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Doniz-Gonzalez A, Vigo V, Nunez MA, Xu Y, Mohyeldin A, Cohen-Gadol AA, Fernandez-Miranda JC. Microsurgical anatomy and the importance of the petrosal process of the sphenoid bone in endonasal surgery. J Neurosurg 2022; 137:1431-1442. [PMID: 35276642 DOI: 10.3171/2021.12.jns212024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/16/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The petrosal process of the sphenoid bone (PPsb) is a relevant skull base osseous prominence present bilaterally that can be used as a key surgical landmark, especially for identifying the abducens nerve. The authors investigated the surgical anatomy of the PPsb, its relationship with adjacent neurovascular structures, and its practical application in endoscopic endonasal surgery. METHODS Twenty-one dried skulls were used to analyze the osseous anatomy of the PPsb. A total of 16 fixed silicone-injected postmortem heads were used to expose the PPsb through both endonasal and transcranial approaches. Dimensions and distances of the PPsb from the foramen lacerum (inferiorly) and top of the posterior clinoid process (PCP; superiorly) were measured. Moreover, anatomical variations and the relationship of the PPsb with the surrounding crucial structures were recorded. Three representative cases were selected to illustrate the clinical applications of the findings. RESULTS The PPsb presented as a triangular bony prominence, with its base medially adjacent to the dorsum sellae and its apex pointing posterolaterally toward the petrous apex. The mean width of the PPsb was 3.5 ± 1 mm, and the mean distances from the PPsb to the foramen lacerum and the PCP were 5 ± 1 and 11 ± 2.5 mm, respectively. The PPsb is anterior to the petroclival venous confluence, superomedial to the inferior petrosal sinus, and inferomedial to the superior petrosal sinus; constitutes the inferomedial limit of the cavernous sinus; and delimits the upper limit of the paraclival internal carotid artery (ICA) before the artery enters the cavernous sinus. The PPsb is anterior and medial to and below the sixth cranial nerve, forming the floor of Dorello's canal. During surgery, gentle mobilization of the paraclival ICA reveals the petrosal process, serving as an accurate landmark for the location of the abducens nerve. CONCLUSIONS This investigation revealed details of the microsurgical anatomy of the PPsb, its anatomical relationships, and its application as a surgical landmark for identifying the abducens nerve. This novel landmark may help in minimizing the risk of abducens nerve injury during transclival approaches, which extend laterally toward the petrous apex and cavernous sinus region.
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Affiliation(s)
- Ayoze Doniz-Gonzalez
- 1Department of Neurosurgery, Stanford Hospital, Stanford, California
- 2Department of Neurosurgery, Hospital Universitario de Canarias, La Laguna, Spain
| | - Vera Vigo
- 1Department of Neurosurgery, Stanford Hospital, Stanford, California
| | - Maximiliano Alberto Nunez
- 1Department of Neurosurgery, Stanford Hospital, Stanford, California
- 3Department of Neurosurgery, Hospital El Cruce, Buenos Aires, Argentina
| | - Yuanzhi Xu
- 1Department of Neurosurgery, Stanford Hospital, Stanford, California
- 4Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Ahmed Mohyeldin
- 1Department of Neurosurgery, Stanford Hospital, Stanford, California
| | - Aaron A Cohen-Gadol
- 5Department of Neurological Surgery, Indiana University, Indianapolis; and
- 6The Neurosurgical Atlas, Carmel, Indiana
| | - Juan C Fernandez-Miranda
- 1Department of Neurosurgery, Stanford Hospital, Stanford, California
- 6The Neurosurgical Atlas, Carmel, Indiana
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Kontzialis M, Ahmed AK, Gallia GL, Texalidis P, Aygun N, Blitz AM. High resolution 3D magnetic resonance imaging of Gruber's ligament: a pilot study. SURGICAL AND RADIOLOGIC ANATOMY : SRA 2022; 44:1157-1163. [PMID: 35909192 DOI: 10.1007/s00276-022-02996-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 07/20/2022] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Gruber's ligament (GL), a surgical landmark, extends from the lateral upper clivus to the petrous apex (PA), forming the superior boundary of Dorello's canal (DC). It overlies the interdural segment of the abducens nerve (CN VI). High-resolution 3D skull base MRI (SB-MRI) demonstrates anatomic details visible to the surgeon, but not well seen on traditional cross-sectional imaging. The aim of this study was to demonstrate visualization of the GL and its relationship to CN VI utilizing contrast enhanced high-resolution SB-MRI. METHODS Two neuroradiologists retrospectively reviewed in consensus the SB-MRIs of 27 skull base sides, among 14 patients. GL detection rate, confidence of detection, and GL length were recorded. When GL was successfully identified, the position of the interdural segment of CN VI within DC was recorded. RESULTS GL was readily identified in 16 skull base sides (59%), identified with some difficulty in 2 skull base sides (7%), and failed to be identified in 9 skull base sides (33%). The mean GL length was 7.1 mm (4.5-9.3 mm). Among the 18 cases where GL was successfully identified, CN VI was readily identified in all cases (100%), coursing the lateral third of DC in 72% of sides, and middle third in the remaining 28% of sides. CONCLUSION GL can be identified in approximately two-thirds of cases utilizing 3D high resolution SB-MRI. CN VI passes most commonly along the lateral third of DC. This is the first report demonstrating visualization of GL and its relation to CN VI, on imaging.
