The effect of a porcine-derived small intestinal submucosa product on wounds with exposed bone in dogs

First-Intention Incisional Wound Healing in Dogs and Cats: A Controlled Trial of Dermapliq and Manuka Honey

This study aimed to compare incisional wound healing in cats and dogs after the topical application of Μanuka honey and a new medical device, Dermapliq. Comparisons were made between each treatment and control, between the two treatments, and between dogs and cats. Twelve cats and twelve dogs were included in this study, and the impact of the two substances was examined through cosmetic, clinical, ultrasonographical, and histological evaluation. The use of Dermapliq in first-intention wound healing achieved a significantly better cosmetic evaluation score and better total clinical score at days 20-41, compared to the control, in both dogs and cats. The ultrasonographically estimated wound area was smaller with Dermapliq compared to the control. Wounds treated with Dermapliq showed histologically less inflammation compared to the control. The use of Manuka honey did not show a significantly better cosmetic score compared to the control. Skin thickening was significantly higher after using Manuka honey compared to the control and so was the total clinical score. However, the median wound area, as was evaluated ultrasonographically, was significantly smaller when wounds were treated with Manuka honey, the difference being more apparent in dogs. Dermapliq was proven to be a better choice in achieving favorable wound healing than Manuka honey in dogs and cats in first-intention healing. In our study, cats had a statistically better cosmetic score and less skin thickening and scar width compared to dogs. Histologically, cats showed significantly less edema, higher inflammation and angiogenesis scores, and lower fibroblast and epidermis thickening scores when compared to dogs.

Comparison of Absorbable and Nonabsorbable Sutures for Intradermal Skin Closure in Dogs

The study aimed to compare incisional wound healing with intradermal suture patterns performed with (a) absorbable suture with burying of the knots and (b) nonabsorbable suture anchored with clips. Ten dogs were included in the study. Surgically created skin incisions were apposed with continuous intradermal suture pattern with 4/0 poliglecaprone 25 with burying of the knots and continuous intradermal pattern with 4/0 polypropylene with clips. Cosmetic, clinical, ultrasonographic and histological scores were evaluated. The intradermal pattern with clips was easier to perform and required significantly less time to complete than the intradermal suture with burying of the knots. Cosmetic, clinical, ultrasonographic and histological evaluation scores did not differ significantly between the techniques. Irrespective of the technique used, the cosmetic, ultrasonographic, clinical and histological appearances of the incisions improved over time. In conclusion, polypropylene was found to be a safe and effective suture material for use with intradermal suture pattern with clips in dogs and to have an easy and quick application. However, in our sample, its earlier removal from wounds than poliglecaprone 25 was not found to be associated with a supposedly beneficial effect on wound healing and scar appearance. Both suture materials can be useful in intradermal suture techniques in dogs.

Evaluation of Incisional Wound Healing in Dogs after Closure with Staples or Tissue Glue and Comparison to Intradermal Suture Pattern

The study aimed to monitor the healing process in the canine skin following surgical incision and closure using staples or tissue glue and to compare them with the intradermal suture pattern. Surgically created skin incisions in 10 dogs were apposed with staples, tissue glue (n-butyl cyanoacrylate) and continuous intradermal pattern. The cosmetic appearance of the wounds was blindly evaluated on days 7, 14 and 28 and once a month until the end of the experiment, i.e., one year after the incision. Ultrasonographic and clinical evaluation was performed on days 0-10, 12, 14, 16, 18, 21, 24 and 28, once a week until the end of the 3rd month and once a month until the end of the experiment. Histopathological evaluation was performed on days 7, 14, 28, 180 and 365. The median time required for the performance of each technique differed significantly between techniques; stapling lasted 21 s, glue 2 min 16 s and intradermal 15 min 37 s. Cosmetic appearance with glue was statistically worse than staples and intradermal. The clinical appearance of intradermal was significantly better than glue and staples. No significant differences were found at histological evaluation; however, glue had the worst score throughout the experiment. The overall evaluation of the techniques showed that glue had the worst score compared to intradermal and staples, with the difference being statistically significant in the first postoperative week. Intradermal suture pattern is much better than glue application for skin closure in dogs, whilst is not significantly better than staples. Staples should be preferred when time is an important factor.

