Temporal artery biopsy

Timing:

• Do not wait for biopsy before starting glucocorticoids, if indicated - the biopsy will remain positive for around a month after starting them

Pre-op:

• Clarify which side/both sides (referring doctor to decide). Note that there is no good evidence to decide whether to do one or both sides. UTD recommends doing unilateral in those with clear unilateral symptoms, and bilateral in others.

Anatomy:

• Superficial temporal artery is a branch of the ECA
• It arises posterior to the ramus of the mandible, within the parotid gland, and ascends anterior to the ear. It courses anteriorly over the zygoma, here dividing into frontal and parietal branches.
• As it passes over the zygoma, it pierces and ascends superficial to the superficial temporal fascia.
• The superficial temporal vein tends to be superficial to the fascia too, and sometimes accompanies the artery.
• The temporal branch of facial nerve ascends in a similar region, but is found below the superficial temporal fascia. Generally it is found 2cm anteriorly to the STA, but in rare cases is found immediately deep to the STA. It is found much closer to STA at the level of the antihelix, so it is best to stay above that level.
• The auriculotemporal nerve can also be found along with STA on rare occasions.

Procedure:

• Supine, head ring, bed positioned with space on both sides of head, shave
• IV ABx
• Head drape - back to back side drapes under head then wrapped around, with wet pack over face
• Mark out artery based on pulse palpation, starting at superior edge of anti-helix and moving upwards
• Linear incision starting at about level of superior aspect of ear (cut skin only)
• Diathermy to stop skin edge bleeding
• Use scissors to cut through fascia
• Self-retaining retractor
• Locate the proximal part of artery (tortuous) and differentiate it from the nerve
  • If you can't find it
    • Feel for pulsations
    • Search each quadrant in turn
  • Nerve should be more anterior, less tortuous, deeper
  • The nerve is more closely associated with the frontal branch of STA - can target a more proximal segment, or extend towards the parietal branch of STA if a longer segment is needed.
• Put 3 medium weck clips at bottom
  • Prefer to ties, as if the tie snaps and artery retracts you end up with a large unsightly wound
• Define 3cm of artery (don't need to fully dissect it out)
• Put 2 medium weck clips at top
• Properly dissect out the artery, putting small weck clips on large branches and ignoring tiny ones
• Haemostasis, LA, closure
  • SQ closes with 3x interrupted 3/0 vicryl, then running vicryl rapide, then dermabond