Rare case of bilateral petrous apex cephalocele

The petrous apex is a pyramidal-shaped structure which is difficult to examine due to difficult anatomical location. Lesions in the petrous apex can be managed surgically or they can be incidental lesions, which are managed conservatively. Petrous apex cephaloceles (PAC) are the cystic lesion due to herniation in the Meckel’s cave of temporal bone. Bilateral PAC is a very rare phenomenon with only 21 cases reported in the literature so far. We present here a case of bilateral PAC, who presented with headache and was managed conservatively.

Download Full-text

Microsurgical Anatomy of the Endoscopy-Assisted Retrosigmoid Intradural Suprameatal Approach to the Meckel's Cave

Operative Neurosurgery ◽

10.1093/ons/opab096 ◽

2021 ◽

Author(s):

Yuanzhi Xu ◽

Benjamin K Hendricks ◽

Maximiliano Alberto Nunez ◽

Ahmed Mohyeldin ◽

Juan C Fernandez-Miranda ◽

...

Keyword(s):

Carotid Artery ◽

Internal Carotid Artery ◽

Internal Carotid ◽

Internal Auditory Canal ◽

Semicircular Canals ◽

Petrous Apex ◽

Microsurgical Anatomy ◽

Meckel’S Cave ◽

Meckel's Cave ◽

Trigeminal Root

Abstract BACKGROUND Understanding the microsurgical anatomical features of the endoscopy-assisted retrosigmoid intradural suprameatal approach (RISA) is critical for surgeons treating petroclival tumors or lesions in the cerebellopontine region that extend into Meckel's cave. OBJECTIVE To evaluate increased exposure for Meckel's cave in the RISA and assess the surgical landmarks for this approach. METHODS A standard retrosigmoid craniotomy to the cerebellopontine region was performed in 4 cadaveric specimens (8 hemispheres) with microscope-assisted endoscopy. The length and depth of the drilling region from the suprameatal tubercle to the petrous apex were analyzed. After opening Meckel's cave and mobilizing the trigeminal root completely, the landmarks for this approach were investigated. RESULTS The endoscopy-assisted RISA facilitates mobilization of the trigeminal root and enhances surgical exposure in the region of Meckel's cave and the petrous apex with increases of 10.1 ± 1.3 mm in depth, 21.4 ± 3.2 mm in length, and 6.4 ± 0.6 mm in height. The posterior and superior semicircular canals, internal auditory canal, superior petrous sinus, and internal carotid artery (petrous segment) served as important landmarks for this approach. One case illustration is presented to describe the application of this approach. CONCLUSION The RISA is suitable mainly for lesions in the posterior fossa that extend into Meckel's cave. The endoscopy-assisted reach optimizes accessibility to the petrous apex region, obviates the need for extensive drilling, and decreases the risk of internal carotid artery injury. Better realization and recognition of microsurgical landmarks and parameters of this approach are crucial for successful outcomes.

Download Full-text

Microsurgical Resection of a Petroclival Epidermoid Cyst Using an Anterior Petrosectomy Approach: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opab364 ◽

2021 ◽

Author(s):

Kunal V Vakharia ◽

Ryan M Naylor ◽

Ashley M Nassiri ◽

Colin L W Driscoll ◽

Michael J Link

Keyword(s):

