1
|
Rotenstreich L, Eran A, Siegler Y, Grossman R, Edery N, Cohen R, Marom A. Unveiling the vulnerability of the human abducens nerve: insights from comparative cranial base anatomy in mammals and primates. Front Neuroanat 2024; 18:1383126. [PMID: 38741761 PMCID: PMC11089250 DOI: 10.3389/fnana.2024.1383126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 04/11/2024] [Indexed: 05/16/2024] Open
Abstract
The topographic anatomy of the abducens nerve has been the subject of research for more than 150 years. Although its vulnerability was initially attributed to its length, this hypothesis has largely lost prominence. Instead, attention has shifted toward its intricate anatomical relations along the cranial base. Contrary to the extensive anatomical and neurosurgical literature on abducens nerve anatomy in humans, its complex anatomy in other species has received less emphasis. The main question addressed here is why the human abducens nerve is predisposed to injury. Specifically, we aim to perform a comparative analysis of the basicranial pathway of the abducens nerve in mammals and primates. Our hypothesis links its vulnerability to cranial base flexion, particularly around the sphenooccipital synchondrosis. We examined the abducens nerve pathway in various mammals, including primates, humans (N = 40; 60% males; 40% females), and human fetuses (N = 5; 60% males; 40% females). The findings are presented at both the macroscopic and histological levels. To associate our findings with basicranial flexion, we measured the cranial base angles in the species included in this study and compared them to data in the available literature. Our findings show that the primitive state of the abducens nerve pathway follows a nearly flat (unflexed) cranial base from the pontomedullary sulcus to the superior orbital fissure. Only the gulfar segment, where the nerve passes through Dorello's canal, demonstrates some degree of variation. We present evidence indicating that the derived state of the abducens pathway, which is most pronounced in humans from an early stage of development, is characterized by following the significantly more flexed basicranium. Overall, the present study elucidates the evolutionary basis for the vulnerability of the abducens nerve, especially within its gulfar and cavernous segments, which are situated at the main synchondroses between the anterior, middle, and posterior cranial fossae-a unique anatomical relation exclusive to the abducens nerve. The principal differences between the pathways of this nerve and those of other cranial nerves are discussed. The findings suggest that the highly flexed human cranial base plays a pivotal role in the intricate anatomical relations and resulting vulnerability of the abducens nerve.
Collapse
Affiliation(s)
- Liat Rotenstreich
- Laboratory for Anatomy and Human Evolution, The Farkas Family Center for Anatomical Research and Education, Rappaport Faculty of Medicine, Department of Neuroscience, Technion – Israel Institute of Technology, Haifa, Israel
| | - Ayelet Eran
- Laboratory for Anatomy and Human Evolution, The Farkas Family Center for Anatomical Research and Education, Rappaport Faculty of Medicine, Department of Neuroscience, Technion – Israel Institute of Technology, Haifa, Israel
- Neuroradiology Unit, Department of Radiology, Rambam Medical Center, Haifa, Israel
| | - Yoav Siegler
- Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel
| | - Rachel Grossman
- Department of Neurosurgery, Rambam Medical Center, Haifa, Israel
| | - Nir Edery
- Department of Pathology, Kimron Veterinary Institute, Bet Dagan, Israel
| | - Roni Cohen
- Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Assaf Marom
- Laboratory for Anatomy and Human Evolution, The Farkas Family Center for Anatomical Research and Education, Rappaport Faculty of Medicine, Department of Neuroscience, Technion – Israel Institute of Technology, Haifa, Israel
| |
Collapse
|
2
|
Ekanem UOI, Chaiyamoon A, Cardona JJ, Berry JF, Wysiadecki G, Walocha JA, Iwanaga J, Dumont AS, Tubbs RS. Prevalence, Laterality, and Classification of Ossified Petroclival Ligaments: An Anatomical and Histological Study With Application to Skull Base Surgery. Cureus 2023; 15:e36469. [PMID: 37090401 PMCID: PMC10117410 DOI: 10.7759/cureus.36469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2023] [Indexed: 04/25/2023] Open
Abstract
Background The petroclival ligament (PL) forms the roof of Dorello's canal (DC). In humans, partial and complete ossification of this ligament have been reported. When completely ossified, DC is transformed into a bony foramen for the abducens nerve and accompanying vascular structures. As this osteological finding might have an impact on skull base surgery, this anatomical study was performed. Methodology Using 100 adult human skulls, the presence of an ossified PL was noted and classified. The diameter of the resultant bony foramen and laterality were documented. Additionally, PL was evaluated histologically in 10 heads. Results Overall, 8% of the sides were found to have partial or complete ossification of the PL. Partial ossification (type I) was noted on 3% of the sides. Completely ossified PL was identified on 5% of the sides. Some ossified ligaments (2.5%) were seen as an ossified bridge (type II), and others (2.5%) were converted into small foramina (type III). Three skulls (3%) were found to have a completely ossified ligament bilaterally. The mean diameter of the underlying DC was 0.8 mm. Partially ossified ligaments were statistically more likely to be on the right sides, and the diameter of the underlying DC was statistically smaller in type III. Histologically, the PL was found to have bone within it on three skull sides. Conclusions An ossified ligament can be found on imaging of the skull base. Moreover, during surgical approaches to the petroclival region and, specifically, DC, skull base surgeons should be cognizant of this anatomical variation.
