Anatomic Variations of the Zygomatic Arch: Rethinking the Indications for the Orbitozygomatic Approach

Temporary zygomatic arch removal (zygomectomy) in the orbitozygomatic approach is sometimes used in surgeries involving complex lesions. Although the orbitozygomatic approach provides wider exposure than the pterional approach, it is more invasive and carries a higher risk of complications. We hypothesized that adequate exposure could be achieved without zygomectomy when the zygomatic arch lies well below the floor of the middle cranial fossa. This study introduces the concept of "Low-set Zygoma" and examines its clinical and anatomical relevance. High-resolution cranial computed tomography scans from 105 adults without craniofacial anomalies (210 sides) were analyzed to measure the vertical distance from the superior margin of the zygomatic arch to the middle cranial fossa floor (middle cranial fossa height). In this study, a Low-set Zygoma was defined as a middle cranial fossa height of ≥ -3.0 mm. Participants were stratified into 2 groups [Low-set Zygoma (≥ -3.0 mm) and non-Low-set Zygoma (< -3.0 mm) ], and demographic variables were assessed using univariate and multivariate statistical analyses. We performed 3 pterional approaches in patients with Low-set Zygoma, where orbitozygomatic approach was typically indicated. Adequate exposure was achieved in all patients, with no complications. Based on computed tomography data, the mean vertical distance from the zygomatic arch to the middle cranial fossa floor was -2.36 mm. Body height was the only independent predictor of a Low-set Zygoma (p = 0.037); individuals shorter than 162.5 cm were significantly more likely to exhibit this anatomical feature. A Low-set Zygoma appears to be a reliable anatomical indicator for avoiding unnecessary zygomectomy and may support more individualized preoperative planning.