Epidermoid Cyst ◽

Cranial Nerves ◽

Residual Tumor ◽

Middle Meningeal Artery ◽

Neural Tube Closure ◽

Petrous Apex ◽

Meckel’S Cave ◽

Postoperative Mri ◽

Meckel's Cave ◽

Anterior Petrosectomy

Abstract Epidermoid cysts are rare, benign lesions that result from inclusion of ectodermal elements during neural tube closure.1 Cysts are composed of desquamated epithelial cells and restrict diffusion on magnetic resonance imaging (MRI).2,3 Symptoms are attributable to anatomic location.4,5 In this video, we illustrate the surgical treatment of an epidermoid cyst located in the right cerebellopontine angle, petrous apex, and Meckel's cave. The patient, a 33-yr-old female with right-sided V1 trigeminal hypoesthesia, underwent surveillance imaging for 2 yr. However, she developed progressive V1 and V2 trigeminal hypoesthesia and imaging revealed enlargement of the lesion. Therefore, surgical resection was pursued. The patient consented to the procedure. The patient underwent a right middle fossa craniotomy and anterior petrosectomy. After identifying the greater superficial petrosal nerve and cutting the middle meningeal artery as it exited foramen spinosum, Kawase's triangle was drilled, and the dura over Meckel's cave and the subtemporal dura were opened. The lesion was resected, taking care to preserve the trigeminal nerve and the basilar artery. A retrosigmoid craniotomy was then fashioned. The cyst and its capsule were dissected off the brainstem and cranial nerves utilizing natural corridors between the trigeminal and vestibulocochlear nerves as well as between the facial and lower cranial nerves. Gross total resection was confirmed on postoperative MRI, and she was discharged home on postoperative day 5. Three months after surgery, she underwent formal pinprick testing, which revealed 95% loss of sensation in V1, 20% loss in V2, and normal sensation in V3. Three-month postoperative MRI showed no residual tumor.

Download Full-text

Combined Petrosal Approach for Resection of a Large Trigeminal Schwannoma With Meckel's Cave Involvement—Part I: Anatomic Rationale and Analysis: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opaa363 ◽

2020 ◽

Author(s):

Ali Tayebi Meybodi ◽

James K Liu

Keyword(s):

Cerebellopontine Angle ◽

Skin Incision ◽

Petrous Apex ◽

Successful Management ◽

Meckel’S Cave ◽

Trigeminal Schwannoma ◽

Skull Base Approach ◽

Meckel's Cave ◽

History Of ◽

Anterior Petrosectomy

Abstract Resection of large trigeminal schwannomas involving both posterior and middle cranial fossae is challenging. The depth of the surgical target in the superomedial corner of the cerebellopontine angle and the petrous apex makes for a difficult lesion to favorably access, expose, and safely resect. Judicious planning of a skull base approach is therefore the most crucial step in successful management of these formidable tumors. When properly chosen, planned, and executed, the combined petrosal approach sets the stage for an optimal exposure of such tumors that involve both posterior and middle cranial fossae. The present video is the first of a 2-part video presentation that explains the anatomic rationale of selecting a combined petrosal approach (anterior petrosectomy and retrolabyrinthine petrosectomy) for the resection of a large trigeminal schwannoma involving the posterior and middle cranial fossae with an extension into Meckel's cave in a 54-yr-old female presenting with 5-yr history of increasing headaches, left-sided face numbness, and disequilibrium. The benefits, risks, and alternatives of the surgical procedure were discussed in detail with the patient and she consented to proceed with surgery. Part I also discusses the important nuances of positioning the patient, as well as planning and execution of the skin incision, including pericranial flap harvesting. Of note, the patient consented to the publication of images obtained from her.

Download Full-text

The Subtemporal Interdural Approach to Dumbbell-Shaped Trigeminal Schwannomas: Cadaveric Prosection

Operative Neurosurgery ◽

10.1227/01.neu.0000227590.70254.02 ◽

2006 ◽

Vol 59 (suppl_4) ◽

pp. ONS-270-ONS-278 ◽

Cited By ~ 9

Author(s):

Samy Youssef ◽

Eun-Young Kim ◽

Khaled M.A. Aziz ◽

Salah Hemida ◽

Jeffrey T. Keller ◽

...

Keyword(s):

