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anterior_transpetrosal_approach

Anterior transpetrosal approach

Anterior transpetrous approach (ATPA) is a less aggressive skull base approach and could provide sufficient exposure for the petroclival region and has additional advantages for a selected group of petroclival meningiomas (PCMs) 1).

Besides, there are also several disadvantages such as troublesome extradural bleeding and the risk of damaging facial nerve and internal carotid artery 2).

The anterior transpetrosal approach (ATPA) stands out as a method for granting entry into the upper and middle clival areas.

Identification and protection of the cochlea during anterior petrosectomy is key to prevent hearing loss. Currently, there is no optimal method to infer the position of the cochlea in relation to the Kawase quadrangle, therefore damage to the cochlea during anterior petrosectomy remains a substantial risk.

Anterior subtemporal and transpetrous apex approaches let us some exposure of deep region, however they require an unacceptable temporal lobe retraction and provide an extremely narrow surgical corridor in cases of large tumors mainly located in the infratentorial space 3) 4).

Indications

Anterior petrosectomy through the middle fossa is a well-described option for addressing cranial base lesions of the petroclival region.

An anterior transpetrosal approach (ATPA) is suitable for treating upper petroclival lesions. However, the limit of the ATPA is reached when the tumor extends posterolaterally over the internal auditory canal (IAC) along the petrous edge. In such cases, ligation of the posterior part of the superior petrosal sinus (SPS) is necessary. To overcome this limitation, Shibao et al. combined the ATPA with a partial posterior petrosectomy in 8 patients who had petroclival meningiomas extending posterolaterally over the IAC 5)

They are extensions of the basic middle fossa approach.

The middle fossa approaches spare the lateral petrous bone and involve resection of the medial petrous bone to various degrees. All of the middle fossa approaches are designed to preserve hearing. Extensions of the middle fossa approaches involve resection of bone within the Kawase triangle and division of the tentorium to provide exposure of the posterior fossa.

see Anterior transpetrosal transtentorial approach.


Borghei-Razavi et al. reviewed pre- and postoperative Multi-Slice CT scan (1mm thickness) of patients with petroclival meningioma between Jan 2009 and Sep 2013 in which anterior petrosectomy was performed to access the posterior fossa part of the tumor. The distances between drilling start and finish edge to the vital anatomical skull base structures such as internal auditory canal (IAC) and superior semicircular canal and petrous apex (petrous part of the carotid artery) were measured and analyzed.

Drilling entrance length is directly related with tumor size. The distances between anatomical structures and drilling points decrease with increasing tumor size, but it always remains a safe margin between drilling points and IAC, internal carotid artery (ICA), and semicircular canals in axial and coronal views.

The Kawase triangle is shown to be a safe anatomical landmark for anterior petrosectomy. The described landmarks avoid damage to the vital anatomical structures during access to the posterior fossa through middle fossa, despite temporal bone anatomical variations and different tumor sizes 6).

Complications

Identification and protection of the cochlea during anterior petrosectomy is key to prevent hearing loss. Currently, there is no optimal method to infer the position of the cochlea in relation to the Kawase quadrangle, therefore damage to the cochlea during anterior petrosectomy remains a substantial risk.

Kawase approach was simulated in eleven specimens. After a subtemporal approach, foramen spinosum and foramen ovale were identified. Anterior petrosectomy was performed and the upper dural transitional fold (UDTF) was identified. Two virtual lines, from foramen spinosum (Line A), and the lateral rim of the foramen ovale (Line B), were projected to intersect the UDTF perpendicularly. The cochlea was exposed and the distances between Lines A and B and the closest point of the outer rim and membranous part of the cochlea were measured.

The average distance between Line A to the bony and membranous edges of the anteromedial cochlea was -0.62±1.38 mm and 0.38±1.63 mm, respectively. The average distance between Line B to the bony and membranous edges of the cochlea was 1.82±0.99 mm and 2.78±1.29 mm, respectively. Line B (cochlear safety line) never intersected the cochlea.

The cochlear safety line is a reliable landmark to avoid the cochlea during the Kawase approach. When expanding the anterior petrosectomy posteriorly, the “cochlear safety line” may be used as a reliable landmark to prevent exposure of the cochlea, therefore preventing hearing loss 7).

Videos

Anterior Transpetrosal Approach for Resection of Recurrent Skull Base Chordoma: 3-Dimensional Operative Video 8).

1)
Ichimura S, Kawase T, Onozuka S, Yoshida K, Ohira T. Four subtypes of petroclival meningiomas: differences in symptoms and operative findings using the anterior transpetrosal approach. Acta Neurochir (Wien) 2008;150:637–645. doi: 10.1007/s00701-008-1586-x.
2)
Xiao X, Zhang L, Wu Z, Zhang J, Jia G, Tang J, Meng G. Surgical resection of large and giant petroclival meningiomas via a modified anterior transpetrous approach. Neurosurg Rev. 2013 Oct;36(4):587-93; discussion 593-4. doi: 10.1007/s10143-013-0484-8. Epub 2013 Jun 18. PubMed PMID: 23775013; PubMed Central PMCID: PMC3771372.
3)
Bambakidis NC, Gonzalez LF, Amin‐Hanjani S, et al: Combined skull base approaches to the posterior fossa. Technical note. Neurosurg Focus 19:E8, 2005
4)
Yang J, Ma SC, Fang T, et al: Subtemporal transpetrosal apex approach: study on its use in large and giant petroclival meningiomas. Chin Med J (Engl) 124:49‐55, 2011
5)
Shibao S, Borghei-Razavi H, Orii M, Yoshida K. Anterior Transpetrosal Approach Combined with Partial Posterior Petrosectomy for Petroclival Meningiomas with Posterior Extension. World Neurosurg. 2015 Apr 1. pii: S1878-8750(15)00350-2. doi: 10.1016/j.wneu.2015.03.055. [Epub ahead of print] PubMed PMID: 25841755.
6)
Borghei-Razavi H, Tomio R, Fereshtehnejad SM, Shibao S, Schick U, Toda M, Kawase T, Yoshida K. Anterior petrosal approach: The safety of Kawase triangle as an anatomical landmark for anterior petrosectomy in petroclival meningiomas. Clin Neurol Neurosurg. 2015 Oct 28;139:282-287. doi: 10.1016/j.clineuro.2015.10.032. [Epub ahead of print] PubMed PMID: 26552034.
7)
Guo X, Tabani H, Griswold D, Tayebi Meybodi A, Sanchez JJ, Lawton MT, Benet A. Hearing Preservation During Anterior Petrosectomy: the “Cochlear Safety Line”. World Neurosurg. 2016 Nov 29. pii: S1878-8750(16)31163-9. doi: 10.1016/j.wneu.2016.11.019. [Epub ahead of print] PubMed PMID: 27913265.
8)
Chabot JD, Gardner P, Fernandez-Miranda JC. Anterior Transpetrosal Approach for Resection of Recurrent Skull Base Chordoma: 3-Dimensional Operative Video. Neurosurgery. 2015 Jun 16. [Epub ahead of print] PubMed PMID: 26083158.
anterior_transpetrosal_approach.txt · Last modified: 2017/06/06 12:31 by administrador