Equine Wound Management E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1883

Veröffentlichungsjahr: 2016

Beschreibung

Now in its third edition, Equine Wound Management is the authoritative resource for both theoretical and practical information on the care of wounds in horses. * The most comprehensive resource on managing equine wounds * Organized by body region * Over 750 color photographs * Summaries at the beginning of each chapter and highlighted key information aid readers to rapidly find relevant information * Companion website offers videos, interactive multiple choice questions and answers, case studies, and images from the book for download

Leseprobe

Table of Contents

Cover

Title Page

About the Editors

List of Contributors

Preface

Acknowledgment

About the Companion Website

CHAPTER 1: Physiology of Wound Healing

Summary

Introduction

Skin anatomy

Phases of wound repair

Mediators of wound repair

Conclusion

References

CHAPTER 2: Differences in Wound Healing between Horses and Ponies

Summary

Horses and ponies: same species, different healing characteristics

First‐intention healing (primary wound closure)

Second‐intention healing

Clinical application of the results of research

Conclusion

References

CHAPTER 3: Selected Factors that Negatively Impact Healing

Summary

Introduction

Patient factors

Wound factors

Conclusion

References

CHAPTER 4: Management Practices that Influence Wound Infection and Healing

Summary

Introduction

Initial assessment

Negative‐pressure wound therapy/vacuum‐assisted closure

Antimicrobial drugs

Anti‐inflammatory drugs

Suture material and pattern

Dressings and bandages

Conclusion

References

CHAPTER 5: Topical Wound Treatments and Wound‐Care Products

Summary

Introduction

Wound cleansers and irrigation solutions

Topically administered antibiotics

Wound‐debridement agents

Corticosteroids

Sugars

Vitamin‐ and mineral‐containing wound products

Herbal products

Miscellaneous topical wound‐care products

Aerosol sprays

Topical fly repellents

References

CHAPTER 6: Update on Wound Dressings: Indications and Best Use

Summary

Introduction

Desirable dressing characteristics

Moist wound healing

Occlusive wound healing

To bandage or not to bandage?

Selected products

Antimicrobial compounds

References

CHAPTER 7: Bandaging and Casting Techniques for Wound Management

Summary

Introduction

Bandages

Splints and casts

Conclusion

References

CHAPTER 8: Approaches to Wound Closure

Summary

Introduction

Evaluation and preparation of the wound

Primary closure

Delayed closure

Second‐intention healing

Conclusion

References

CHAPTER 9: Selection of Suture Materials, Suture Patterns, and Drains for Wound Closure

Summary

Introduction

Suture material and selection

Surgical needles

Suturing techniques

Staples

Tissue adhesives

New directions

Support for sutured wounds

Drains

Conclusion

References

CHAPTER 10: Principles and Techniques for Reconstructive Surgery

Summary

Introduction

Cutaneous blood supply

Physical and biomechanical properties of skin

General principles of reconstructive surgery

Tension‐reducing suturing techniques

Skin stretching and expansion techniques

Skin mobilization procedures to reduce tension

Cosmetic closure of defects of various shapes

Vascularized free‐tissue transfers (axial‐pattern skin flaps)

Conclusion

References

CHAPTER 11: Management of Wounds of the Head

Summary

Introduction

Lacerations

Scalping and degloving injuries of the head

Fractures of the facial bones

Nasocutaneous and sinocutaneous fistulas

Conclusion

References

CHAPTER 12: Management of Wounds of the Neck and Body

Summary

Introduction

Wounds of the neck

Wounds of the body

Puncture wounds

Chronic draining tracts

Abscesses, hematomas, and seromas

Traumatic abdominal hernias

Conclusion

References

CHAPTER 13: Management of Wounds of the Distal Extremities

Summary

Introduction

Wound categories

Wounds involving the fetlock, metacarpus/metatarsus, and/or carpus/tarsus

Wounds involving the pastern

Lacerations and avulsion wounds of the hoof capsule

Penetrating wounds to the foot

Conclusion

References

CHAPTER 14: Degloving Injuries of the Distal Aspect of the Limb

Summary

Introduction

Healing of degloving injuries on the distal aspect of the limb

Healing of degloving injuries with exposed bone

Management of degloving injuries

Conclusion

References

CHAPTER 15: Exuberant Granulation Tissue

Summary

Introduction

Physiology and pathology

Factors affecting the formation of exuberant granulation tissue

Differential diagnoses

Prevention of exuberant granulation tissue

Treatment of exuberant granulation tissue

Conclusion

References

CHAPTER 16: Diagnosis and Management of Wounds Involving Synovial Structures

Summary

Introduction

Location of Injuries

Synovial anatomy and physiology

Pathogenesis of synovial infections

Time to treatment

Clinical findings

Wound assessment

Synoviocentesis

Imaging

Treatment

Complications

Prognosis

Special considerations

Conclusion

References

CHAPTER 17: Tendon and Paratenon Lacerations

Summary

Introduction

Tendon anatomy and function

Tendon healing

Diagnosis and treatment

Conclusion

References

Webliography

CHAPTER 18: Free Skin Grafting

Summary

Introduction

Classification of grafts

Requirements for graft acceptance

Physiologic events associated with graft acceptance

Causes of graft failure

Preparation of the wound

Preparation of the donor site

Grafting techniques

Aftercare

Storing split‐thickness sheet grafts

Use of allografts and xenografts

Conclusion

References

CHAPTER 19: Management of Severely Infected Wounds

Summary

Introduction

Origins of severe wound infections

Targeted treatment approach

References

CHAPTER 20: Treatment of Burn Injuries, Gunshot Wounds, and Dog‐Bite Wounds

Summary

Burn injuries

Gunshot wounds

Dog‐bite wounds

Conclusion

References

CHAPTER 21: Sarcoid Transformation at Wound Sites

Summary

Introduction

Etiopathogenesis

Clinical aspects

Identification

Differential diagnosis of sarcoid‐contaminated wounds

Pathology

Treatment/management

Prognosis

Prevention

Conclusion

References

CHAPTER 22: Innovative Adjunctive Approaches to Wound Management

Summary

Introduction

Innovative adjunctive approaches

Conclusion

References

Index

End User License Agreement

List of Tables

Chapter 01

Table 1.1 Cytokines involved in wound repair.

Chapter 03

Table 3.1 National Research Council Operative Wound Classifications.

Table 3.2 Clinical manifestations of the increasing bacterial impact on wound healing.

Chapter 04

Table 4.1 Doses for non‐steroidal anti‐inflammatory drugs commonly used in horses.

Chapter 05

Table 5.1 Commercially available wound cleansers.

Table 5.2 Indications and contraindications for cleansers with and without antiseptics. MRSA, methicillin‐resistant

Staphylococcus aureus

; VRE, vancomycin‐resistant enterococci.

Table 5.3 Proteolytic enzymes for wound debridement.

Table 5.4 Examples of herbal wound‐care products.

Table 5.5 Aerosol sprays.

Chapter 06

Table 6.1 Desirable characteristics of dressings and their clinical significance.

Table 6.2 Dressings classified according to their materials of composition, their indications and contraindications, instructions for use, and examples of products.

Table 6.3 Dressing selection to promote healing in specific types of wounds. Please refer to Table 6.2 for further descriptions of the dressings and instructions for use.

Table 6.4 Antimicrobial dressings.

Chapter 07

Table 7.1 Common examples of materials used for the secondary and tertiary layers of a wound bandage.

Table 7.2 Examples of common casting materials and how they are used in the making of a cast. Note that the time to initially dry (set) and then harden to full strength (cure) depends on the temperature of the water in which the cast material is soaked: aim for room‐temperature water.

Chapter 09

Table 9.1 Characteristics of the most commonly used non‐absorbable and absorbable suture materials.

Table 9.2 Guidelines for suture material selection in equine wound management.

Table 9.3 Minimal number of throws required (including the first) for a secure square knot in interrupted suture patterns and continuous suture patterns. abs, absorbable; non‐abs, non‐absorbable; mono, monofilament; multi, multifilament.

Table 9.4 Appositional suture patterns for wound management.

Table 9.5 Tension suture patterns for wound management.

Table 9.6 Characteristics of the most commonly used passive drains.

Table 9.7 Characteristics of the most commonly used drains in active drainage.

Chapter 10

Table 10.1 Classification of local skin flaps according to their design.

Chapter 16

Table 16.1 Bursae to consider when evaluating wounds in the horse. Bursae are located between the listed tendon/ligament and bone.

Table 16.2 Antimicrobials used for regional limb perfusion.

Chapter 19

Table 19.1 Common bacterial isolates from various wounds in horses, and recommendations for interim systemic antibiotic therapy.

Table 19.2 Cytologic features of common equine wound pathogens.

Table 19.3

In vitro

antibiotic sensitivity patterns for the pathogens listed in Table 19.2.

Table 19.4 Local and regional routes of antibiotic delivery.

Table 19.5 Guidelines for duration of antibiotic therapy in specific types of wounds.

Chapter 21

Table 21.1 Main differentiating clinical features for sarcoid‐affected wounds.

List of Illustrations

Chapter 01

Figure 1.1 Temporal profile of synchronized phases and gain in tensile strength of healing cutaneous wounds. Solid lines show the healing profile of laboratory animals while superimposed shaded areas show the profile of healing full‐thickness wounds on the limb of horses. It should be noted that the timescale is suggestive and depends on the size and extent of the wound.

Figure 1.2

(a)

Diagram of a cross‐section of skin, showing the epidermal and dermal compartments.

(b)

Diagram of the layers of the epidermis of horse skin.

Figure 1.3 Illustration of a full‐thickness cutaneous wound showing the cellular and molecular components present 3 days after injury. FGF, basic fibroblast growth factor; IGF, insulin‐like growth factor; KGF, keratinocyte growth factor; PDGF, platelet‐derived growth factor; TGF, transforming growth factor; VEGF, vascular endothelial growth factor.

Figure 1.4 Illustration of a full‐thickness cutaneous wound 5 days after injury showing angiogenesis, fibroplasia, and epithelialization. uPA, urokinase‐type plasminogen activator; tPA, tissue‐type plasminogen activator; MMP, matrix metalloproteinase.

Figure 1.5 This metatarsal wound failed to heal for 7 months as a result of chronic low‐grade inflammation due to exposure as well as superficial and deep infection. The wound in fact became larger rather than smaller, illustrating suspension of the healing process.

Figure 1.6 Large full‐thickness metatarsal wound that healed partially by second intention and was subsequently grafted successfully. The wound showed excellent epithelialization from the healing margin of the wound. The healthy epithelial tissue is characterized by an area of hyperemia adjacent to it.

Figure 1.7 Photomicrograph of a wound edge sample of tissue. Normal unwounded skin to the left demonstrating epidermal appendages (h, hair follicles); new hyperplastic epithelium (EH) to the right, overlying granulation tissue bed.

Figure 1.8

(a)

A 5‐day‐old, full‐thickness, experimentally created wound over the dorsal surface of the fetlock. Granulation tissue is beginning to fill the wound.

(b)

The same wound, 75 days after creation. Neoepidermis is thin, dry, and hairless, and could be easily traumatized.

Chapter 02

Figure 2.1

(a)

Wound on the elbow of a horse, which suffered dehiscence following primary closure, as a result of infection.

(b)

Wound on the distal aspect of the limb of a 4‐year‐old pony with an open fetlock joint and damage to the lateral collateral ligament. The wound was sutured approximately 8 hours after it occurred and it healed successfully, without dehiscence.

Figure 2.2 Wound area as a function of time (mean + s.e.m.). HMT, metatarsal wounds of horses; HB, body wounds of horses; PMT, metatarsal wounds of ponies; PB, body wounds of ponies.

Figure 2.3 After 3 weeks, the limb wounds of horses

(a)

contained more exuberant granulation tissue than the limb wounds of ponies

(b)

. In the same timeframe, the wounds on the buttocks of horses

(c)

and ponies

(d)

had formed some exuberant granulation tissue protruding above all wound margins.

Figure 2.4

(a)

By 4 weeks after wounding, the granulation tissue of the limb wounds of horses was traversed by grooves and clefts, and on its surface was a purulent exudate.

(b)

The granulation tissue of pony wounds, on the other hand, was smooth, regular, and had a healthy pink color.

Figure 2.5 Typical microscopic appearance of the granulation tissue of metatarsal wounds 6 weeks after wounding (DAP‐filter, MIB).

(a)

In horses, many brown‐colored cells, actively synthesizing DNA and preparing for mitosis, were present. Note the irregular arrangement of the fibroblasts in the tissue and the presence of polymorphonuclear leukocytes.

(b)

In ponies, only a few brown‐stained cells are seen in the regularly organized granulation tissue.

Figure 2.6 After 9 weeks of healing, the contribution of contraction to wound closure can be appreciated by observing the tattoo patterns close to the original margin of the wound.

(a)

The metatarsal wounds of horses have decreased in size. The tattoos show that the wounds have contracted minimally, whereas pronounced epithelialization is visible.

(b)

Closure of the metatarsal wounds of ponies was, to a large extent, the result of contraction and some epithelialization.

(c)

The buttock wounds of horses also healed mainly by contraction, with a small amount of epithelialization.

(d)

The buttock wounds of ponies healed, mainly by contraction, with very little epithelialization. The scar of this pony was unfortunately superficially damaged while shaving the hairs around the scar for the photographs.

Figure 2.7 Relative contribution of contraction and epithelialization to wound closure. For abbreviations see Figure 2.2. The correlation between the epithelialized area and wound contraction is inversed, so that wounds demonstrating the most contraction show the least amount of epithelialization (pony versus horse wounds, body versus limb wounds).

Figure 2.8 Scar of a metatarsal wound of a horse

(a)

and a buttock wound of a pony

(b)

1.5 years after healing. The limb wound in the horse healed mainly by epithelialization, leaving an unsightly scar. The buttock wound of the pony closed mainly by wound contraction, leaving no visible scar.

Figure 2.9 Schematic representation of the healing phases of wounds of equids. Inflammation should initially be stimulated (green shaded area) until the wound has filled with granulation tissue, and, thereafter, it should be arrested (pink shaded area) to reduce the formation of Exuberant Granulation Tissue and facilitate contraction and epithelialization. In fact, horse wounds should be treated so that the pattern of healing resembles that of ponies.

Figure 2.10

(a)

This traumatic wound on the dorsal surface of the metatarsus of a horse, with extensive undermining, was treated with alginate dressings to stimulate the acute inflammatory response.

(b)

After 13 days, the wound was filled with healthy and contracting granulation tissue.

