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- Author or Editor: Megan R. Williams x
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Abstract
OBJECTIVE
To assess the efficacy of an equine-origin liquid amnion allograft (ELAA) derived from both amniotic fluid and amniotic membrane on the healing time of experimentally induced distal limb wounds in horses.
ANIMALS
8 adult horses.
PROCEDURES
On day 0, horses were anesthetized and a 2.5 X 2.5-cm, full-thickness skin wound was created on the dorsal aspect of each metacarpus and bandaged. On day 9, wound margins were injected with ELAA (treatment) or 0.9% NaCl (control). Bandages were changed at specific intervals through day 91 and, on each occasion, wounds were photographed to allow calculation of wound area. Exuberant granulation tissue was resected, if present. Wounds were deemed healed when completely epithelialized. Mean wound area was compared between groups throughout the study period.
RESULTS
Only 1 wound (control) remained unhealed at day 91. No difference was found between the treatment and control groups in either wound area over time (P = 1.0) or time for wounds to reduce in size by 95% (P = .2) Exuberant granulation tissue required resection twice (1 control wound and 1 treatment wound).
CLINICAL RELEVANCE
In this model, a single treatment with ELAA administered locally by SC injection did not accelerate distal limb wound healing in horses. However, it is possible that naturally occurring, chronic, or nonhealing wounds would respond differently.
Abstract
OBJECTIVE
To describe the microvascular anatomy of the equine hind limb suspensory ligament.
ANIMALS
18 hind limbs harvested from 9 adult horses euthanized for reasons unrelated to lameness.
METHODS
A catheter was placed in the transected cranial tibial artery at the level of the mid-distal tibia for each hind limb and used to inject 120 to 150 mL of contrast medium (2 limbs) to identify principal vasculature using contrast-enhanced CT or India ink (11 limbs) to identify microvasculature using the Spalteholz tissue-clearing technique. Routine histologic evaluation was performed on transverse sections from 4 hind limbs.
RESULTS
The hind limb suspensory ligament is principally supplied by branches of the medial and lateral plantar metatarsal arteries and, to a lesser extent, the medial and lateral plantar arteries as well as the associated proximal and distal deep plantar arches. A uniformly distributed intraligamentous microvascular supply was observed without relative deficiencies in vascularity between the proximal, midbody, and distal regions. Histologic examination supported these findings, demonstrating a network of connective tissue surrounding and entering the suspensory ligament containing cross-sections of branches of the principal vasculature.
CLINICAL RELEVANCE
The equine hind limb suspensory ligament has a uniformly distributed and abundant microvascular supply throughout its length, with no evidence of relative deficiency of vascular supply in any region. A region of hypovascularity does not appear to be a viable explanation for the high rate of injury to and commonality of lameness associated with the proximal hind suspensory ligament in horses.
Abstract
Objective—To determine the microvascular anatomy of the suspensory ligament of the forelimb of horses.
Sample—17 cadaveric forelimbs from 9 adult horses with no known history of forelimb lameness.
Procedures—The median artery of the forelimb was cannulated proximal to the antebrachiocarpal joint and injected with contrast medium for CT evaluation of the gross vasculature (n = 2) or India ink to evaluate the microvasculature (12). Routine histologic evaluation was performed on an additional 3 forelimbs to confirm the microvascular anatomy.
Results—The vascular supply of the suspensory ligament of the forelimb originated from branches of the medial and lateral palmar and palmar metacarpal vessels as well as the proximal and distal deep palmar arches. An abundant, longitudinally oriented microvascular supply was evident throughout the length of the suspensory ligament without distinct variation among the proximal, midbody, and distal regions. The intraligamentous blood supply originated from a periligamentous vascular plexus that surrounded the suspensory ligament throughout its length. Histologic findings indicated the presence of a periligamentous connective tissue plexus, which contained vessels that penetrated and anastomosed with an extensive network of intraligamentous vessels throughout the length of the suspensory ligament.
Conclusions and Clinical Relevance—The suspensory ligament of the equine forelimb had an abundant intraligamentous microvascular supply throughout its entire length. The absence of an obvious hypovascular area suggested that regional variations in healing rates of the suspensory ligament are not associated with the microvascular anatomy.
Abstract
OBJECTIVE
To determine whether a stainless steel implant sterilized with a novel cold atmospheric plasma sterilization (CAPS) device adversely affects local tissues in rabbits and whether CAPS was as effective as steam sterilization with an autoclave to inactivate Pasteurella multocida.
ANIMALS
31 healthy New Zealand White rabbits.
PROCEDURES
Steam-autoclaved stainless steel implants inoculated with P multocida underwent a second steam autoclave sterilization (AIA) or CAPS (AICAPS). One AIA implant and 3 AICAPS implants were randomly placed subcutaneously at 4 sites in 21 rabbits (84 implants). These rabbits were monitored daily for 5 days for evidence of systemic illness and local tissue reactions at the implantation sites and then euthanized. Samples were taken from each implant site for bacterial culture and histologic examination.
RESULTS
Cultures of samples obtained from all sites were negative for bacterial growth. No significant difference was observed in mean skin thickness or erythema between AIA and AICAPS implant sites on any observed day. Also, individual histologic grades for the epidermis, dermis, subcutis, and muscle and total histologic grade were not significantly different between AIA and AICAPS implant sites.
CONCLUSIONS AND CLINICAL RELEVANCE
Cold atmospheric plasma sterilization was noninferior to steam sterilization of P multocida–contaminated stainless steel implants in the rabbits in the present study. However, studies of the efficacy of CAPS for inactivation of other important bacteria are needed.