Abstract

Purpose

The purpose of this study was to determine if the treatment of chronic pressure sores on the hips of elephants with direct contact low-level infrared therapy would stimulate the healing process, and if it did, to assess the quality and rate of healing.

Introduction

Decubital ulcers or pressure sores on the hips and other pressure-sensitive areas of the skin of elephants may develop when the animal lies on its side for extended periods of time. The weight of the animal may significantly decrease the circulation to various pressure spots, causing the skin and underlying connective tissue to devitalize, resulting in an open wound. If the animal continues to lay on the open lesion, the tissue is further damaged and deep ulcerations may result.

Treatment historically has been focused on solving the reason(s) the elephant may be spending more time down. Elephants reaching advanced ages or that have a foot or limb ailment may continue to lay down frequently regardless of the treatment. Rubber stall mats with extra bedding have been provided in an effort to alleviate some of the pressure to these wounds. Pressure-induced ulcerations in the skin have been kept clean, and a variety of topical antiseptic agents have been used with little success. Tissue growth factor beta (TGFB; Genetech, 460 Point San Bruno Blvd., South San Francisco, CA 94080 USA) has been used topically in the treatment of pressure sores with varying success.

Biostimulation of wounds of this type in humans with low-level light in the infrared spectrum has been shown to accelerate the healing process by stimulating fibroblast production, quickening collagen synthesis, and enhancing the immune system to combat invading pathogens.¹ A system using low-level light infrared therapy (LLLT) (Equi-Light, 2100 South Dayton, Denver, CO 80231 USA) was designed and used successfully in horses. The treatment frequency, duration of therapy, and wound care were adapted to the elephant from equine protocols.

History

A 58-yr-old female Asian elephant (Elephas maximus), managed in a free contact system, had a lengthy history of varying degrees of discomfort in all of its limbs. The left carpal joint became increasingly stiff starting approximately 14 yr ago. For the past 5 yr, the right carpal joint has shown progressive signs of stiffness. This elephant has always tended to sleep more than the other elephants, but would lay on either side. Towards the end of 1995 evidence of lameness was exhibited in the right stifle joint. At this time, the elephant would lay only on its left side.

Treatment

Two pressure sores developed in the tissue near the left ischial tuberosity. The wounds initially appeared as areas of devitalized tissue. The wounds were debrided and measured 10x7 cm and 0.5x0.5 cm at the time the treatment using the LLLT system began. Prior to each treatment the wounds were debrided, and any macerated or necrotic tissue was removed by gently scrubbing the area.

The LLLT system uses light energy created by light-producing diodes attached to a flexible pad. Each LLLT pad consists of 60 superluminous diodes that each produce 10 mw/cm² of infrared irradiation. Each pad is connected to a power source by a length of electrical wire. The pads were covered with a protective clear plastic wrap and were placed directly over the wound and attached to the surrounding skin with a wide cloth tape. The tape held the pads securely in direct contact with the wounds. The pads were arranged in such a way to allow the area being treated to be permeated with infrared radiation. After each treatment, the pads were removed and a thin layer of 0.9% isotonic saline gel (Normlgel, Scott Health Care, Philadelphia, PA 19113 USA) was applied to keep the area moist. The lesions were treated initially for 30 min, with the time increased to 45 min daily for 60 days, and then every other day until the end of the experimental period. A trainer was present during the treatment times to ensure the elephant did not remove the pads. The elephant did not seem to react to the treatment.

Results

The first 4 wk proved to be a trial and learning period. The time of treatment was increased until the LLLT treatment caused the production of a clear serous fluid from the sores. Presence of this exudate had proven desirable in treating similar wounds in other species.

Not all of the devitalized tissue had been removed prior to irradiating in the first 2 wk and the wounds enlarged and deepened during this time. By the end of the third week, the treatment techniques had been adjusted and the pressure sores began to fill in with healthy granulation tissue, and the wound margins began to close.

During the next 2 mo, the size of the pressure sores continued to reduce in diameter. No infection or other problems were seen during that time. The healing wound margins were made up of a well-vascularized connective tissue. Granulation tissue in both lesions was a deep red and the tissue was even with the epidermis. Three months after treatment began, the larger lesion measured 3.5x1.5 cm.

Discussion

The speed of healing was comparable to that in humans and other animals. Dressings on the wounds were unable to be maintained, and the wounds were frequently exposed to dirt and other contaminants. The lack of infection during the treatment period appeared to be significant. Irradiation of the pressure sores of this elephant seemed to promote significant granulation tissue, and allowed significantly faster resolution of these wounds when compared to similar lesions on other elephants.

Literature Cited

1.  Enwemeka, Chukuka S. 1988. Laser biostimulation of healing wounds: specific effects and mechanisms of action. J. Ortho. Sports Phys. Ther. 9(10):333–338.