(c)

A different traumatic wound at a similar location in a horse, but with less undermining and no involvement of the metatarsal bone. The wound was treated with several types of silver foam dressing that do not modulate inflammation.

(d)

After 20 days, the wound was filled with EGT characterized by an irregular surface, riddled by a deep cleft. This wound failed to contract.

Figure 2.11

(a)

A large degloving injury on the dorsal surface of the metacarpus of a pony, with exposed bone and lacerated extensor tendons. The wound was debrided and treated with alginate dressings to stimulate inflammation.

(b)

After 15 days, the exposed bone was covered and the wound was filled by granulation tissue. Treatment was continued with a foam dressing. A wound of these dimensions and depth may require at least twice the time to achieve a similar outcome when treated with a non‐adherent dressing that is not interactive.

Chapter 03

Figure 3.1 Example of extensive trauma to the distal aspect of the limb. The wounds were incurred several days prior to presentation and were caused by entrapment of the foot between panels. The wounds’ size and the degree of lameness had increased despite antimicrobial and anti‐inflammatory therapy. Both wounds communicated with the pastern joint, and a stress radiograph confirmed rupture of the lateral collateral ligament of the proximal interphalangeal joint.

(a)

Lateral view.

(b)

Medial view.

Figure 3.2 A sterile needle has been placed into the distal interphalangeal (coffin) joint at a site remote to the wound.

Figure 3.3 Granulating cast sore 3 weeks after the removal of a cast used to manage a laceration over the dorsal surface of the fetlock. Concentric rings of granulation tissue have formed as a result of differential movement between the skin, subcutaneous tissues, paratenon, and the underlying common digital extensor tendon. A portion of the tendon is visible distally with the proximal portion of the tendon covered by granulation tissue.

Figure 3.4 Degloving injury of 3 months duration involving the dorsal surface of the metatarsus. A linear defect in the unhealthy‐looking granulation tissue was associated with wound drainage as well as stalled wound contraction, signs indicating the presence of a sequestrum. The sequestrum was removed from the sedated, standing horse using local anesthesia.

Figure 3.5 Example of an inverted “V”‐shaped wound over the dorsal surface of the carpal region. This configuration compromises blood supply to the skin and subcutaneous tissues, resulting in poor wound healing.

Figure 3.6 Example of a flap wound over the dorsal surface of the carpal region. The flap is positioned such that it is at odds with the limb’s major distribution of blood vessels.

(a)

At presentation, ~6 hours after injury; note the absence of subcutaneous tissue at the proximal limit of the flap. The tip of the flap felt cool. After cleansing the wound, the skin flap was elevated into its normal position, after which a bandage splint was applied.

(b)

Five days after injury. The skin flap had retracted, and a healthy bed of granulation tissue had formed. This flap should have been stabilized, in as normal a position as possible, using a few large tension sutures. This would have prevented retraction of the skin flap, which complicates delayed closure of the wound.

Figure 3.7 Example of a wound that would not heal after repeated attempts to excise the granulation tissue. Histologic examination of the tissue revealed a squamous cell carcinoma.

Figure 3.8 A chronic, non‐healing wound at the commissure of the mouth. Despite repeated sharp debridement and excision of the granulation tissue, followed by primary closure of the defect, the wound would not heal. Histologic examination of the granulation tissue revealed habronemiasis.

Figure 3.9 Example of a chronic wound showing local signs of infection: the granulation tissue has an irregular surface (clefts and tunnels), has become exuberant, and is covered by unhealthy exudate.

Chapter 04

Figure 4.1

(a)

Example of a wound on the dorsal surface of the proximal metatarsus, close to the hock. The tarsometatarsal and distal intertarsal joints were injected with sterile isotonic saline solution to investigate a potential communication with the wound. These tarsal joints were not affected, however, exposure of the third metatarsal bone created a risk for sequestrum formation.

(b)

A Waterpik® Water Flosser was used for wound cleansing and irrigation and the limb was radiographed 7 days later to determine whether a sequestrum had developed.

Figure 4.2 Example of a heel bulb laceration

(a)

where the foreign body (barbed wire) was not identified during visual appraisal and digital exploration of the wound. However, it was clearly identified on radiographs of the hoof

(b, c)

. None of the adjacent synovial cavities (navicular bursa, coffin joint, digital flexor tendon sheath) had been breached by the wound. The barbed wire was localized and removed under general anesthesia.

Figure 4.3 This horse suffered a penetrating wound to the lateral surface of the distal antebrachium 3 weeks earlier. Initial exploration revealed several pieces of wood in the wound, which were subsequently removed. Following debridement and irrigation, the wound was sutured and the horse received antimicrobial therapy. The horse became non‐weight‐bearing within 7 days and the wound broke open and began to drain 10 days postoperatively.

(a)

Craniocaudal contrast radiographic study revealing multiple filling defects (a result of pieces of wood) in the carpal canal.

(b)

Lateral radiographic view identifying multiple filling defects in the carpal canal.

Figure 4.4 A sterile needle has been placed in the distal interphalangeal (coffin) joint at a site remote from the wound.

Figure 4.5

(a)

Example of a severe wound on the dorsal surface of the antebrachium where, due to excessive contamination and the presence of non‐viable tissue, closure was delayed until a bed of healthy granulation tissue had formed.

(b)

Initially, the wound was packed with hypertonic saline‐soaked gauze (Curasalt™ Covidien Animal Health/Kendall) to assist autolytic debridement and the flap was temporarily replaced into a normal position and secured using several large tension sutures placed in a near–far–far–near pattern, to reduce tension and to prevent skin flap retraction.

(c)

Once a healthy bed of granulation tissue was present, the wound underwent delayed secondary closure using a combination of near–far–far–near and simple interrupted suture patterns.

Figure 4.6

(a)

Example of an acute and mildly contaminated wound. After sharp debridement the wound was closed primarily. Due to the location over the point of the shoulder the wound was under tension.

(b)

A combination of tension‐relieving sutures (near–far–far–near and vertical mattress), in addition to four horizontal mattress sutures with rubber stents, were used to reduce the risk of dehiscence. Suture loops were placed 10 cm above and below the suture line in order to secure a stent bandage to prevent contamination and to reduce edema (stent bandage not shown). A drain was used and made to exit ventral to the wound and away from the suture line, to achieve effective drainage of the dead space. The drain was sutured in place (topmost suture and ventral suture at the exit point of the Penrose drain).

Chapter 05

Figure 5.1 Wound on the thigh of a pony. The wound had dehisced partially after suturing. The location of this wound makes bandaging difficult. The simplest means of stimulating healing for such wounds is to apply topical products.

Figure 5.2

(a)

Irrigation of an acute wound using sterile isotonic saline solution. This type of passive gravity fluid flow does not provide sufficient pressure to remove contaminants or overcome the forces with which bacteria adhere to the wound. Photo courtesy of Denis Verwilghen.

(b)

To achieve an appropriate pressure (10–14 psi) fluid should be firmly expressed from a 60‐mL syringe with a 19‐gauge needle or through devices or spray bottles constructed to deliver the appropriate pressure. (See also Figure 5.3 and Table 5.1.)

Figure 5.3 Wound irrigation device (Wound flushing unit, Kruuse) constructed to achieve appropriate pressure (10–14 psi) during wound irrigation. Moderate fluid pressure is needed to overcome the adhesion of contaminants and bacteria to the wound. High fluid pressure should be avoided because it may drive bacteria deeper into the wound.