Cleavage Plane ◽

Histological Study ◽

Petrous Apex ◽

Gasserian Ganglion ◽

Middle Fossa ◽

Meckel’S Cave ◽

Anterior Transpetrosal Approach ◽

Single Compartment ◽

Meckel's Cave ◽

Superior Petrosal Sinus

Abstract OBJECTIVE: Successful resection of dumbbell-shaped trigeminal schwannomas via a subtemporal interdural approach requires an understanding of both the anatomy related to the bone dissection of the petrous apex (Kawase's triangle or quadrilateral) and meningeal anatomy. We studied the meningeal anatomy related to this approach and describe the dural incisions and stepwise mobilization. METHODS: Meningeal anatomy around Meckel's cave and porus trigeminus was examined during the subtemporal interdural anterior transpetrosal approach in both sides of 15 cadaveric heads. Histological study of the Meckel's cave region was performed in two cadaveric heads. RESULTS: The Gasserian ganglion and trigeminal roots have two layers of dura propria on their dorsolateral surface: an inner layer from the posterior fossa dura propria that constitutes the dorsolateral wall of Meckel's cave and an outer layer from the dura propria of the middle fossa. The cleavage plane between these two layers continues distally as the cleavage plane between the epineural sheaths of the trigeminal divisions and the dura propria of the middle fossa. This cleavage plane serves as the anatomic landmark for the interdural exposure of the contents of Meckel's cave. The superior petrosal sinus is sectioned at the medial aspect of Kawase's triangle and reflected along with the porus trigeminus roof. CONCLUSION: Understanding the critical meningeal architecture in and around Meckel's cave allows experienced cranial neurosurgeons to develop a subtemporal interdural approach to dumbbell-shaped trigeminal schwannomas that effectively converts a multiple-compartment tumor into a single-compartment tumor. Dural incisions and stepwise mobilization complements our previous description of the bony dissection for this approach.

Download Full-text

Paratrigeminal, Paraclival, Precavernous, or All of the Above? A Circumferential Anatomical Study of the C3-C4 Transitional Segment of the Internal Carotid Artery

Operative Neurosurgery ◽

10.1093/ons/opx121 ◽

2017 ◽

Vol 14 (4) ◽

pp. 432-440 ◽

Cited By ~ 2

Author(s):

Eleonora Marcati ◽

Norberto Andaluz ◽

Sebastien C Froelich ◽

Lee A Zimmer ◽

James L Leach ◽

...

Keyword(s):

Carotid Artery ◽

Internal Carotid Artery ◽

Cavernous Sinus ◽

Internal Carotid ◽

Anatomical Study ◽

Posterior Longitudinal Ligament ◽

Petrous Apex ◽

Meckel’S Cave ◽

Endoscopic Endonasal ◽

Meckel's Cave

Abstract BACKGROUND Although the term paraclival carotid pervades recent skull base literature, no clear consensus exists regarding boundaries or anatomical segments. OBJECTIVE To reconcile various internal carotid artery (ICA) nomenclatures for transcranial and endoscopic-endonasal perspectives, we reexamined the transition between lacerum (C3) and cavernous (C4) segments using a C1-C7 segments schema. In this cadaveric study, we obtained a 360°-circumferential view integrating histological, microsurgical, endoscopic, and neuroradiological analyses of this C3-C4 region and identified a distinct transitional segment. METHODS In 13 adult, silicone-injected, formalin-fixed cadaveric heads (26 sides), transcranial-extradural-subtemporal and endoscopic-endonasal CTguided dissections were performed. A quadrilateral area was noted medial to Meckel's cave between cranial nerve VI, anterolateral and posterolateral borders of the lateral-paratrigeminal aspect of the precavernous ICA, and posterior longitudinal ligament. Endoscopically, a medial-paraclival aspect was defined. Anatomical correlations were made with histological and neuroradiological slides. RESULTS We identified a distinct precavernous C3-C4 transitional segment. In 18 (69%) specimens, venous channels were absent at the quadrilateral area, on the paratrigeminal border of the precavernous ICA. A trigeminal membrane, seen consistently on the superior border of V2, defined the lateral aspect of the cavernous sinus floor. The medial aspect of the precavernous ICA corresponded with the paraclival ICA. CONCLUSION Our study revealing the juncture of 2 complementary borders of the ICA, endoscopic endonasal (paraclival) and transcranial (paratrigeminal), reconciles various nomenclature. A precavernous segment may clarify controversies about the paraclival ICA and support the concept of a “safe door” for lesions involving Meckel's cave, cavernous sinus, and petrous apex.

Download Full-text

Endoscopic Management of a Rare Case of Nasal Glioma in Meckel's Cave in an Adult: Case Report

min - Minimally Invasive Neurosurgery ◽

10.1055/s-0030-1262812 ◽

2010 ◽

Vol 53 (04) ◽

pp. 191-193 ◽

Cited By ~ 3

Author(s):

M. K. Kasliwal ◽

V. K. Anand ◽

E. Lavi ◽

T. H. Schwartz

Keyword(s):

Case Report ◽

Rare Case ◽

Endoscopic Management ◽

Adult Case ◽

Meckel’S Cave ◽

Nasal Glioma ◽

Meckel's Cave

Download Full-text

Petrous Apex Meningioma with Extension into Meckel's Cave: Resection using a Retrosigmoid Intradural Suprameatal Approach

