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Freitas‐da‐Costa P, Madeira MD. Functional anatomy of the orbit in strabismus surgery: Connective tissues, pulleys, and the modern surgical implications of the "arc of contact" paradigm. J Anat 2024; 244:887-899. [PMID: 38243145 PMCID: PMC11095312 DOI: 10.1111/joa.14009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 12/27/2023] [Accepted: 01/08/2024] [Indexed: 01/21/2024] Open
Abstract
Oculomotricity is a multidimensional domain characterised by a delicate interplay of anatomical structures and physiological processes. This manuscript meticulously dissects the nuances of this interplay, bringing to the fore the integral role of the extraocular muscles (EOMs) and their intricate relationship with the myriad orbital connective tissues as it harmoniously orchestrates binocular movements, ensuring synchronised and fluid visual tracking. Historically, the peripheral oculomotor apparatus was conceptualised as a rudimentary system predominantly driven by neural directives. While widely accepted, this perspective offered a limited view of the complexities inherent in ocular movement mechanics. The twentieth century heralded a paradigm shift in this understanding. With advances in anatomical research and imaging techniques, a much clearer picture of the gross anatomy of the EOMs emerged. This clarity challenged traditional viewpoints, suggesting that the inherent biomechanical properties of the EOMs, coupled with their associated tissue pulleys, play a pivotal role in dictating eye movement dynamics. Central to this revised understanding is the "arc of contact" paradigm. This concept delves deep into the mechanics of eye rotation, elucidating the significance of the point of contact between the EOMs and the eyeball. The arc of contact is not just a static anatomical feature; its length and orientation play a crucial role in determining the effective torque generated by a muscle, thereby influencing the amplitude and direction of eye rotation. The dynamic nature of this arc, influenced by the position and tension of the muscle pulleys, offers a more comprehensive model for understanding ocular kinematics. Previously overlooked in traditional models, muscle pulleys have now emerged as central players in the biomechanics of eye movement. These anatomical structures, formed by dense connective tissues, guide the paths of the EOMs, ensuring that their pulling angles remain optimal across a range of gaze directions. The non-linear paths resulting from these pulleys provide a more dynamic and intricate understanding of eye movement, challenging two-dimensional, linear models of orbital anatomy. The implications of these revelations extend beyond mere theoretical knowledge. The insights garnered from this research promise transformative potential in the realm of strabismus surgery. Recognising the pivotal role of muscle pulleys and the "arc of contact" paradigm allows for more precise surgical interventions, ensuring better post-operative outcomes and minimising the risk of complications. Surgical procedures that previously relied on basic mechanical principles now stand to benefit from a more nuanced understanding of the underlying anatomical and physiological dynamics. In conclusion, this manuscript serves as a testament to the ever-evolving nature of scientific knowledge. Challenging established norms and introducing fresh perspectives pave the way for more effective and informed clinical interventions in strabismus surgery.
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Affiliation(s)
- Paulo Freitas‐da‐Costa
- Department of OphthalmologySão João University Hospital CenterPortoPortugal
- Department of Surgery and Physiology, Faculty of MedicineUniversity of PortoPortoPortugal
- Anatomy Unit, Department of Biomedicine, Faculty of MedicineUniversity of PortoPortoPortugal
| | - Maria Dulce Madeira
- Anatomy Unit, Department of Biomedicine, Faculty of MedicineUniversity of PortoPortoPortugal
- Center for Health Technology and Services Research (CINTESIS)PortoPortugal
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Zacharewski N, Killory BD. Duplicate Left-Sided Vagus Nerve: Intraoperative Imaging, Management, and Placement. J Neurol Surg Rep 2023; 84:e59-e60. [PMID: 37213414 PMCID: PMC10195161 DOI: 10.1055/s-0043-1768713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 08/12/2022] [Indexed: 05/23/2023] Open
Abstract
Introduction Duplicate cranial nerves are fundamentally rare anatomical variants. Few case reports have documented cranial nerve duplication. One previous case report has reported a vagus nerve with a smaller secondary accessory nerve component. We present the first reported case of duplicate vagus nerves identical in size and thickness with otolaryngological diagnostic confirmation. Case Description A 25-year-old woman with seizures refractory to medical management decided to undergo placement of a vagus nerve stimulator. During carotid sheath microdissection, two parallel nerve tracts were identified. The two nerves were identical in size and width. Proximal dissection confirmed that the two nerves were independent of one another and neither was a branching segment. To confirm duplicate vagus nerves, otolaryngology was consulted intraoperatively and the duplicate nerves were verified. The vagus nerve stimulator was placed in typical fashion around the medial nerve. Conclusion This is the first reported case of duplicate vagus nerves identical in size and with confirmation by otolaryngology. The authors would like to highlight the operative management of the vagus nerve stimulator placement as well as integrity of the diagnostic conclusions based on size, further dissection, and specialist consultation.
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Affiliation(s)
- Nicholas Zacharewski
- Department of Neurosurgery, Hartford Hospital, Hartford, Connecticut, United States
- Address for correspondence Nicholas Zacharewski Brendan Killory, MD, Hartford Healthcare Medical Group Department of Neurosurgery, 85 Seymour St Suite 1003,
Hartford, CT 06117United States
| | - Brendan D. Killory
- Department of Neuroscience, Trinity College, Hartford, Connecticut, United States
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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.
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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
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4
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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.
