Can autologous thrombin with a rest fraction of ethanol be used safely for activation of concentrated autologous platelets applied on nerves?

The use of concentrated platelet-rich plasma (cPRP) as a source of growth factors is reported to be beneficial for an enhanced osteogenesis in spine surgery. Today both bovine and autologous thrombin is used for activating the platelets and thus releasing the growth factors. In order to prevent transmission of organisms and the development of antibodies, autologous thrombin seems to be the logical choice. However, the preparation of autologous thrombin is cumbersome and consumes a part of the cPRP. In order to overcome this problem, a commercial autologous thrombin kit (activAT, Dideco, a Sorin Group company, Italy) has been developed which produces autologous thrombin out of platelet-poor plasma. A possible disadvantage of this kit could be the rest fraction of 1.18% of ethanol in the platelet gel. In a pig model, the influence of different ethanol concentrations on the ischiadic nerve was studied. The study consisted out of four groups; a control group (n=6), a group with platelet gel 0% ethanol (n=6), a group with platelet gel 1.18% ethanol (n=6) and a group with platelet gel 3.8% ethanol (n=7). In all the groups, the ischiadic nerve was dissected and the myelin sheet opened after which the wound was closed (control group) or one of the three therapies was applied. After 12 h, the animal was sacrificed and the ischiadic nerve was submitted for histological examination. Myelin sheaths appeared normal in all cases. No axonal swelling was observed. No statistically significant differences were observed for neutrophilic and eosinophilic infiltration nor for collagen necrosis between groups. Platelet gel prepared by the use of a commercial autologous thrombin kit and containing 1.18% of ethanol can be safely used on nerves.