Figure 5.4 An acute, severely contaminated degloving injury. This wound is at high risk of developing infection, and will therefore benefit from being irrigated with an antiseptic solution. Photo courtesy of Tinamaria Jensen, Vinding Forlag and Tinamarias Digital Publishing.

Figure 5.5 Hypochlorous acid made through electrochemical treatment of dilute saline solution, whereby a pH‐neutral solution of hypochlorous acid, and its salt, sodium hypochlorite, is generated (Vetericyn, Oculus Innovative Sciences). Hypochlorous acid is highly active against all Gram‐positive and Gram‐negative bacterial, viral and fungal pathogens, including drug‐resistant staphylococci; moreover, it combines rapid bacterial kill with low cytotoxicity

in vitro

. These desirable characteristics make hypochlorous acid very useful for wound cleansing.

Figure 5.6 Granulating wound on the dorsomedial surface of the metatarsus.

(a)

The wound developed exuberant, fragile, unhealthy looking granulation tissue with signs of surface inflammation and infection.

(b)

The wound was treated by excision of exuberant granulation tissue and topical application of clindamycin under a non‐adherent dressing, and 1 week later the granulation tissue was healthy with scant exudation.

(c)

The wound went on to heal without complications with no further application of antimicrobials.

Figure 5.7 Sutured wound on the ventral abdomen. Autolytic debridement is taking place in the wound; the exudate is produced through that process and is not a sign of infection. The wound has dehisced partially, probably because sutures have been placed too close to the wound margins, which are now undergoing autolytic debridement.

Figure 5.8 Severe, circumferential wound on the plantar surface of the left metatarsus of a mare. The wound shows signs of chronic inflammation with tenacious exudate and formation of exuberant granulation tissue. This wound will benefit from short‐term topical application of a glucocorticoid cream (e.g., triamcinolone). Photo courtesy of Jørgen Didriksen.

Figure 5.9 Sugardine (icing sugar mixed with iodine) applied to a hoof abscess after paring and draining of the abscess.

Chapter 06

Figure 6.1 Dressing materials soaked in tenacious exudate. The exudate forms a partially or completely occlusive shield over the wound, because it is impermeable to water vapor and oxygen. The effects of the applied dressing may thus change in the presence of such thick exudate. This type of exudate may result from autolytic debridement, chronic inflammation or wound infection, i.e. from very different (patho)physiologic processes that require different treatments.

Figure 6.2 Limb wound where bandaging was discontinued. A scab has formed over the wound, and healing will continue under the scab, albeit at a slower rate and with a poorer cosmetic outcome than if appropriate dressings had been applied. The propensity for formation of EGT is reduced in wounds that are left uncovered. Contamination of the scab with bedding material or dirt rarely causes clinical problems.

Figure 6.3 Unsightly scar that developed in a wound after bandaging was discontinued due to financial constraints. Same horse as in Figures 6.8 and 6.16.

Figure 6.4 Tulle gras dressing. This dressing is indicated for use on minor burns and scalds, lacerations, abrasions, and other skin loss wounds of limited extent. Tulle gras dressings are non‐absorbent, and a secondary layer of absorbent material must be placed over the dressing.

Figure 6.5 Gauze‐like (also called dry or plastic film‐faced) dressing. This type of dressing is made from compressed cotton and is covered by a non‐adherent, thin, perforated polyester film. It is freely permeable to water vapor and oxygen. This type of dressing is mainly indicated for wounds healing by primary intention.

Figure 6.6 Experimental wound 28 days after the wound was created by surgical excision of 1 × 1 cm skin and periosteum. The wound was dressed with a non‐adherent, gauze‐like dressing during the 28 days study period. EGT mushrooming over the wound margin is apparent.

Figure 6.7 Alginate dressings. When exudate is absorbed into the dressing, alginate fibers swell, partially dissolve, and form a gel. The gel provides a moist environment in the wound and, by doing so, promotes healing. The rope form (right) contains silver, which causes the gray color. Rope dressings are useful for packing cavities.

Figure 6.8 Wound requiring ingrowth of granulation tissue. Alginate dressings are useful for stimulating the formation of granulation tissue. In wounds where exudation is sparse, the alginates should be moistened with sterile saline solution before being applied to the wound. Same horse as in Figures 6.3 and 6.16.

Figure 6.9 Severe degloving injury with large area of exposed bone. The wound was dressed with moistened alginates, and formation of granulation tissue is apparent at the wound edges. Moreover, capillary ingrowth, evident as pin‐point red or dark spots, is evident in the cortex of the exposed third metatarsal bone (inset). Alginates are not marketed for use on exposed bone, but studies and experience have demonstrated their efficacy for stimulating ingrowth of granulation tissue over the denuded bone (see text for further details).

Figure 6.10 Hydrofiber dressing.

Figure 6.11 Necrotic wound sustained when the limb was caught as the horse attempted to jump over its stall door. The wound is dry and would benefit from application of a hydrogel dressing to soften the scab and stimulate autolytic debridement.

Figure 6.12 Hydrogel dressings: amorphous hydrogel to the right, sheet hydrogel to the left. Hydrogels are useful for donating moisture to dry wounds and for preventing desiccation of exposed bone or tendon.

Figure 6.13 Hydrocolloid dressing. This dressing is fully occlusive, has a large absorptive capacity and provides moist wound healing. It has been implicated in the formation of EGT in horses; consequently, wounds dressed with hydrocolloids should be monitored closely.

Figure 6.14 Foam dressings. Several types are shown, both with and without an adhesive border. Foams are used for wounds that have completely filled in with granulation tissue. To the right two “lite” foams are shown. These are indicated for wounds with little or no exudation, where application of a regular foam dressing might cause desiccation of the wound. The two “lite” foams shown also have a soft silicone adhesive layer on the surface. Soft silicone coating has several advantages, as it improves handling properties (by preventing slippage) of the dressing, increases patient comfort and reduces disruption of healing tissues during dressing change. Several regular foams also have a soft silicone layer (see text and Table 6.2 for details).

Figure 6.15 Film dressings. An example of a spray‐on film dressing is shown to the right. Films are used as a “second skin” to protect the wound in the last stages of healing or to dress wounds healing by primary intention. Film dressings have very little absorptive capacity.

Figure 6.16 Large wound on the limb, in which healing is progressing well. The wound bed is filled with healthy granulation tissue, epithelialization is evident as the pale rim at the wound’s margin. The wound may at this stage be protected by a spray‐on film or dressed with a “lite” foam to limit desiccation, which would reduce the rate of epithelialization.

Figure 6.17 Acute wound dressed with a silicone gel sheet to prevent the formation of EGT. The wound was dressed with the silicone gel sheet until almost completely healed, and it healed without complications.

Figure 6.18 Wound on the limb, which suffered substantial dehiscence after primary closure. The remaining distal part of the skin flap is clearly necrotic (dark, dry) and will also dehisce over time. This wound should be treated with a thorough surgical or hydrosurgical debridement and covered with an alginate dressing containing silver to reduce bioburden and to stimulate the formation of granulation tissue. Although hydrocolloids may encourage autolytic debridement and the formation of granulation tissue, they are contraindicated in wounds with heavy exudation and signs of infection.

