Full-thickness skin grafts in dogs and cats versus humans
The report by Riggs et al1 on full-thickness skin grafts in dogs and cats highlights the difficulties in identifying factors associated with the outcome of such a complex procedure. Importantly, although Riggs et al focused on graft take, functional outcome should also be considered when planning any wound closure procedure. In this regard, full-thickness skin grafts are typically preferred because of better resilience and aesthetics, less contraction, the potential for sensation to return, and simpler donor harvest.
In human medicine, plastic surgeons perform full-thickness skin grafting on a daily basis, and many of our patients are also uncooperative and have complex chronic wounds. The report by Riggs et al suggests that there may be differences in the approaches used in human versus veterinary medicine that could have an impact on graft failure. Although methods used in human medicine do not guarantee success, they may improve the chances of a successful graft outcome.
For example, outcome following grafting of granulated wounds may be poor because of complex biofilm2 and excess granulation tissue interfering with plasmatic imbibition. In human medicine, we typically scrub the wound with an iodine-based skin preparation to decontaminate it before draping the patient and then debride most of the granulation tissue with the edge of a metal ruler, controlling bleeding and lavaging with saline solution before placing the graft.
Because inosculation with capillary ingrowth and reattachment occurs over the first 72 hours after grafting, preventing the dressing and limb from moving relative to the graft during this period is imperative. If the graft is placed directly on a moving structure such as muscle, then the limb must be immobilized to prevent the muscle moving. In addition, in human medicine, the periphery of the graft is typically sutured to the wound edge with resorbable sutures, with additional sutures placed in a continuous pattern to “quilt” the graft onto the bed. This reduces lateral movement of the graft and minimizes separation of the graft from the graft bed by compartmentalizing bleeding or fluid accumulation. Fenestrating the graft provides multiple drainage points for fluid egress.
Finally, following graft placement, I typically use a simple dressing of paraffin-impregnated gauze covered with gauze dampened with chlorhexidine solution secured with adhesive tape and additional bandaging layers as necessary. My aim is to keep the limb, graft, and dressings immobile until graft inspection 10 to 14 days after graft placement. Alternatively, a layer of semipermeable nonadherent film can be placed directly over the graft first. This allows the bandage to slide on the graft without shearing and is useful if movement is anticipated between the graft and bandage. Early wound inspection while changing the bandage materials down to this layer is easy with little risk of graft damage.
Use of negative-pressure bandages to augment graft take is well recognized3,4 but adds expense and further technical challenges I have generally found to be unnecessary when meticulous attention is paid to sound grafting technique.
Duncan Bayne, FRCS
Department of Plastic Surgery
Queen Victoria Hospital Foundation Trust
Holtye Road, East Grinstead, West Sussex, England
1. Riggs J, Frazer Jennings JL, Friend EJ, et al. Outcome of full-thickness skin grafts used to close skin defects involving the distal aspects of the limb in cats and dogs: 52 cases (2005–2012). J Am Vet Med Assoc 2015; 247: 1042–1047.
2. Swanson EA, Freeman LJ, Seleem MS, et al. Biofilm-infected wounds in a dog. J Am Vet Med Assoc 2014; 244: 699–707.
3. Genecov DG, Schneider AM, Morykwas MJ, et al. A controlled subatmospheric pressure dressing increases the rate of skin graft donor site reepithelialization. Ann Plast Surg 1998; 40: 219–225.
4. Avery C, Pereira J, Moody A, et al. Clinical experience with the negative pressure wound dressing. Br J Oral Maxillofac Surg 2000; 38: 343–345.
The authors respond:
On behalf of the authors, we want to thank Dr. Bayne for taking the time to comment on full-thickness skin grafting in humans. We note with interest the many similarities in our aims (successful graft take and functional outcome) but also some differences in relation to grafting procedures that may be applicable to veterinary patients. It would be worth commenting that just as there are differences between animal species with regard to wound healing, as mentioned in our paper, there are also differences between humans and animals with regard to integument anatomy and wound healing that have the potential to influence the ability for successful graft take. However, in the era of translational medicine, we appreciate closer collaborations with our human medical colleagues as a two-way process.
Julia Riggs, MA, VetMB
The Queen's Veterinary School Hospital
Department of Veterinary Medicine
University of Cambridge
Cambridge, England
Jackie Demetriou, BVetMed
Dick White Referrals
Station Farm
London Road, Six Mile Bottom, Cambridgeshire, England
