Anatomical Analysis of the Vagoaccessory Triangle and the Triangles Within: The Suprahypoglossal, Infrahypoglossal, and Hypoglossal-Hypoglossal Triangles

Authors

Ali Tayebi Meybodi, Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona, USA.Follow
Leandro Borba Moreira, Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona, USA.Follow
Xiaochun Zhao, Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona, USA.Follow
Mark C. Preul, Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona, USA.Follow
Michael T. Lawton, Division of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona, USA. Electronic address: Michael.Lawton@BarrowBrainandSpine.com.Follow

Document Type

Article

Abstract

BACKGROUND: Rootlets of the lower cranial nerves create a web that limits microsurgical maneuverability in the cerebellomedullary cistern (CMC). The vagoaccessory triangle (VAT) and 2 triangles within it were defined to identify surgical routes to aneurysms of the posterior inferior cerebellar artery (PICA). Dividing the VAT into 2 triangles (suprahypoglossal [SHT] and infrahypoglossal [IHT]), although elegant, oversimplifies CMC anatomy. The triangle formed by the superior and inferior hypoglossal rootlets (hypoglossal-hypoglossal triangle [HHT]) needs consideration as well. METHODS: Far-lateral craniotomy was performed on 10 cadaveric heads bilaterally. Areas of CMC triangles were calculated. Relationships between the PICA origin and the adjacent triangles were analyzed. Vertebral artery (VA) exposure and clipping lengths were recorded for each triangle. RESULTS: The area of SHT was almost twice those of IHT and HHT. The average VA depth relative to VAT increased significantly when moving distally from proximal VA (P < 0.001), but VA exposure and clipping lengths were not significantly different between triangles. IHT, HHT, and SHT defined VA subsegments (V, V, and V), with PICA most commonly originating from V. Based on our cadaveric measurements, the V subsegments were identified with 76% accuracy in angiograms. CONCLUSIONS: Based on this study, VAT should be divided into 3 triangles, not 2. Splayed rootlets of cranial nerve XII and multiple outlet foramina create an important space different from the previously recognized SHT and IHT. These triangles provide corridors to vascular pathologies. V subsegments may be approximated from imaging studies and may help with preoperative planning.

Medical Subject Headings

Cadaver; Cranial Nerves (anatomy & histology); Humans; Skull Base (anatomy & histology)

Publication Date

3-3-2019

Publication Title

World neurosurgery

E-ISSN

1878-8769

Volume

126

First Page

e463

Last Page

e472

PubMed ID

30825626

Digital Object Identifier (DOI)

10.1016/j.wneu.2019.02.073

Recommended Citation

Tayebi Meybodi, Ali; Borba Moreira, Leandro; Zhao, Xiaochun; Preul, Mark C.; and Lawton, Michael T., "Anatomical Analysis of the Vagoaccessory Triangle and the Triangles Within: The Suprahypoglossal, Infrahypoglossal, and Hypoglossal-Hypoglossal Triangles" (2019). Neurosurgery. 1335.
https://scholar.barrowneuro.org/neurosurgery/1335