Steven F. Swaim

Evaluation of fibrin sealants in cutaneous wound closure

Human fibrin sealant (HFS) and bovine fibrin sealant (BFS) were delivered as preformulated fibrinogen-thrombin mixtures that are light activated. These formulations were evaluated in the healing of incised cutaneous wounds in beagle dogs. Four groups were differentiated by sealant type and study duration with group: BFS for 10 days, HFS for 10 days, BFS for 30 days, and HFS for 30 days. Healing was evaluated by noting incidences of open wounds, laser Doppler perfusion imaging (LDPI), planimetry, breaking strength, and histopathology. In the absence of tension, both sealants tended to hold wound edges together; however, HFS tended to be better than its controls and BFS. Both sealants augmented suture closure, necessitating fewer sutures for wound closure. At 5 and 30 days BFS wounds had more perfusion than HFS wounds, indicating more inflammation. At 10 and 30 days BFS wounds had larger scar areas than their controls, while scar areas of HFS wounds were smaller than either BFS wounds or controls. Breaking strengths indicated that HFS wounds were stronger than their controls and BFS wounds. Histologically, mild to moderate chronic-active inflammation was observed in wounds receiving either sealant, and this persisted longer in BFS wounds. Overall, HFS had positive qualities, thus showing potential for functional and cosmetic wound closure.

Review of Wound Management in Raptors

Abstract Birds of prey encounter many injuries that make treatment a challenging process. These include electrocution, trauma-associated cuts and abrasions, gunshot wounds, barbed wire and leghold trap ensnarement, puncture wounds, and damage from inappropriate housing and husbandry. The mechanism of wound healing is similar to that seen in mammals, with a continuous progression through the phases of inflammation, proliferation, and remodeling. Healing by primary closure (suturing) is generally preferable to healing by secondary intention, though the latter is more common in raptors because of the delayed presentation of most wounds. Debridement and lavage, with chlorhexidine at a 0.05% solution being considered to provide optimal results, are required for all wounds. Many topical medications are used to manage open wounds in raptors, including recently developed wound-healing stimulants. Bandage materials used are the same as those used for other species, though the type of bandage varies according to the uniqueness of avian anatomy. Specific injuries such as bumblefoot, degloving, frostbite, digital amputation, and crop laceration may require special consideration.

Bandages and Topical Agents

Bandages are included in the regimen of therapy of superficial wounds. Bandages have varying functions depending upon the type of wound to which they are applied. When bandaging recently inflicted open wounds, the primary bandage layer may be dry-to-dry, wet-to-dry, or wet-to-wet, depending upon the type of tissue and exudate present on the wound. These bandages aid in debriding and cleansing a wound. The secondary layer of such bandages serves primarily to absorb material from the wound, and the tertiary bandage layer serves to hold the other bandage layers in place. Once an open wound is well into the repair stage of healing, an occlusive bandage may be considered to help enhance epithelialization of the wound. Bandages for wounds associated with compound fractures must include some form of fixation for the fracture. Other types of bandages are designed to (1) cover closed wounds, (2) provide pressure over a wound, and (3) relieve pressure over wounds or impending wounds. Bandages for closed wounds provide protection and allow for absorption of exudate that may be present. Pressure bandages are used to control minor hemorrhage, edema, and excess granulation tissue. With impending decubital ulcers, actual decubital ulcers, or repaired decubital ulcers, it is necessary to have a bandage designed to relieve pressure over the lesion. Many substances have been described for topical application to wounds. This section presents information on some substances available to or commonly used by veterinarians. It includes information on the wound lavage solutions chlorhexidine diacetate, povidone-iodine, hydrogen peroxide, and sodium hypochlorite solutions. Topical antibacterial agents are used to help prevent wound infection. The triple antibiotics, silver sulfadiazine, nitrofurazones, and gentamicin sulfate are some commonly used antibacterial agents. Hydrophilic agents are used to diffuse fluids through the wound tissues to bathe the tissues from the inside. Dry starch copolymer flakes and dextran polymer beads are two substances that help bathe the wound with the bodys own fluids. Other topical medications are used to selectively act upon various wound tissues and exudates to aid in cleansing the wound; these include organic acid preparations and enzymatic debriding agents. In addition, a live yeast-cell derivative has been described for enhancing tissue oxygen consumption, epithelialization, and collagen synthesis in wounds.

Dynamics Analysis of Ground Contact Pressure of English Pointer Dogs

In this study force sensing resistors were used to determine thepressure on the central area of each of the weight bearing pads of thefore and hind paws of dogs at the walk. Six adult normal healthy EnglishPointer dogs were used in this project. Pressure data were collected byaffixing a force sensing resistor to the central area of the groundcontact surface of each weight bearing paw pad of the right fore andhind limbs. Pressure signal data from stance phase during walking wereanalyzed. Within paw pads, the pressure graphs were consistent in formand magnitude. Within paws, there were significant pressure differencesamong pads on both fore and hind limbs. The coefficient of restitution,the embedding dimension, and the Lyapunov exponents were calculated. Theability to measure and analyze pressure on individual paw pads providesinsight into soft tissue stresses on the palmar/plantar surface of thepaw. Pressure at a wound site on the pads has a detrimental effect onwound healing and a better understanding these stresses will be ofbenefit when suturing and bandaging pad wounds. Such information isespecially important in athletic and working dogs, e.g. search andrescue dogs.

