Infraorbital Nerve Damage
Damage to the infra-orbital canal and its nerve can occur during maxillary cheek tooth repulsion, especially in young horses where the infra-orbital canal sits immediately medio-dorsal, or dorsal to the apical aspect of the alveolus. In many young horses, it is difficult to understand how such nerve damage is avoided during a standard repulsion. If the infraorbital nerve is damaged by repulsion techniques, clinical signs may occur within hours in a proportion of horses, and can include violent headshaking, distress, and rubbing (even excoriating) the ipsilateral nostril off adjacent structures. Such cases usually do not respond to corticosteroid, non-steroidal anti-inflammatory, or opiate therapy, but may respond in the short-term to acetylpromazine therapy. Thankfully most cases show spontaneous resolution of clinical signs within 1 to 2 weeks of nerve injury. However, some cases of trigeminal damage can cause longer term headshaking (Ogden et al. 2022). Infraorbital nerve damage is much less likely following Steinmann pin repulsion, but long term signs of clinical trigeminal neuropathy can rarely occur following use of this technique.