Use of a semitendinosus myocutaneous flap for the coverage of hindlimb full-thickness skin defects in cats

BACKGROUND

The management of feline hindlimb full-thickness skin defects is challenging. On the other hand, the use of a semitendinosus (ST) myocutaneous flap for their coverage has not been reported.

OBJECTIVES

To describe the ST flap and compare it with second intention healing for managing hindlimb full-thickness skin defects.

METHODS

In 12 purpose-bred laboratory domestic short-haired cats, two wounds were made on each tibia. The wounds in group A (n = 12) were covered with ST flaps, and those in group B (n = 12) were left to heal by second intention. In both groups, clinical assessment scoring and planimetry were performed between one-30 d postoperatively. Computed tomography-angiography (CTA) was performed on days zero, 10, and 30, and histological examinations were performed on days zero and 14 and at 6 and 12 mon postoperatively.

RESULTS

Statistically significant differences in the clinical assessment scores were observed between groups A and B on days 14 (p = 0.046) and 21 (p = 0.016). On the other hand, the time for complete healing was similar in the two groups. CTA revealed significant differences in the muscle width (day 0 compared to days 10 and 30 [p = 0.001, p = 0.026, respectively], and days 10 to 30 [p = 0.022]), ST muscle density, and the caliber of the distal caudal femoral artery and vein (day 0 compared to day 10 [p < 0.001], and days 10 to 30 [p < 0.001]). Histologically significant differences in inflammation, degeneration, edema, neovascularization, and fibrosis were observed on day 14 compared to zero and 6 mon, but no differences were found between the time interval of 6 and 12 mon.

CONCLUSIONS

An ST flap can be used effectively to manage hindlimb full-thickness skin defects.

Novel use of a combination of extracellular matrices for wound healing following resection of a large inferior eyelid mass in a miniature Hereford

CASE DESCRIPTION

A 9-month-old miniature Hereford heifer was evaluated for a mass on the right inferior eyelid that had progressed in size over 3 months.

CLINICAL FINDINGS

Physical examination revealed a firm, ulcerated, pedunculated mass on the right inferior eyelid that extended from the medial quarter to beyond the lateral canthus of the eye. The base of the mass measured 7.4 × 6.7 cm, and the dorsal margin of the base of the mass was approximately 3 mm ventral to the inferior eyelid margin. Histologic evaluation of incisional biopsy specimens from the mass was consistent with fibrosarcoma.

TREATMENT AND OUTCOME

The mass was surgically resected with care taken to preserve the eyelid margin. The resulting 10 × 8.5-cm surgical wound was treated with adjunct CO₂ laser therapy and closed by primary closure at its medial and central aspects and placement of a 4.6 × 2.6-cm lyophilized equine amnion multilayer graft and 2 sheets of 4-ply porcine small intestinal submucosa at its lateral aspect. The grafts were kept moist by alternating topical antimicrobial and artificial tear ointments for 3 weeks. The wound healed without complications, resulting in a functional and aesthetically pleasing outcome despite the development of moderate ectropion at the lateral aspect of the inferior eyelid.

CLINICAL RELEVANCE

Results suggested that a combination of extracellular matrix scaffolds may be an alternative to extensive skin flaps for management of large dermal wounds, particularly wounds resulting from blepharoplasty where preservation of an eyelid margin is desired.

Comparison of continuous intradermal with simple interrupted suture pattern: an experimental study in dogs

The aim of the study was to compare incisional wound healing in intradermal and simple interrupted suture patterns. Ten dogs were included. Surgically created skin incisions were apposed with (a) continuous intradermal pattern, (b) simple interrupted pattern, [both with 3/0 poliglecaprone 25], and (c) continuous intradermal pattern with 4/0 poliglecaprone 25. Cosmetic, clinical and histologic scores were evaluated. Simple interrupted sutures required significantly less time than intradermal sutures to complete. Cosmetic evaluation scoring was not statistically significant among the techniques. Irrespectively of the technique, the cosmetic, clinical and histologic appearance of the incisions improved over time. The cosmetic and histologic differences between the techniques were large during the first month, but decreased latter, whereas clinical differences persisted. The clinical appearance of the intradermal pattern was initially very good, worsened during the second postoperative month, and improved afterwards. Intradermal pattern with 4/0 poliglecaprone 25 was superior in terms of cosmetic, clinical and histologic appearance compared to simple interrupted pattern and to intradermal pattern with 3/0 poliglecaprone 25 for skin closure in dogs.

