essay 20 - surgical Sutures and suturing - Instruments and Materials. Types of sutures and knots. Techniques

what are Surgical sutures

• the term “ suture” refers to any strand of material used to ligate blood vessels or approximate tissues for the purpose of closing a wound.

• sutures are fundamental in both minor and major surgical procedures

what are the optimal suture characteristics

1. high, uniform tensile strength

2. prolonged tensile retention in vivo followed by controlled absorption

3. consistent uniform diameter

4. sterility

5. pliability for ease of handling and knot security

6. freedom from tissue irritating substances

7. predictable performance during and after placement

list the classification of sutures

• absorbable sutures

• non absorbable sutures

What are Absorbable sutures

• these are broken down by enzymatic digestion (natural) or hydrolysis (synthetic) and absorbed by the body overtime. premature suture wetting may begin early degradation. absorbable sutures are unsuitable for patients with fever, infection, protein deficiency or impaired healing

list the absorbable sutures

1. natural absorbable sutures (Digested by enzymes)

• collagen

• plain surgical gut

• fast absorbing surgical gut

• Chromic gut

2. synthetic absorbable sutures (Broken Down via hydrolysis)

• vicryl (polyglactin 910)

• dexon II (polycaprolate)

• monocryl (poliglecapron 25)

• polysorb

• PDS II (polydioxanone)

• maxon

• V-Loc

list the structures of Sutures and examples

• monofilament = e.g caprosyn

• multifilament = various e.g vicryl

describe non absorbable sutures

• these sutures resist enzymatic degradation and remain indefinitely unless removed

describe the types of non absorbable sutures

1. natural

• silk

• cotton

• surgical steel

2. synthetic

• nylon

• polyester (mersiline , ethibond)

• Polybutester (novafil, vascufil)

• polypropylene (prolene, surgipro II)

indications for non absorbable sutures

• permanent internal support

• Skin Closure (to be removed)

• patients with Reactions to absorbables or hypertrophic/ keloid tendencies

• prosthetic fixation

describe the structures of sutures

• monofilament = single, smooth strand - less tissue drag, but more difficult to handle

• multifilament: braided - easier handling and knot security, but more tissue drag and risk of harbouring bacteria

what are the knot tying principles

1. firm, non slip knot (flat and square)

2. minimal bulk to reduce tissue reaction

3. avoid friction or “sawing” to prevent suture weakening

4. handle suture gently - avoid crushing with forceps

5. apply appropriate tension - avoid over tightening

6. maintain traction on the first loop

7. final throw should lie horizontally

8. Change position to tie Flat, secure knots if needed

9. extra throws don't increase strength but may be needed for slippery materials

List the types of knots

1. simple knot

2. square knot (reef knot)

3. surgeon's knot

4. slip knot

5. granny knot (crossed knot)

describe a simple knot

• one overhand throw; not used alone because it lacks security

describe a square knot (reef knot)

• most common surgical knot

• made by alternating the direction of each throw (right over left, then left over right)

• provides a secure and stable closure

describe a surgeon's knot

• Modified Square Knot with an extra turn in the first throw (Double overhand), followed by a standard second throw

• useful for maintaining tension during knot tying when tissues are under stress (e.g elastic tissues)

• offers increased friction and temporary stability before completing the knot

Describe a slip knot

• forms a loop that can be tightened or loosened

• occasionally used for ligating vessels or deep tissue closures

• less secure than square or surgeons knot if used alone

describe a granny knot (crossed knot

• formed by repeating the same direction in throws (e.g Right Over Left Twice)

• should be avoided- prone to slipping and reduced knot strength

describe suture removal - clinical protocol

• once tissue healing allows non absorbable sutures must be removed to avoid infection or scarring

• steps:

1. Clean Area with antiseptic (e.g hydrogen peroxide to remove crust)

2. pick up one end of the suture with forceps

3. cut near the skin entry point

4. pulled through the side opposite the knot to avoid dragging contaminated suture through tissue

what are some considerations that should be taken when selecting suture material

• select suture material based on

— Tissue Type

— required strength and healing time

— risk of infection

— patient specific factors

choosing the correct needle shape and size during suturing

• curved needles (e.g 3/8, ½ circle) are common in oral surgery

• cutting needles for tough tissues (e.g skin)

• tapered needles for softer tissue (e.g mucosa)

General Principle for suturing technique

1. use atraumatic technique - handle tissue gently

2. the needle should enter tissue at 90 degree angle to avoid tearing and ensure even depth

3. the bite distance from the incision line should be ~2-3mm

4. pass the needle through equal amount of tissues on both sides of the wound to avoid tension

5. use the minimum number of sutures required for effective wound approximation

6. knot should not lie over the incision line - place laterally to reduce irritation and risk of dehiscence

