Infraorbital nerve block

Infraorbital nerve blocks can be used as part of the management of trigeminal neuralgia or the rarer isolated infraorbital neuralgia. Ultrasound guidance is useful to identify the infraorbital nerve directly as well as identify anatomical variations ^1,2.

Indications

• infraorbital neuralgia non-responsive to conservative management ¹

• post-operative pain relief, e.g. after facial or oral surgery ³

Procedure

Equipment

• ultrasound machine, high-frequency linear probe, sterile probe cover +/- sterile gel

• skin cleaning product

• sterile drape, sterile field, sharps tray

• blunt drawing up needle, 25-gauge hypodermic needle, 3 mL syringe

• injectate: numerous have been described in the literature

  • 5-15 mg lidocaine +/- 1.5 mg dexamethasone ^1,2

  • neurolytic agents, e.g. glycerol, alcohol, phenol, tetracaine ^1,4

• sterile gauze

• adhesive dressing

Technique

• patient lying prone, head in neutral position ¹

• the infraorbital foramen can be palpated through the skin ³

• skin prep and drape

• high-frequency linear probe can be used to identify the infraorbital foramen either in the

  • transverse plane: placed parallel and 1 cm inferior to the inferior orbital rim ¹

  • longitudinal plane: placed on a line between the ipislateral canine tooth and the external orbital rim, rotating the superior end of the probe medially ³

• infraorbital foramen should be seen as a hypoechoic "break" or "dimple" in the bone with the emerging infraorbital neurovascular bundle (color Doppler can be useful to confirm the presence of vessels) ^1-3

• the needle is inserted either

  • in-plane from lateral-to-medial (transverse scanning) or inferior-to-superior (longitudinal scanning) to the foraminal opening ^1,2,4

  • out-of plane (transverse scanning) from 10 mm lateral to the mid-nasal ala and advanced superolaterally ⁴

• aspiration test to avoid intravascular injection, followed by injection observing spread under ultrasound ^1,2,4

Complications

• associated with any injection, e.g. bleeding/hematoma, infection, medication allergy ^1,4

• specific to infraorbital nerve blocks

  • nerve damage, e.g. mechanical damage from direct needle contact or pressure from injection ²

  • double vision ⁴

  • serious complications are reported to be rare ⁴