• Anticoagulants• Antiplatelet medications• Collagen and Vascular Diseases• Local factors

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Layers of Skin

• Fascial closure is usually, but not always required.

• Approximation of the subcutaneous tissue aids in healing by closing dead space.

• Approximation of dermis achieves good surface alignment and relieves tension so the epidermis can be closed with a good cosmetic result.

• The best cosmetic results occur if the epidermis is perfectly aligned and tension free. This is ensured by proper closure of the deeper layers.

Epidermis

Dermis

Subcutaneous tissue

Deep fascia

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Suture Material

• Absorbable vs. Non-Absorbable

• Natural vs. Synthetic

• Monofilament vs. Braided

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Suture Material

• Absorbable – Natural: Gut - beef serosa or sheep submucosa– Synthetic: Vicryl, Monacryl, PDS

• Non-Absorbable – Natural: Silk, Steel, Cotton– Synthetic: Nylon, Prolene, Ethibond, Dacron

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Suture Material• Monofilament – Monacryl, Nylon, Prolene, PDS, Gut, Steel

• Braided– Silk, Cotton, Vicryl*, Ethibond, Dacron

* Manufactured in monofilament and braided 13

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Suture Material

• Uncoated – Plain suture. If absorbable, breaks down faster.

• Coated– Chromic, Polyglactin, Antibiotic. If absorbale, delays

breakdown.

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Suture Size (Diameter)

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Suture Size (Diameter)

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Suture Properties• Absorption: – Progressive breakdown and loss of mass and/or

volume of suture material; does not correlate with initial tensile strength. Ultimately, tensile strength is lost as the suture degrades.

• Capillary Absorption :– Extent to which absorbed fluid is transferred along

the suture.

• Fluid Absorption:– Ability to take up fluid after immersion.

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Suture Properties

• Tensile Strength:– Measure of a material or tissue's ability to resist

deformation and breakage

• Breaking Strength: – The tension at which suture failure occurs. The

maximum limit of the tensile strength.

• Elasticity:– Measure of the ability of the material to regain its

original form and length after deformation. If deformed beyond its elastic property, the suture is greatly weakened.

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Suture Properties• Plasticity:– Measure of the ability to deform without breaking.

• Memory:– Inherent tendency of suture material to retain its

shape. Related to the elasticity, plasticity, and diameter of the suture.

• Pliability:– Ease of manipulating the suture, such as the ability

to adjust knot tension and to secure knots. Related to the suture material, filament type, and diameter.

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Suture Properties• Straight-Pull Tensile Strength:– Linear breaking strength of suture material.

• Knot Strength:– Amount of force necessary to cause a knot to slip

(related to the coefficient of friction and plasticity)

• Knot-Pull Tensile Strength:• Breaking strength of the knot. (10-40% weaker at knot)

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Suture Properties• Suture Pullout Value:– The amount of force on a suture required to cause

tissue failure. • Measurement of the strength of a particular tissue• Variable depending on anatomic site and composition

(fat, 0.2 kg; muscle, 1.27 kg; skin, 1.82 kg; fascia, 3.77 kg)

• Wound Breaking Strength: – Limit of tensile strength of a healing wound at

which separation of wound edges occurs. Based on collagen properties.

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Suture Construction

• The point is the sharpest portion and is used to penetrate the tissue. Shape varies. Delicate!

• The body represents the mid portion of the needle. Solid Steel. Strongest portion.

• The swage is the portion to which the suture material is attached. Instrumentation here will break or weaken the suture.

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Needle Types

• Tapered:– The needle penetrates and passes through tissues

by stretching without cutting.

–Used for easily penetrated tissues (SubQ, Dura, Peritoneum, Abdominal Viscera).

–Minimizes potential tearing, bleeding, and tissue damage. 23

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Needle Types

• Cutting:–Conventional versus Reverse Cutting

– The needle has 2 opposing cutting edges

–Designed for penetration through dense tissue24

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Needle Types

• Intestinal– Either a Taper-Cutting or a Taper-Point needle.

Designed to make a hole slightly smaller than the diameter of the suture. The hole is then ‘sealed’ by the suture.

– Especially good for the GI tract, biliary tract, dura, urogenital tract, and blood vessels. 25

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Needle Types

• Blunt – Blunt-Point design for suturing tissue that is

extremely friable or densely vascular.

– Liver, spleen, kidney, pancreas.

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Needle Shapes

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Needle Sizes

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Suture Technique• A needle holder is used to

grasp the needle at the distal portion of the body, one half to three quarters of the distance from the tip of the needle.

• The needle holder should not be tightened excessively because damage to both the needle and the needle holder may result.

• Incorrect placement of the needle in the needle holder may result in a bent needle, injury to the tissue, and/or an undesirable angle of entry into the tissue.

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Suturing Technique• A needle holder is held with

the first and fourth fingers in the appropriate finger holes. The second and third fingers are used for stabilization and fine control of the instrument.