Comparative evaluation of metallic skin staples or polypropylene sutures for primary closure of teat wounds in sheep

AIMS

To compare stainless steel staples and polypropylene suture material for primary closure of wounds after teat amputation in ewes and to assess progress of healing in the presence or absence of intramammary infection (IMI).

METHODS

Chios-cross ewes, aged 3-5 years were randomly allocated to be infected in one teat with 1,200-1,500 cfu of Mannheimia haemolytica 5 days after parturition (groups A and B; n = 8 in each group) or remain uninfected (groups C and D; n = 4 in each group). On the following 4 days one teat from each ewe was amputated 2.5 cm from the teat end and the wound was closed using skin staples (groups A and C) or polypropylene sutures (groups B and D). Clinical evaluation of wound healing was performed between 1-21 days after surgery. On day 21 tissue sections were collected for tensiometric and histological evaluation.

RESULTS

The mean interval from the start to finish of wound closure was shorter when staples were used than when sutures were used (p < 0.001). Healing scores were lower (improved) for ewes in group A than B between days 1-7 after surgery (p = 0.005), but were similar between days 10-21 (p = 0.43). Healing scores were similar in groups C and D (p = 0.98). The tensile strain at maximum load was higher in tissue from group A than B (p = 0.001) and D (p = 0.004), but all other tensiometric measures were similar between groups. Histologically, collagen density was higher in sections from group A than B (p = 0.05) and D (p = 0.01), and angiogenesis was lower in sections from group A than B (p = 0.03) and D (p = 0.01).

CONCLUSIONS AND CLINICAL RELEVANCE

Skin staples and polypropylene sutures can be used effectively for primary closure of teat wounds, even in the presence of IMI. Skin staples had the advantage of a reduction in surgical time.

ABBREVIATION

IMI: intramammary infection.

Extracellular matrix scaffolds for treatment of large volume muscle injuries: A review

OBJECTIVE

Large muscular or musculotendinous defects present a dilemma because of the inadequacies of current treatment strategies. Extracellular matrices (ECM) are potential clinically applicable regenerative biomaterials. This review summarizes information from the preclinical literature evaluating the use of ECM for muscle regeneration in animal models of volumetric muscle loss (VML).

STUDY DESIGN

Literature review.

SAMPLE POPULATION

Animal models of VML in which surgical repair was performed with an ECM product, with or without added cell populations.

METHODS

PubMed, Google Scholar, CAB abstracts, and Scopus were searched for preclinical studies using ECM in animal models of VML. The search terms "extracellular matrix," "VML," "muscle regeneration," "cell seeded," and "scaffold" identified 40 articles that met inclusion criteria of an animal model of VML in which surgical repair was performed with an ECM product, with or without added cell populations. Key skeletal muscle repair mechanisms and experimental findings on scaffold type, VML location, and experimental animal species were summarized.

CONCLUSIONS

Satellite cells and basal lamina are key endogenous contributors to skeletal muscle regeneration. ECM as a dynamic tissue component may provide structural integrity, signaling molecules, and a 3-dimensional topography conducive to muscle regeneration. Preclinical models of muscle repair most commonly used mice and rats (88%). Most experimental lesions were created in abdominal wall (33%), anterior tibialis (33%), latissimus dorsi (10%), or quadriceps (10%) muscles. Matrices varied markedly in source and preparation. Experimental outcomes of ECM and cell-seeded ECM implantation for muscle regeneration in VML were highly variable and dependent on matrix tissue source, preparation method, and anatomic site of injury. Scar tissue formation likely contributes to load transfer. Nonappendicular lesions had better regenerative results compared with appendicular VML.

