Wound Healing and Suture Knowledge ASR Certification Prep

Wound Healing and Suture Knowledge ASR Certification Prep Kim Bayer, SRS, BS, CVT, LATg

Tissue Handling / Technique Goal is to minimize trauma ¬ Gentle use minimal tension with tissue Retractors should be placed to avoid excessive tension ¬ Proper use of instruments DO NOT CRUSH ¬ Use Proper Technique ¬ Keep Tissue Moist Dry tissue is dead tissue ¬ Minimize Time

Incisions n Heal side-to-side, not end-to-end – There is little advantage to making an incision too small to easily view the surgical site

Tissue Handling / Technique Different surgical techniques induce different levels of damage Ø cutting with sharp instrument û û û minimal traumatic cuts / divides the cells little adjacent cell damage Øcutting with scissors û û û causes crush and tear trauma relatively traumatic adjacent cell damage

Tissue Handling / Technique üblunt dissection between / along tissue planes Øminimal trauma

Tissue Handling / Technique clamping tissue with hemostats / etc. û causes crushing of the cells û very traumatic û causes release of vasoconstrictors, clotting factors û proper for clamping vessels for ligation / hemostasis

Tissue Handling / Technique provide gentle retraction with proper instruments

Tissue Handling / Technique Keep Tissue Moist “The solution to pollution is dilution” þIrrigate, rinse the incision surgery site þLavage, irrigate body cavities

Hemostasis n Bleeding should be stopped whenever possible – Excessive bleeding may cause hematomas or increase dead space – Hematomas prevent wound apposition and retard healing – Blood is a natural food for micro-organisms and a large clot will help protect them from the body’s immune system » Bacteria inside the clot will be protected n Bleeding may be slowed or stopped by applying pressure, clamping, electro/thermocautery, and with various chemicals – Excessive pressure may lead to tissue necrosis

Dead Space and a Clean Wound n n n Remove all non-essential material Wounds with excessive debris should be thoroughly lavaged with an appropriate sterile fluid (isotonic saline, LRS, Tis-U-Sol, etc. ) to flush them away Dead Space is an open area in closed tissue – Filled with room air, it prevents tissue apposition, provides a space for blood and other fluid influx, and may harbor micro-organisms

Dead Space

Classification of Wounds n Clean – Standard surgical wound n Clean-contaminated – Clean wounds that are contaminated by entry into a viscus resulting in minimal spillage of contents n Contaminated – Lacerations, fractures, gross spillage from the GI tract, resulting from a break in aseptic technique – Within 6 hours of initial colonization a wound can be infected

Classification of Wounds n Dirty-infected – Caused by perforated viscera, abscesses, or a prior clinical infection – Ongoing infection at time of surgery may lead to a 400% increase in infection rates

Problems n Infection – The source of infection should always be determined – Before closure of an infected wound the wound should be drained, debrided, and a small opening or drain left in n Dehiscence – Wound reopens – May result from too much tension on tissue, improper suturing technique, or improper suture materials

Wound Healing n n Skin and fascia are the strongest but regain tensile strength quite slowly Stomach and small intestine are weak, but heal quickly

Physiology of Wound Healing Phases of Wound Healing Inflammatory Phase Migration /Proliferation Phase Maturation Phase Healed Incision Inflammatory Migration /Proliferation Maturation

Physiology of Wound Healing Inflammatory Phase Ø 0 - 5 Day û can be prolonged Øinflammatory and “clean-up” process û plasma, cells, fibrin, blood components û neutrophils, monocytes • remove debris • “remove the trash” Øepithelialization / migration (as early as 48 hours) Øclinically characterized by swelling, redness, warmth Østrength due to suture Incision Inflammatory

Physiology Inflammatory Response Clinical Signs ü swelling ü redness ü warmth / heat Course / Duration ü peak within 24 hours, ü subsiding by day 3 Inflammation results in pain / discomfort

Wound Healing-Phases n Phase 1 – Inflammatory response causes an outpouring of tissue fluids, accumulation of cells and fibroblasts, and increased blood supply – Leukocytes produce enzymes to dissolve and remove damaged tissue debris

Wound Healing-Phases n Phase 1 (day 1 to 5) – Inflammatory response phase – Fluids flow into the wound a scab forms – Localized edema, pain, fever, and erythema present – Basal cells migrate over the incision from the skin to cover the wound – Closure material is the primary source of tensile strength

Wound Healing-Phases n Phase 2 – Fibroblasts begin forming collagen fibers in the wound » Beginning of the return of tensile strength

Wound Healing-Phases n Phase 2 (day 5 to 14) – Fibroblasts migrate toward the wound site » Begin forming collagen fibers – Tensile strength rapidly increases – Lymphatics recanalize – Blood vessels bud – Granulation tissue forms – Capillaries develop

Physiology Maturation Phase Øbegins ~ day 14 and continues for months Øcollagen fibers become oriented along the “stress” line of the incision and form crosslinks • increases tensile strength Øcontraction Healed Incision Maturation