7. do not over tighten - sutures should approximate, not strangulate

8. cut tails short, unless longer lengths are needed for future adjustments or removal

list the types of suturing techniques

1. interrupted sutures

2. continuous sutures

3. figure of eight (Criss cross) sutures

4. purse-string suture

5. sling suture

6. suspensory sutures

describe interrupted sutures

• each is tied and cut individually

• advantages = secure, good tension control, less likely to fail as a whole

• disadvantages = time consuming, more foreign material

• Simple interrupted = Standard and Most used; good for basic closure

• horizontal mattress = provides tension release. Often used in flap edges

• vertical mattress = ensures deep and superficial tissue approximation. For thicker issues

describe continuous sutures

• a single strand runs through the entire wound and is tied only at the ends

• advantages = faster, distributes tension evenly

• disadvantages= if one point fails, the whole line can loosen

• simple continuous = basic running stitch

• locking continuous (ford interlocking) = Each pass locks the stitch. bad tension distribution, often used in skin

• subcuticular = placed in dermis only (not used in intraoral mucosa)

describe Figure of eight (Criss cross) stitches

• often used for socket closure after extraction

• forms in “X” across the wound

• provides a secure hemostasis and covers open sockets or membranes

describe purse string sutures

• circular stitch that tightens like a drawstring

• rarely used intraorally; occasionally for closing biopsy punches or around tubes

describe sling sutures

• especially useful in periodontal flap surgeries

• wraps around a tooth to stabilised a flap on one side

• Two types:

1. single sling = around one tooth

2. double sling = around two adjacent teeth

describe suspensory sutures

• anchor the tissue flap to the periosteum or bone

• provide enhanced stability, especially in implant or grating procedures

what are the instruments for suturing

• needle holder (mayo-hegar) = to grasp and drive the needle

• tissue forceps (adson or Debakery) = to hold tissue gently

• scissors (suture scissors) = to cut sutures precisely

• suture needle = swaged (eyeless), curved, often 3/8 or ½ circle

• suture material = absorbable or non absorbable

List the suture patterns

• U-shaped vertical (vertical mattress)

• U-shaped vertical (attached)

• U-shaped vertical (not attached)

• P-shaped suture

• P-shaped attached

• P-shaped not attached

• Base vertical (vertical mattress variant)

• Base horizontal (classic horizontal mattress)

• Intradermal/subcuticular

describe U-shaped vertical (vertical mattress)

1. how to do it:

• First bite = far from wound edge on one side → exit far on opposite side

• second bite = return near the wound edge → Exit Near on opposite side

• tie

2. Entry/ exit

• far-far than Near-near (vertical plane)

3. important

• create U shape

• gives excellent eversion and strong tension control

Describe U-shaped vertical (attached)

How to do it:

• Same as vertical mattress, but the loop is anchored by taking a small extra bite at the edge before tying.

Entry/Exit:

• Far–far, near–near + small anchoring bite.

Important:

• Prevents loop sliding.

• More stable in mobile mucosa.

describe U‑Shaped Vertical (Not Attached)

How to do it:

• Standard vertical mattress only.

• No anchoring bite.

Entry/Exit:

• Far–far, near–near.

Important:

• Loop is free.

• Used when you only need eversion, not anchoring.

describe P‑Shaped Suture

How to do it:

• First bite: deep bite on one side → exit opposite side.

• Second bite: small, superficial bite near the corner or flap tip → exit close by.

• Tie so the long limb pulls tissue in one direction.

Entry/Exit:

• Long bite + short bite = P‑shape.

Important:

• Used for corners, flap tips, directional traction.

describe P‑Shaped Attached

How to do it:

• Same as P‑shaped, but the short bite is anchored into the tissue edge.

Entry/Exit:

• Long bite + anchored short bite.

Important:

• Prevents corner from rotating or tearing.

• Best for flap apex stabilization.

describe P‑Shaped Not Attached

How to do it:

• Long bite + short superficial bite, but no anchoring.

Entry/Exit:

• Long bite + free short bite.

Important:

• Used when you want gentle directional pull without fixing the corner tightly.

describe Base Vertical (Vertical Horizontal Mattress Variant)

How to do it:

• Two bites placed above and below the wound (vertical orientation).

• Tie to distribute tension vertically.

Entry/Exit:

• Enter above wound → exit opposite above.

• Enter below wound → exit opposite below.

Important:

• Spreads tension vertically.

• Good for fragile tissue.

describe Base Horizontal (Classic Horizontal Mattress)

How to do it:

• Enter left side of wound → exit right side.

• Move a few millimeters distally.

• Re‑enter right side → exit left side.

• Tie to create a horizontal “box”.

Entry/Exit:

• Enter left → exit right.

• Re‑enter right → exit left.

Important:

• Spreads tension horizontally.

• Good for friable tissue and wound edges under tension.

describe Intradermal / Subcuticular

How to do it:

• Continuous suture placed within the dermis, running parallel to wound.

• No external stitches.

Entry/Exit:

• Enter at one end of wound → weave through dermis → exit at opposite end.

Important:

• Best cosmetic closure.

• No eversion needed.

• Common in facial or clean surgical wounds.