CLINICAL SIGNIFICANCE

The preponderance of current evidence supports the use of ECM for muscle defect repair only in specific instances, such as nonappendicular and/or partial-thickness defects. Consequently, clinical use of ECM in veterinary patients requires careful consideration of the specific ECM product, lesion size and location, and loading circumstances.

The Effect of a Hydrocolloid Dressing on Second Intention Wound Healing in Cats

The objective of the present study was to evaluate the effect of a hydrocolloid dressing on second intention wound healing in cats. Two full-thickness skin wounds, measuring 2 × 2 cm, were created on both sides of the dorsal midline of 10 cats; bilaterally, one randomly selected wound was bandaged with a hydrocolloid dressing and the second one (control) with a semiocclusive pad. Subjective clinical evaluation of granulation tissue formation, of the quantity and nature of wound exudate, and planimetry were performed on the right-side wounds, and histological examination on the left. No significant differences in subjective clinical evaluation or in planimetry were observed between the hydrocolloid-treated wounds and controls. Most wounds had serous or absence of exudate (41.25% and 25%, respectively), whereas purulent exudate was observed in 7.5% of wounds. Edema was significantly increased in the hydrocolloid-treated wounds compared with controls on day 7 but no significant differences in the other histological variables were observed.

Vakuumassistierte Wundbehandlung (Negative Pressure Wound Therapy, NPWT) in der Kleintiermedizin

Die Behandlung offener Wunden gehört zu den alltäglichen Herausforderungen in der Tiermedizin. In den letzten Jahren hat sich mit der vakuumassistierten Wundbehandlung (Negative Pressure Wound Therapy, NPWT) eine neue Therapieform entwickelt. Durch ihren Einsatz lassen sich die Heilung offener Wunden und die Einheilungsrate freier Hauttransplantate beim Kleintier signifikant verbessern. In diesem Überblick werden Wirkweise, Indikationen sowie Komplikationen der Negative Pressure Wound Therapy dargestellt.

Principles of Wound Management and Wound Healing in Exotic Pets

The care of wounds in exotic animal species can be a challenging endeavor. Special considerations must be made in regard to the animal's temperament and behavior, unique anatomy and small size, and tendency toward secondary stress-related health problems. It is important to assess the entire patient with adequate systemic evaluation and consideration of proper nutrition and husbandry, which could ultimately affect wound healing. This article summarizes the general phases of wound healing, factors that affect healing, and principles of wound management. Emphasis is placed on novel methods of treating wounds and species differences in wound management and healing.

Effects of two occlusive, hydrocolloid dressings on healing of full-thickness skin wounds in cats

OBJECTIVES

To determine the effects of two occlusive, hydrocolloid dressings on second intention wound healing in cats.

METHODS

Three 2×2 cm full-thickness skin wounds were created on each side of the trunk of 10 cats. Two bilateral wounds were bandaged using different hydrocolloid dressings, namely Hydrocoll and DuoDerm while a semi-occlusive pad (Melolin) was applied to the third bilateral wound (control group). Wound planimetry, subjective evaluation of wound healing, and qualitative bacterial cultures were performed on the right-sided wounds, whereas left-sided wounds were subjected to histological examination.

RESULTS

Subjective evaluation revealed accelerated (p <0.01) granulation tissue formation in hydrocolloid-treated wounds. The amount of wound exudate was initially greater (p <0.01) in these wounds. Seventeen out of 120 evaluated wounds (14.2%) produced purulent exudate, 11 of which showed Staphylococcus aureus growth. Fewer control wounds (3/17) emitted purulent exudate, but all of them yielded moderate bacterial growth as compared to hydrocolloid-treated wounds (8/17) which had a low incidence of bacterial growth. The only significant difference in histological variables was increased cellular infiltration noted on day 7 in Hydrocoll-treated wounds compared to controls. No significant differences in planimetry variables were found between groups.

CLINICAL SIGNIFICANCE

Despite the initially increased amount of wound exudate and the low growth of Staphylococcus aureus, hydrocolloid dressings accelerate granulation tissue formation and can hence be suggested for second intention wound healing in cats.