Wound Healing-Phases n Phase 3 – Sufficient collagen is now laid down to withstand normal stress

Wound Healing-Phases n Phase 3 (day 14 until done) – Tensile strength continues to improve for as long as one year – Skin regains 70 to 90% of its original strength – Collagen content remains constant but crosslinks with other fibers – Scar is formed which grows paler as new vessel construction tapers off – Wound contraction occurs over a period of weeks or months

Wound Healing Types n First Intention – Wound edges brought together during closure at the time of surgery n Second Intention – Wound is left open and heals from the bottom up – Slower than first intention and creates more granulation and scar tissue n Third Intention – Wound is initially not closed and remains open until a granulation bed formed, then the granulated tissue is closed using standard techniques – Useful in infected wounds » Infected tissue should not be closed or it will dehiss » Infection is resolved naturally, or with topical and systemic treatments

Closure / Suturing Proper Apposition ØRestore alignment of the tissues Øclose / decrease dead space Øbalance adequate closure with too much suture • suture is a foreign body and too much can effect healing

Closure / Suturing Proper Suture Øuse minimal size suture that has sufficient strength Øknot security Øabsorbable vs. non-absorbable

Sutures n Ideal suture material · All-purpose, composed of material which could be used in any surgical procedure (the only variables being size and tensile strength) · Sterile · Nonelectrolytic, noncapillary, nonallergenic, and noncarcinogenic · Nonferromagnetic, as is the case with stainless steel sutures · Easy to handle

Sutures n Ideal suture material · Minimally reactive in tissue and not predisposed to bacterial growth · Capable of holding securely when knotted without fraying or cutting · Resistant to shrinking in tissues · Absorbed with minimal tissue reaction after serving its purpose · Doesn’t exist!

Sutures n Surgeon should select suture materials for – High uniform tensile strength (quality) – Permitting use of finer sizes » Suture should be the smallest diameter that will do the job – Consistent uniform diameter – Sterile – Pliable for ease of handling and knot security – Freedom from irritating substances or impurities for optimum tissue acceptance – Predictable performance

Sutures n Size – Generally stated in “oughts”; i. e. , 3 -0, 5 -0, etc. – 2 -0 is larger than 4 -0, 0 is larger than 2 -0, etc. – Some suture and wire is larger than 0, then numbered 1 and higher » 2 is larger than 1, 6 is larger than 1, etc. – From smallest to largest: » 7 -0, 3 -0, 0, 1, 3, 7, etc.

Sutures Monofilament is a single strand » Passes through tissue easily, won’t harbor microorganisms » Ties easily » May be weakened by crushing (clamping in forceps or needle holders) » Has more “memory” n Continues to hold the shape as it lay in the package » Good for percutaneous sutures » Knots may slip over time due to the slipperiness of the suture

Sutures Multifilament is a bundle of strands, like rope » Affords greater tensile strength, pliability, flexibility, and knot security » May harbor micro-organisms and “wick” them down the suture n Should not be used for percutaneous sutures

Sutures Absorbable suture holds temporarily but gradually loses tensile strength and is eventually mostly or completely absorbed

Absorbable Sutures Surgical Catgut: Plain or Chromic Absorbed by proleolytic enzymatic digestive process. Polyglactin 910 : Vicryl® Polyglycolic acid: Dexon® Poliglecaprone 25: Monocryl® Polydixanone: PDSII® Polyglyconate: Maxon® Absorbed by Hydrolysis

Sutures Nonabsorbable suture will retain tensile strength and not be absorbed » Many nonabsorbable sutures (silk) will lose some tensile strength over time » Useful for device fixation, areas of extreme tension, slow healing areas, or percutaneous skin sutures » Selected for procedures where the suture should be permanent

Non-Absorbable Sutures Monofilament Polypropylene: Polyester Fiber: Mersilene®, Dacron®, Ethibond®, Ti. cron® Monofilament Nylon: Ethilon®, Dermalon® Braided Nylon: Nurolon®, Surgilon® Silk Surgical Stainless Steel Wire

Conventional Cutting Needle needle body is triangular and has a sharpened cutting edge on the inside Primarily used for skin closure.

Reverse Cutting Needle cutting edge on outer curve For tough, difficult-to-penetrate tissues

Taper Point Needle needle body is round and tapers smoothly to a point Used for soft, easily penetrated tissues

Blunt Point Needle Taper body For blunt dissection and suturing friable tissue

Spatula Needle flat on top and bottom with a cutting edge along the front to one side Primarily used for eye surgery

Surgeon’s Knot n Extra throws do not add appreciable strength to the knot and may, in fact, weaken it while adding extra bulk – An initial double throw followed by one or two single throws is more than sufficient – The exception is nylon monofilament sutures, where two successive double throws are useful to prevent slippage

Suture Patterns n Simple Interrupted – Maintains strength and tissue position if one portion fails – Requires more time and suture material – Has minimal holding power against stress

