Comparison of the Role of the Subcutaneous Tissues in Cutaneous Wound Healing in the Dog and Cat MARK W. BOHLING, DVM, RALPH A. HENDERSON, DVM, MS, Diplomate ACVS, STEVEN F. SWAIM, DVM, MS, STEVEN A. KINCAID, DVM, PhD, and JAMES C. WRIGHT, DVM, PhD Objective—To describe and compare the contribution of the subcutaneous tissues to 1st and 2nd intention cutaneous wound healing in the dog and cat. Study Design—Experimental study. Animals—Domestic shorthaired cats (n ¼ 6) and 6 beagle dogs. Methods—Paired wounds were created on either side of the dorsal midline; the subcutaneous tissue was removed on 1 side and left intact on the other. Square, open wounds of the dorsal aspect of the thorax were observed for 21 days to monitor granulation tissue formation, wound contraction, epithelialization, and total healing (contraction þ epithelialization). Breaking strength of sutured linear wounds was measured 7 days after wounding. Laser-Doppler perfusion imaging (LDPI) was used to measure cutaneous perfusion. Results—First intention healing: subcutaneous tissue removal had no consistent effect on sutured wound strength at 7 days in dogs or cats. Second intention healing: removal of subcutaneous tissue reduced wound perfusion, granulation, contraction, epithelialization, and total healing. Granulation tissue formation and wound contraction were delayed to a significantly greater degree in cats than in dogs (Po.05). Two dogs (33%) had minor wound infections. Conclusions—The subcutaneous tissues make an important contribution to 2nd intention cutaneous healing. Dog and cat wounds had delayed 2nd intention healing when subcutaneous tissues were removed; wounds in dogs, but not cats, had largely recovered from this delay by 21 days. Clinical Relevance—Extensive debridement of subcutaneous tissue may delay wound healing par- ticularly in feline patients. A higher risk for wound infections may accompany extensive removal of subcutaneous tissues in dogs. r Copyright 2006 by The American College of Veterinary Surgeons INTRODUCTION S URGICAL RECONSTRUCTION after removal of large volumes of tissue (e.g. for treatment of neopl- asia, trauma, or infection) presents special challenges to the surgeon. Rapid uncomplicated wound healing, al- ways a primary goal of surgery, is particularly desirable for large wounds or wounds over vital structures because failure of wound repair is potentially catastrophic. A limited number of reports, 1–4 and our clinical experience have indicated that in cases that require resection of large amounts of subcutaneous tissue, cats may be predisposed to certain types of large nonhealing wounds, including formation of indolent pocket wounds and ‘‘pseudo-heal- ing’’ wounds. 1–4 It may be that the removal of large amounts of subcutaneous tissue necessitated in these ex- cisions is itself a predisposing factor to problematic wound healing. These observations led us to review the role of the subcutaneous tissues in wound healing, and especially whether species differences exist. Address reprint requests to Mark Bohling, DVM, Department of Small Animal Clinical Sciences, C247 Veterinary Teaching Hospital, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4544. E-mail: mwbohling@mail.ag.utk.edu. Submitted May 2005; Accepted July 2005 From the Auburn University College of Veterinary Medicine, Auburn, AL. r Copyright 2006 by The American College of Veterinary Surgeons 0161-3499/04 doi:10.1111/j.1532-950X.2005.00105.x 3 Veterinary Surgery 35:3–14, 2006