Wound Care

Wound care requires an understanding of normal wound healing, causes of delays of wound healing, and the management of wounds. Every wound must be treated as an individual with regard to cause, chronicity, location, and level of microbial contamination, as well as patient factors that affect wound healing. Knowledge of wound care products available and when negative pressure wound therapy and drain placement is appropriate can improve outcomes with wound healing. Inappropriate product use can cause delays in healing. As a wound healing progresses, management of a wound and the bandage material used must evolve.

Comparative wound healing--are the small animal veterinarian's clinical patients an improved translational model for human wound healing research?

Despite intensive research efforts into understanding the pathophysiology of both chronic wounds and scar formation, and the development of wound care strategies to target both healing extremes, problematic wounds in human health care remain a formidable challenge. Although valuable fundamental information regarding the pathophysiology of problematic wounds can be gained from in vitro investigations and in vivo studies performed in laboratory animal models, the lack of concordance with human pathophysiology has been cited as a major impediment to translational research in human wound care. Therefore, the identification of superior clinical models for both chronic wounds and scarring disorders should be a high priority for scientists who work in the field of human wound healing research. To be successful, translational wound healing research should function as an intellectual ecosystem in which information flows from basic science researchers using in vitro and in vivo models to clinicians and back again from the clinical investigators to the basic scientists. Integral to the efficiency of this process is the incorporation of models which can accurately predict clinical success. The aim of this review is to describe the potential advantages and limitations of using clinical companion animals (primarily dogs and cats) as translational models for cutaneous wound healing research by describing comparative aspects of wound healing in these species, common acute and chronic cutaneous wounds in clinical canine and feline patients, and the infrastructure that currently exists in veterinary medicine which may facilitate translational studies and simultaneously benefit both veterinary and human wound care patients.

Metacarpophalangeal collateral ligament reconstruction using small intestinal submucosa in an equine model

Xenogeneic porcine small intestinal submucosa (SIS) is a natural, biodegradable matrix that has been successfully used as a scaffold for repair of tissue defects. The goal of this study was to compare a collateral ligament transection surgically reconstructed with an anchored SIS ligament to a sham-operated control procedure for the correction of joint laxity using an equine model. Ten metacarpophalangeal joints from 10 horses had complete transection of the lateral collateral ligament. In 6 horses, the collateral ligament was reconstructed with a multilaminate strip of SIS anchored with screws into bone tunnels proximal and distal to the joint. The sham controls had similar screws, but no SIS placed. Clinical compatibility and effectiveness were evaluated with lameness, incisional quality, and joint range of motion, circumference and laxity. Ligament structure and strength was quantified with serial high resolution ultrasound, histology, and mechanical testing at 8 weeks. Surgical repair with SIS eliminated joint laxity at surgery. SIS-treated joints had significantly less laxity than sham treatment at 8 weeks (p < 0.001). SIS-treated ligaments demonstrated a progressive increase in repair tissue density and fiber alignment that by week 8 were significantly greater than sham-treated ligament (p < 0.03). SIS-repaired ligament tended to have greater peak stress to failure than sham-treatment (p < 0.07). Cellularity within the ligament repair tissue and inflammation within the bone tunnel was significantly greater in the SIS-treated limbs (p < 0.017). Within the first 8 weeks of healing, SIS implanted to reinforce collateral ligament injury was biocompatible in the joint environment, restored initial loss of joint stability, and accelerated early repair tissue quality. SIS ligament reconstruction might provide benefit to early ligament healing and assist early joint stability associated with ligament injury.

Evidence-based wound management: a systematic review of therapeutic agents to enhance granulation and epithelialization

Successful management of open wounds in dogs requires knowledge of the physiology of wound healing and application of that knowledge to choose appropriate therapeutic intervention. The authors' objective was to investigate whether or not there are any available therapeutic agents that enhance granulation or epithelialization of open wounds in dogs. Based on the literature identified in the authors' review, there is insufficient evidence to make a recommendation for or against any of the topical wound agents or procedures studied.

Effects of porcine small intestinal submucosa on elution characteristics of gentamicin-impregnated plaster of Paris

OBJECTIVE

To evaluate effects of small intestinal submucosa (SIS) on elution properties of plaster of Paris (POP).