Collapse
Affiliation(s)
| | - Arada Chaiyamoon
- Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, THA
| | - Juan J Cardona
- Department of Neurosurgery, Tulane University School of Medicine, New Orleans, USA
| | - J Franklin Berry
- Department of Neurosurgery, Tulane University School of Medicine, New Orleans, USA
| | - Grzegorz Wysiadecki
- Department of Anatomy and Histology, Medical University of Poland, Lodz, POL
| | - Jerzy A Walocha
- Department of Anatomy, Jagiellonian University Medical College, Krakow, POL
| | - Joe Iwanaga
- Department of Neurosurgery, Tulane University School of Medicine, New Orleans, USA
| | - Aaron S Dumont
- Department of Neurosurgery, Tulane University School of Medicine, New Orleans, USA
| | - R Shane Tubbs
- Department of Anatomical Sciences, St. George's University, St. George's, GRD
- Department of Neurosurgery and Structural & Cellular Biology, Tulane University School of Medicine, New Orleans, USA
- Neurosurgery and Ochsner Neuroscience Institute, Ochsner Health System, New Orleans, USA
| |
Collapse
|
3
|
Karapinar BO, Warille AA, Baş O, Emirzeoğlu M, Bilgiç S. An atypical anatomical variation of the petrosphenoidal ligament in a newborn cadaver. SURGICAL AND RADIOLOGIC ANATOMY : SRA 2023; 45:137-141. [PMID: 36592185 DOI: 10.1007/s00276-022-03072-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 12/23/2022] [Indexed: 01/03/2023]
Abstract
PURPOSE To report an atypical anatomical variation of the petrosphenoidal ligament in a newborn cadaver and to discuss its clinical significance. METHODS During a study of ten newborn cadavers, the skull base was dissected to reveal the anatomy of the petrosphenoidal ligament and its relationship with the abducens nerve. An atypical anatomical variation was observed, and this is described. The length of the right and left ligaments to the point where it splits into two arms, the joint length of the two ligaments at the junction of the clivus, the length of the ligament proceeding to the posterior clinoid process, and the abducens nerve's diameter as it passes below the ligament were measured on ImageJ software. RESULTS The petrosphenoidal ligaments were y-shaped, and the attachment of the proximal ligaments was bifid. In the midline above the clivus, some ligament bundles joined the contralateral petrosphenoidal ligament, whilst another group of bundles originated at the posterior clinoid process. At the entry to Dorello's canal, the abducens nerve had a diameter of 0.59 mm on the left and 0.65 mm on the right. The part of the ligaments converging on the clivus in the midline after dividing into two arms was 10.68 mm. CONCLUSIONS We think that this case report will provide useful information for surgical procedures to the petroclival region, transnasal surgical approaches, and surgical interventions involving the carotid artery.
