# Endoscope-assisted Transmastoid Infralabyrinthine approach to the petrous apex: A new corridor for multicompartmental jugular foramen tumors

## TL;DR

This paper introduces a new surgical approach using an endoscope to access hard-to-reach brain tumors near the petrous apex.

## Contribution

The novel endoscope-assisted transmastoid infralabyrinthine approach (e-TIA) is proposed for accessing multicompartmental jugular foramen tumors.

## Key findings

- The e-TIA provides sufficient working space for endoscope and surgical instruments in cadaveric and clinical cases.
- The dual-corridor strategy with anterolateral approach allows resection of tumors extending into the cervical portion.
- The e-TIA enables near total tumor resection without new neurological complications in clinical cases.

## Abstract

Multicompartmental jugular foramen tumors may extend anteriorly and superiorly toward the petrous apex, posing significant challenges for traditional surgical corridors.

The authors study the feasibility of endoscope-assisted transmastoid infralabyrinthine approach (e-TIA) to access the superior aspect of petrous apex.

Five cadaveric specimens were studied. A reference object was placed transnasally at the petrous apex to assess surgical exposure. To assess the working space of e-TIA, cross-sectional area was measured using three-dimensional reconstruction. Furthermore, we reviewed three patients with multicompartmental jugular foramen tumor in which this corridor was used.

The e-TIA, initiated with a 30° endoscope using the chopstick technique, accessed the superior petrous apex, Meckel's cave, and the internal carotid artery (ICA) from its cervical to lacerum segments. Radiological analysis demonstrated that the approach trajectory shifts at the cochlea level. Cross-sectional area analysis revealed that the e-TIA corridor provides sufficient space for manipulation of the endoscope, suction, and drill. Clinically, near total resection was achieved in all cases without new neurological complications.

The e-TIA offers a systematic extension to the superior petrous apex and the ICA from its cervical to the lacerum segments. utilizing an angled endoscope to enhance visualization. When combined with an anterolateral approach, this dual-corridor strategy provides a unique “looking-up” line of sight to the petrous bone. Overall, the e-TIA represents a promising option in selected multicompartmental jugular foramen tumors with petrous apex extension.

•The e-TIA accesses the superior petrous apex, Meckel's cave, and the ICA from the cervical to lacerum segment.•The corridor offers sufficient space for 30° endoscope, chopstick technique, simultaneous instrument use.•Dual-corridor strategy with the anterolateral approach allows resection of tumors extending into the cervical portion.•The e-TIA is a promising option for selected multicompartmental jugular foramen tumors with petrous apex extension.

The e-TIA accesses the superior petrous apex, Meckel's cave, and the ICA from the cervical to lacerum segment.

The corridor offers sufficient space for 30° endoscope, chopstick technique, simultaneous instrument use.

Dual-corridor strategy with the anterolateral approach allows resection of tumors extending into the cervical portion.

The e-TIA is a promising option for selected multicompartmental jugular foramen tumors with petrous apex extension.