Bioelastic membranes for topical application of a thromboxane synthetase inhibitor for protection of skin from pressure injury: a preliminary study.

A previous study showed that topical exposure to bioelastic‐thromboxane synthetase inhibitor‐matrix resulted in local tissue concentrations of thromboxane synthetase inhibitor sufficient for thromboxane synthetase inhibition. The objective of this research was to use an animal model to determine if a dressing having controlled release of thromboxane synthetase inhibitor (dazmegrel) could be used to prevent tissue breakdown over pressure points, i.e., lesion at the assistive device–skin interface. The animal model studies utilized the greyhound, a dog that has thin skin, angular conformation, limited body fat and is predisposed to pressure ulcers similar to those occurring in humans. The model uses a short‐limb walking cast on one pelvic limb with the severity of the dermal pressure lesions induced over the medial malleolus controlled by the amount of padding in the cast and length of time the cast is in place. The bioelastic matrix loaded with dazmegrel provided protection from shearing and pressure skin injury over the medial malleolus, as evidenced by a decrease in epidermal abrasion/ulceration as measured with planimetry. Histopathologic evaluation of the skin over the medial malleolus indicated a protective function of the bioelastic matrix as measured as lower numbers of neutrophils, lymphocytes, and decreased collagen density compared to such numbers when no bioelastic matrix was present. These studies provided evidence that bioelastic‐thromboxane sythetase inhibitor‐ matrix helps in preventing or reducing the severity of pressure lesions, e.g., assistive device–skin interface wounds.

Chronic problem wounds of dog limbs

Other dermatoses are capable of affecting the limbs and paws of dogs. One should approach the diagnostic workup of these cases in an organized manner, first obtaining a thorough history and performing a physical examination. A variety of diagnostic tests, including skin scrapings, cytology, fungal cultures, bacterial cultures, hematology, serum biochemical profiles, urinalysis, serology, radiology, histopathology, and direct immunofluorescence testing, may be necessary before a definitive diagnosis is reached. Therapy may be surgical, medical, or a combination of both depending upon the etiologic agent.

The Use of Skin Flaps and Grafts for Wound Management in Raptors

Abstract Managing large open wounds in birds is challenging because of the limited amount of skin and the difficulties associated with bandaging. New techniques involving the use of skin flaps, autografts, and extracellular matrix grafts are emerging to the forefront of wound management as viable options in avian patients. Understanding the anatomy of the avian integument is important when considering the use of one of these forms of reconstruction as a wound management technique in birds. Here we review the use of skin grafts and flaps in avian patients in relation to the anatomy of the avian integumentary.

Nasal and Facial Reconstruction in a Dog Following Severe Trauma

Successful reconstruction of the nasomaxillary region requires closure of oronasal communication and maintenance of a patent upper airway. A dog with traumatic amputation of the nasomaxillary region was presented for reconstructive surgery. Staged surgical procedures were performed with the goal of closing the oronasal fistula, reapposing facial tissues, forming a granulation bed in each nasal passage, and harvesting and placing mucosal grafts in the nasal passages. A novel technique for developing a granulation tissue bed for mucosal grafts using silicone rubber tubing was employed. The end result of the reconstructive surgeries was a relatively cosmetic appearance with patent nasal openings.

Use of a thromboxane synthetase inhibitor in the presence of dermal pressure

Preliminary research was conducted to ascertain the potential for a thromboxane synthetase inhibitor (TSI) in preventing the early histopathologic and biochemical changes associated with impending dermal pressure injury. In the presence of dermal pressure over a bony prominence in greyhound dogs, a systemically administered TSI resulted in lower dermal levels of thromboxane A2 (TxA2) and an absence of histopathologic lesions when compared to dogs receiving a placebo. The results indicate a potentialfor TSIs as adjunctive therapy in the prevention of decubital ulcers by counteracting the TxA2-related vasoconstriction and thrombosis with their resultant ischemic necrosis of the skin.

Contact Pressure of Quadrupedal Animals

In this study we determine the pressure on the central area of each of the weight bearing pads of the paws of dogs at the walk. Pressure signal data from stance phase during walking were analyzed. Within paws, there were significant pressure differences among pads on both fore and hind limbs. The coefficient of restitution, the embedding dimension, and the Lyapunov exponents were calculated. The ability to measure and analyze pressure on individual paw pads provides insight into soft tissue stresses on the palmar/plantar surface of the paw. Pressure at a wound site on the pads has a detrimental effect on wound healing and a better understanding these stresses will be of benefit when suturing and bandaging pad wounds. Such information is especially important in athletic and working dogs, e.g. search and rescue dogs.Copyright