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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: 8] [Impact Index Per Article: 2.0] [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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Comparison of lateral and medial rectus muscle in human: an anatomical study with particular emphasis on morphology, intramuscular innervation pattern variations and discussion on clinical significance. Surg Radiol Anat 2020; 42:607-616. [PMID: 31897658 DOI: 10.1007/s00276-019-02400-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 12/13/2019] [Indexed: 10/25/2022]
Abstract
This paper aims to present various aspects of the anatomy of horizontal (i.e., lateral and medial) rectus muscles. It mainly compares morphology and detailed patterns of intramuscular innervation of those muscles. It is also one of the first reports that uses the Sihler's stain to examine human extraocular muscles. The study was conducted on 80 isolated cadaveric hemi-heads. Sihler technique of nerves staining served to expose the course of intramuscular branches of the oculomotor and abducens nerves. The lateral rectus was longer (48 mm versus 46.5 mm) and more distant from the limbus (6.8 mm versus 5.7 mm) than the medial rectus muscle. Three variants of the abducens nerve primary division were observed in the lateral rectus muscle. In the medial rectus muscle, the motor branch from the oculomotor nerve was more evenly divided into sub-branches. In both examined horizontal rectus muscles, primary muscular branches split into secondary sub-branches, which undergo numerous further divisions. The most numerous terminal sub-branches formed the terminal plexus. The distance between the insertion and the anterior-most end of the terminal plexus referenced to the total length of the muscle ranged from 35.4 to 48.5% for the lateral rectus muscle and from 36.3 to 50.5% for medial rectus muscle. Both horizontal rectus muscles share similar general pattern of distribution of intramuscular nerves, with characteristic root-like arborizations of sub-branches. The terminal nerve plexus was observed near half of both muscles' length. Knowledge of variations and innervation pattern of the extraocular muscles may be relevant during ophthalmology surgeries.
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Haładaj R, Wysiadecki G, Tubbs RS. Intramuscular innervation of the lateral rectus muscle evaluated using sihler's staining technique: Potential application to strabismus surgery. Clin Anat 2019; 33:585-591. [PMID: 31429984 DOI: 10.1002/ca.23452] [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: 07/06/2019] [Revised: 08/15/2019] [Accepted: 08/15/2019] [Indexed: 12/20/2022]
Abstract
The latest research suggests that the abducens nerve may be divided into subbranches that reach functionally distinct zones of the lateral rectus muscle. The goal of the study was to examine this muscle's innervation, including the detailed distribution of the intramuscular subbranches of the abducens nerve. Twenty-five lateral rectus muscle specimens were harvested (with the orbital segment of the abducens nerve), fixed in 10% formalin solution, and stained with Sihler's whole mount nerve staining technique. Subbranches running to the lateral rectus divided into two main groups: superior and inferior. Both groups of subbranches are distributed in a fan-shaped manner, show a characteristic "tree-like" branching pattern and form terminal plexus near the proximal half of the lateral rectus muscle. However, some smaller subbranches run as far as the muscle's insertion, and recurrent subbranches also reach its origin. With respect to their course to the muscle's origin or insertion, the smallest subbranches running within the muscle may be associated with innervation of the tendon. In the majority of cases (88%), superior and inferior subbranches of the abducens nerve overlapped in the central one-third of the lateral rectus muscle's width so that any clearly distinct anatomical segments of the muscle could be observed based on Sihler's technique. In the remaining 12% of specimens, superior and inferior groups of subbranches innervated two distinct compartments of the lateral rectus muscle with no overlapping. Dense, fan-shaped distribution of abducens nerve intramuscular subbranches can be observed within the lateral rectus muscle. Clin. Anat. 33:585-591, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Robert Haładaj
- Department of Normal and Clinical Anatomy, Interfaculty Chair of Anatomy and Histology, Medical University of Lodz, Łódź, Poland
| | - Grzegorz Wysiadecki
- Department of Normal and Clinical Anatomy, Interfaculty Chair of Anatomy and Histology, Medical University of Lodz, Łódź, Poland
| | - R Shane Tubbs
- Department of Neurosurgery, Seattle Science Foundation, Seattle, Washington
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Labuschagne JJ, Hammer N. Duplicated Vagus Nerve in Adolescence: Case Report and Review of Literature. World Neurosurg 2019; 131:180-185. [PMID: 31408750 DOI: 10.1016/j.wneu.2019.08.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 01/24/2023]
Abstract
BACKGROUND Vagus nerve stimulation (VNS) has become an increasingly popular procedure for the treatment of epilepsy and depression. Significant complications or side effects associated with VNS surgery may result from either the inadvertent direct injury to the vagus nerve as part of the surgical approach, placement of the electrode, or the concomitant stimulation of vagal efferent fibers. To mitigate these effects, the recognition of anatomic variants that may place the nerve at increased risk is necessary. CASE DESCRIPTION During microsurgical dissection of the carotid sheath for the implantation of a vagus nerve stimulator in a 17-year-old male patient with refractory epilepsy, additional nonidentified nerve tissue was found running parallel to the vagus nerve. These fibers were two thirds of the thickness of the vagus nerve and ran medial to it, from the most superior to the most inferior aspect of the carotid sheath dissection, found at a distance of at least 4 cm in a craniocaudal direction. This duplicated nerve did not appear to branch from the vagal trunk nor exit the sheath but rather paralleled the course of the vagus nerve. The parallel course and the proximity of the unidentified nerve make this structure likely to be a duplicated vagus nerve. CONCLUSIONS This is the first reported case of cervical vagus nerve duplication presented in the literature. Surgeons performing VNS implantations should be cognizant of this potential anomaly in order to avoid inadvertent injury to the nerve.
