Vacuum-assisted Closure (Turtle VAC) in the Management of Traumatic Shell Defects in Chelonians

Transcription

1 Vacuum-assisted Closure (Turtle VAC) in the Management of Traumatic Shell Defects in Chelonians Maud Lafortune, DMV, MSc, DACZM, James F.X. Wellehan, DVM, MS, DACZM Darryl J. Heard, BVMS, PhD, DACZM, Elijah Rooney-DelPino, BS, Christine V. Fiorello, DVM, PhD, Elliott R. Jacobson, MS, DVM, PhD, DACZM Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA A bstract : Wound management is an important and challenging aspect of care in the chelonian patient. Shell injuries are slow to heal and wound management is labor intensive. While shell fractures can be reduced with screws and wire or metal bridging, shell defects exposing underlying soflt-tissue are usually treated with wet-to-dry bandages. These bandages need to be changed twice a day and continuous care is generally needed for weeks to months due to the slow healing process of chelonians. Vacuum-assisted closure has been shown to increase the rate of wound healing in humans, and offers an alternative to wetto-dry bandages. This technique is particularly well suited for use in chelonians. We report the use of vacuum-assisted closure in 13 chelonian patients with traumatic shell defects, where underlying tissue was exposed. K ey words : Turtle, tortoise, vacuum-assisted closure, chelonian, shell repair, shell fracture, turtle VAC. I ntroduction Trauma is a common cause for presentation of cheloni ans to the veterinarian. In the au th o rs experience, vehicular trauma and bite wounds from dogs are the most common causes for shell trauma in chelonian patients. Several techniques have been described for shell repair, such as epoxy, metal screws and wire (R osskopf and Woerpel, 1981, Bonner, 2000, Richards, 2001, Mitchell and Diaz-Figueroa, 2004). The use of epoxy materials pre vents drainage and cleaning of the underlying wound, and due to concerns about wound care and infection, is now being replaced by other methods o f stabilization. Shell injury repair methods that permit care of the underlying wound include reducing fragments with screws and wire, metal bridges, or screw s and plates (R o ssk o p f and Woerpel, 1981, Richards, 2001, M itchell and D iazfigueroa, 2004). In some cases, shell defects are present, revealing a sofit-tissue wound. The preferred treatment for these open wounds historically has consisted of lavage and wet-to-dry bandages. Reported healing times for shell damage have been variable, ranging from 3 months (Rosskopf and Woerpel, 1981), m (Mitchell and D iaz-f igueroa, 2004), and up to one to tw o years (McArthur, 2004). Vacuum-assisted closure is a wound management tech nique used in human medicine to assist tissue healing (V.A.C., K.C.I. USA, San Antonio, TX). It promotes healing by creating sub-atmospheric pressure at the wound site, preventing microbial contamination, continuously suctioning fluids, and prom oting granulation tissue (Morykwas, et al, 1997, Joseph, et al, 2000). This tech nique has been shown to reduce healing time in mammals as compared to standard wet-to-dry bandages (Morykwas, et al, 1997, Joseph, et al, 2000). In veterinary medicine, vacuum-assisted closure has been used for wound manage ment of a tiger (Lafortune, et al, 2002), as well as cats and Journal of Herpetological Medicine and Surgery dogs (Wheeler, 2004). Chelonians are anatomically, physi ologically and tem peram entally w ell suited for this technique. They are not prone to rolling and tangling the vacuum hose, have a hard shell that makes bandage place ment easier, often present with large slow-healing open wounds, and frequently have problems with soft tissue pulling away from shell defects. M aterials and M ethods Between January 2002 and June 2004, 243 chelonians from 36 species were evaluated at the Zoological Medicine service of the Veterinary Medical Teaching Hospital of the University of Florida. O f these, 158 (65%) were wild ani mals donated to the department for evaluation. Reasons for presentation of free-living chelonians included vehicular trauma (n=65, 41%), dog attack (n=30, 19%), other trauma (n=4, 3%), and other causes (n=59, 37%). O f 99 trauma cases, 34 chelonians were euthanatized or died within the first week of presentation (34%), 13 were euthanatized or died after the first week of treatment (13%), and 52 were successfully treated and released (52%). The Turtle VAC was used in 13 patients with shell defects, representing 13% o f the trauma cases. These patients included eight gopher tortoises, G o p h eru s polyphem us, two yellow bellied sliders, Trachemys scripta scripta, an Eastern box turtle, Terrapene Carolina Carolina, a Florida cooter, P seudem ys concinna concinna, and a Florida chicken turtle, D eirochelys reticularia chrysea, with weights varying from 0.13 Kg to 5.80 Kg. M aterials Purpose-specific vacuum-assisted closure bandage mate rials are commercially manufactured by KCI USA, 8023 Vantage Drive, PO Box , San Antonio, TX , WOUND VAC, (210) , Fax:

2 (210) Website address: The Turtle VAC dressing in chelonians requires five materials: Elastic tape material such as Elastikon (Johnson & Johnson Medical Inc., Arlington, Texas ) 2.5 cm wide is used to cover any metal parts used for shell fracture repair or cracks in the shell of the animal, and to secure the suction tubing to the patient. Sterile open-cell polyurethane reticulated sponge. This sponge / foam can be purchased from KCI or alternatively from a hardware store (air conditioning filter foam) and gas sterilized. Sterile plastic tubing is needed to connect the wound to the suction pump. Clear occlusive adhesive material is used to cover the sponge and create the necessary seal (Steri-Drape and Tegaderm, 3M, St-Paul, MN ). It is applied over the sponge, including the site of entry for the suction tubing into the sponge, and adheres to the shell. A suction pump is necessary to create and maintain constant sub-atmospheric pressure on the wound. Several sizes of purpose-built suction pumps can be rented from KCI. Alternatively, a surgery suction device can be utilized. The advantages of the KCI vacuum-assisted closure pump are smaller size, lower volume output, precision negative pressure and an alarm system that indicates when the seal has been breached. material such as Vetrap (3M) has been used successfully to protect Turtle VAC dressings. Bandages are changed every day initially, then every two to five days depending on the amount of fluid produced and the appearance of the wound. The sponge and bandage are replaced with new materials. Therapy is tailored to each case, and the treatment is generally required for a period of time ranging from five days to a few weeks. to vacuum e shell Figure 1. Drawing representing the Turtle VAC in place: opencelled sponge, occlusive dressing, and tubing. M ethods After reduction of the shell fractures, if present, all sharp wire or screws from the fracture repair are covered with the adhesive tape (Elastikon ). Cracks may also be covered to help with the seal (Figures 1-5). The polyurethane sponge is cut with scissors to the shape of the wound and placed into the defect. Several layers can be used to cover the wound, and several wounds can be covered as long as the sponges are all connected (Figure 5). Plastic tubing is embedded into the sponge after a slit is made into the sponge to better anchor the tubing. Side holes can be added on the extremity of the tube that is buried into the sponge (Figure 5). The clear adhesive bandage is used to cover the sponge and surrounding shell in order to create an airtight seal (Figure 5). The tube is connected to the suction pump and the suction is provided continuously at negative cm Hg. The sponge and clear bandage should contract. If a leak in the bandage is present, supplemental adhesive tape is added to seal the defect. Injuries to the bridge can be difficult to seal due to the connection with the front or rear leg and their respective fossa. Taping pieces of gauze cranial to the leg into the prefemoral fossa will stabilize the rear leg in extension (Figure 5). The adhesive clear dressing can then be placed into the prefemoral fossa to complete the seal. Injuries to the plastron are commonly seen on land tortoises following dog attacks. They are treated in a similar fashion as carapacial wounds but the dressing may need to be covered to protect it from trauma from an active chelonian (Figures ). Elastic bandage Figure 2. Florida cooter, Pseudemys concinna concinna, with shell fracture and defect - initial presentation. Figure 3. Same Florida cooter, Pseudemys concinna concinna, as in Figure 2. The wounds were cleaned and fractures stabilized under general anesthesia. An esophagostomy tube has been placed for nutritional support and parenteral medication. A shell defect is present on the right caudal bridge and carapace. Journal of Herpetological Medicine and Surgery 5

3 Figure 4. Same Florida cooter, Pseudemys concinna concinna, as in Figures 2 and 3. The metal wires are covered with adhesive bandage (Elastikon ). The sponge can now be placed into the shell defect and covered with clear adhesive tape. Figure 7. Turtle VAC on an Eastern box turtle, Terrapene Caroli na Carolina with carapacial shell defect. Figure 8. Turtle VAC on a Gopher tortoise, Gopherus polyphemus, with wounds on plastron received from a dog attack. Note Figure 5. Same Florida cooter, Pseudemys concinna concinna, as in Figures 2 through 4. Turtle VAC in place. The sponge is placed into the defect and covered with a clear adhesive dress ing. The leg is been kept in extension by placing gauze pads cranially into the femoral fossa in order to help with the seal. that the suction is not activated at this time; the sponge and dress ing do not have a contracted appearance. Elastic bandage (Vetrap ) can be used to protect the dressing in active chelonians. The Turtle VAC is terminated when a nice granulation bed is apparent and no more fluid is collected from the wound area. R esults O f the 13 chelonians treated with Turtle VAC, eight were successfully treated and released, three died or were euthanatized due to concurrent injuries, and two were euthanatized due to failure of treatment. O f the released animals, VAC duration varied from 3-43 d, with an aver age of 16 d. Total length of stay at the VMTH for these released animals varied between l i d and 43 d, with an average of 31 d. Figure 6. Same Florida cooter, Pseudemys concinna concinna, as in Figure 2 thru 5 after eight days of Turtle VAC therapy. There is healthy granulation tissue over the wound and the shell edges. 6 Journal of Herpetological Medicine and Surgery D iscussion The Turtle VAC, in the management of the traumatic wounds of the chelonians described here, appeared to has ten healing and greatly improved the management of shell defects in which lung or other tissues were pulling away

