Transient Mydriasis, A Rare Ocular Complication After Maxillary Nerve Block

Although maxillary nerve block (MNB) is one of the most common procedures performed in bimaxillary surgery, complications or adverse effects can still occur. We describe the case of a healthy 21-year-old male, requiring bimaxillary surgery. Ultrasound-guided MNB using the lateral pterygoid plate approach via the pterygopalatine fossa by a posterior infra-zygomatic approach was performed before surgery, and 5 mL of 0.3% ropivacaine was injected into both sides. After extubation, the patient experienced blurred vision on one side. His left pupil showed mydriasis and was dilated to 8 mm, and light reflexes disappeared, but there were no other symptoms of oculomotor nerve palsy such as ptosis or eye movement disorders. Sixteen hours later, the patient's pupils returned to normal size without any other symptoms. Unilateral incomplete oculomotor nerve palsy resulting in transient mydriasis secondary to MNB is a rare complication, not previously reported in the literature. Although a MNB reportedly provides satisfactory analgesia for midface surgery and chronic maxillofacial pain syndromes, a safe and reliable MNB technique has not been reported. Transient mydriasis due to left sphincter pupillae palsy caused by the anesthetic solution or local hematoma after puncture involving the left oculomotor nerve was assumed. Most ocular complications secondary to MNB are transient and benign, and should not cause panic among physicians and patients. In order to reduce the ocular complications caused by MNB, the supra-zygomatic approach should be chosen to avoid vital vascular damage and reduce the volume of local anesthetics.