Collapse
Affiliation(s)
- Burak Oğuzhan Karapinar
- Department of Medical Services and Techniques, Ondokuz Mayıs University Health Services of Vocational School, Samsun, Turkey.
| | - Aymen A Warille
- Department of Anatomy, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Orhan Baş
- Department of Anatomy, Faculty of Medicine, Samsun University, Samsun, Turkey
| | - Mehmet Emirzeoğlu
- Department of Anatomy, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Sait Bilgiç
- Department of Anatomy, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| |
Collapse
|
4
|
Clarke E, Golberg M, Smędra A, Mazur M, Mazurek A, Balawender K, Barszcz K, Żytkowski A. Bilateral caroticoclinoid foramen and unilateral abducens nerve canal found on the fetal skull – Case report. TRANSLATIONAL RESEARCH IN ANATOMY 2022. [DOI: 10.1016/j.tria.2022.100224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
5
|
Leonel LCPC, Rezende NC, Alexander AY, Agosti E, Rush D, Kenning TJ, Link MJ, Pinheiro-Neto CD, Peris-Celda M. The Lingual Process of the Sphenoid Bone and the Petrolingual Ligament: Surgical Anatomy, Landmarks, and Clinical Relevance. Oper Neurosurg (Hagerstown) 2022; 23:e360-e368. [DOI: 10.1227/ons.0000000000000407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/29/2022] [Indexed: 11/06/2022] Open
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
The effect of morphological variability of Dorello's canal on surgical procedures - a review. Ann Anat 2022; 243:151939. [PMID: 35378252 DOI: 10.1016/j.aanat.2022.151939] [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: 11/04/2021] [Revised: 03/26/2022] [Accepted: 03/27/2022] [Indexed: 11/22/2022]
Abstract
Dorello's canal is an arched structure of bone-fibrous character located in the petroclival venous confluence atop the petrosal bone in the petroclival region. It is bordered by the petrosphenoidal ligament, the petrous part of the temporal bone and the lateral border of the upper part of clivus. Its content in the vast majority of variants comprises the abducens nerve, the inferior petrosal sinus, the venous drainage and the dorsal meningeal artery or its medial branch. With the development of microsurgical techniques, this area has gained huge clinical importance, mainly concerning the order in which the above-mentioned elements (especially the position of the abducens nerve) are arranged in relation to each other. These structures appear in different variant forms and necessitate an individual clinical approach. The main purpose of this review is to present condensed information about possible intercorrelations among them and to indicate, on the basis of the available literature and research, possible surgical approaches and the need to consider the variability when treatments in this region are planned.
Collapse
|
8
|
Abstract
An ossified left petroclinoid ligament was found during routine dissection of the skull base in an adult male cadaver. The petroclinoid ligament is clinically and surgically important given its anatomical relationships to cranial nerves III, V, and VI, so its ossification is a risk factor for injuries due to trauma, increased intracranial pressure, and vascular and tumor compression resulting in abducens and oculomotor palsies. The causes of petroclinoid ligament ossification are yet to be completely elucidated although several reports have associated them with age-related and physiological processes. Assessing the integrity of the petroclinoid ligament is important during skull base surgical interventions to avoid postoperative complications. Therefore, this paper reviews the petroclinoid ligament and its variation, the ossified petroclinoid ligament.
Collapse
Affiliation(s)
| | - Pervez A Khan
- Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine
| | - Joe Iwanaga
- Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine.,Division of Gross and Clinical Anatomy, Department of Anatomy, Kurume University School of Medicine
| | - Aaron S Dumont
- Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine
| | - R Shane Tubbs
- Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine.,Department of Structural & Cellular Biology, Tulane University School of Medicine.,Department of Neurosurgery, Ochsner Health System.,Department of Anatomical Sciences, St. George's University
| |
Collapse
|
9
|
Iwanaga J, Altafulla JJ, Gutierrez S, Dupont G, Watanabe K, Litvack Z, Tubbs RS. The Petroclinoid Ligament: Its Morphometrics, Relationships, Variations, and Suggestion for New Terminology. J Neurol Surg B Skull Base 2019; 81:603-609. [PMID: 33381363 DOI: 10.1055/s-0039-1692699] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/11/2019] [Indexed: 10/26/2022] Open
Abstract
The anatomy and definition of the petroclinoid ligament (PCL) and its relationship with the abducens nerve are variably described. The goal of this study was to clarify the anatomy of the PCL and better elucidate its relationship with the abducens nerve. Thirty-six sides from 18 fresh-frozen adult cadaveric heads were used in this study. Specimens were all Caucasian and derived from 10 males and 8 females. The mean age at death was 79 years. Dissection of the PCL and abducens nerve was performed using a surgical microscope. The anterior and posterior attachments of the PCL, and position of the abducens nerve were noted. Subsequently, the width, thickness, and length of the ligament, and diameter of the abducens nerve were measured. Thirty-one sides (86.1%) were found to have a PCL, on two sides (5.6%), the PCL was ossified, and on three sides (8.3%), the PCL was absent. The width, thickness, and length of the PCL ranged from 0.54 to 3.39, 0.07 to 0.49, and 3.27 to 17.85 mm, respectively. No PCL had an anterior attachment onto the posterior clinoid process but rather, the clivus. Therefore, based on our findings, the PCL would be better described as the petroclival ligament.