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Affiliation(s)
- Jason John Labuschagne
- Netcare Unitas Hospital, Centurion, South Africa; Department of Neurosurgery, University of Witwatersrand, Johannesburg, South Africa; Department of Pediatric Neurosurgery, Nelson Mandela Children's Hospital, Johannesburg, South Africa.
| | - Niels Hammer
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Department of Trauma, Orthopedic and Plastic Surgery, University Hospital of Leipzig, Leipzig, Germany; Fraunhofer Institute for Machine Tools and Forming Technology, Dresden, Germany
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11
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Dupont G, Altafulla J, Iwanaga J, Watanabe K, Tubbs RS. Ossification of the roof of the porus trigeminus with duplicated abducens nerve. Anat Cell Biol 2019; 52:211-213. [PMID: 31338240 PMCID: PMC6624332 DOI: 10.5115/acb.2019.52.2.211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 11/27/2022] Open
Abstract
Ossification of parts of the intracranial dura mater is common and is generally accepted as an age-related finding. Additionally, duplication of the abducens nerve along its course to the lateral rectus muscle is a known, although uncommon anatomical variant. During routine cadaveric dissection, an ossified portion of dura mater traveling over the trigeminal nerve's entrance (porus trigeminus) into the middle cranial fossa was observed unilaterally. Ipsilaterally, a duplicated abducens nerve was also observed, with a unique foramen superolateral to the entrance of Dorello's canal. To our knowledge, there has been no existing report of a simultaneous ossified roof of the porus trigeminus with an ipsilateral duplicated abducens nerve. Herein, we discuss this case and the potential clinical and surgical applications. We believe this case report will be informative for the skull base surgeon in the diagnosis of neuralgic pain in the frontomaxillary, andibular, orbital, and external and middle ear regions.
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Affiliation(s)
| | - Juan Altafulla
- Seattle Science Foundation, Seattle, WA, USA.,Swedish Neuroscience Institute, Swedish Medical Center, Seattle, WA, USA
| | - Joe Iwanaga
- Seattle Science Foundation, Seattle, WA, USA.,Seattle Science Foundation, Seattle, WA, USA
| | - Koichi Watanabe
- Division of Gross and Clinical Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
| | - R Shane Tubbs
- Seattle Science Foundation, Seattle, WA, USA.,Department of Anatomical Sciences, St. George's University, St. George's, Grenada, West Indies
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12
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Ipsalali HO, Ciftci AC, Kilic D, Sendemir G, Seyhan S, Kaya I, Ortug G. Variations of the 6 th cranial nerve (nervus abducens) in the petroclival region: A microsurgical study. Morphologie 2019; 103:103-109. [PMID: 30713002 DOI: 10.1016/j.morpho.2019.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 11/28/2022]
Abstract
The aim of this study is to present the variations of nervus abducens in localization and number as it pierces the clival dura mater. The calvaria of 16 cadaveric heads were removed by making horizontal incisions from Glabella to Inion in both sides of the head. The dura mater was dissected. Cerebrum and cerebellum were taken out by obtuse dissection. Dissections of cavernous sinus were made under the stereomicroscope and the findings were photographed. Out of 16 specimens, one of them was excluded. Fifteen heads were bilaterally analyzed. Analysis of these nerves presented four different variations. Variation types a classified CN VI as a single trunk and entering a single dural pore with 77% occurrence. Variation type b classified CN VI with two branches running in the petroclival region and entering a single dural pore with 10% occurrence. Variation type c classified CN VI as 2 trunks and entering 2 separate but close dural pores with 10% occurrence. Variation type d classified CN VI with 2 distinct trunks and 2 branches entering 2 separate but close dural pores with 3% occurrence. CN VI plays a major role in the clinic of the eye. Due to its intracranial and extracranial course, injuries to the head and to the nerve may result in malfunctioning of the lateral muscles of the eye. Therefore, the variations of branching, relations and its course were analyzed.
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Affiliation(s)
- H O Ipsalali
- School of Medicine, Bahcesehir University Istanbul, Turkey
| | - A C Ciftci
- School of Medicine, Bahcesehir University Istanbul, Turkey
| | - D Kilic
- School of Medicine, Bahcesehir University Istanbul, Turkey
| | - G Sendemir
- School of Medicine, Bahcesehir University Istanbul, Turkey
| | - S Seyhan
- School of Medicine, Bahcesehir University Istanbul, Turkey
| | - I Kaya
- School of Medicine, Bahcesehir University Istanbul, Turkey
| | - G Ortug
- Department of Anatomy-Chair, School of Medicine, Bahcesehir University, Istanbul, Turkey.
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13
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Unilateral duplicated abducens nerve coursing through both the sphenopetroclival venous gulf and cavernous sinus: a case report. Surg Radiol Anat 2018. [DOI: 10.1007/s00276-018-2003-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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.
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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
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Pizzolorusso G, Cirotti A, Pizzolorusso F. Petrobasilar, petroclival, or petrosphenoidal canal of the abducens nerve. Acta Neurochir (Wien) 2017; 159:2147-2148. [PMID: 28918488 DOI: 10.1007/s00701-017-3327-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Gianfranco Pizzolorusso
- Research Department, Accademia di Osteopatia e Anatomia (A.O.A.), Via Martiri della Loggia 31, 76123, Andria, BT, Italy.
- Research Department, Accademia Italiana Osteopatia Tradizionale - Marche (A.I.O.T. Marche), Via Einaudi 108, 62012, Civitanova Marche, MC, Italy.
- , Via Isonzo 16, 66100, Chieti, CH, Italy.
| | - Andrea Cirotti
- Research Department, Accademia di Osteopatia e Anatomia (A.O.A.), Via Martiri della Loggia 31, 76123, Andria, BT, Italy
- Research Department, Accademia Italiana Osteopatia Tradizionale - Marche (A.I.O.T. Marche), Via Einaudi 108, 62012, Civitanova Marche, MC, Italy
| | - Felice Pizzolorusso
- Research Department, Accademia di Osteopatia e Anatomia (A.O.A.), Via Martiri della Loggia 31, 76123, Andria, BT, Italy
- Research Department, Accademia Italiana Osteopatia Tradizionale - Marche (A.I.O.T. Marche), Via Einaudi 108, 62012, Civitanova Marche, MC, Italy
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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
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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.