Figure 6.19 Dialkylcarbamoylchloride (DACC) dressings. These antibacterial dressings work by hydrophobic–hydrophobic interaction. Bacteria are retained in the dressing and removed at dressing change. A pad with an adhesive border (left) and a gauze suited for packing cavities (right) are shown.

Chapter 07

Figure 7.1

(a)

A penetrating injury to the sole of the foot has been cleaned, irrigated, and covered with sterile gauze.

(b)

Conforming gauze (Kling™ or Conform) can be used to hold the primary layer in place on the bottom of the foot.

(c)

A cotton pad is folded into a square and then placed over the sole of the foot with the edges drawn up and over the foot and coronary band.

(d)

Elastic, self‐adhesive material (Vetrap™) is used as a tertiary layer to hold the cotton in place.

(e)

Duct tape is used to make a patch in a square or a cross configuration to be placed on the bottom of the foot. It is best to do this on a clean metal surface and not a painted wall as the paint may peel off when the patch of duct tape is removed. This patch is centered over the sole of the foot with the edges coming up around the sides of the foot bandage.

(f)

To complete the foot bandage, elastic adhesive tape is applied (without tension) over the skin to prevent bedding or dirt from entering between the bandage and the skin/hoof. The final bandage provides some padding to the injured foot but also absorbs drainage and protects from further contamination.

(g)

A view of the bottom of the foot with the bandage in place. The horse should be kept in a clean and dry environment to complement the action of the protective, waterproof duct tape.

Figure 7.2 For wounds of the pastern region it is preferable to attach the bandage to the hoof to prevent upwards migration of foreign material under the bandage.

Figure 7.3

(a)

The first step in creating a distal limb bandage is to place a dressing on the wound or suture line. This is held in place with some soft roll gauze, such as Conform.

(b)

Cotton padding is used as the secondary layer of a distal limb bandage. It must extend distally past the coronary band; it is important to avoid finishing the bandage directly over the coronary band where it may rub and cause irritation. The cotton layer protects the limb and may absorb excess exudate.

(c)

The tertiary layer, consisting of elastic, self‐adhesive material, is applied using even pressure. It must cover the underlying layer of cotton except for a small border both proximally and distally, in an effort to avoid placing undue pressure on uncovered skin.

(d)

Elastic, adhesive tape is then applied, without tension, both proximally and distally to cover the extremities of the bandage and prevent bedding or dirt from migrating under the bandage.

(e)

This distal limb bandage is used to cover a wound over the cannon bone; consequently, it need not be attached to the hoof. The distal extremity rests a few centimeters above the coronary band thus sparing it from rubbing and irritation.

Figure 7.4

(a)

The first step in creating a carpal bandage is to place an appropriate dressing on the wound or suture line. This is gently held in place with conforming gauze that can be placed in a figure‐of‐eight pattern around the carpus.

(b)

The secondary layer of cotton padding is applied as for a distal limb bandage, taking care to avoid bunching.

(c)

The tertiary layer is applied using even tension and overlapping by 50% the width of each turn of the elastic, self‐adhesive material.

(d)

The bandage with the tertiary layer in place; note the snug fit required to avoid bandage slippage and bunching that would be detrimental to both the wound and the skin of the limb.

(e)

The top and bottom of the bandage can be attached to the skin using elastic, adhesive tape, applied without tension. Placement of a stall bandage distally would eliminate the need for the lowermost band of tape and may help prevent distal slippage of the carpal bandage.

(f)

To prevent the development of a pressure sore over the protuberance of the accessory carpal bone, a releasing incision is made in the bandage directly overlying this site. This protuberance can be palpated through the bandage.

Figure 7.5

(a)

A hock bandage is fashioned similarly to a carpal bandage. The selected dressing is applied to the wound and held in place using conforming gauze that is applied, in a figure‐of‐eight pattern, above and below the point of the hock.

(b)

The secondary layer is placed by conforming the cotton pad around the tibia and then slightly bunching it around the cannon bone when the tertiary layer is applied. As is the case with a forelimb bandage, the tertiary layer must be applied using snug, even tension and making sure to leave some cotton distally and proximally so as to avoid exerting pressure on unprotected skin. Moreover, less tension must be used when running over the point of the hock, to allow this joint to flex in spite of the bandage.

(c)

The proximal and distal extremities of the bandage can be sealed with loose turns of elastic, adhesive tape. More can be used proximally to help prevent distal slippage of the bandage.

Figure 7.6

(a)

Alternative hock bandage. A strip of elastic adhesive tape (e.g. Elastikon®) is placed longitudinally over the plantar surface of the hock region.

(b)

The strip of Elastikon® is held in place at its proximal limit by circumferential rolls of the same tape.

(c)

Bandage complete; both the proximal and distal limits of the strip of Elastikon® are secured with the same tape. The strip of Elastikon® helps limit disruption of the bandage during hock flexion.

Figure 7.7 The addition of a distal limb bandage may help hold the carpal or tarsal bandage in place. Moreover, in the acute phase of wound healing, this bandage may aid in controlling the development of edema distal to the wound.

Figure 7.8

(a)

A rectal sleeve can be sliced lengthwise and attached over the plantar surface of the bandage. This should help protect it from becoming wet and may also reduce the ability of the horse to rub the two limbs together in an effort to dislodge the bandage.

(b)

Cranial view of the rectal sleeve acting as a “rain jacket.”

Figure 7.9

(a)

Mesh stockinette is very useful when making a head bandage, due to its natural elasticity and the ease with which it can be torn to form eye and ear holes.

(b)

The mesh stockinette is drawn up over the head, tearing or cutting generous holes for the eyes and ears. Care must be taken to avoid occluding the nostrils or rubbing the eyes.

(c)

The two extremities of the mesh have a tendency to roll up thus uncovering the wound or interfering with the eyes. An elastic, adhesive tape (such as Elastikon®) can be applied, with light tension, to fix the two extremities to the skin.

(d)

The elastic, adhesive tape can be placed over the frontal sinus area and then looped around the face, rostrally, and behind the ears, caudally. The loops must be placed without tension but the tape may exert a small amount of compression on the dressing over the wound.

(e)

Elastic, adhesive tape has been looped behind the ears. Where the bandage passes under the throatlatch area, care must be taken to ensure it is not too tight; a finger should be easily inserted between the bandage and the underlying skin.

Figure 7.10 A commercial abdominal bandage has been placed over the primary and secondary layers of a bandage. Elastic, adhesive tape is used cranially to attach the bandage to the skin and thereby prevent caudal slippage.

Figure 7.11 A stent bandage, made from a baby diaper, has been sutured over a wound dressing to treat a chronic abscess, which developed over the

tuber coxae

following a fracture leading to bony sequestration.

Figure 7.12 A dropped fetlock is a sign of flexor tendon laxity in this foal. It developed in response to a 2‐week period of distal limb bandaging to treat a skin laceration over the medial metacarpal area. A gradual increase in exercise should help resolve the laxity; a special orthopedic shoe with a heel extension may also be required.

Figure 7.13 Examples of materials commonly used to build a splint: PVC pipe (that can be padded at both ends), duct tape, and white tape. The duct tape may be used temporarily (for transportation to a referral center) but the permeable white tape is preferred for chronic use as it is less likely to cause sweating under the bandage and subsequent skin maceration. Cast material can also be used to form a splint.

