A Surgical Protocol for Infraorbital Nerve Chronic Constriction Injury in Mice

Trigeminal neuropathic pain arises from injury to sensory pathways of the trigeminal system and is associated with persistent changes in neuronal excitability, gene expression, and pain-related behaviors. Infraorbital nerve chronic constriction injury (IoN-CCI) is a widely used model for investigating the cellular and molecular mechanisms underlying chronic orofacial neuropathic pain. This video demonstrates a surgical approach for IoN-CCI in adult mice by placing a single controlled constrictive ligature around the infraorbital nerve while preserving the gross anatomical continuity of the nerve. The protocol includes preoperative preparation, anesthesia and analgesia, extraoral exposure of the infraorbital nerve, placement and tightening of the ligature, wound closure, perioperative care, and postoperative monitoring. The ligature is tightened under magnification until a mild indentation is visible without complete nerve occlusion, transection, or discoloration. Key procedural considerations include accurate nerve identification, consistent ligature placement and tension, and standardized postoperative care. Related IoN-CCI paradigms have been associated with long-lasting mechanical hypersensitivity and molecular changes within trigeminal ganglion neurons. This protocol provides a detailed method for studying mechanisms associated with trigeminal nerve injury and chronic orofacial neuropathic pain.