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Affiliation(s)
- Marinos Kontzialis
- Department of Radiology, Northwestern University Feinberg School of Medicine, 676 N St Clair Street, Chicago, IL, 60611, USA.
| | - A Karim Ahmed
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gary L Gallia
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Pavlos Texalidis
- Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Nafi Aygun
- Department of Diagnostic Imaging and Interventional Radiology, Moffitt Cancer Center, Tampa, FL, USA
| | - Ari M Blitz
- Department of Radiology, Case Western Reserve University School of Medicine University Hospitals, Cleveland, OH, USA
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Detailed imaging of abducens nerve anatomy using contrast-enhanced 3D-TOF MR angiography. Clin Imaging 2021; 79:330-336. [PMID: 34399289 DOI: 10.1016/j.clinimag.2021.07.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 11/21/2022]
Abstract
PURPOSE Cranial nerves (CNs), particularly CN IV and VI are difficult to visualize with conventional MRI techniques, particularly within the cavernous sinus region. The aim of this study was to evaluate the capacity of high-resolution contrast enhanced 3D time-of-flight (TOF) MR angiography using new generation 3 T imaging technology to provide detailed visualization of CN VI anatomy, particularly within the cavernous sinus and petroclival regions. METHODS Two neuroradiologists conducted bilateral evaluation of CN VI visibility in 23 patients for nerve segments located in the petroclival segment (dural cave and Dorello's canal), and three divisions of the cavernous sinus. All images were collected using contrast enhanced TOF MR angiography using a new generation 3 T machine. RESULTS Of the CN VI segments assessed, average visibility of CN VI was best achieved in Dorello's canal. Overall visibility of CN VI within the regions inspected was best achieved in the axial view, with the exception of the dural cave, which was best assessed using the coronal view. We also identified strong agreement in assessment of nerve visibility between the two reviewers. We also identified a putative CN6 duplication and a small schwannoma, highlighting the fidelity of our approach. CONCLUSION Contrast enhanced 3D TOF MR angiography can visualize CN VI anatomy, particularly within the petrocavernosal region and cavernous sinus with simultaneous visualization of arterial and venous structures. This cannot be easily achieved using traditional MRI techniques. This imaging technique might be used with new generation machines to evaluate CN VI anatomy and pathologies within the petrocavernosal region and cavernous sinus, especially relating to vascular pathologies.
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Wysiadecki G, Radek M, Tubbs RS, Iwanaga J, Walocha J, Brzeziński P, Polguj M. Gross and Micro-Anatomical Study of the Cavernous Segment of the Abducens Nerve and Its Relationships to Internal Carotid Plexus: Application to Skull Base Surgery. Brain Sci 2021; 11:brainsci11050649. [PMID: 34065668 PMCID: PMC8156379 DOI: 10.3390/brainsci11050649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/08/2021] [Accepted: 05/12/2021] [Indexed: 11/23/2022] Open
Abstract
The present study aims to provide detailed observations on the cavernous segment of the abducens nerve (AN), emphasizing anatomical variations and the relationships between the nerve and the internal carotid plexus. A total of 60 sides underwent gross-anatomical study. Five specimens of the AN were stained using Sihler’s method. An additional five specimens were subjected to histological examination. Four types of AN course were observed: a single nerve along its entire course, duplication of the nerve, division into separate rootlets at the point of contact with the cavernous part of the internal carotid artery (ICA), and early-branching before entering the orbit. Due to the relationships between the ICA and internal carotid plexus, the cavernous segment of the AN can be subdivided into a carotid portion located at the point of contact with the posterior vertical segment of the cavernous ICA and a prefissural portion. The carotid portion of the cavernous AN segment is a place of angulation, where the nerve always directly adheres to the ICA. The prefissural portion of the AN, in turn, is the primary site of fiber exchange between the internal carotid plexus and either the AN or the lateral wall of the cavernous sinus.