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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.
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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
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Yamashiro T, Yonahara M, Yonaha A, Kinoshita R, Tsubakimoto M, Iraha R, Murayama S. Bilateral duplication of the abducens nerves: an incidental finding on magnetic resonance imaging. Jpn J Radiol 2015; 33:772-5. [PMID: 26507983 DOI: 10.1007/s11604-015-0494-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/15/2015] [Indexed: 10/22/2022]
Abstract
Although anomaly of the abducens nerve, including duplication, has been reported in anatomical papers, no radiological report exists regarding a duplicated abducens nerve observed on magnetic resonance (MR) imaging. We encountered a case of bilateral duplication of the abducens nerves, which was found incidentally on MR scans from an 11-year-old boy. He did not have any symptoms of eye movement related to abducens nerve abnormality; thus, the duplication was considered to be a normal variant in this patient. Radiologists should be aware that duplication of the abducens nerve may occur and can be diagnosed on MR, particularly when diagnosing symptomatic patients or as a preoperative assessment for microsurgery of the nerve.
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Affiliation(s)
- Tsuneo Yamashiro
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan.
| | - Michiko Yonahara
- Department of Ophthalmology, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
| | - Ayano Yonaha
- Department of Otorhinolaryngology-Head and Neck Surgery, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
| | - Ryo Kinoshita
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
| | - Maho Tsubakimoto
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
| | - Rin Iraha
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
| | - Sadayuki Murayama
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
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Wysiadecki G, Polguj M, Topol M. An unusual variant of the abducens nerve duplication with two nerve trunks merging within the orbit: a case report with comments on developmental background. Surg Radiol Anat 2015; 38:625-9. [PMID: 26501961 PMCID: PMC4911371 DOI: 10.1007/s00276-015-1573-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/12/2015] [Indexed: 11/27/2022]
Abstract
This study reports the first case of abducens nerve duplication along its entire intracranial course, ending within the orbit. A distinct abducens nerve duplication reaching the common tendinous ring (annulus of Zinn), as well as another split within the intraconal segment of the nerve have been revealed. Additionally, two groups (superior and inferior) of abducens nerve sub-branches to the lateral rectus muscle were visualised using Sihler's stain. The analysed anatomical variation has never been reported before and it seems to be in the middle of the spectrum between the cases of duplication occurring only within the intracranial segments of the abducens nerve found in the literature and those continuing throughout the whole course of the nerve. Abducens nerve duplication may be treated as a relic of early stages of ontogenesis. Such a variant might result from alternative developmental pathways in which axons of the abducens nerve, specific for a given segment of the lateral rectus muscle, run separately at some stage, instead of forming a single stem.
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Affiliation(s)
- Grzegorz Wysiadecki
- Department of Normal and Clinical Anatomy, Interfaculty Chair of Anatomy and Histology, Medical University of Lodz, ul. Narutowicza 60, 90-136, Łódź, Poland.
| | - Michał Polguj
- Department of Angiology, Interfaculty Chair of Anatomy and Histology, Medical University of Lodz, ul. Narutowicza 60, 90-136 Łódź, Poland
| | - Mirosław Topol
- Department of Normal and Clinical Anatomy, Interfaculty Chair of Anatomy and Histology, Medical University of Lodz, ul. Narutowicza 60, 90-136, Łódź, Poland
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21
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Özgür A, Esen K, Kara E, Temel GO. Visualization of the Abducens Nerve in its Petroclival Segment Using Contrast-Enhanced FIESTA MRI: The Size of the Petroclival Venous Confluence Affects Detectability. Clin Neuroradiol 2015; 27:97-103. [DOI: 10.1007/s00062-015-0415-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/15/2015] [Indexed: 11/30/2022]
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22
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Sectional anatomy of the abducens nerve: according to 3D-SPACE magnetic resonance sequences correlated with cryosectional specimens. Surg Radiol Anat 2015; 37:921-9. [DOI: 10.1007/s00276-015-1452-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 02/24/2015] [Indexed: 10/23/2022]
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23
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Demer JL. Compartmentalization of extraocular muscle function. Eye (Lond) 2015; 29:157-62. [PMID: 25341434 PMCID: PMC4330271 DOI: 10.1038/eye.2014.246] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 08/29/2014] [Indexed: 01/18/2023] Open
Abstract
Ocular motor diversity exceeds capabilities of only six extraocular muscles (EOMs), but this deficiency is overcome by the plethora of fibers within individual EOMs surpassing requirements of homogeneous actuators. This paper reviews emerging evidence that regions of individual EOMs can be differentially innervated to exert independent oculorotary torques, broadening the oculomotor repertoire, and potentially explaining diverse strabismus pathophysiology. Parallel structure characterizes EOM and tendon fibers, with little transverse coupling of experimentally imposed or actively generated tension. This arrangement enables arbitrary groupings of tendon and muscle fibers to act relatively independently. Coordinated force generation among EOM fibers occurs only upon potentially mutable coordination of innervational commands, whose central basis is suggested by preliminary findings of apparent compartmental segregation of abducens motor neuron pools. Humans, monkeys, and other mammals demonstrate separate, nonoverlapping intramuscular nerve arborizations in the superior vs inferior compartments of the medial rectus (MR) and lateral rectus (LR) EOMs that could apply force at the superior vs inferior portions of scleral insertions, and in the medial vs lateral compartments of the superior oblique that act at the equatorial vs posterior scleral insertions that might preferentially implement incycloduction vs infraduction. Magnetic resonance imaging of the MR during several physiological ocular motor behaviors indicates differential compartmental function. Differential compartmental pathology can influence clinical strabismus. Partial abducens palsy commonly affects the superior LR compartment more than the inferior, inducing vertical strabismus that might erroneously be attributed to cyclovertical EOM pathology. Surgery may selectively manipulate EOM compartments.