Collapse
Affiliation(s)
- Joe Iwanaga
- Seattle Science Foundation, Seattle, Washington, United States.,Division of Gross and Clinical Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
| | - Juan J Altafulla
- Seattle Science Foundation, Seattle, Washington, United States.,Swedish Medical Center, Swedish Neuroscience Institute, Seattle, Washington, United States.,Department of Neurosurgery, Hospital Santo Tomas, Panama City, Panama
| | | | - Graham Dupont
- Seattle Science Foundation, Seattle, Washington, United States
| | - Koichi Watanabe
- Division of Gross and Clinical Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
| | - Zachary Litvack
- Swedish Medical Center, Swedish Neuroscience Institute, Seattle, Washington, United States
| | - R Shane Tubbs
- Seattle Science Foundation, Seattle, Washington, United States.,Department of Anatomical Sciences, St. George's University, St. George, Grenada
| |
Collapse
|
10
|
Touska P, Hasso S, Oztek A, Chinaka F, Connor SEJ. Skull base ligamentous mineralisation: evaluation using computed tomography and a review of the clinical relevance. Insights Imaging 2019; 10:55. [PMID: 31115710 PMCID: PMC6529485 DOI: 10.1186/s13244-019-0740-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/04/2019] [Indexed: 02/08/2023] Open
Abstract
Objectives To determine the frequency, morphologic and demographic characteristics, and clinical relevance of the mineralisation of six skull base ligaments (interclinoid, caroticoclinoid, petrosphenoid, posterior petroclinoid, pterygospinous, and pterygoalar). Methods This is a retrospective review of 240 CT scans of the paranasal sinuses (ages 6–80 years). A limited systematic review was performed primarily using Embase and Medline databases. Results Ligamentous mineralisation was well delineated on CT and occurred at ≥ 1 location in 58.3% of patients. There was a nonsignificant trend towards a greater incidence with advancing age. The interclinoid and posterior petroclinoid ligaments were most commonly mineralised (22.1% and 18.3%, respectively); the petrosphenoid and pterygoalar ligaments were least frequently mineralised (10.8% and 6.3%, respectively). The mean age of patients with posterior petroclinoid mineralisation was significantly greater than those with interclinoid and petrosphenoid mineralisation and was not seen in patients aged 6–20 years. The literature review highlighted the clinically relevant potential for mineralised ligaments to cause barriers to surgical access (e.g. to the foramen ovale), increase the risk of neurovascular injury during surgery at the skull base (e.g. during anterior clinoidectomy), and predispose to neural impingement. Conclusions Skull base ligamentous mineralisation is commonly encountered on CT imaging. Given the potentially significant clinical implications, an understanding of the morphological appearances is of importance to those planning interventions at the skull base. To the authors’ knowledge, this study is the first to comprehensively evaluate such a wide range of skull base ligaments using CT. For some ligaments, the incidence on CT has not been previously described.
