The Combined Endoscopic Endonasal Far Medial and Open Postauricular Transtemporal Approaches As a Lesser Invasive Approach to the Jugular Foramen: Anatomic Morphometric Study With Case Illustration

Abstract

Background: Access to the jugular foramen (JF) requires extensive approaches. An endoscopic endonasal far medial (EEFM) approach combined with a postauricular transtemporal (PTT) approach may provide adequate exposure with limited morbidities.

Objective: To provide a quantitative anatomic comparison of the EEFM, the PTT, and the combined EEFM/PTT approaches. A clinical case of the combined approach is presented.

Methods: Five cadaveric heads were dissected. Each specimen received PTT and EEFM approaches on opposite sides followed by an EEFM approach on the side of the PTT approach. Morphometric and quadrant analyses were conducted. Three groups were obtained and compared: PTT (group A), EEFM (group B), and combined (group C).

Results: Group B had a significantly higher area of exposure of the JF as compared to group A (112.3 and 225 mm2, respectively, P = .004). The average degree of freedom (DOF) in the cranio-caudal plane for groups A and B was 63.6 and 12.6 degrees, respectively (P < .00001). Group A had a higher DOF in the medial-lateral plane than group B (49 vs 13.4 degrees, respectively, P < .00001. The average volume of exposure in groups A and B was 1469.2 and 1897.4 mm3, respectively (P = .02). By adding an EEFM approach to the PTT approach, an additional 56.1% of the anterior quadrant was exposed, representing a 584.4% increase in the anterior exposure.

Conclusion: The PTT and EEFM approaches provide optimal exposures to different aspects of the JF and in combination may constitute a less invasive alternative to the more extensive approaches.

Keywords: Chondrosarcoma; Clivus; Endoscopic endonasal far medial approach; Jugular foramen; Postauricular transtemporal approach.