Supraorbital and supratrochlear nerve block

Basic. The notch can usually be felt, and the injection is shallow.

The supraorbital and supratrochlear nerves are end branches of the frontal nerve, from the ophthalmic division of the trigeminal nerve (V1).

The supraorbital nerve leaves the orbit through the supraorbital notch or foramen on the upper orbital rim, about 2–2.5 cm from the midline, in line with the pupil when the eye looks straight ahead. It runs up under frontalis to supply the forehead and scalp as far back as the crown.

The supratrochlear nerve leaves the orbit about 1 cm nearer the midline, above the trochlea, and supplies the middle of the forehead and the upper eyelid.

The supraorbital artery runs with the nerve and can be seen with colour Doppler.

• Supraorbital notch: on the upper orbital rim in line with the pupil.
• Supratrochlear point: about 1 cm towards the midline from the notch, at the upper inner corner of the orbit.

• Forehead and front-scalp skin surgery, lacerations and skin grafts.
• Part of a scalp block for craniotomy, including awake craniotomy and pin fixation.
• Upper eyelid and brow surgery.
• Headache and supraorbital neuralgia (pain clinic).

• Supraorbital nerve (V1)
• Supratrochlear nerve (V1)

Surface anatomy, relevant structures and landmarks

Feel the notch on the upper orbital rim in line with the pupil.

Positioning

Supine, eyes closed. Put a finger on the upper orbital rim to keep the needle out of the orbit.

Block technique

• Insert the needle just above the notch, aiming slightly upwards, until it touches bone or lies just above the notch. Do not enter the foramen.
• Aspirate and inject 1–2 mL.
• For the supratrochlear nerve, move about 1 cm towards the midline and inject 1 mL; or make a line of injection along the brow from the notch to the midline.
• Press firmly for a minute afterwards to limit bruising.

Needle choice

25–27 G, 25 mm.

Neurostimulation technique

Not used.

Choice of local anaesthetic (including volume)

• 1–2 mL per nerve of 1–2% lidocaine with adrenaline, or 0.25–0.5% levobupivacaine or bupivacaine for longer effect.

Show scan

Frontalis Frontalis muscleBone Frontal boneNotch Supraorbital notch

Positioning

Supine, with the operator at the head end.

Scanning technique

• Place a small linear probe along the brow, just above the upper orbital rim.
• Slide along the rim to find the break in the bright bone line: the notch or foramen.
• Colour Doppler shows the supraorbital artery in the notch.

Structures to identify

• Frontal bone (bright line)
• Supraorbital notch or foramen
• Supraorbital artery
• Supraorbital nerve
• Frontalis and orbicularis oculi

Position / ergonomics

Stand at the head of the bed.

Probe

Small linear high-frequency (hockey-stick) probe.

Settings

Superficial or small parts preset, depth 1.5–2 cm.

Depth

0.3–0.8 cm.

Needle size

25–27 G, 25 mm.

Needling technique

Out of plane, or in plane from the side, aiming at the notch.

Optimal needle-tip position

Next to the notch, superficial to the bone and outside the foramen.

Drug choice

See above.

Volume

1–2 mL per nerve.

Optimal current if nerve stimulation is used

Not used.

Muscle responses acceptable

Not applicable.

Testing block success

• Numb forehead and front of the scalp on that side

Not used.

• Keep a finger on the orbital rim so the needle cannot slip into the orbit.
• Press on the site after injection; the eyelid bruises easily.
• Block both nerves: the supratrochlear covers the middle of the forehead.
• For a midline incision, block both sides.

• Allam and colleagues (2018) reviewed the anatomy and ultrasound-guided techniques for the supraorbital, infraorbital, mental and other trigeminal branches.
• Osborn and Sebeo (2010) described the supraorbital and supratrochlear blocks as the front part of the scalp block for craniotomy.
• Guilfoyle and colleagues (2013) pooled seven trials of scalp blocks (including these nerves) for craniotomy and found less pain in the first hours after surgery.

• Allam AE, Khalil AAF, Eltawab BA, Wu WT, Chang KV. Ultrasound-guided intervention for treatment of trigeminal neuralgia: an updated review of anatomy and techniques. Pain Res Manag 2018;2018:5480728. PubMed
• Osborn I, Sebeo J. 'Scalp block' during craniotomy: a classic technique revisited. J Neurosurg Anesthesiol 2010;22:187–194. PubMed
• Guilfoyle MR, Helmy A, Duane D, Hutchinson PJA. Regional scalp block for postcraniotomy analgesia: a systematic review and meta-analysis. Anesth Analg 2013;116:1093–1102. PubMed