Two Triangles as Landmarks for the Upper Parapharyngeal Internal Carotid Artery: Surgical Anatomy and Relevance for the Endoscopic Anterior Transmaxillary and Endonasal Approaches to the Infratemporal Fossa and Parapharyngeal Space

Background and Objectives: The upper parapharyngeal internal carotid artery (upper-ppICA) is perhaps one of the most challenging segments of the artery to surgically localize and control. Understanding the relevant anatomy is crucial for endoscopic access to the infratemporal fossa (ITF) and parapharyngeal spaces (PPS). This study evaluates the surgical significance of two anatomical triangles (six key points), namely, the “ACCESS” and “DANGER” triangles as the landmarks for the upper-ppICA localization during the endoscopic sublabial anterior transmaxillary and endonasal approaches (ESATMA and EEA).

Methods: To conduct this study, five cadaveric specimens (10 sides) were dissected. The ITF and PPS were accessed first through the ESATMA and at a second stage in combination with the EEA. The anatomical relationships of the critical ITF and PPS contents with upper-ppICA were defined and subsequently dissected. The two anatomical triangles were defined, described, and stereotactically measured using neuronavigation.

Results: To identify the upper-ppICA, six specific points were designated within the ESATMA: A (cranial entry point of the lingual nerve), B (lingual nerve junction point with the base of the maxillary sinus), C (eustachian tube cartilage junction point with the maxillary sinus base), D (cranial entry point of the middle meningeal artery (MMA)), E (origin of the MMA from the internal maxillary artery [IMA]), and F (junction point of the posterior inferior margin of levator veli palatini and maxillary sinus base). The distance from the upper-ppICA (at the same axial level) to the A, B, C, D, E, and F points was measured as at 22.2, 19.5, 31.7, 12.1, 12.1, and 10.5 mm by via ruler, respectively. Furthermore, two triangles were defined: (1) The “ACCESS” triangle of points ABC was initially encountered and facilitated access to the ppICA and (2) the DANGER triangle, constituted of points DEF, and as its name denotes, was the final gate to the upper ppICA. These triangles reliably localized the upper-ppICA as a key step in the anatomical exploration of the pterygopalatine fossa, ITF, and PPS via the ESATMA.

Conclusion: The two triangles described herein (6 key points) serve as novel anatomical landmarks for the localization of the upper-ppICA during the ESATMA, with or without EEA biportal entry, in accessing the ITF and PPS. These landmarks can be utilized independently or in conjunction, offering valuable guidance for surgeons in the efficient and safe treatment of tumors or other lesions within these regions.

Fig. 1 The six key points and the two triangles of the ITF and PPS through the endoscopic sublabial anterior transmaxillary approach.

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Artikel online veröffentlicht:
07. Februar 2025