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Affiliation(s)
- J L Demer
- Departments of Ophthalmology and Neurology, Stein Eye Institute, David Geffen Medical School, University of California, Los Angeles, CA, USA
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Hypertropia in unilateral isolated abducens palsy. J AAPOS 2014; 18:235-40. [PMID: 24924275 PMCID: PMC4079534 DOI: 10.1016/j.jaapos.2014.01.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 12/29/2013] [Accepted: 01/05/2014] [Indexed: 11/22/2022]
Abstract
PURPOSE To evaluate the incidence and features of hypertropia in abducens nerve palsy. METHODS The records of consecutive patients with unilateral, isolated, previously unoperated abducens nerve palsy were reviewed for binocular alignment on cover testing, Krimsky measurement, or Hess screen testing. Patients with associated cranial nerve palsy (including bilateral abducens palsies), orbital disease, myasthenia gravis, Horner syndrome, hemiplegia, cerebellar signs, arteritis, or previous strabismus surgery were excluded. Control subjects underwent complete examination to confirm normality. RESULTS A total of 79 patients were included (40 males; mean age 49.2 years). Hypertropia in lateral or central gazes was present in 15 of 79 cases (19%) on alternate cover or Krimsky testing, in 32 of 56 cases (57%) on Hess screen testing, and absent in all 30 normal controls. Of cases with hypertropia, the mean of the greatest hypertropia in lateral or central gaze on was 5.0(Δ) ± 2.3(Δ) (standard deviation; range, 1(Δ)-8(Δ)) routine clinical examination, and 5.8(Δ) ± 4.2(Δ) (range, 2(Δ)-24(Δ)) on Hess screen testing. Of 39 cases with partial abducens palsy evaluated by Hess screen testing, the ipsilesional eye was hypertropic in 24 (61%) and hypotropic in 15 cases (39%). CONCLUSIONS Small-angle hypertropia is common in isolated, unilateral abducens and does not imply existence of multiple cranial neuropathies or skew deviation.
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Peris-Celda M, Graziano F, Russo V, Mericle RA, Ulm AJ. Foramen ovale puncture, lesioning accuracy, and avoiding complications: microsurgical anatomy study with clinical implications. J Neurosurg 2013; 119:1176-93. [DOI: 10.3171/2013.1.jns12743] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Foramen ovale (FO) puncture allows for trigeminal neuralgia treatment, FO electrode placement, and selected biopsy studies. The goals of this study were to demonstrate the anatomical basis of complications related to FO puncture, and provide anatomical landmarks for improvement of safety, selective lesioning of the trigeminal nerve (TN), and optimal placement of electrodes.
Methods
Both sides of 50 dry skulls were studied to obtain the distances from the FO to relevant cranial base references. A total of 36 sides from 18 formalin-fixed specimens were dissected for Meckel cave and TN measurements. The best radiographic projection for FO visualization was assessed in 40 skulls, and the optimal trajectory angles, insertion depths, and topographies of the lesions were evaluated in 17 specimens. In addition, the differences in postoperative pain relief after the radiofrequency procedure among different branches of the TN were statistically assessed in 49 patients to determine if there was any TN branch less efficiently targeted.
Results
Most severe complications during FO puncture are related to incorrect needle placement intracranially or extracranially. The needle should be inserted 25 mm lateral to the oral commissure, forming an approximately 45° angle with the hard palate in the lateral radiographic view, directed 20° medially in the anteroposterior view. Once the needle reaches the FO, it can be advanced by 20 mm, on average, up to the petrous ridge. If the needle/radiofrequency electrode tip remains more than 18 mm away from the midline, injury to the cavernous carotid artery is minimized. Anatomically there is less potential for complications when the needle/radiofrequency electrode is advanced no more than 2 mm away from the clival line in the lateral view, when the needle pierces the medial part of the FO toward the medial part of the trigeminal impression in the petrous ridge, and no more than 4 mm in the lateral part. The 40°/45° inferior transfacial–20° oblique radiographic projection visualized 96.2% of the FOs in dry skulls, and the remainder were not visualized in any other projection of the radiograph. Patients with V1 involvement experienced postoperative pain more frequently than did patients with V2 or V3 involvement. Anatomical targeting of V1 in specimens was more efficiently achieved by inserting the needle in the medial third of the FO; for V2 targeting, in the middle of the FO; and for V3 targeting, in the lateral third of the FO.
Conclusions
Knowledge of the extracranial and intracranial anatomical relationships of the FO is essential to understanding and avoiding complications during FO puncture. These data suggest that better radiographic visualization of the FO can improve lesioning accuracy depending on the part of the FO to be punctured. The angles and safety distances obtained may help the neurosurgeon minimize complications during FO puncture and TN lesioning.