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0038-1676996 ◽

2019 ◽

Vol 80 (S 03) ◽

pp. S300-S301

Author(s):

Stephan A. Munich ◽

Jacques J. Morcos

Keyword(s):

Trigeminal Nerve ◽

Retrosigmoid Approach ◽

Petrous Apex ◽

Middle Fossa ◽

Meckel’S Cave ◽

Meckel's Cave ◽

Grade Ii

The retrosigmoid intradural suprameatal approach was first introduced in 1983 by Samii et al, as a modification of the classic retrosigmoid approach intended to open Meckel's cave, exposing the trigeminal nerve and access the middle fossa.1 The area of bone resected in this approach is similar to that removed in a Kawase's approach.2 Whereas the direction of drilling in a Kawase's approach is from anterior and superior, it is from posterior and inferior in the retrosigmoid intradural suprameatal approach. Seoane and Rhoton quantified the exposure of Meckel's cave, finding that this approach allowed access, on average, to the posterior 10.3 mm of Meckel's cave.3 This was confirmed by Chanda and Nanda who found that suprameatal drilling resulted in a mean gain of exposure of the trigeminal nerve of 10.7 mm.4 In this video, we present the case of a patient when an enlarging petrous apex meningioma with extension into Meckel's cave (Fig. 1). The patient underwent a retrosigmoid intradural suprameatal approach to achieve a Simpson's grade II resection. This approach was ideally suited for this case to obtain access to tumor located at the petrous apex and within Meckel's cave (Fig. 2). Without access to Meckel's cave provided in this approach a significant portion of tumor would have remained in situ.The link to the video can be found at: https://youtu.be/eNldkF4a_OI.

Download Full-text

Retrosigmoid Intradural Suprameatal Approach: Advantages and Disadvantages from an Anatomical Perspective

Operative Neurosurgery ◽

10.1227/01.neu.0000220673.79877.30 ◽

2006 ◽

Vol 59 (suppl_1) ◽

pp. ONS-1-ONS-6 ◽

Cited By ~ 9

Author(s):

Amitabha Chanda ◽

Anil Nanda

Keyword(s):

Trigeminal Nerve ◽

Internal Auditory Canal ◽

Semicircular Canals ◽

Petrous Apex ◽

Microsurgical Anatomy ◽

Meckel’S Cave ◽

Advantages And Disadvantages ◽

Meckel's Cave ◽

Trigeminal Root ◽

Neurovascular Structures

Abstract OBJECTIVE: To assess the advantages and disadvantages of the retrosigmoid intradural suprameatal approach by studying the microsurgical anatomy. This study was performed primarily to assess the advantages of the retrosigmoid intradural suprameatal approach by measuring the amount of increased exposure it provides for lesions of the cerebellopontine and petroclival region as well as to identify the disadvantages of the approach. METHODS: Twenty sides of 10 cadaver heads (embalmed and injected) were dissected under ×3 to ×40 magnification. A standard retrosigmoid craniotomy was made. The cerebellopontine cistern was entered to expose the neurovascular structures, and the internal auditory canal was opened by drilling the margin of the internal auditory meatus. After this, the suprameatal tubercle was drilled, followed by additional drilling to resect the petrous apex. The trigeminal root was mobilized completely after opening Meckel's cave. During drilling, care was taken to preserve the posterior and superior semicircular canals, petrosal sinus, and the internal carotid artery. RESULTS: The approach enhanced the exposure of the cerebellopontine cistern and Meckel's cave. There was an additional exposure of 10.7 ± 1.16 mm length of trigeminal nerve on the right side and an additional 10.7 ± 1.25 mm on the left. This helped to mobilize and further retract the trigeminal root. Although it facilitated the view of the neurovascular structures medial to the internal acoustic meatus, the depth of exposure did not vary much from a traditional retrosigmoid approach nor did it increase the angle of exposure or the visualization of the clivus and more medially located structures. CONCLUSION: This approach is suitable for lesions mainly in the posterior fossa with some extension into the middle fossa in the anterolateral direction. The key benefits of this approach are the length of trigeminal nerve exposure and the subsequent mobilization that improves visualization of the structures medial to the internal auditory canal, to the petrous apex, Meckel's cave, and the posterior end of the cavernous sinus.

Download Full-text