Classic and Modified Infratemporal Fossa Type A Approaches to the Jugular Foramen: A Practical Step-by-Step 3D Guide for Surgeons

Objectives: The classic infratemporal fossa (ITF) type A approach to the jugular foramen is a complex surgical approach incorporating anterior transposition of the facial nerve and subtotal petrosectomy. Since the original description 4 decades ago, several modifications have been proposed to enhance hearing and facial nerve outcomes. Anatomic atlases describing these approaches frequently present idealized views that do not accurately replicate the surgeons’ vantage and may not reflect limitations encountered intraoperatively. Meant as a practical guide for surgeons and trainees, this study presents a step-by-step surgical guide for the traditional and modified ITF type A approaches to the jugular foramen. Methods: Four formalin-fixed, latex-injected cadaveric specimens were dissected under microscopic magnification; each specimen was used to demonstrate one of four variations of the ITF approach. Each critical approach step was documented with three-dimensional (3D) and two-dimensional (2D) photographic images. After dissection, the four approach modifications were presented side-by-side for direct comparison of surgical exposure and access to critical structures including the jugular foramen and bulb, carotid artery, lower cranial nerves, middle ear and hypotympanum, and retrofacial region. Results: Four dissections, ranging from maximal structural preservation to maximal exposure were performed: (1) modified ITF approach with preservation of the external auditory canal and fallopian bridge technique; (2) modified ITF approach with preservation of the external auditory canal and limited inferior mastoid-segment facial nerve mobilization; (3) modified ITF approach with subtotal petrosectomy and fallopian bridge technique; and (4) classic ITF type A approach with subtotal petrosectomy and anterior facial nerve transposition. Step-by-step 3D and 2D images were presented with comparisons across approaches at each step. While the classic ITF type A approach offered the greatest surgical exposure of the jugular foramen and petrous carotid artery, more limited dissections with preservation of the external auditory canal and fallopian bridge offered excellent access to critical structures. Conclusions: Modifications of the classic ITF type A approach exhibit substantial variability in surgical exposure, which is particularly important in optimizing visualization. Meant as a practical guide for surgeons, this study demonstrates the variability in access to critical structures with commonly utilized ITF approach modifications. Publication History Article published online: 15 February 2022 © 2022. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany