“Basic surgical skills” Wound Healing and Surgical Instrument’s.

“Basic surgical skills”

Wound Healing andSurgical Instrument’s

Overview

1. CDC wound classification2. Types of wound healing3. Instruments

1. Suture material2. Needle

4. Basic suturing technique1. Simple interrupted suture2. Suture removal

CDC wound classification

Contaminated– Includes:

• Open traumatic wounds (open fractures, penetrating wounds)• Operative procedures involving:

– Spillage from the GI, GU or biliary tracts– A break in aseptic technique (open cardiac massage)

– Microorganisms multiply so rapidly that a contaminated wound can become infected within 6 hours

Infected– Heavily contaminated/infected wound prior to operation– Includes:

• Perforated viscera• Abscesses• Wounds with undetected foreign body/necrotic tissue

CDC wound classification (cont…)

Clean– Uninfected operative wound in which no inflammation is

encountered and no systemic tracts are entered (respiratory, alimentary etc)

– Closed by primary intention and are usually not drained Clean, contaminated

– Operative wound in which systemic tract(s) are entered under controlled conditions and without contamination

Wound healing: Primary intention (I)

Optimum closure method since wound heals in minimum time with no separation of its edges and minimal scar formation

Takes place in 3 phases:

Wound healing: Primary intention (I)

1. Inflammatory• Begins immediately and

completed by Day 3-7• Initially, haemostasis

occurs• Then the wound is

prepared for repair by:– Extravasation of tissue

fluid, cells and fibroblasts– Increasing blood supply to

the wound– Debridement of tissue

debris by proteolytic enzymes

• No increase in tensile strength of tissue and wound healing is dependent on approximation of edges by closure material

Wound healing: Primary intention (II)

2. Proliferative• Starts from Day 3 onwards• Fibroblasts form a collagen

matrix (granulation tissue)• This matrix:

– Determines the tensile strength and pliability of the healing wound

– Becomes vascular, supplying the nutrients and oxygen necessary for wound healing

• Tensile strength increases until wound is able to withstand normal stress

Wound healing: Primary intention (II)

• Wound contraction also occurs:– Wound edges pull together in

order to close the wound– If successful, it results in a

smaller wound with less need for repair by scar formation

– Beneficial in areas such as the buttocks or trochanter

– Harmful in areas such as the hand, neck and face (can cause disfigurement and excessive scarring)

– Skin grafting reduces contraction in undesirable locations

Wound healing: Primary intention (III)3. Remodelling

• May continue for a year or longer• Following completion of collagen deposition, vascularity

decreases and any surface scar becomes paler• Resulting scar size is dependent upon the initial volume

of granulation tissue

The percentage recovery of the tensile strength of the wound is:– About 20% after 2 weeks– About 50% after 5 weeks– About 80% after 10 weeks

Wound healing: Secondary intention Occurs when the wound fails to heal by

primary intention due to:– Infection– Excessive trauma– Tissue loss

More complicated and prolonged than healing by primary intention

There may be excessive formation of granulation tissue which:– Contains myofibroblasts which lead to gradual but

marked wound contraction– May protrude above the wound surface, prevent

epithelialisation and thus require treatment

– Imprecise approximation of tissue (leaving dead space)

Wound healing: Delayed primary closure

Used in management of contaminated and infected wounds with extensive tissue loss and a high risk of infection (eg. trauma following RTA, penetrating injury)

Steps taken include:– Debridement of nonviable tissues, usually

under sedation– Leaving wound open with gauze packing

inserted– Wound approximation within 3-5 days if no

infection is evident– If infection is present, the wound is allowed to

heal by secondary intention

Instruments: Forceps & needle-holder

Small toothed forceps (Addison forceps) grasp the skin edges during suturing

Hold in the first three fingers in a similar way to a pen

Grasp the needle-holder by partially inserting the thumb and ring finger into the loops of the handle

The free index finger provides additional control and stability

Instruments: Needle (I) The main types of needle include:

– Tapered• Gradually taper to the point and cross-

section reveals a round, smooth shaft• Used for tissue that is easy to penetrate,

such as bowel or blood vessels

– Cutting• Triangular tip with the apex forming a

cutting surface• Used for tough tissue, such as skin (use of a

tapered needle with skin causes excess trauma because of difficulty in penetration)

– Reverse cutting needle• Similar to a conventional cutting needle

except the cutting edge faces down instead of up

• This may decrease the likelihood of sutures pulling through soft tissue

Instruments: Needle (II) Most sutures with the suture material swaged

onto the base of the needle Shapes vary from a quarter circle to five-eighths

of a circle, depending on how confined the operating field is

Choice of needle should ‘alter the tissue to be sutured as little as possible’ and is dependent on:

– The tissue being sutured (when in doubt about selection of a taper point or cutting needle, choose the taper for everything except skin sutures)

– Ease of access to the tissue

– Individual preference

Instruments: Properties of suture material Handling of a suture

– Memory• Tendency to stay in one position• Leads to difficulty in tying sutures and knot unravelling

– Elasticity• Ability to return to its original length after stretching• High elasticity sutures should be used in oedematous

tissue– Knot strength

• Force required for a knot to slip• Important to consider when ligating arteries

Tensile strength– Force necessary to break a suture– Important to consider in areas of tension (linea alba)

Tissue reaction– Undesirable since inflammation worsens the scar– Maximal between Day 3&7

Non-absorbable or absorbable Monofilament or multifilament

Instruments: Monofilament or multifilament Monofilament (Ethilon or Prolene)

– Consists of a single smooth strand– Less traumatic since they glide through tissues with

less friction– May be associated with lower rates of infection– More likely to slip and should be secured with 5 or 6

‘throws’ (in contrast to 3 throws with multifilament)– Preferred for skin closure because they provide a

better cosmetic result Multifilament (Mersilk or Mersilene)

– Consists of multiple fibres woven together

– Easier to handle and tie and knots are less likely to slip

Instruments: Non-absorbable suture material

Composed of materials which can be:– Naturally occurring (Mersilk, cotton and steel)– Synthetic (Prolene, Ethilon, Nurolon, etc)

Sutures may be:– Left in place

indefinitely (during closure of abdominal fascia)

– Removed following adequate healing (closure of superficial laceration)

Instruments: Absorbable suture material Composed of biodegradable materials which

can be:– Naturally occurring (degraded enzymatically)

• Catgut– Consists of processed collagen from animal intestines– Broken down after 7 days

• Chromic catgut– Consists of intestinal collagen treated with chromium– Loses tensile strength after 2-3 weeks and is broken down

after 3 months

– Synthetic• Degraded non-enzymatically by hydrolysis when water

penetrates the suture filaments and attacks the polymer chain

• Tend to evoke less tissue reaction than those occurring naturally

Subclassified according to degradation time

Instruments: Size of suture material Size originally scaled from 0-3 As technology advanced and sutures became

smaller, extra 0s were added Scale now ranges from 3 (largest) to 12/0

(smallest)

Size Uses

7/0 and smaller Ophthalmology, microsurgery

6/0 Face, blood vessels

5/0 Face, neck, blood vessels

4/0Mucosa, neck, hands, limbs,

tendons, blood vessels

3/0 Limbs, trunk, gut blood vessels

2/0 Trunk, fascia, viscera, blood vessels

0 and largerAbdominal wall, fascia, drain sites,

arterial lines, orthopaedics

Instruments: Suture material summary

M ersilk

N atur al

N urolon

E thibond

Braided

E thilon

Prolene

M onofi lament

S ynthet ic

N on- absor bable

Catgut

N atural

Vicryl r apide

S ynthet ic

S hor t term

Braided vicryl

Braided

M onocryl

M onofi lament

M edium term

Panacryl

Braided

PDS I I

M onofi lament

Long term

A bsorbable

Arming the needle-holder

Grasp the needle two-thirds the distance from its pointed end

Avoid grasping the needle at its proximal or distal extremities since this will prevent damage to the suture