Figure 7.14 A roll of fiberglass cast tape is unrolled then folded back on itself repeatedly with a slight side‐to‐side overlap. In this particular case, it was for application to the sole of the foot and is thus much shorter than it would be for creating a distal or full‐limb splint.

Figure 7.15

(a)

Cast splint for the hindlimb. The cast splint has cured and is ready to be applied to the hindlimb.

(b)

Vetrap™ is used to affix the cast splint to the bandage. Elastikon® is used to prevent the end of the self‐adherent tape from unraveling (center) and to further secure the splint proximally and distally.

Figure 7.16

(a)

A length of PVC pipe is placed as a palmar splint over a distal limb bandage. Splints are used to limit fetlock flexion, thereby reducing the tension sustained by wounds located on the dorsal surface of the metacarpal/tarsal area. The splint must span the distance between the floor and the proximal extremity of the cannon bone. Cotton is placed to fill the void between the splint and the palmar/plantar surface of the pastern, thereby assisting in the restriction of fetlock flexion.

(b)

Alternatively, heat may be used to enable bending of the PVC pipe so that it conforms to the angle of the pastern.

(c)

The splint is attached with white tape, overlapping each turn by 50% and running with even tension up and down in the limb. The tape should be applied only where the underlying area has been generously padded.

(d)

With the splint now in place, it is apparent that the heel bulbs remain exposed; in the long‐term, this may favor the development of rub sores. Optimally, the bandage material must cover all the skin underneath the splint.

Figure 7.17 The materials required to build and apply a cast: cast padding (Delta dry), fiberglass cast material, and the components to make Technovit® (an acrylic that can be applied to the bottom of the foot to reinforce this area). Thick (black) felt is also required for placing at the top edge of the cast.

Figure 7.18

(a)

An example of a commercial boot that can be placed on the limb contralateral to that being cast, to equalize the length of the limbs. Several boot products are commercially available although a wooden block or commercial shoe can be used as an alternative. This particular commercial boot is reusable and has a soft pad on the interior.

(b)

A distal limb cast was placed on the left forelimb to assist in the treatment of a flexor tendon laceration. To equalize the length of the forelimbs and thereby avoid overloading the contralateral limb, a boot with Velcro straps (in this case reinforced with elastic tape) has been placed on the right forelimb. A soft elastic bandage has been applied around the cast to prevent abrasive trauma to the skin of the other limb if the horse lies down.

Figure 7.19

(a)

Application of a phalangeal cast in the standing horse. The limb is held off the ground to apply a single layer of cast padding (yellow) to the pastern and hoof regions and a fiberglass cast tape to the bottom of the foot (not shown). A ring of orthopedic felt, underlying the foam, is placed at the proximal pastern.

(b)

A roll of 12.5‐cm fiberglass cast tape was applied to the bottom of the foot. The remainder of the cast is being applied to the pastern up to the middle of the ring of orthopedic felt.

(c)

Excess stockinette is removed in preparation for rolling the remaining portion distally over the cast.

(d)

The rolled stockinette is secured to the cast with 5‐cm white, non‐elastic adhesive tape.

(e)

Technovit® has been applied to the bottom of the cast.

Figure 7.20 When a full‐limb cast is applied to aid in the healing of a wound, a sling may be used to keep the horse standing and thereby avoid placing significant force on the bones of the immobilized limb upon lying down and rising. Potentially severe complications such as long bone fractures and rupture of the

peroneus tertius

can be minimized using this precaution. An alternative is to keep the horse cross‐tied.

Chapter 08

Figure 8.1 Example of a fresh skin wound on the medial surface of the right hock, with sharp edges, caused by a metal gate. The wound was partially closed primarily, leaving its ventral extent unsutured to allow drainage. A vertical mattress suture pattern, with tubing used as stents, was selected to counter the tension that results from flexion of the hock. The sutured wound was then supported by a full limb bandage. Placing a bandage over stents can result in pressure necrosis, so the wound should be monitored closely for signs of this complication. Pressure on the bandage overlying the wound should be reduced to decrease the likelihood of pressure necrosis from developing beneath the stents. If damage to skin beneath the stents appears, the limb should be left unbandaged, or the stents should be removed in a staged approach.

Figure 8.2 Heel bulb laceration of several days duration that was managed by delayed secondary closure. The cause was barbed wire. The horse was severely lame on the affected limb, and the wound was exudative and swollen, indicating infection.

Figure 8.3 Example of a large wound in the axillary area that was managed by second‐intention healing. At the time the horse was presented, granulation tissue had already filled the wound bed, and subcutaneous emphysema, which commonly accompanies wounds in the axillary region, was not observed.

Figure 8.4 Example of a wound that can be partially closed and in which a drain should be used.

(a)

Acute wound of <4 hours duration involving the proximal region of the antebrachium. Note the skin flap at the distal aspect of the wound is displaced distad. Suturing the skin flap into its normal position would create a sizeable dead space underneath the skin flap.

(b)

The wound could not be completely closed because of tension. Note the Penrose drain exiting the undermined skin flap at the distal limit of the flap. The drain was anchored by sutures attaching it to the skin, proximad and distad. The drain’s exit site was covered with a sterile bandage.

Figure 8.5 In this extensive degloving injury to the distal aspect of the limb, the extensor tendons are lacerated and the metacarpal bone stripped of its periosteum. Despite gross contamination and the likelihood that a portion of the skin flap would suffer avascular necrosis, primary closure was attempted to protect the deep tissues from desiccation until granulation tissue covered the bony surface. Healing even a small portion of a wound by primary closure reduces the amount of second‐intention healing required, thereby minimizing scarring and improving functional and cosmetic outcomes.

(a)

Sterile gel has been placed in the wound during cleansing and preparation of the skin flap, prior to irrigating the wound.

(b)

Releasing incisions have been made to reduce tension on the primary closure and to allow drainage; these are best made in the skin surrounding the wound rather than in the skin flap, the blood supply to which is already compromised. Stents made of plastic tubing are used in combination with a horizontal mattress suture pattern, interspersed with sutures placed in a simple interrupted pattern. This repair was protected by a bandage–cast for 2 weeks. This wound healed well, with only a small portion of the skin flap (2 cm) at the proximal extent of the wound lost to necrosis 1 week after primary closure. Placing a bandage over stents can result in pressure necrosis so the wound should be monitored closely for signs of this complication. Pressure on the bandage overlying the wound should be reduced to decrease the likelihood of pressure necrosis from developing beneath the stents. If damage to skin beneath the stents appears, the limb should be left unbandaged, or the stents should be removed in a staged approach.

Figure 8.6

(a)

Example of a wound in which primary closure was deferred due to the patient’s compromised systemic status (i.e., shock requiring administration of fluids and a blood transfusion) and contamination of the wound with hair and soil. The wound was irrigated daily, dressed with honey, and bandaged.

(b)

Delayed primary closure was undertaken 2 days after injury, after the horse’s systemic status had improved and stabilized. The flap has been debrided and is being irrigated with polyionic fluids.

(c)

A horizontal mattress suture pattern, in combination with stents made of plastic tubing, has been used to close the wound. In an effort to ensure adequate drainage of fluid produced by the wound, a passive drain (Penrose tubing) and an active drain (homemade with a syringe) have been placed, and the most ventral portion of the wound has been left unsutured. A simple approximating or everting suture pattern is commonly used, in addition to the mattress tension sutures, to maintain integrity of the sutured incision if the mattress tension sutures must be removed to avoid pressure necrosis caused by the accompanying stents.