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Affiliation(s)
- Grzegorz Wysiadecki
- Department of Normal and Clinical Anatomy, Chair of Anatomy and Histology, Medical University of Lodz, ul. Żeligowskiego 7/9, 90-752 Łódź, Poland;
- Correspondence:
| | - Maciej Radek
- Department of Neurosurgery, Spine and Peripheral Nerve Surgery, Medical University of Lodz, University Hospital WAM-CSW, 90-549 Łódź, Poland;
| | - R. Shane Tubbs
- Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, LA 70112, USA; (R.S.T.); (J.I.)
- Department of Neurosurgery and Ochsner Neuroscience Institute, Ochsner Health System, New Orleans, LA 70433, USA
- Department of Neurology, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Department of Anatomical Sciences, St. George’s University, Grenada FZ 818, West Indies
- Department of Surgery, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Joe Iwanaga
- Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, LA 70112, USA; (R.S.T.); (J.I.)
- Department of Neurology, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Department of Anatomy, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
| | - Jerzy Walocha
- Department of Anatomy, Jagiellonian University Medical College, 33-332 Kraków, Poland;
| | - Piotr Brzeziński
- Department of Histology and Embryology, Chair of Anatomy and Histology, Medical University of Lodz, 90-752 Łódź, Poland;
| | - Michał Polguj
- Department of Normal and Clinical Anatomy, Chair of Anatomy and Histology, Medical University of Lodz, ul. Żeligowskiego 7/9, 90-752 Łódź, Poland;
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Sato M, Cho KH, Yamamoto M, Hirouchi H, Murakami G, Abe H, Abe S. Cavernous sinus and abducens nerve in human fetuses near term. Surg Radiol Anat 2020; 42:761-770. [PMID: 32112281 DOI: 10.1007/s00276-020-02443-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 02/10/2020] [Indexed: 11/30/2022]
Abstract
A long tortuous course of the abducens nerve (ABN) crossing a highly curved siphon of the internal carotid artery is of interest to neurosurgeons for cavernous sinus surgery. Although a "straight" intracavernous carotid artery in fetuses can change into an adult-like siphon in infants, there is no information on when or how the unique course of ABN is established. Histological observations of 18 near-term fetuses (12 specimens of frontal sections and 6 specimens of sagittal sections) demonstrated the following: (I) the ABN consistently took a straight course crossing the lateral side of an almost straight intracavernous carotid artery; (II) the straight course was maintained when sympathetic nerves joined; (III) few parasellar veins of the developing cavernous sinus separated the ABN from the ophthalmic nerve; and (IV) immediately before the developing tendinous annulus for a common origin of extraocular recti, the ABN bent laterally to avoid a passage of the thick oculomotor nerve. Since the present observations strongly suggested morphologies at birth and in infants, major angulations of the ABN as well as the well-known course independent of the other nerves in the cavernous sinus seemed to be established during childhood. In the human body, the ABN might be a limited example showing a drastic postnatal change in course. Consequently, it might be important to know the unique course of ABN before performing endovascular interventions and skull base surgery for petroclival and cavernous sinus lesions without causing inadvertent neurovascular injuries to neonates or infants.
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Affiliation(s)
- Minako Sato
- Department of Anatomy, Tokyo Dental College, Tokyo, Japan
| | - Kwang Ho Cho
- Department of Neurology, Wonkwang University School of Medicine and Hospital, Institute of Wonkwang Medical Science, 895, Muwang-ro, Iksan-si, Jeollabuk-do, 54538, Republic of Korea.
| | | | | | - Gen Murakami
- Department of Anatomy, Tokyo Dental College, Tokyo, Japan.,Division of Internal Medicine, Jikou-Kai Clinic of Home Visits, Sapporo, Japan
| | - Hiroshi Abe
- Department of Anatomy, Akita University School of Medicine, Akita, Japan
| | - Shinichi Abe
- Department of Anatomy, Tokyo Dental College, Tokyo, Japan
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Salaud C, Decante C, Ploteau S, Hamel A. Dural arteries of the dorsoclival area. Surg Radiol Anat 2019; 42:179-187. [DOI: 10.1007/s00276-019-02320-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/30/2019] [Indexed: 01/17/2023]
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