Deconstruction of the Surgical Approach to the Jugular Foramen Region: Anatomical Study

Abstract

Keywords► jugular foramen ► far lateral ► infralabyrinthine approach ► styloid process ► occipital condyle ► cranial nerves ► distal cervical approach AbstractIntroduction The jugular foramen occupies a complex and deep location between the skull base and the distal-lateral-cervical region. We propose a morphometric anatomical model to deconstruct its surgical anatomy and offer various quantifiable targetguided exposures and angles-of-attack.Methods Six cadaveric heads (12 sides) were dissected using a combined postauricular infralabyrinthine and distal transcervical approach with additional anterior transstyloid and posterior far lateral exposures. We identified anatomical landmarks and combined new and previously described contiguous triangles to expose the region; we defined the jugular and deep condylar triangles. Angles-of-attack to the jugular foramen were measured after removing the digastric muscle, styloid process, rectus capitis lateralis, and occipital condyle.Results Removing the digastric muscle and styloid process allowed 86.4°laterally and 85.5°anteriorly, respectively. Resecting the rectus capitis lateralis and jugular process provided the largest angle-of-attack (108.4°posteriorly). The occipital condyle can be drilled in the deep condylar triangle only adding 30.4°medially. A purely lateral approach provided a total of 280.3°. Cutting the jugular ring and mobilizing the vein can further expand the medial exposure.Conclusion The microsurgical anatomy of the jugular foramen can be deconstructed using a morphometric model, permitting a surgical approach customized to the pathology of interest.

Simplifying the Surgical Classification and Approach to the Posterolateral Skull Base and Jugular Foramen Using Anatomical Triangles

“…Contents of the different triangles along with their respective measurements have been previously reported [ 11 ]. Table 2 summarizes the triangles as they relate to the modifications of the LDC-RATT approach, including the different possible surgical steps and exposure advantages related to the jugular foramen region.…”

“…The lateral approach (i.e., LDC-RATT) is versatile and can be customized to the specific anatomical location of the lesion (Figure 10B ) [ 11 ]. The styloid process may be removed to gain part of the exposure obtained from a preauricular subtemporal-infratemporal fossa approach (anterior group) [ 8 , 18 ].…”

“…Detaching the digastric muscle and mobilizing it inferiorly exposed the TP-C1 and the surrounding deep muscular triangles: (iv) suboccipital triangle between the superior and inferior oblique muscles (Figure 3A ) [ 14 ], and (v) condylar triangle between the superior oblique and rectus capitis lateralis muscles (Figure 3A ) [ 15 ]. We also previously defined the (vi) “jugular triangle” between rectus capitis lateralis, TP-C1, and the base of the styloid process, as the lateral limit to the jugular foramen (Figure 3A ) [ 11 ]. We proposed the (vii) “deep condylar triangle” between the condylar emissary vein, the jugular process of the occipital bone (site of insertion of rectus capitis lateralis), and the transverse process of the atlas (Figure 3B ) [ 11 ].…”

“…We also previously defined the (vi) “jugular triangle” between rectus capitis lateralis, TP-C1, and the base of the styloid process, as the lateral limit to the jugular foramen (Figure 3A ) [ 11 ]. We proposed the (vii) “deep condylar triangle” between the condylar emissary vein, the jugular process of the occipital bone (site of insertion of rectus capitis lateralis), and the transverse process of the atlas (Figure 3B ) [ 11 ]. This helped us delineate exactly where the occipital condyle is located from a lateral perspective.…”

“…The senior author (JHR) traditionally adopted the lateral distal cervical retro-auricular transtemporal (LDC-RATT) approach because it offers direct access to the JF, is versatile, and can be tailored to individual lesions [ 9 , 10 ]. We recently deconstructed this approach into anatomical triangles and analyzed its different angles of exposure [ 11 ].…”