Comparison of intraoral and percutaneous approaches for infraorbital nerve block

The infraorbital nerve block is frequently used during repair of facial lacerations; both percutaneous and intraoral approaches are used. The authors compared the two techniques for pain of administration and anesthetic effectiveness.

A prospective, randomized, single-blind, crossover study was conducted using 12 healthy volunteers, aged 25-41 years. No patient had prior experience with infraorbital nerve anesthesia, lidocaine allergy, active oral/facial infection, or previous facial fractures. Bilateral infraorbital nerve blocks were done using the intraoral technique on one side and the percutaneous technique on the other. Both techniques were used by the same investigator and were carried out with 27-gauge needles and 2.5 mL of 2% buffered lidocaine at room temperature injected over 20 seconds. The oral mucosa was topically anesthetized with viscous lidocaine for 1 minute prior to intraoral injection. The orders of the blocks and sides of the face anesthetized were randomized. Pain of injection, anesthetic efficacy (anesthesia of upper lip), time to anesthetic onset, and duration of anesthesia were evaluated.

By visual-analog pain scale scores, there was less pain by the intraoral approach, although this difference did not achieve significance (p = 0.08). Overall, nine of the 12 subjects considered the intraoral technique less painful than the percutaneous approach (p = 0.14). The intraoral approach produced upper-lip anesthesia in 12 of 12 subjects, versus nine of 12 for the percutaneous technique (p = 0.25). The duration of anesthesia was longer with the intraoral approach (1.6 +/- 0.8 hours versus 0.9 +/- 0.4 hours) than with the percutaneous approach (p = 0.04). The two techniques were similar in times to anesthetic onset.

The intraoral approach to the infraorbital nerve block after adjunctive topical anesthesia appeared at least as effective in producing upper-lip anesthesia as the percutaneous approach without adjunctive topical anesthesia. Although the volunteers subjectively preferred the intraoral approach and visual-analog pain scores were lower for this approach, these differences did not achieve statistical significance. The intraoral approach was associated with a longer duration of upper-lip anesthesia.