Preoperative Exposure of Sigmoid Sinus Trajectory in Posterolateral Cranial Base Approaches Using a New Landmark Through a Neurosurgical Perspective

Abstract

The location of burr holes in posterolateral cranial base approaches should be appropriate to provide an adequate operative field, and surgical freedom is crucial for bone window opening. The aim of this study was to search for more convenient and easily detectable landmarks in comparison with current landmarks in posterolateral cranial base surgery. Twenty 3-dimensional reconstructed head and neck computed tomography angiography images (group 1) and 20 cadaver heads (group 2) were evaluated. An imaginary line connecting the angle of the mandible and the mastoid tip was extended upward. A second line passing through the lateral edge of the zygomatic arch was also extended posteriorly. The authors examined if the first line met with the sigmoid sinus throughout its course and determined the location of the intersection point of these 2 lines relative to the sigmoid-transverse sinus junction. The intersection point did not correspond to the sinus region in 3 images from group 1 and 4 specimens from group 2. The matching of the mandibula-mastoid line trajectory with the sigmoid sinus course was unacceptable in 4 images and 5 cadavers. For venous anatomy preservation and anatomic skull base fossa orientation during posterolateral cranial base approaches, upward extension of the mandibula-mastoid line can be a proper landmark for surgical planning in this region. The authors' proposed superficial anatomical line and intersection point over the skull could be used as a reliable indicator for the external projection of the sigmoid sinus and an appropriate initial burr-hole location.

Temporal Bone Landmarks of the Transversesigmoid Sinus Junction: An Anatomical Study in Dried Human Skulls

“…In order to perform an effective craniotomy, neurosurgeons should create an appropriately-sized cranial opening while avoiding injury of the adjacent major venous sinuses. [1][2][3][4][5][6][7][8][9][10] Since the posterior boundary of temporal craniotomy is determined using the position of TSSJ, precise identification of this major venous structure, especially the anterosuperior margin of the venous junction, is crucial. Moreover, despite technological advancements in the neuronavigation system, which helps facilitate safer and faster surgery 2 , it is not usually available in a resource-limited public hospital or emergency situation.…”

“…[18][19] However, the prevalence of type I asterion was round 10-20% and generally not mentioned in anatomical studies for surgical purposes. [1][2][3][4][5][6][7][9][10][15][16] Since the aim of our study was practical usage, we used only conspicuous suture lines. The prevalence of this bone is highest in the lambdoid suture followed by posteriorly located sutures such as parieto-mastoid suture.…”

“…In order to maximize craniotomy size and to avoid inadvertent venous sinus injury, localization of this major venous sinus is crucial during planning for craniotomy. [1][2][3][4][5][6][7][8][9] Although the neuronavigation system is extremely useful nowadays, it is not generally available in a resource-limited public hospital or emergency situation. 2 As a result, anatomical landmarks are still important for neurosurgeons, especially when performing initial burr hole placement.…”

“…2 As a result, anatomical landmarks are still important for neurosurgeons, especially when performing initial burr hole placement. [1][2][3][4][5][6][7][8][9] The temporal bone is known for its complexity with various bony landmarkssuch Original Article SMJ as the squamosal suture, parietomastoid suture, and supramastoid crest. There has been controversy in previous anatomical studies regarding the best bony landmark of TSSJ in which the intersection between the squamosal and parietomastoid sutures and the intersection between the squamosal suture and supramastoid crest have been mentioned.…”

The Occipitalis Muscle as an Adjunct Superficial Landmark for the Transverse Sinus and Transverse-Sigmoid Junction: An Anatomical Study With Application to Posterior Cranial Fossa Surgery

“…Several studies have examined various superficial cranial landmarks for identifying deeper-lying dural venous sinuses [1][2][3]. In this study, we hypothesized that the OM might be a reliable superficial landmark for identifying the deeper-lying transverse sinus (TS) and transverse-sigmoid sinus junction (TSJ).…”