• Surgeons who have mastered the foundational techniques can then modify their technique as needed (eg. ‘palming’ the driver).

• When suturing, always sow towards yourself.

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• The tissue must be stabilized to allow needle placement. Toothed or plain forceps may be used to gently grasp the tissue. Excessive trauma to the tissue being should be avoided to reduce the possibility of tissue strangulation and necrosis.

• Forceps are meant primarily for grasping tissue. Not for handling the needle.

• Sometimes it is necessary to grasp the needle as it exits the tissue after a pass. Grasping and stabilizing the needle should be done prior to releasing the needle holder. Otherwise, the needle may become lost in the tissues.

Suturing Technique

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• The needle should always penetrate the tissue at a 90° angle; that is, in a perpendicular plane. This minimizes the size of the entry wound and promotes a proper path through the tissue. Not doing so results in excessive tissue damage and sub-optimal or incorrect positioning of the suture.

• The distance traveled, depth, and angle of the suture depends on the surgeon goal. In general, the 2 sides of the stitch being placed should be mirror images, with the needle also exiting the tissue in a perpendicular plane.

Suture Technique

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• Simple, uncomplicated wounds

• Easy technique to learn

• If one breaks, integrity of closure is maintained

• Slow to apply

• Skill required to get ideal

spacing and tension

Simple Interrupted

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• Simple, uncomplicated wounds

• Physics similar to simple interrupted

• Even tension along suture

• Fast application

• Less knots, but break one and the whole stitch unravels

Simple Running

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• Can be either running or interrupted

• Simple, uncomplicated wounds

• Excellent cosmetic closure

• No stitches to remove

• Technically more difficult to master

• Doesn’t hold in thin skin

Subcuticular

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• Achieves good wound edge eversion

• Some claim cosmetically superior to vertical mattress

• Thick skin and subcutaneous tissue– Feet, hands, back

• Good for wounds under tension

• Makes a “box” shape

Horizontal Mattress

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• Excellent for deep wounds and/or wounds under high tension

• If done well, very good cosmetic result

• Good eversion of wound edges

• Thick skin and subcutaneous tissue

• Approximates deep tissue and superficial tissue with one stitch

Vertical Mattress

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Other Common Stitches

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Knot Tying

• Make sure you tie a square knot • Reverse your hands• If you don’t…

– Granny knots and slip knots will not hold – Require more throws – add to bulk– Increased likelihood of dehiscence or infection 39

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Knot Tying

• Square (Reef) Knot: essential for knot strength

• Surgeon’s Knot: double throw on the first half-hitch

• Slip Knot: good for tension and can be converted to a square not by crossing hands

• Number of throws • Too many

– Bulky knot is a nidus for infection• Too few

– May not hold

• Tails• According to a any good surgeon, there are only two suture tail

lengths: 1) too short and 2) too long…40

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• The needle holder is placed parallel with the incision (or vessel) being tied. The long end of the suture is wrapped around the tip of the needle holder in a clockwise direction forming a loop. The short end of the suture is grasped with the needle holder and pulled through the loop. Bring the short end of the suture toward you. This creates the first hitch of a square knot.

• The second hitch is formed by wrapping the long end of the suture around the instrument in a counterclockwise direction. The short end of the suture is then grasped and pulled through the loop. Pull the needle holder away from you, squaring the knot.

Instrument Tie

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• The greatest precision in maintaining constant tension on the suture during the tying process

• Preferred by most surgeons (especially when others are tying)

• Easier of the techniques to master successfully

• More reliably produces square knots

• If you want to be a surgeon, master this technique

Two Handed Tie

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• The one-handed knot is so named because all of the maneuvering, including releasing and re-grasping the free end, is done with one hand. The other hand merely holds the fixed segment taut.

• One handed knots have the advantage of allowing more speed in tying, but have less tension control of the segments.

• The maneuvering is done with the left hand so that a surgeon tying his own knots during suturing can continue to hold the needle holder in his right hand.

• More difficult to achieve excellent square knots. Unforgiving of lapses in technique.

One Handed Tie

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Suture Removal

• Abdomen 10-12 days• Back 10-12 days• Chest 10-12 days• Extremity 10-14 days• Hands & Feet 10-14 days• Knee & Elbow 12-14 days• Scalp 10-12 days

• Eyebrow 4-5 days• Eyelid 4-5 days• Face 4-5 days• Lip 4-5 days• Neck 5-6 days• Oral Cavity 6-8 days• Pinna (ear) 4-6 days

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Summary• Essential to aid in wound healing and achieve acceptable

cosmesis when closing wounds.

• Mastery is essential to all aspects of surgery, from maintaining hemostasis to restoring proper function of the organ systems.

• Knowledge of the suture materials, needles (type, size, and shape), instruments, and techniques are absolutely necessary in order to be a competent surgeon.

• Everyone thinks they can tie, but there is a big difference between simply being able to do something and doing it correctly. Tie secure, square knots.

• Master Two Handed Ties first.

• Practice, Practice, Practice! 46

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Questions?

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