(d)

Approximately 8 days after injury and 6 days after delayed primary closure, the cranial portion of the skin flap became necrotic (note the leathery appearance) due to insufficient blood supply.

(e)

The necrotic portion of the skin flap was excised, and the underlying wound bed, which was filled with healthy granulation tissue, was gently cleansed. The remaining wound healed by contraction and epithelialization, without complication, within 4 weeks.

Figure 8.7 Same wound as in Figure 8.2.

(a)

The wound, 5 days later, after cleansing, debridement, and administration of antimicrobial therapy. Note the healthy bed of granulation tissue. This wound is ready for delayed secondary closure.

(b)

The wound, after excising granulation tissue. A portion of the lateral ungual cartilage was damaged and, therefore, excised (white tissue proximal to the gloved digit).

(c)

The partially sutured wound. The coronary band has been apposed at the heel bulb, but the skin at the dorsal limits of the wound (just to the right of the last suture) could not be apposed due to a tissue deficit (missing skin). A phalangeal cast was applied after surgery and left in place for 2 weeks.

(d)

The wound 2 weeks after cast removal. The sutured portion of the wound healed primarily, and the area of tissue deficit (granulating wound) healed by second intention beneath a bandage. The coronary band healed primarily, obviating the development of a defect in the hoof wall.

Figure 8.8 Injury at the tail head.

(a)

The large skin flap did not include any underlying muscle. The wound was closed primarily, in the field, by the referring veterinarian. Clipping of the hair initially proved difficult due to the attitude of the very young horse at the time of wounding.

(b)

The thinness and the orientation of the skin flap (the base was located caudally and the dominant blood supply arrived from the cranial extremity/apex of the flap), combined with inadequate ventral drainage, thereby trapping exudate, led to necrosis of the flap and the development of infection beneath it. Although it was ultimately lost, the flap served temporarily as a “biologic bandage.” The necrotic tissue was excised.

(c)

The area beneath the necrotic skin flap is covered by healthy granulation tissue.

(d)

The wound bed, after cleansing and debridement. A few sutures were placed to anchor the skin of the tail head to prevent it from retracting further.

(e)

The wound, left to heal by second intention, has contracted and has a pink epithelial rim approximately 1 week after cleansing and debridement.

Figure 8.9 This wound, located on the dorsal surface of the metatarsus in a draft horse, was initially left to heal by second intention until healthy granulation tissue filled the wound.

(a)

After this had occurred, skin grafting was considered because contraction and epithelialization appeared unlikely to result in rapid and complete healing of the wound. The wound was implanted with island grafts, rather than being covered with a sheet graft, because of the owner’s financial constraints.

(b)

10 days after island grafting. Tufts of hair surrounded by raised new epithelium are observed. In some areas, there is evidence of coalescence between the new epithelial islands. Approximately 80% of the punch grafts ultimately survived, which is the expected percent of graft “take” for island grafting.

Chapter 09

Figure 9.1 Characteristics of sutures most commonly used in veterinary medicine. TS, tensile strength.

Figure 9.2 Various shapes of surgical suture needles.

Figure 9.3 Various point and body designs of surgical suture needles.

Figure 9.4 Simple interrupted suture pattern. Knots should be offset so they do not rest upon the apposed skin margins. Sutures should be placed close enough to prevent gaping. a = distance from the wound edge the suture should be placed to ensure optimal holding strength (>0.5 cm). b = minimal distance between two consecutive suture bites (±0.5 cm).

Figure 9.5 Surgical knots.

(a)

Surgeon’s.

(b)

Square.

Figure 9.6 Suture placement for a subcutaneous continuous or running suture pattern. The initial knot is buried in the subcutaneous tissues.

Figure 9.7 Simple interrupted suture pattern. The independent nature of each suture allows for mobility and use in irregularly shaped areas.

Figure 9.8 Interrupted intradermal suture.

Figure 9.9

(a)

Cruciate mattress suture pattern.

(b)

Inverted cruciate mattress suture pattern.

Figure 9.10

(a)

Interrupted vertical mattress suture pattern. These sutures provide precise edge‐to‐edge skin apposition with slight eversion after they are tied. They also minimally compromise skin vasculature.

(b)

Interrupted vertical mattress suture pattern used to decrease dead space.

(c)

Alternating vertical mattress and simple interrupted suture patterns to prevent skin inversion. Note: There is no biomechanical advantage over a simple interrupted suture pattern when placed as described. The alternating vertical mattress suture pattern can however be placed widely to reduce tension on the primary suture line or associated with rubber “stents” or buttons.

Figure 9.11 The Allgöwer corium vertical mattress suture pattern. This minimally traumatic suture pattern provides good apposition of skin margins with minimal or no eversion of the skin edges.

Figure 9.12

(a)

Horizontal mattress suture pattern. Slight eversion and some gaping of the wound edges occur after they are tied.

(b)

If the sutures are tied too tightly or if tissues swell excessively after placement, reduction of the skin blood supply occurs (elevated tissue and dashed lines within the suture pattern) and can impair wound healing.

Figure 9.13 Suture placement through all skin layers in a simple continuous suture pattern.

Figure 9.14 Continuous intradermal suture pattern. The suture should pass through the dermis perpendicular to the long axis of the wound. Suture bites in the dermis should be of equivalent depth. Spacing between bites should also be regular.

Figure 9.15 Continuous mattress suture pattern.

(a)

Horizontal mattress.

(b)

Vertical mattress.

Figure 9.16 Continuous locking or Ford interlocking suture pattern.

(a)

Passage of the suture.

(b)

Tying the suture after completion.

Figure 9.17

(a)

Vertical mattress sutures are preplaced and the skin edges apposed with towel clamps.

(b)

Two rows of vertical mattress sutures are used to reduce the tension at the site of primary closure.

(c)

Three rows of vertical mattress suture are used to reduce the tension at the site of primary closure. In both

b

and

c

, placement of interrupted vertical mattress sutures is in an “echelon” pattern.

Figure 9.18 Widely placed interrupted horizontal mattress and simple interrupted sutures reduce tension on the primary repair site and prevent eversion of the skin edges.

Figure 9.19 Quilled or stented tension sutures augmented by supports (rubber stents or buttons).

Figure 9.20 A far–near near–far suture pattern. The far component reduces tension while the near component holds the tissue edges in apposition.

Figure 9.21

(a)

Single modified locking loop suture pattern.

(b)

Double modified locking loop suture pattern.

Figure 9.22 The three‐loop pulley suture pattern. Each loop is oriented 120 degrees relative to the others. The first loop is in a near‐far suture pattern

(a)

, the second loop is equidistant from the transected ends of the tendon

(b)

, and the third loop is placed in a far–near pattern

(c, d)

.

Figure 9.23 Intraneural suture pattern.

Figure 9.24 Walking sutures. Skin around the initial wound is undermined. Using absorbable suture material, the first bite is taken deep within the dermis (without penetrating the epidermis). The second bite is taken in the underlying fascia toward the center of the wound or the opposite wound margin. Tying the suture advances the skin flap in the chosen direction. Walking sutures are placed on both sides of the wound until the skin margins are close enough to allow closure with an appositional suture pattern placed without tension.