Collapse
Affiliation(s)
- Philip Touska
- Department of Radiology, Guy's and St. Thomas' NHS Foundation Trust, 2nd Floor Tower Wing, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK.
| | - Sultana Hasso
- Department of Radiology, Guy's and St. Thomas' NHS Foundation Trust, 2nd Floor Tower Wing, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK
| | - Alp Oztek
- Department of Radiology, University of Washington Medical Center, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Fungayi Chinaka
- Department of Radiology, Guy's and St. Thomas' NHS Foundation Trust, 2nd Floor Tower Wing, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK
| | - Steve E J Connor
- Department of Radiology, Guy's and St. Thomas' NHS Foundation Trust, 2nd Floor Tower Wing, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK.,Department of Neuroradiology, King's College Hospital NHS Trust, Denmark Hill, Brixton, London, SE5 9RS, UK.,School of Biomedical Engineering and Imaging Sciences Clinical Academic Group, King's College London, King's Health Partners, Guy's Hospital, London, UK
| |
Collapse
|
11
|
Wang JMH, Edwards BA, Loukas M, Oskouian RJ, Tubbs RS. Supernumerary Abducens Nerves: A Comprehensive Review. World Neurosurg 2017; 112:39-45. [PMID: 29158094 DOI: 10.1016/j.wneu.2017.11.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 11/07/2017] [Accepted: 11/09/2017] [Indexed: 11/17/2022]
Abstract
BACKGROUND Branching and/or replication of the abducens nerve is not an uncommon occurrence. Although numerous variations have been documented, the rarest forms are duplicated or triplicated nerves, where multiple nerve roots originate from the brainstem, travel intracranially, and attach to the lateral rectus as separate entities. METHODS We conducted a systematic literature search on the topic of supernumerary abducens nerve, using PubMed and Google Scholar. RESULTS After screening, 16 studies were included: 11 cadaveric studies and 6 case reports. CONCLUSIONS In this paper, we review the literature on variations found, discuss current hypotheses and clinical relevance, and propose future studies. Neurosurgeons should be aware of such nerve variants when viewing imaging or operating in the regions traversed by the abducens nerve.
Collapse
Affiliation(s)
- Joy M H Wang
- Department of Anatomical Sciences, St. George's University, Grenada, West Indies.
| | - Bryan Adam Edwards
- Department of Anatomical Sciences, St. George's University, Grenada, West Indies
| | - Marios Loukas
- Department of Anatomical Sciences, St. George's University, Grenada, West Indies
| | | | - R Shane Tubbs
- Seattle Science Foundation, Seattle, Washington, USA
| |
Collapse
|
12
|
Ogden M, Ozveren MF, Kayacı S. Petrobasilar, petroclival or petrosphenoidal canal of the abducens nerve. Acta Neurochir (Wien) 2017; 159:2145-2146. [PMID: 28942544 DOI: 10.1007/s00701-017-3324-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/04/2017] [Indexed: 10/18/2022]
Affiliation(s)
- Mustafa Ogden
- Faculty of Medicine, Department of Neurosurgery, Kirikkale University, Yahsihan, 71450, Kirikkale, Turkey.
| | - Mehmet Faik Ozveren
- Faculty of Medicine, Department of Neurosurgery, Kirikkale University, Yahsihan, 71450, Kirikkale, Turkey
| | - Selim Kayacı
- Faculty of Medicine, Department of Neurosurgery, Erzincan University, Erzincan, Turkey
| |
Collapse
|
13
|
Anatomic variation of the abducens nerve in a single cadaver dissection: the "petrobasilar canal". Acta Neurochir (Wien) 2017; 159:677-680. [PMID: 28144774 DOI: 10.1007/s00701-017-3096-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 01/19/2017] [Indexed: 10/20/2022]
Abstract
Anatomic variations of the petrosphenoid ligament, Dorello's canal and the course of the abducens nerve have been extensively described over the past years. In the present report of a single cadaver dissection, we describe an unusual course of the abducens nerve at the level of the petrous bone. The right abducens nerve did not enter Dorello's canal, but ran below the petrous bone through a narrow canal in the petrobasilar suture, which we called the "petrobasilar canal". No anatomic variations of the left abducens nerve were noted.