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Affiliation(s)
- Maria Peris-Celda
- 1Microsurgical Neuroanatomy Laboratory, Department of Neurosurgery, Louisiana State University Health Sciences Center, New Orleans, Louisiana
- 2Department of Neurosurgery, La Fe University Hospital, Valencia, Spain; and
| | - Francesca Graziano
- 1Microsurgical Neuroanatomy Laboratory, Department of Neurosurgery, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Vittorio Russo
- 1Microsurgical Neuroanatomy Laboratory, Department of Neurosurgery, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Robert A. Mericle
- 3Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Arthur J. Ulm
- 1Microsurgical Neuroanatomy Laboratory, Department of Neurosurgery, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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[Anterior petrosal approach - analysis of the surgical technique in cadavers simulation]. Neurol Neurochir Pol 2013; 47:363-74. [PMID: 23986427 DOI: 10.5114/ninp.2013.36761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of the study was to present consecutive stages of the anterior petrosal approach (APA). Eight simulations of APA were performed on non-fixed human cadavers without any known pathologies of the head and neck. The consecutive stages of the procedure were documented with photographs and schemes. The starting point for APA is a temporal craniotomy and extradural exposition of the base of the middle cranial fossa. Mobilisation of the trigeminal nerve allows for removal of the apex of the petrous bone. Approach to the upper part of the clivus is achieved by elevation of the temporal lobe and section of the tentorium and superior petrosal sinus with surrounding dura. Anterior petrosal approach is a reproducible technique, which provides surgical penetration of the upper clivus and related regions. This approach is particularly useful in the treatment of tumors of the mentioned above anatomical areas.
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Clark RA, Demer JL. Differential lateral rectus compartmental contraction during ocular counter-rolling. Invest Ophthalmol Vis Sci 2012; 53:2887-96. [PMID: 22427572 PMCID: PMC3367472 DOI: 10.1167/iovs.11-7929] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 06/20/2011] [Accepted: 03/01/2012] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The lateral rectus (LR) and medial rectus (MR) extraocular muscles (EOMs) have largely nonoverlapping superior and inferior innervation territories, suggesting functional compartmental specialization. We used magnetic resonance imaging (MRI) in humans to investigate differential compartmental activity in the rectus EOMs during head tilt, which evokes ocular counter-rolling, a torsional vestibulo-ocular reflex (VOR). METHODS MRI in quasi-coronal planes was analyzed during target-controlled central gaze in 90° right and left head tilts in 12 normal adults. Cross sections and posterior partial volumes of the transverse portions of the four rectus EOMs were compared in contiguous image planes 2 mm thick spanning the orbit from origins to globe equator, and used as indicators of contractility. RESULTS Horizontal rectus EOMs had significantly greater posterior volumes and maximum cross sections in their inferior compartments (P < 10(-8)). In orbit tilt up (extorted) compared with orbit tilt down (intorted) head tilts, contractile changes in LR maximum cross section (P < 0.0001) and posterior partial volume (P < 0.05) were significantly greater in the inferior but not in the superior compartment. These changes were not explainable by horizontal or vertical eye position changes. A weaker compartmental effect was suggested for MR. The vertical rectus EOMs did not exhibit significant compartmental contractile changes during head tilt. Mechanical modeling suggests that differential LR contraction may contribute to physiological cyclovertical effects. CONCLUSIONS Selective activation of the two LR, and possibly MR, compartments correlates with newly recognized segregation of intramuscular innervation into distinct compartments, and probably contributes to noncommutative torsion during the VOR.
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Affiliation(s)
- Robert A. Clark
- From the Departments of Ophthalmology and Neurology, Neuroscience and
Biomedical Engineering Interdepartmental Programs,
David Geffen Medical School, University of California, Los Angeles, California
| | - Joseph L. Demer
- From the Departments of Ophthalmology and Neurology, Neuroscience and
Biomedical Engineering Interdepartmental Programs,
David Geffen Medical School, University of California, Los Angeles, California
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Joo W, Yoshioka F, Funaki T, Rhoton AL. Microsurgical anatomy of the abducens nerve. Clin Anat 2012; 25:1030-42. [DOI: 10.1002/ca.22047] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/08/2012] [Accepted: 01/23/2012] [Indexed: 11/11/2022]
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Demer JL, Clark RA, da Silva Costa RM, Kung J, Yoo L. Expanding repertoire in the oculomotor periphery: selective compartmental function in rectus extraocular muscles. Ann N Y Acad Sci 2011; 1233:8-16. [PMID: 21950970 PMCID: PMC3286355 DOI: 10.1111/j.1749-6632.2011.06112.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Since connective tissue pulleys implement Listing's law by systematically changing rectus extraocular muscle (EOM) pulling directions, non-Listing's law gaze dependence of the vestibulo-ocular reflex is currently inexplicable. Differential activation of compartments within rectus EOMs may endow the ocular motor system with more behavioral diversity than previously supposed. Innervation to horizontal, but not vertical, rectus EOMs of mammals is segregated into superior and inferior compartments. Magnetic resonance imaging in normal subjects demonstrates contractile changes in the lateral rectus (LR) inferior, but not superior, compartment during ocular counter-rolling (OCR) induced by head tilt. In human orbits ipsilesional to unilateral superior oblique palsy, neither LR compartment exhibits contractile change during head tilt, although the inferior compartment contracts normally in contralesional orbits. This suggests that differential compartmental LR contraction assists normal OCR. Computational simulation suggests that differential compartmental action in horizontal rectus EOMs could achieve more force than required by vertical fusional vergence.
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Affiliation(s)
- Joseph L Demer
- Department of Ophthalmology, University of California, Los Angeles, Los Angeles, California 90095-7002, USA.
