Basic surgical skills SCRUBS

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

CDC wound classification 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 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

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: 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 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 Get people to follow along

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 4/0 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

Instruments: Suture material summary

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

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

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

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

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…

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

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

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

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

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

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: Steps involved in removal: 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 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

References Ethicon Student BMJ Boston University School of Medicine 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