Infraorbital Nerve Block
Distribution: This is the 2nd division of CN V. It supplies the maxillary region.
Clinical uses: Nasal surgery (FESS, septoplasty, rhinoplasty); Upper lip surgery (Cleft lip)
Complications: hematoma, intravascular injection
Techniques:
Transnasal (subcutaneous needle advancement through the nostril under the ala of the nose)
Translabial (subcutaneous needle advancement under lip above the gum line)
Percutaneous
With the index finger of your non-dominant hand, sweep the inferior margin of orbital rim until you palpate a small depression, like a chip in the bone—this is the infraorbital notch. The infraorbital foramen usually lies 8-10mm inferior to the infraorbital notch. Advance your needle towards the foramen, but remain caudad to your finger tip to avoid accidental intravascular puncture or advancement into the foramen itself.
This could lead to nerve damage and damage to the orbital contents. After a (-) aspiration, deposit your local anesthetic (1-3mL is plenty). If you are going percutaneously, remember to sterilize the puncture site prior to injection. Lastly, after the injection is complete, we typically massage or compress the local into the surrounding tissue, as it tends to form a visibly large lump.
Having said all that, because pediatric patients come in all sizes, a recent paper by Song et al may provide a more consistent guide for patients of all ages. They advocate for imaging connecting two lines, one extending horizontally from the lateral margin of the nose (the alae), and a vertical line extending from the infraorbital notch. In this cadaveric study, the authors found the infraorbital foramen was generally located along the upper 1/3 of the vertical line. This is represented by the above picture on the left.
In my mind, the saving grace of this block is that it is a field block. The infraorbital nerve undergoes extensive branching, so as long as you are in the general vicinity, odds are in your favor the block will be effective, especially if after injection you manual compress the local deposit to spread it around.
Prabhu et al compared infraorbital blocks vs peri-incisional injection using identical volumes and concentrations for repair of cleft lip. They found the infraorbital nerve block analgesia lasted around 8 hours, while the analgesia of the peri-incisional injection lasted only around 2hrs. Takmaz et al compared infraorbital block vs saline injection at the end of surgery. Patients who received LA had 4x lower FLACC scores four the first 4 hrs, less nausea, delayed time to acetaminophen rescue, decreased total acetaminophen consumption, and no patient requiring narcotic rescue. Rajmani et al randomized patients to either infraorbital nerve block vs. IV fentanyl for cleft lip repair. They found improved analgesia and quicker awakening/feeding times in the patients who received an infraorbital block vs. those who received fentanyl.
Song, W.C., Kim, S.H., Paik, D.J., Han, S.H., Hu, K.S., Kim, H.J. and Koh, K.S., 2007. Location of the infraorbital and mental foramen with reference to the soft-tissue landmarks. Plastic and reconstructive surgery, 120(5), pp.1343-1347.
Prabhu, K.P.K., Wig, J. and Grewal, S., 1999. Bilateral infraorbital nerve block is superior to peri-incisional infiltration for analgesia after repair of cleft lip. Scandinavian journal of plastic and reconstructive surgery and hand surgery, 33(1), pp.83-87.
Rajamani, A., Kamat, V., Rajavel, V.P., Murthy, J. and Hussain, S.A., 2007. A comparison of bilateral infraorbital nerve block with intravenous fentanyl for analgesia following cleft lip repair in children. Pediatric Anesthesia, 17(2), pp.133-139.
Takmaz, S.A., Uysal, H.Y., Uysal, A., Kocer, U., Dikmen, B. and Baltaci, B., 2009. Bilateral extraoral, infraorbital nerve block for postoperative pain relief after cleft lip repair in pediatric patients: a randomized, double-blind controlled study. Annals of plastic surgery, 63(1), pp.59-62