What is the optimum incision for superficial temporal artery biopsy? An anatomical study using body donors

Superficial temporal artery (STA) biopsy remains an important diagnostic investigation for giant cell (temporal) arteritis. Incisions should optimise STA exposure while avoiding the temporal branch of the facial nerve. However, the widely used Gillies incision, a 2 cm temporal incision 2.5 cm anterior and superior to the auricular helix within the hairline, has been shown to be inconsistent for STA access.

In this study of 20 hemifaces from 10 body donors (mean age 87.1; range 75-93; n = 3 females), STA branches were mapped using a Cartesian grid referenced to the anterior crus-lateral canthus axis. Four 2 cm incisions were modelled: Gillies, pre-auricular, and two novel algorithmically optimised incisions targeting frontal and parietal branches. Access was defined as incision-to-vessel distance of ≤ 0.5 cm or ≤ 1.0 cm. All donors had provided written consent for anatomical research under the Human Tissue Act 2004.

The Gillies incision accessed the frontal branch in ≤ 1.0 cm in 11/20 (55%) and ≤ 0.5 cm in 3/20 (15%); parietal access was ≤ 1.0 cm in 8/19 (42%) and ≤ 0.5 cm in 4/19 (21%). Pre-auricular incision improved access: ≤ 1.0 cm for frontal 13/20 (65%) and parietal 18/19 (94.7%) branches. Optimised frontal and parietal incisions achieved ≤ 1.0 cm access in 19/20 (95%) and 18/19 (94.7%) respectively.

Our findings suggest that the Gillies incision may not be a reliable approach for accessing the frontal or parietal branches of the STA. Pre-auricular and algorithmically optimised frontal and parietal incisions achieved high, branch-specific access but require clinical validation.