APin firing or thermocautery has therapeutic value for certain conditions in the horse. When done properly, the AAEP considers pin firing an acceptable form of therapy.

(Editor’s note: In 2006, the AAEP updated its position on pin firing to read: “Thermocautery may have therapeutic value for certain conditions in the horse. When applied judiciously and in conjunction with appropriate analgesia and aftercare, the AAEP considers the modality an acceptable form of therapy in cases that have proven refractory to conventional treatment.”)

Pin firing is a therapy that uses a small, red-hot probe to cause cauterization (burning) of tissue in horses with chronic injuries to produce an abundant, serous inflammatory process. As opposed to other inflammation processes such as infections or bruising, serum has little or no fibrin (clotting material) or cellular content and does not coagulate. Firing causes maximal exudation, or oozing, and minimal tissue degeneration. The flooding of serum seems to flush out any chronic irritation, and it does not displace old scar tissue