Open the suture packet with one tear to reveal the needle

Simple interrupted stitch: Steps 1&2

Grasp the skin edge with the forceps and slightly evert the skin edge

Then pronate the needle-holder so that the needle will pierce the skin at 90o

Ensure the trailing suture material is out of the way to avoid tangling

Drive the needle through the full thickness of the skin by supinating the needle-holder

Keeping the shaft of the needle perpendicular to the skin allows the curvature of the needle to traverse the skin as atraumatically as possibleImages courtesy of BUMC


Release the needle and pronate the needle-holder

Regrasp the needle proximal to its pointed end

Maintain tension with the forceps to prevent the needle from retracting

Again, supinate the needle-holder to rotate the needle upwards and through the tissue


Regrasp the needle in order to rearm the needle-holder (due to HIV risks it is better to use the forceps to do this)

Grasp and slightly evert the opposing skin edge with the forceps

Pronate the needle-holder


Again, supinate the needle-holder to rotate the needle through the skin, keeping the shaft 90° to the skin surface

After releasing the needle, pronate the needle-holder before regrasping the needle…


…and again supinate the needle-holder to rotate the needle through the skin

Pull the suture material through the skin until 2-3 cm is left protruding

Discard the forceps and use your free hand to grasp the long end in preparation for an instrument tie

Place the needle-holder between the strands


Wrap the long strand around the needle-holder to form the loop for the first throw of a square knot

Rotate the needle-holder away yourself and grasp the short end of the suture


Now draw the short end back through the loop towards yourself

Now tighten the first throw


The throw should be tightened just enough to approximate the skin edges but not enough to strangulate the tissue

To begin the second throw of the square knot, wrap the long strand around the needle-holder by bringing the long strand towards yourself


Rotate the needle-holder towards yourself to retrieve the short end

Grasp the short end and draw it through the loop by pulling it away from yourself

Simple interrupted stitch: Step 19&20

Finally, tighten the second throw securely against the first

Ensure the knot is to one side of the wound to avoid involvement in the clot

In one hand hold the scissors as shown

With the other hand maintain tension on the suture material

Slide the tips of the scissors down the strands to the point where they will be cut

Cut the suture material leaving 4-5mm tails (important for removal of external non-absorbable sutures)

Suture removal Sutures should be removed:

– Face: 3-4 days– Scalp: 5 days– Trunk: 7 days– Limb: 7-10 days– Foot: 10-14 days

Steps involved in removal:– Reassure patient that the procedure is not painful– Cleanse the skin with hydrogen peroxide– Grasp one of the suture ‘tails’ with forceps and

elevate– Slip the tip of the scissors under the suture and cut

close to the skin edge (to minimise the length of contaminated suture that will be pulled through the wound)

– Gently pull the knot with the forceps and reinforce the wound Proxi-Strips if required

Summary Wound classification

– Clean– Clean, contaminated– Contaminated– Infected

Types of wound healing– Primary intention– Secondary intention– Delayed primary closure

Suture material– Properties

• Natural or synthetic• Non-absorbable or absorbable• Monofilament or multifilament

– Size• Ranges from 3 – 12/0

References Ethicon

– Knot Manual http://www.jnjgateway.com/public/useng/5256ethicon_encyclopedia_of_knots.pdf

– Wound Closure Manual http://www.jnjgateway.com/public/useng/ethicon_wcm_feb2004.pdf

Student BMJ– Taylor B and Bayat A, (May 2003, June 2003 &

July 2003), Basic plastic surgery techniques and principles.

Boston University School of Medicine– http://www.bumc.bu.edu/departments/

pagemain.asp?page=5734&departmentid=69

“Basic surgical skills” Wound Healing and Surgical Instrument’s.

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