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

2. Overview CDC wound classification Types of wound healing Instruments
Suture material
Needle
Basic suturing technique
Simple interrupted suture
Suture removal

3. 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
Perforated viscera
Abscesses
Wounds with undetected foreign body/necrotic tissue

4. 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

5. 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:

6. 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

7. 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

8. 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

9. 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

10. 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)

11. 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

12. 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
Get people to follow along

13. 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

14. 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

15. 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

16. 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

17. 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)

18. 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

20. 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
4/0
Mucosa, neck, hands, limbs, tendons, blood vessels
3/0
Limbs, trunk, gut blood vessels
2/0
Trunk, fascia, viscera, blood vessels
0 and larger
Abdominal wall, fascia, drain sites, arterial lines, orthopaedics

21. Instruments: Suture material summary

22. Arming the needle-holder
Open the suture packet with one tear to reveal the needle
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

23. 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 possible
Images courtesy of BUMC

24. Simple interrupted stitch: Steps 3&4
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

25. Simple interrupted stitch: Steps 5&6
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

26. Simple interrupted stitch: Steps 7&8
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…

27. Simple interrupted stitch: Steps 9&10
…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

28. Simple interrupted stitch: Steps 11&12
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

29. Simple interrupted stitch: Steps 13&14
Now draw the short end back through the loop towards yourself
Now tighten the first throw

30. Simple interrupted stitch: Steps 15&16
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

31. Simple interrupted stitch: Steps 17&18
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

32. 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)

33. Suture removal Sutures should be removed: Steps involved in removal:
Face: 3-4 days
Scalp: 5 days
Trunk: 7 days
Limb: 7-10 days
Foot: 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

34. Summary Wound classification Types of wound healing Suture material
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

35. References Ethicon Student BMJ Boston University School of Medicine
Knot Manual
Wound Closure Manual
Student BMJ
Taylor B and Bayat A, (May 2003, June 2003 & July 2003), Basic plastic surgery techniques and principles.
Boston University School of Medicine