Intradural anterior petrosectomy for petroclival meningiomas: a new surgical technique and results in 5 patients

Technical note

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Excision of petroclival meningiomas remains a surgical challenge. Extradural anterior petrosectomy is widely used as a skull base approach for these tumors; however, this approach has significant procedure-related morbidity. The authors describe an alternative technique of tailored intradural petrosectomy for removal of petroclival meningiomas. This technique was used successfully in 5 patients. Gross-total or near-total resection was possible in 2 patients, whereas a subtotal removal was achieved in 3 patients, without significant morbidity. The petrous drilling was tailored depending on the extent of tumor. Transsylvian intradural anterior petrosectomy is a safe approach for petroclival meningiomas. This approach avoids problems related to subtemporal retraction and rationalizes the degree of bone drilling.

Abbreviations used in this paper:FTOZ = frontotemporoorbitozygomatic; GSPN = greater superficial petrosal nerve; IAM = internal acoustic meatus; ICA = internal carotid artery; MCA = middle cerebral artery; PCA = posterior cerebral artery; PCoA = posterior communicating artery; SCA = superior cerebellar artery.

Article Information

Address correspondence to: Sunil K. Gupta, M.Ch., Department of Neurosurgery, Postgraduate Institute for Medical Education and Research, Sector 12, Chandigarh 160012, India. email:

Please include this information when citing this paper: published online October 5, 2012; DOI: 10.3171/2012.9.JNS12429.

© AANS, except where prohibited by US copyright law.



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    Drawing and operative specimen showing the outline of the craniotomy and the single FTOZ bone flap.

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    Stepwise illustrations of the intradural petrosectomy approach. A: Wide opening of the sylvian fissure with visualization of the optic nerve, ICA (IC), and tentorial edge (black arrow pointing down). The frontal lobe, temporal lobe, and the sphenoparietal veins (black arrow pointing to the right) are shown. B: Division of the sphenoparietal veins (black arrow pointing to the right) as well as opening of the sylvian fissure (black arrow pointing down designates the tentorial edge) allows the temporal lobe to fall posteriorly and away from the middle fossa floor, with visualization of the third cranial nerve and the tumor. C: The tentorium is incised behind the entry of the fourth cranial nerve. The petrous bone and the gasserian ganglion are exposed. D: The final view after intradural partial anterior petrosectomy and tumor removal. The seventh and eighth cranial nerves are seen entering the IAM after the bone has been drilled and the dura along the posterior surface of the petrous bone has been sectioned. The sixth cranial nerve is also seen entering the Dorello canal. BS = brainstem; F = frontal lobe; GG = gasserian ganglion; O = optic nerve; P = petrous bone; T = temporal lobe; t = tumor; 3, 4, 6, 7–8 = third, fourth, sixth, and seventh–eighth cranial nerves.

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    Intraoperative photographs. A: Retractors supporting the frontal (Fr) and temporal (Tp) lobes after sylvian fissure opening, with the severely stretched third cranial nerve over the tumor. The tentorial edge (white arrow) and the middle fossa floor are clearly visualized. B: The tentorial edge has been cut and the tumor is being decompressed between the third, fourth, and fifth (5) cranial nerves. C: Further tumor excision below the tentorium, with visualization of the PCoA (P.Com) and SCA. D: Coagulation of dura over the petrous bone and exposure of the gasserian ganglion. E and F: Anterior petrosectomy lateral to the gasserian ganglion, with progressive tumor removal. See legend to Fig. 2 for definitions of abbreviations.

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    Cadaveric dissection demonstrating intradural petrosectomy. A: After incising the tentorial edge (black arrow), the dura over the petrous bone has been stripped, exposing the gasserian ganglion in the Meckel cave (white arrow designates the ICA). B: The petrous bone just lateral to the lateral edge of the gasserian ganglion has been drilled in a posterior direction approximately 5–6 mm lateral to the lateral edge. The dura (D) along the posterior surface of the drilled petrous bone is visible. The black and white arrows in the upper part of the panel are as defined in panel A, with the addition of a white arrow in the lower part of the panel designating the petrous bone. C: After cutting the dura, the seventh–eighth cranial nerve complex is visible entering the IAM at the lateral edge of the drilled bone. D: The gasserian ganglion has been sectioned and the petrous bone up to the apex has been drilled, exposing the position of the ICA in the carotid canal. This ICA was visible after the petrous bone under the anterior part of the gasserian ganglion was drilled. The sixth cranial nerve is visible. See legend to Fig. 2 for definitions of abbreviations.

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    Photograph showing measurements on a human skull that demonstrate the horizontal separation between the lateral edge of the gasserian ganglion (point A) at the level of petrous ridge and a perpendicular projection of the medial edge of the IAM on the petrous ridge (point B).

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    Case 3. Preoperative (left) and postoperative (right) CT scans showing total excision of a petroclival meningioma.

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    Case 5. Preoperative MRI studies (A and B) obtained in a patient with a large petroclival meningioma, with postoperative CT scans (C and D) showing subtotal excision. The arrow designates the partial intradural petrosectomy.



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