Introduction: The superficial temporal artery (STA) is an important branch of the external carotid for the neurosurgeon: it lies directly over the pterional entry zone and is often damaged, intentionally or otherwise. Furthermore, the STA is a favored afferent for EC-IC bypasses, and it is prudent to preserve it when possible. In this review, our aim is to discuss the relevant morphological characteristics of the STA when considering its preservation and use for microsurgical anastomosis: the vessel’s caliber and branching pattern.
Methods: We reviewed the English literature using the PUBMED database through January 2017 for anatomical studies of the STA through either cadaveric or radiological methods. Studies which recorded the branching location relative to the zygoma and the diameter of the STA and branches were included.
Results: A total of 15 studies met our criteria. Together, 161 cadavers were evaluated for patency and anatomical relations. All specimens had an intact STA with over 85% of samples having a frontal branch and 82% having a parietal branch with a diameter over 1mm. The mean diameter of the STA and branches were larger in cadaveric specimens compared to radiologic samples (p = 0.012). Across all groups, the frontal branches had larger diameters than the parietal branches (p = 0.032). The STA consistently branched above the zygoma (40 – 90.4% of samples) independent of study method (p = 0.26).
Conclusions: The morphological patterns of STA distribution are similar across the reviewed literature. Cadaveric studies consistently overestimate the caliber of the STA in comparison to radiological studies, likely due to post-fixation artifacts and differences in measurement methods. The frontal branch, when reported, is significantly dominant over the parietal branch of the STA, and both branches have diameters greater than 1mm, which is accepted as an appropriate caliber for arterial bypass.
Patient Care: Ligation of the superficial temporal artery during routine neurosurgery cases is not without morbidity and precludes future use of that artery in EC-IC bypass. We hope that this review of the literature will guide surgical decision making and equip neurosurgeons to preserves as much of the STA as possible.
Learning Objectives: The superficial temporal artery branches over the zygoma, with the frontal branch dominant over the parietal. Cadaveric studies consistently overestimate arterial diameter compared to radiographic studies.