The patient is placed in a supine position. A total of 2 mL of local anesthetic is drawn up in a 5-mL sterile syringe. When treating conditions involving the infraorbital nerve thought to have an inflammatory component such as infraorbital neuralgia, acute herpes zoster, neuritis, and postherpetic neuralgia, 40 to 80 mg of depot steroid may be added to the local anesthetic.

The basis for the use of ultrasound when performing infraorbital nerve block is its ability to easily identify the discontinuity of the hyperechoic image associated with the infraorbital foramen when imaging the infraorbital ridge. To perform ultrasound-guided infraorbital nerve block, the infraorbital foramen on the affected side is identified by palpation (Fig. 12.5). The foramen can usually be found ˜2.5 to 2.8 cm laterally from the midline. The skin overlying the infraorbital foramen is then prepped with antiseptic solution. Care must be taken to avoid allowing the antiseptic solution to flow into the eye. A high-frequency small linear or hockey stick transducer is then placed in the transverse plane over the previously identified infraorbital notch and slowly moved from a medial to lateral direction until a discontinuity in the infraorbital ridge is identified (Figs. 12.6 and 12.7). Alternatively, a longitudinal view can be utilized. In most patients, color Doppler can be utilized to identify the infraorbital artery, which exits the infraorbital foramen along with the infraorbital nerve (see Fig. 12.8).

Once the nerve and artery are identified, a 22-gauge, 1½-inch needle is inserted under real-time ultrasound imaging utilizing an in-plane approach and advanced toward the nerve with care being taken to avoid entering the foramen. The needle is advanced until it approaches the periosteum of the underlying bone. A paresthesia may be elicited, and the patient should be warned of such. The needle should not enter the infraorbital foramen, and should this occur, the needle should be withdrawn and redirected slightly more medially.