Contralateral Transmaxillary Approach for Resection of Chondrosarcoma of the Petrous Apex: A Case Report

Comparative Anatomy of the Contralateral Transmaxillary Approach Alone and With Ipsilateral Transpterygoid Extension: Quantitative Insights on Surgical Exposure and Maneuverability in the Petroclival Region

BACKGROUND AND OBJECTIVES

Beyond qualitative evidence legitimizing endoscopic corridors through contralateral transmaxillary (CTM) and endonasal ipsilateral transpterygoid (ITP) corridors to the petrous apex and petroclival region, surgical feasibility by direct quantitative comparative anatomy is sparse. Our cadaveric study addresses this by performing the CTM approach followed by ITP extension to quantify the extent of petrous apex resection, instrument maneuverability, and working distance to petrous apex.

METHODS

Anatomic dissections were performed bilaterally on 5 latex-injected human cadaveric heads (10 petrous bones). After CTM dissections were quantified, the ITP approach was added enlarging initial exposure. Differences were measured with statistical significance when P values are < .05.

RESULTS

The mean petrosectomy volume was 0.958 cm3 with CTM and 1.987 cm3 with CTM + ITP, corresponding to 14.53% and 30.52% petrous apex resection, respectively. Craniocaudal instrument mobility was more limited in the lateral extent of dissection compared with the midline for both CTM (8.062° vs 14.416°) and CTM + ITP (5.4° vs 14.4°). The CTM approach achieved the lateral-most dissection at the body of the petrous apex (15.936 mm), with lateralization more limited in the superior petroclival region (9.628 mm) and the inferior petroclival region (8.508 mm). Angle of surgical maneuverability increased superiorly vs inferiorly in the CTM approach (mean 12.596° vs 8.336°, respectively). The CTM approach offered the shortest mean working distance (88.624 mm) to the petroclival region compared with the bi-nares approach (100.5 mm). CTM + ITP achieved greater lateralization in the superior (21.237 mm) and inferior (22.087 mm) aspects of the petroclival region compared with the CTM approach.

CONCLUSION

Operative considerations are discussed in accessing target neurovascular structures through the uniquely shaped corridors formed by the CTM or combined CTM + ITP. Allowing mobilization of the internal carotid artery laterally and eustachian tube inferiorly, addition of the ITP allowed for larger petrosectomy than CTM alone, especially in the inferior and lateral aspects of the petrous bone.

Contralateral Transmaxillary Corridor Used in Endoscopic Endonasal Approach for Resecting Adenoma Invading the Retrocarotid Area of the Cavernous Sinus and Beyond: Surgical Anatomy, Patient Selection Algorithm, and Illustrative Cases

BACKGROUND AND OBJECTIVES

The cavernous internal carotid artery (cICA) and its branches can make it challenging to approach the lateral portion of the retrocarotid area of the cavernous sinus (RcACS) and surrounding areas during the endoscopic endonasal approach (EEA). This can sometimes require more invasive transcranial approaches, causing a higher risk of complications. We sought to explore the feasibility of adding a contralateral transmaxillary (CTM) corridor to improve access to the RcACS during EEA.

METHODS

We performed EEA and CTM extensions on 6 cadavers (12 sides) using image guidance. The depth of the surgical corridor, the surgical exposure, the angle of attack, and the trajectory to the anterior genu of the cICA were measured. Two illustrative clinical cases are presented.

RESULTS

Compared with the contralateral transnasal approach, the CTM corridor provided a 10.76 (5.32)-mm shorter distance ( P < .001), 36.23% (20.70%) larger surgical exposure ( P < .001), and a 24.6° (3.4°) more parallel trajectory to the anterior genu of the cICA ( P < .001). The mean angle of the lateral nasal wall line and the middle eye line was equal to the mean angle of the contralateral transnasal ( P = .075) and CTM ( P = .262) approaches, respectively. The CTM corridor allowed us to achieve near-total resection of the RcACS and beyond in 2 invasive adenomas with significant lateral extension.

CONCLUSION

The CTM corridor is a feasible addition to standard EEA to access the RcACS and beyond, providing a more medial-to-lateral trajectory and improved access. The middle eye line can be used as a reference to help select patients for this approach.

Recent progress in endoscopic skull base surgery: Functional preservation and multiportal approaches

Over the past couple of decades, endoscopic skull base surgery (ESBS) has significantly evolved and is applied to a broad range of skull base pathologies, including sinonasal malignancies. Recent studies have demonstrated remarkable progress of ESBS in complete resection with low morbidity and extension of its application to larger and more complex lesions. In this review, we focus on the evolution of functional preservation and multiportal approaches. Progress in preoperative assessments and surgical techniques improved the preservation of olfactory function after ESBS. The technical feasibility of olfaction preservation even after resection of olfactory groove lesions has been reported. To overcome the limitations of extending use of the endoscopic endonasal approach in surgical fields, various types of multiportal approaches, including combinations of the endoscopic endonasal and transorbital, transmaxillary, or transoral approach, have been reported, as they are useful for complete resection of extensive pathologies while limiting morbidity. These innovative techniques are still in the process of maturation. Hence, an ongoing critical evaluation is essential to ensure efficacy.

Midline Skull Base Meningiomas: Transcranial and Endonasal Perspectives

Simple Summary

Skull base meningiomas have always represented a challenge for neurosurgeons. Despite their histological nature, they may be associated with unfavorable outcomes due to their deep-seated location and the surrounding neurovascular structures. Over time, several corridors have been proposed, each one carrying its own pros and cons. During the last decades, the endoscopic endonasal route has been asserted among the classic routes for a growing number of midline and paramedian lesions. Therefore, the aim of our paper is to present a comprehensive review of the indications and techniques for the management of skull base meningiomas, emphasizing the ambivalent and complementary role of the low and high routes.

Abstract

Skull base meningiomas have always represented a challenge for neurosurgeons. Despite their histological nature, they may be associated with unfavorable outcomes due to their deep-seated location and the surrounding neurovascular structures. The state of the art of skull base meningiomas accounts for both transcranial, or high, and endonasal, or low, routes. A comprehensive review of the pertinent literature was performed to address the surgical strategies and outcomes of skull base meningioma patients treated through a transcranial approach, an endoscopic endonasal approach (EEA), or both. Three databases (PubMed, Ovid Medline, and Ovid Embase) have been searched. The review of the literature provided 328 papers reporting the surgical, oncological, and clinical results of different approaches for the treatment of skull base meningiomas. The most suitable surgical corridors for olfactory groove, tuberculum sellae, clival and petroclival and cavernous sinus meningiomas have been analyzed. The EEA was proven to be associated with a lower extent of resection rates and better clinical outcomes compared with transcranial corridors, offering the possibility of achieving the so-called maximal safe resection.

How I do it? Resection of residual petrous apex chordoma with combined endoscopic endonasal and contralateral transmaxillary approaches

BACKGROUND

The petrous apex is one of the most challenging areas of the skull base to access.

METHOD

We present a case of residual petrous apex chordoma posterolateral to the paraclival segment of the internal carotid artery (ICA) resected with combined endoscopic endonasal and contralateral transmaxillary (CTM) approaches, without lateralization of the ICA.

CONCLUSION

This case demonstrates the value of the CTM corridor in resecting petrous apex lesions that are posterolateral to the paraclival segment of the ICA.