Figure 9.25 Proper placement of a Penrose drain to facilitate passive drainage. The proximal end of the drain is buried within the proximal aspect of the wound and is secured with a single penetrating suture tied on the outside of intact skin adjacent to the wound. The distal end exits the wound below its most distal aspect through a single stab incision in a dependent position near the wound. The wound is subsequently closed.

Figure 9.26 Wound over the carpus managed with multiple tension sutures and a Penrose drain exiting the wound distally through a stab incision in a dependent position near the wound. The drain was removed within 5 days and the wound healed by primary intention under a full limb Robert Jones bandage.

Figure 9.27 Snyder Hemovac wound drainage device – 800 mL. Bellows‐type drain reservoir, used as active drainage system.

Figure 9.28 Active drainage system (Jackson–Pratt drain connected to a bellows type Snyder Hemovac reservoir) being used in the management of septic arthritis (shoulder joint).

Figure 9.29 Homemade active drain constructed by connecting one end of a tube to a Jackson–Pratt drain and the other end to a three‐way stopcock. The stopcock is attached to a 60‐mL syringe that acts as a drain reservoir. The plunger of the syringe is withdrawn to achieve the desired negative pressure and held in that position by introducing a large needle through the syringe plunger.

Figure 9.30 Suture patterns commonly used to secure a suction drain to the body or limb.

(a)

“Chinese finger trap” suture pattern.

(b)

“Double clove hitch” pattern.

Chapter 10

Figure 10.1 Tension lines and maximal extensibility of the skin of the forelimb are parallel to the limb’s long axis.

(a)

Forelimb in its normal position at rest. Skin extensibility is evaluated by pinching the skin, parallel and perpendicular to the limb’s long axis, over the dorsal mid‐metacarpal region.

(b)

Carpus and fetlock flexed. Skin extensibility and tension remains the same.

(c)

Carpus and fetlock flexed. Skin extensibility is assessed perpendicular to the limb’s long axis over the dorsal mid‐metacarpal region. Compared to skin tension with the limb in its normal position, skin tension has increased markedly, and the extensibility has decreased.

Figure 10.2 Transverse laceration involving the dorsal surface of the fetlock joint. The wound gapes widely while the joint is flexed, whereas the wound’s edges were in contact when the fetlock was extended. The severed end of the common digital extensor tendon protrudes from the wound.

Figure 10.3 This large solitary melanoma on the right ventrolateral thoracic region in a cow is used to illustrate the value of movement of a part to determine the correct axis for excision and to predict the extent of excision required to remove this lesion. The melanoma was freely movable, somewhat pedunculated, and appeared to be attached by a stalk of skin approximately 10 cm in diameter while the cow was standing.

(a)

With the cow anesthetized and in left lateral recumbency, the right limb was extended forward as would occur during walking or when resting in sternal recumbency. The lesion became sessile when the limb was extended.

(b)

The extent of excision required to remove the melanoma was greater than would have been predicted while the animal was standing. The limb was maintained in extension during surgery to ensure that the appropriate surgical approach, skin mobilization, and suturing techniques to close the wound were selected.

Figure 10.4 Solitary melanoma on the caudal thigh of a horse. A sterile marking pen was used to draw this fusiform pattern on the skin in preparation for excision.

Figure 10.5 Illustration of the presuturing technique.

Figure 10.6 Technique of mesh overlay used to decrease tension on a sutured wound on the thigh of horse.

(a)

This wound was sutured under great tension.

(b)

Using the technique of mesh overlay, a polypropylene mesh was placed over the sutured wound, and one edge of the mesh was sutured to the skin on one side of the wound.

(c)

The other side of the mesh was sutured to the skin on the opposite side of the wound using pre‐placed Mayo sutures. When the sutures were tightened and tied, tension on the sutured incision was transferred to the mesh. Tension was distributed over a wider area by placing two or more staggered rows of simple interrupted sutures anchoring the mesh to the skin.

(d)

The mesh overlay 10 days after surgery.

Figure 10.7 Schematic drawing of a skin stretching system (Secure Closure

TM

) being used to stretch skin and the underlying subcutaneous tissue over exposed bone without undermining the skin. (a) Application of the system involves placement of two straight 8‐cm long needles in the dermis opposite each other and 0.5 cm from the wound edges (small circles axial to the hooks in the skin contact plate). The skin contact U'shaped arms are secured to the skin by two inward‐facing intradermal hooks (two hooks on each U‐shaped plate) that, after insertion through the skin, abut against previously placed intradermal pins.

(b)

The threaded screw is tightened to increase tension, which is monitored by a tension gauge located on the device, and the wound is brought into apposition, ready for suturing.

Figure 10.8 A simple, mechanically assisted method of closure that uses hypodermic or spinal needles or Kirschner wires (K‐wires) combined with sutures.

Figure 10.9

(a)

A silicone elastomer tissue expander is positioned on the limb at the proposed site of implantation. The clear expander is to the right and the injection dome is to the left.

(b)

The tissue expander has been inserted in the subcutaneous tissue, and the injection portal will be implanted nearby.

(c)

Sterile isotonic saline solution is being injected into the injection dome to inflate the expander until the skin becomes taut.

(d)

Note the tissue expansion (swelling) on the lateral surface of the metacarpus.

Figure 10.10 Undermining the skin using a scalpel. The scalpel blade is oriented flat against the fascia; it is then used to make a clean incision, following the contour of the anatomic part, which separates the attachment of the subcutaneous tissue from the underlying fascia. One cleanly made incision is preferred to multiple small shallowly made incisions, which create more tissue trauma and a greater risk of hemorrhage.

Figure 10.11 A scissor is being inserted with the blades in a half‐closed position. This position allows the scissor to be used as a cutting instrument to separate the subcutaneous tissue from its attachments to the underlying fascia.

Figure 10.12 Example of how removal of exuberant granulation tissue (debulking) allows wound closure.

(a)

Plantar view of a non‐healing wound of ~6 months’ duration. The chronic exuberant granulation was acting as a barrier, which prevented healing by second intention (epithelialization and/or contraction) of the wound.

(b)

Side view of the same. Note how the skin has attempted to heal over the chronic granulating mass. At this point, it is likely that skin has undergone biologic creep that will allow closure of the wound with little tension on the suture line, following excision of the granulation tissue.

(c)

Following removal of the exuberant tissue, the skin edges were easily apposed with sutures. Because there was considerable dead space in which blood could accumulate, a drain was used. A distal limb cast was applied and left in place for 2 weeks. The cast was removed by the referring veterinarian, and the distal portion of the limb was maintained in a bandage for 1 week after cast removal. Primary healing was ultimately achieved.

Figure 10.13 Illustration of the mesh expansion method.

(a)

The skin adjacent to the fusiform defect is being undermined to separate the subcutaneous tissue attachments to the underlying fascia.

(b)

Strategically placed stab incisions, 10–15 mm long, are made through the full thickness of the undermined skin.

(c)

Following apposition of the skin edges with simple interrupted sutures, the stab incisions open in a mesh fashion to reduce tension on the primary suture line.

Figure 10.14 Closure of a chevron‐shaped skin laceration where the tip of the chevron has been lost.

Figure 10.15 V–Y plasty being used to reduce skin tension at the ventral palpebrum.

(a)

The apex of the V‐shaped incision is directed away from the palpebrum and the V is undermined.

(b)

The apex of the V is advanced toward the palpebrum, and the Y‐shaped incision is apposed with sutures placed in a simple interrupted pattern.

Figure 10.16 Z plasty.

(a)