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.