Collapse
|
14
|
Inal M, Muluk NB, Burulday V, Akgül MH, Ozveren MF, Çelebi UO, Şimşek G, Daphan BÜ. Investigation of the calcification at the petroclival region through Multi-slice Computed Tomography of the skull base. J Craniomaxillofac Surg 2016; 44:347-52. [PMID: 26922483 DOI: 10.1016/j.jcms.2016.01.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/14/2015] [Accepted: 01/26/2016] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVES The aim of this paper was a retrospective investigation of calcification at the petroclival region using Multi-slice Computed Tomography (MSCT). METHODS One hundred thirty skull bases were reviewed. The images were acquired with a 64 slice CT (MSCT). At first images were taken at the axial plane; and then coronal and sagittal reconstructions of raw data were performed. Later investigations were carried out on these 3-dimensional images (3-D imaging). Petrosphenoidal ligament (PSL) (Gruber's ligament) and posterior petroclinoid ligament (PPCL) calcifications were evaluated as "none, partial or complete calcification" for the right and left sides. RESULTS In the right PSL, there were partial calcifications in 9.8% and complete calcifications in 2.3%. Calcification ratio was 9.8% partial and 2.9% complete in the left PSL. In the right side, there were 26.6% partial and 5.2% complete calcifications of PPCL. In the left side, there were 29.5% partial and 4.6% complete PPCL calcifications. PPCL calcification was detected more in males compared to females in the right and left sides. In older patients, left PSL; right and left PPCL calcification were detected more. CONCLUSION PPCL calcifications cannot be differentiated from PSL calcifications in MSCT slices. The distinction can be easily done in 3-D views. The presence of ossified ligaments may make surgeries in this region difficult, and special care has to be taken to avoid injuries to structures which pass under these ossified ligaments. Particularly in elderly patients, the appropriate surgical instrument for the PSL calcifications should be prepared preoperatively. If PSL is calcified, 6th cranial nerve palsy may not occur even though increased intracranial pressure syndrome is present. Whereas, in lateral trans-tentorial herniations, 3rd cranial nerve palsy occurs in earlier periods when PSL is calcified. Moreover, in subtemporal and transtentorial petrosal approaches, knowing the PSL calcification preoperatively is important to avoid damaging the 6th cranial nerve during surgery.
Collapse
Affiliation(s)
- Mikail Inal
- Kirikkale University, School of Medicine, Department of Radiodiagnostics, Kirikkale, Turkey
| | - Nuray Bayar Muluk
- Kirikkale University, School of Medicine, Department of Otolaryngology, Kirikkale, Turkey.
| | - Veysel Burulday
- Kirikkale University, School of Medicine, Department of Radiodiagnostics, Kirikkale, Turkey
| | - Mehmet Hüseyin Akgül
- Kirikkale University, School of Medicine, Department of Neurosurgery, Kirikkale, Turkey
| | - Mehmet Faik Ozveren
- Kirikkale University, School of Medicine, Department of Neurosurgery, Kirikkale, Turkey
| | - Umut Orkun Çelebi
- Kirikkale University, School of Medicine, Department of Radiodiagnostics, Kirikkale, Turkey
| | - Gökçe Şimşek
- Kirikkale University, School of Medicine, Department of Otolaryngology, Kirikkale, Turkey
| | - Birsen Ünal Daphan
- Kirikkale University, School of Medicine, Department of Radiodiagnostics, Kirikkale, Turkey
| |
Collapse
|
15
|
Raikos A, Smith JD. Anatomical variations: How do surgical and radiology training programs teach and assess them in their training curricula? Clin Anat 2015; 28:717-24. [PMID: 25974002 DOI: 10.1002/ca.22560] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 04/09/2015] [Accepted: 04/09/2015] [Indexed: 11/07/2022]
Abstract
Sound knowledge of anatomy and Anatomical variations plays an integral role in surgical and radiology specialties. This study investigated the current teaching and assessment trends on Anatomical variations in various surgical and radiology specialty training curricula in Canada and Australia. A survey was sent to 122 Program Directors and Chairs of specialty committees in Canada and Directors of Training/Education in Australia of selected surgical and radiology specialties. A total of 80.7% of respondents report that their training curricula include Anatomical variations. The highest rated classes of variations included in the curriculum are arterial (76%), venous (68%), followed by organs (64%). All trainees learn about Anatomical variations from surgeons and radiologists (100%) and via suggested textbooks of the specialty (87.1%). A total of 54.8% report that specialty training curricula do not suggest specific anatomical variation classifications for the trainees to learn, and 16.1% are uncertain if the colleges provide such kind of instruction. Trainees typically communicated findings of variations in case presentations and clinic's meetings. About 32.3% of respondents report that Anatomical variations are not assessed in their training curriculum. About 39.3% of experienced clinicians in the study report they encounter variations on a monthly basis and 25 and 21.4% on a weekly and daily basis, respectively. Surgical and radiology colleges need to investigate for hidden curriculum in their specialty training programs to ensure there are no gaps in knowledge and training related to Anatomical variations. Most educational leaders surveyed believe more teaching on Anatomical variations in the first 4 years of training would benefit resident doctors.