4 Figure 9. Same Gopher tortoise, Gopherus polyphemus, as in Figure 8 with severe wound on plastron inflicted by a dog attack on day one. There is a deep tissue deficit in the pectoral area reaching up to 1.5 cm in depth, and soft tissue trauma on both forelegs. Figure 10. Same Gopher tortoise, Gopherus polyphemus, as in Figurers 8 and 9 after 16 d on Turtle VAC The tissue has filled in and is healing well. This animal was treated with Turtle VAC for a total of 43 d. It was then transferred to Fish & Wildlife Authorities for release. from overlying shell. Although this alternative to wet-todry bandages requires specialized materials such as open-celled sponges, clear bandaging material, and a suction pump, these elements are relatively inexpensive and readily available. For this bandaging method to be successful, it is essential that the seal and suction be maintained at all times. If the seal cannot be maintained or the suction must be stopped, the bandage should be removed. Leaving the wound partially sealed without suction may promote bacterial growth and could lead to infection. In two cases, poor seal and consequent inadequate suction pressure were considered to be the primary causes of treatment failure. In humans, contraindications to vacuum-assisted closure include fistulas other than enteric or blind fistulas, necrotic tissue with eschar present, untreated osteomyelitis, and malignancy in the wound (KCI, 2001). The dressing should not be placed directly over exposed blood vessels or organs, or over an actively bleeding wound. In chelonians with carapacial fractures, it is important to have an intact coelomic membrane present over the lungs. In animals with open lung wounds, the edges are closed with sutures to form a seal. Alternatively, a mesh or a layer of non-adherent dressing can be placed as a protective barrier under the vacuum-assisted closure dressing (KCI, 2001). It is unknown if this technique is painful to chelonians. In humans, the pain is considered minimal and bandage changes are performed in unsedated patients. Nevertheless, pur chelonian patients were given analgesics due to their shell fractures. The technique appears to be well tolerated, and many animals were observed eating on their own while being treated with the Turtle VAC. One disadvantage of this technique, especially for aquatic species, is that immersion of the Turtle VAC dressing is not advised. Immersion of the patient can cause water to leak into the wound and be suctioned into the system. The chelonian should be kept out of the water during the treatment, but may be allowed to soak in water between bandage changes for 30 minutes to a few hours. Hydration of the patient should be monitored closely, as the technique and the reduced access to water appears to dehydrate some patients. Oral or parenteral fluids should be administered if indicated. Concurrent use of an esophagostomy feeding tube is a convenient and effective method of maintaining hydration and providing medical and nutritional support. Future work on waterproofing the technique would be useful for treating marine and fresh water turtles with traumatic injuries. In conclusion, the Turtle VAC is a valuable technique for treating traumatic chelonian shell defects where the underlying tissue is exposed. It appears to accelerate healing time as compared to wet-to-dry bandages (weeks compared to months), and reduce lung atelectasis. However, controlled studies of healing time and degree of atelectasis using traditional wet-to-dry bandages versus the Turtle VAC technique would be needed to validate these clinical impressions. Journal of Herpetological Medicine and Surgery 7

5 References Bonner BB Chelonian Therapeutics. Vet Clin North Am Exot Anim Pract, 3: Joseph E, Hamori CA, Bergman S, Roaf E, Swann NF, Anastasi GW A prospective randomized trial of vacuum-assisted closure versus standard therapy o f chronic nonhealing wounds. Wounds: a Compendium of Clinical Research and Practice, 12: The Vacuum-assisted Closure Physician and caregiver refrence manual, Kinetic Concepts Inc, San Antonio, Texas. Lafortune M, Fleming GJ, Wheeler, Goebel T, Mozingo DD Management of severe skin wounds in a young tiger (Panthera tigris). Proc Am Assoc Zoo Vet, McArthur S, Hernandez-Divers SJ Surgery. In: McArthur S, Wilkinson R, Meyer J (eds): Medicine and Surgery of Tortoises and Turtles. Blackwell Publishing Ltd, Oxford, UK: Mitchell MA, Diaz-Figueroa O Wound management in reptiles. Vet Clin North Am Exot Anim Pract, 7(1): Morykwas MJ, Argenta LC, Shelton-Brown El, McGuirt W Vacuum assisted closure: A new method for wound control and treatment: Animal studies and basic foundation. Ann Plast Surg, 38: Richards J Metal bridges- a new technique of turtle shell repair. JHMS, ll(4): Rosskopf WJ, Woerpel RW Repair of shell damage in tortoises. Mod Vet Pract 62(12): Wheeler JL, DVM, MS. Personal communication Small Animal Medicine Department, Veterinary Medical Teaching Hospital, University of Florida, PO Box , Gainesville, FL, Journal of Herpetological Medicine and Surgery