Successful treatment of 15 cases of canine traumatic aural hematoma using autologous platelet rich plasma (PRP)

Platelet-rich plasma (PRP) derived from whole blood, is characterized by platelet (PLT) concentrations above baseline in a small volume of plasma that can accelerate the healing process [1] by providing elevate concentration of platelet-derived growth factors [2] which can stimulate cell proliferation and decrease of inflammatory reaction. Following the excellent results obtained on a small number of subjects previously reported in a preliminary study [3], in this prospective in vivo study we aimed to describe the clinical efficacy of autologous PRP in the treatment of canine traumatic aural hematoma secondary to otitis externa. After approval by the Ethics Committee of the University of Milan and with the owner informed consent, 20 ml of citrate whole blood were obtained from the cephalic vein of 15 dogs with traumatic aural hematoma of different breeds, 6 males and 9 females, with a age range of 1 -15 years (mean ± DS: 7,4 ± 3,7 years). All subjects had a history of multiple centesis, sometimes associated with injections of cortisone in situ, with subsequent recurrences of hematoma. PRP was produced using a semi-automatic closed system (CPUNT 20, Eltek group, Casale Monferrato, Alessandria, Italy) for veterinary use [4]. The serum-hematic content of the auricular pinna was completely drained using one or more 20G needles (depending of hematoma organization) and, using the same hole of the drainage inlet, the PRP was then injected. The dogs were subjected to weekly follow up for a minimum of 45 days from the first treatment. In case of partial or total recurrence of the aural hematoma of the first follow-up, the treatment was repeated with the same procedure. No dog has been subjected to anaesthesia during the procedures. At D0 the aural hematoma was present for 17 ± 13 days and the mean of the drained serum-hematic content was 23 ± 30 ml. Four dogs had a partially organized aural hematoma. 1.3 ± 0.6 ml of PRP were injected, with a mean concentration of 1185 ± 908 x 103/μl PLT (minimum value: 308 x 103/μl PLT maximum value: 4141 x 103/μl PLT, 500% mean increase compared to whole blood). 12/15 subjects were treated with a single application (Group A1), 3/15 with two applications (Group A2). 2/15 subjects were lost after the first follow up. For the remaining 13/15 the mean healing time was 15.8 ± 8.1 days (A1) and 24 ± 5.2 days (A2). No subjects showed recurrences at 45 days follow up. No side effects have been registered. The in situ administration of PRP was effective in the treatment of traumatic aural hematoma secondaty to otitis externa in dogs, leading to complete resolution of the disease in all treated subjects. [1] Marx R.E. Platelet-Rich Plasma (PRP), what is PRP and what is not PRP? Implant Dentistry 2001, 10, 225-228. [2] Souza T.F. et al. Healing and expression of growth factors (TGF-β and PDGF) in canine radial ostectomy gap containing platelet-rich plasma. Vet Comp Orthop Trauma, 2012, 25, 445-452. [3] Perego R. et al. Efficacia clinica del plasma ricco di piastrine (prp) autologo ottenuto con metodo chiuso semi-automatico nel trattamento dell’otoematoma nel cane. 2017. 56° Congresso AIVPA, Piacenza. [4] Perego R. et al. Evaluation of a commercial closed system for autologous platelet-rich plasma production in dog. 2016. ESVCP-ESVONC Congress, Nantes.