Collapse
Affiliation(s)
- Athanasios Raikos
- Department of Anatomical Sciences, Faculty of Health Sciences & Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Janie Dade Smith
- Department of Anatomical Sciences, Faculty of Health Sciences & Medicine, Bond University, Gold Coast, Queensland, Australia
| |
Collapse
|
16
|
Özgür A, Esen K. Ossification of the petrosphenoidal ligament: multidetector computed tomography findings of an unusual variation with a potential role in abducens nerve palsy. Jpn J Radiol 2015; 33:260-5. [PMID: 25749833 DOI: 10.1007/s11604-015-0410-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 02/26/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE The petrosphenoidal ligament (PSL) forms the roof of Dorello's canal in which the abducens nerve courses. An ossified PSL may play a role in abducens nerve palsy although it is controversial. Therefore, we aimed to investigate the incidence and the imaging features of PSL ossification using multidetector computed tomography (MDCT). MATERIALS AND METHODS Consecutive head CT scans, performed between January 2014 and May 2014, were retrospectively evaluated by two radiologists to look for a partial or complete ossification at the expected site of the PSL using axial, reformatted coronal and sagittal images. RESULTS We found 46 patients (32 men, 14 women) with ossification of the PSL out of 523 head CT scans (46/523, 8.8%). A total of 61 PSL ossifications (31 unilateral; 15 bilateral) were found in 1,046 petroclival regions (61/1,046, 5.8%). Of these 61 ossifications, 34 (34/523, 6.5%) were on the right and 27 (27/523, 5.1%) were on the left; 38 (38/1,046, 3.6%) were classified as partial and 23 (23/1,046, 2.2%) were classified as complete. CONCLUSION Ossification of the PSL is not a rare finding on MDCT. This imaging technique can reliably demonstrate the imaging features of an ossified PSL.
Collapse
Affiliation(s)
- Anıl Özgür
- Department of Radiology, Faculty of Medicine, Mersin University, 34. Cadde, Çiftlikköy Kampüsü, 33343, Mersin, Turkey,
| | | |
Collapse
|
17
|
Tomio R, Toda M, Sutiono AB, Horiguchi T, Aiso S, Yoshida K. Grüber's ligament as a useful landmark for the abducens nerve in the transnasal approach. J Neurosurg 2014; 122:499-503. [PMID: 25380109 DOI: 10.3171/2014.10.jns132437] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Extended endoscopic transnasal surgeries for skull base lesions have recently been performed. Some expert surgeons have attempted to remove tumors such as chordomas, meningiomas, and pituitary adenomas in the clival region using the transnasal approach and have reported abducens nerve injury as a common complication. There have been many microsurgical anatomical studies of the abducens nerve, but none of these studies has described an anatomical landmark of the abducens nerve in the transnasal approach. In this study the authors used cadaver dissections to describe Grüber's ligament as the most reliable landmark of the abducens nerve in the transnasal transclival view. METHODS The petroclival segment of the abducens nerve was dissected in the interdural space-which is also called Dorello's canal, the petroclival venous gulf, or the sphenopetroclival venous confluence-using the transnasal approach in 20 specimens obtained from 10 adult cadaveric heads. RESULTS The petroclival segment of the abducens nerve clearly crossed and attached to Grüber's ligament in the interdural space, as noted in the transnasal view. The average length of the dural porus to the intersection on the abducens nerve was 5.2 ± 1.0 mm. The length of the posterior clinoid process (PCP) to the intersection on Grüber's ligament was 6.4 ± 2.6 mm. The average width of Grüber's ligament at the midsection was 1.6 ± 0.5 mm. CONCLUSIONS Grüber's ligament is considered a useful landmark, and it is visible in most adults. Thus, surgeons can find the abducens nerve safely by visualizing inferolaterally along Grüber's ligament from the PCP.
Collapse
|