Suture Patterns n Horizontal Mattress – Tension suture – Useful in skin of dog, cow, and horse – Rapid and involves less suture material – Difficult to apply without excessive eversion – Should pass just below the dermis

Suture Patterns n Horizontal Mattress – Tightness should be such that the skin edges just meet

Suture Patterns n Vertical Mattress – Tension suture – Stronger than the horizontal mattress – Time consuming and requires more suture material

Suture Patterns n Cross-mattress – Tension suture – Brings tissue into good apposition » Useful in suturing stumps (amputations) – Also useful for rib apposition and abdominal muscle closure

Suture Patterns n Gambee or Crushing – Useful in intestinal anastamoses » Permits minimal leakage – May reduce fluid passage through the lumen underneath – Crushing is similar to a vertical mattress pattern

Suture Patterns n Simple Continuous – Usually used for lines no longer than 5” – Involves one diagonal pass and one perpendicular pass – Provide minimal tensionholding but hold tissue together in good apposition – Creates a good seal • More prone to failure if any portion is broken

Suture Patterns n Running – Both deep and shallow passes advance – Regularity more difficult – Slightly faster than a simple continuous pattern – Weaker than a simple continuous pattern

Suture Patterns n Ford Interlocking – More stable in the event of partial failure or breakage – Provides greater tissue stability – Uses more suture material

Suture Patterns n Lembert – Closes hollow viscera – Provides inversion and creates a good fluid-tight seal

Suture Patterns n Halsted – Combination mattress and Lembert pattern

Suture Patterns n Connell – Begun with a single inverting vertical mattress suture – Continues for the length of the incision

Suture Patterns n Cushing – Modified Connell where the needle and suture do not enter the lumen – Provides a better fluidtight seal than the Connell pattern

Suture Patterns n Parker-Kerr – A single layer of Cushing covered by a single layer of Lembert – Used for infected uterine stumps and some bowel closures – Provides complete clamping to prevent leakage during suturing

Suture Patterns – Rochester-Carmalt forceps are used to clamp the lumen shut and then slowly withdrawn while placed suture is tightened to prevent spillage of contents

Suture Patterns n Guard – Modified Cushing – Closes incisions of the rumen, intestine, and uterus – Needle does not enter the lumen – Starts slightly higher than start of incision

Suture Patterns n Continuing Everting Mattress – Provides increased strength – Rapid placement

Suture Patterns n Subcuticular – Does not penetrate the surface of the skin – Rapid and uses little suture material – Used to close the uppermost layer of the skin incision – Requires no suture removal

Suture Patterns n Subcutaneous – May use simple interrupted, simple continuous, or horizontal mattress – Simple continuous is fast and eliminates dead space

Suture Patterns n Quilted – Exteriorized skin suture through plastic tubing to resist excessive tension and stress – Useful for high-tension closures

Suture Patterns n Far-far, Near-near – Tension pattern – Overlapping suture pattern provides extra strength but requires extra suture material

Suture Patterns n Near-far, Far-near – Tension pattern – Overlapping suture pattern provides extra strength but requires extra suture material

Suture Patterns n Mayo Mattress – Useful for midline abdominal closures, abdominal hernia repair, and secondary cleft palate repair

Suture Patterns n Bunnell – Used for apposing tendons » Requires a high degree of closure strength – Uses non-absorbable suture – Uses a double-armed suture

Suture Patterns n Modified Bunnell – Used for apposing tendons » Requires a high degree of closure strength – Uses nonabsorbable suture – Uses a single-armed suture

Suture Patterns n Cerclage Wiring – Used for fracture repair – Wire/pin placed in the bone center to hold it together – Wire winds about the bone under the periosteum

Suture Patterns n Hemicerclage – Wire goes through holes drilled in the bone

Suture Patterns for Specific Tissues n n Skin- simple interrupted, horizontal mattress, vertical mattress, continuous apposing or everting Subcutaneous tissue- simple continuous Fascia- simple continuous (primary), simple interrupted, vertical mattress, far-near, near-far, Mayo mattress Peritoneum- simple continuous (two-layer), and simple interrupted – Very thin and fragile in horse, close muscle instead

Suture Patterns n Vessels- simple interrupted and simple continuous n Viscera- direct appositional Cushing suture n Muscle- simple continuous, simple interrupted, and horizontal mattress n Tendons- Bunnell n Bone- hemicerclage and cerclage

References n § Clinical Textbook for Veterinary Technicians; Mc. Curnin, D. M. ; W. B. Saunders Co. , Philadelphia, 1994 Ethicon Wound Closure Manual; Available at http: //www. ethiconinc. com/wound_management/procedure/w ound/ Fundamental techniques in Veterinary Surgery; Knecht, C. D. ; Allen, A. R. ; Williams, D. J. : Johnson, J. H. ; W. B. Saunders Philadelphia, 1981 Davis + Geck Veterinary Suture Manual, 1991