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Microsurgical anatomy of the abducens nerve. Surg Radiol Anat 2011; 34:3-14. [DOI: 10.1007/s00276-011-0850-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 06/28/2011] [Indexed: 11/26/2022]
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Moon KS, Jung S, Lee KH, Lee MC. Cavernous Hemangioma of the Abducens Nerve: Clinical Implication of Duplicated Variants: Case Report. Neurosurgery 2011; 69:E756-60; discussion E760. [DOI: 10.1227/neu.0b013e31821bf957] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND AND IMPORTANCE:
A cavernous hemangioma arising from the abducens nerve has not been previously reported in the literature. Based on the surgical experience with this case, the authors discuss the clinical importance and resectability potential of a duplicated abducens nerve.
CLINICAL PRESENTATION:
A 54-year-old woman presented with a recurrence of diplopia that had occurred 3 years before this admission and had spontaneously resolved without any specific treatment. On admission, there were no specific neurological deficits. Magnetic resonance imaging revealed a cone-shaped mass on the right anterior cerebellopontine angle with hemorrhagic change. Surgical resection via a standard right lateral suboccipital approach was performed. A cystic mass was found emerging from the entry zone of the Dorello canal and encircling the larger branch of the duplicate abducens nerve. Because there was no demarcation between the mass and origin branch, both were removed en bloc. Pathology revealed the presence of a cavernous hemangioma mixed with nerve tissue. Despite preserving a small branch of the duplicate abducens nerve, the patient had permanent right abducens palsy.
CONCLUSION:
A cavernous hemangioma arising from the abducens nerve should be suspected as a possible diagnosis for a cystic mass on the anterior cerebellopontine angle. Although duplication of the abducens nerve has not been clearly confirmed on clinical grounds, sacrificing the larger branch during surgery may lead to permanent abducens palsy, as in our case.
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Affiliation(s)
- Kyung-Sub Moon
- Departments of Neurosurgery, Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Gwangju, South Korea
| | - Shin Jung
- Departments of Neurosurgery, Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Gwangju, South Korea
| | - Kyung-Hwa Lee
- Departments of Pathology, Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Gwangju, South Korea
| | - Min-Cheol Lee
- Departments of Pathology, Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Gwangju, South Korea
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da Silva Costa RM, Kung J, Poukens V, Yoo L, Tychsen L, Demer JL. Intramuscular innervation of primate extraocular muscles: unique compartmentalization in horizontal recti. Invest Ophthalmol Vis Sci 2011; 52:2830-6. [PMID: 21220556 PMCID: PMC3088565 DOI: 10.1167/iovs.10-6651] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 11/05/2010] [Accepted: 11/06/2010] [Indexed: 12/28/2022] Open
Abstract
PURPOSE It has been proposed that the lateral rectus (LR), like many skeletal and craniofacial muscles, comprises multiple neuromuscular compartments subserving different physiological functions. To explore the anatomic potential of compartmentalization in all four rectus extraocular muscles (EOMs), evidence was sought of possible regional selectivity in intramuscular innervation of all rectus EOMs. METHODS Whole orbits of two humans and one macaque monkey were serially sectioned at 10 μm thickness and stained with Masson's trichrome. Three-dimensional reconstruction was performed of the intramuscular courses of motor nerves from the deep orbit to the anterior extents of their arborizations within all four rectus EOMs in each orbit. RESULTS Findings concorded in monkey and human orbits. Externally to the global surface of the lateral (LR) and medial rectus (MR) EOMs, motor nerve trunks bifurcated into approximately equal-sized branches before entering the global layer and observing a segregation of subsequent arborization into superior zones that exhibited minimal overlap along the length of the LR and only modest overlap for MR. In contrast, intramuscular branches of the superior and the nasal portion of the inferior rectus were highly mixed. CONCLUSIONS Consistent segregation of intramuscular motor nerve arborization suggests functionally distinct superior and inferior zones within the horizontal rectus EOMs in both humans and monkeys. Reduced or absent compartmentalization in vertical rectus EOMs supports a potential functional role for differential innervation in horizontal rectus zones that could mediate previously unrecognized vertical oculorotary actions.
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Affiliation(s)
| | | | | | | | - Lawrence Tychsen
- Departments of Ophthalmology and Visual Sciences
- Anatomy and Neurobiology, and
- Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Joseph L. Demer
- From the Departments of Ophthalmology
- Neuroscience
- Neurology, and
- Bioengineering Interdepartmental Programs, University of California, Los Angeles, California; and
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Peng M, Poukens V, da Silva Costa RM, Yoo L, Tychsen L, Demer JL. Compartmentalized innervation of primate lateral rectus muscle. Invest Ophthalmol Vis Sci 2010; 51:4612-7. [PMID: 20435590 PMCID: PMC2941164 DOI: 10.1167/iovs.10-5330] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 03/26/2010] [Accepted: 03/27/2010] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Skeletal and craniofacial muscles are frequently composed of multiple neuromuscular compartments that serve different physiological functions. Evidence of possible regional selectivity in LR intramuscular innervation was sought in a study of the anatomic potential of lateral rectus (LR) muscle compartmentalization. METHODS Whole orbits of two humans and five macaque monkeys were serially sectioned at 10-microm thickness and stained with Masson trichrome. The abducens nerve (CN6) was traced anteriorly from the deep orbit as it branched to enter the LR and arborized among extraocular muscle (EOM) fibers. Three-dimensional reconstruction was performed in human and monkey orbits. RESULTS Findings were in concordance in the monkey and human orbits. External to the LR global surface, CN6 bifurcated into approximately equal-sized trunks before entering the global layer. Subsequent arborization showed a systematic topography, entering a well-defined inferior zone 0.4 to 2.5 mm more posteriorly than branches entering the largely nonoverlapping superior zone. Zonal innervation remained segregated anteriorly and laterally within the LR. CONCLUSIONS Consistent segregation of intramuscular CN6 arborization in humans and monkeys suggests functionally distinct superior and inferior zones for the LR. Since the LR is shaped as a broad vertical strap, segregated control of the two zones could activate them separately, potentially mediating previously unappreciated but substantial torsional and vertical oculorotary LR actions.