SAMPLE POPULATION

27 POP cylinders, 27 POP spheres, and 9 polymethylmethacrylate (PMMA) spheres.

PROCEDURES

Pellets were loaded with gentamicin (50 mg/g) and divided into 7 groups of 9 beads each: PMMA spheres; POP cylinders coated with 0, 4, or 8 layers of SIS; and POP spheres coated with 0, 4, or 8 layers of SIS. Gentamicin concentration was measured 6, 12, 18, 24, 32, 40, and 48 hours and 3, 4, 5, 7, 14, 21, 28, 35, and 42 days after wrapping. Porosity was evaluated via scanning electron microscopy. Curvature factor of elution curves, total amount of drug released (TDR), time required to reach 50% of total release (TDR(t50)), and number of days with concentrations > or = 1 microg/mL were compared among groups.

RESULTS

SIS decreased the curvature factor and increased the TDR(t50) and TDR of POP spheres and cylinders. Curvature factor of the PMMA-release curve remained lower than that for any POP group, but all POP groups wrapped in SIS released more gentamicin than PMMA spheres. Gentamicin concentrations remained > or = 1 microg/mL in SIS-wrapped POP and PMMA groups throughout the study. Wrapping POP in SIS minimized the increase in porosity of pellets.

CONCLUSIONS AND CLINICAL RELEVANCE

Wrapping POP with SIS slows the release and increases the amount of gentamicin leaching from spheres and cylinders. All groups wrapped in SIS maintained antimicrobial concentrations greater than the minimum inhibitory concentration of most pathogens.

Initial wound management

A wounded patient can be presented to the veterinary surgeon under a number of circumstances. The wound could result from external trauma,such as vehicle trauma or an animal fight, or it could have been created by surgical intervention, such as the removal of a mass. A wound could also be secondary to a failed initial attempt at wound closure. No matter what the cause, initial wound management often follows similar pathways. A successful wound closure and healing outcome is often dependent on adherence to basic principles of wound assessment, appropriate care, and reassessment. This article covers the approach to and specific options for the initial stages of wound management.

Topical and Systemic Medications for Wounds

There are a plethora of topical and systemic medications available to the veterinary practitioner today that aid the wound healing process. Some of these help to maintain a moist environment. Others increase growth factors, provide local energy sources, control infection, provide for debridement, increase wound blood flow and temperature, or reduce wound edema. Modern wound care requires that the proper products(s)be used, depending on the condition of the wound and the phase of wound healing. This article discusses various wound care products and provides guidelines on their use.

Use of porcine renal capsule matrix as a full-thickness dermal wound-healing material in rats

OBJECTIVE

To compare the utility of porcine renal capsule matrix (RCM) with porcine small intestinal mucosa (SIS) in a rat full-thickness skin wound model.

METHOD

Groups of rats had surgically-created wounds filled with either SIS or RCM. On each rat a contralateral wound was left unfilled (RCM-U or SIS-U). Wound diameter was measured 3, 7, 12, 17, 26 and 30 days after creation. Wound sites sampled 3, 7, 14, 28, 42 and 56 days after wound creation were numerically graded for degree of histologic change and for collagen content, based on intensity of trichrome staining.

RESULTS

Wounds in all groups rapidly contracted to less than 50% of the original diameter within 12 days. There were no differences in wound diameter between RCM- and SIS-treated wounds at any time point, but these wounds had significantly greater (p < 0.001) diameters than their unfilled counterparts on days 7, 12 and 17. There were no differences in histologic scores or trichrome-staining scores between RCM- and SIS-treated wounds and their unfilled counterparts at any time point, except for a greater (p < 0.05) histologic score in SIS-treated wounds compared with unfilled controls on day 14. In both treatment groups an acute inflammatory response at the wound site was soon replaced by an influx of macrophages and fibroblasts.

CONCLUSION

The results show that RCM is equivalent to SIS for the treatment of full-thickness wounds and that these materials may enhance wound healing in terms of wound-tissue collagenisation and maturation. These materials therefore merit further study in other wound-care models.