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Affiliation(s)
| | | | | | | | - Lawrence Tychsen
- the Departments of Ophthalmology and Visual Sciences
- Anatomy and Neurobiology, and
- Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Joseph L. Demer
- From the Departments of Ophthalmology and
- Neurology and
- the Neuroscience and
- Bioengineering Interdepartmental Programs, University of California, Los Angeles, Los Angeles, California; and
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Choi CY, Han SR, Yee GT, Lee CH. A case of aberrant abducens nerve in a cadaver and review of its clinical significance. J Korean Neurosurg Soc 2010; 47:377-80. [PMID: 20539798 DOI: 10.3340/jkns.2010.47.5.377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 02/24/2010] [Accepted: 03/22/2010] [Indexed: 11/27/2022] Open
Abstract
The abducens nerve usually travels from the brainstem to the lateral rectus muscle as a single trunk. However, it has been reported that this nerve could split into branches occasionally. We attempted to show the aberrant course of abducens nerve in a specimen with unilateral duplicated abducens nerve and review relevant literatures. The micro-dissections were performed in a head specimen injected with colored latex under the microscope. The abducens nerve was duplicated unilaterally. This nerve emerged from the pontomedullary sulcus as a single trunk and splitted into two branches in the prepontine cistern. These two separate branches were piercing the cerebral dura of the petroclival region respectively. The slender lower branch passed between the petroclinoid and petrosphenoid ligaments and the thick lower one passed under the petrosphenoid ligament. These two branches united just lateral to the ascending segment of internal carotid artery in the cavernous sinus. The fact that there are several types of aberrant abducens nerve is helpful to perform numerous neurosurgical procedures in the petroclival region and cavernous sinus without inadvertent neurovascular injuries.
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Affiliation(s)
- Chan-Young Choi
- Department of Neurosurgery, Ilsan Paik Hospital, College of Medicine, Inje University, Goyang, Korea
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Kim JH, Hwang JM. Normal abduction in a patient with duplicated abducens nerve. KOREAN JOURNAL OF OPHTHALMOLOGY 2006; 19:305-6. [PMID: 16491823 DOI: 10.3341/kjo.2005.19.4.305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To our knowledge, there has been no report of ophthalmologic findings related with a duplicated abducens nerve in the ophthalmic literature. This study reports such findings. METHODS An ophthalmologic examination was performed in one patient with a duplicated abducens nerve, revealed with thin-sectioned magnetic resonance imaging (MRI) across the brainstem level. RESULTS The MRI disclosed a duplicated left abducens nerve. The patient was orthotropic in five cardinal positions, and her ductions and versions were full. CONCLUSIONS One patient with a duplicated abducens nerve showed orthotropia and normal ocular movement.
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Affiliation(s)
- Jae Hyoung Kim
- Department of Radiology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
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Ziyal IM, Bozkurt G, Bilginer B, Gülsen S, Ozcan OE. Abducens Nerve Palsy in a Patient With a Parasagittal Meningioma. Neurol Med Chir (Tokyo) 2006; 46:98-100. [PMID: 16498221 DOI: 10.2176/nmc.46.98] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A 67-year-old female presented with isolated unilateral abducens nerve palsy progressing in 10 days. There were no signs of elevated intracranial pressure. Magnetic resonance imaging revealed a right parasagittal meningioma. The tumor was grossly totally removed and the patient's nerve palsy gradually improved within 3 weeks. The mechanism of the isolated abducens nerve palsy in this case is attributed to compression of the abducens nerve by entrapment of the cerebrospinal fluid just before entering Dorello's canal under the petrolingual ligament. Linear forces in the midsagittal plane due to the mass effect of the tumor may have temporarily increased the local cerebrospinal fluid pressure and caused 'pseudoentrapment' of the abducens nerve.
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Affiliation(s)
- Ibrahim M Ziyal
- Department of Neurosurgery, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
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Abstract
We studied the size of the clival region (length, widest and narrowest diameter, and distance between two jugular tuberculi) in 77 skull bases or occipital and sphenoid bones from skeletons aged 3-80 years. The comparison of the measurement points among the age groups (3-10, 11-25, 26-60, and 61-80 years) showed that the final length of the clivus was reached by 11 years of life in both men and women, and then remained constant throughout life. All other measurements did not differ among the age groups. Also, only the length of the clivus strongly correlated with age (Pearson's r = 0.336, P = 0.0028). It seems that the postnatal age up to 11 years of life is the crucial time of the development of the clivus, when the final adult width of the clivus is first reached, followed by the finalization of its growth in length.
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Affiliation(s)
- Jelena Krmpotić-Nemanić
- Department of Anatomy "Drago Perović", Medical Faculty Zagreb, Salata 11, 10000 Zagreb, Croatia
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Alkan A, Sigirci A, Ozveren MF, Kutlu R, Altinok T, Onal C, Sarac K. The cisternal segment of the abducens nerve in man: three-dimensional MR imaging. Eur J Radiol 2004; 51:218-22. [PMID: 15294328 DOI: 10.1016/j.ejrad.2003.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Revised: 10/03/2003] [Accepted: 10/07/2003] [Indexed: 11/24/2022]
Abstract
PURPOSE The goal of this study was to identify the abducens nerve in its cisternal segment by using three-dimensional turbo spin echo T2-weighted image (3DT2-TSE). The abducens nerve may arise from the medullopontine sulcus by one singular or two separated rootlets. MATERIAL AND METHODS We studied 285 patients (150 males, 135 females, age range: 9-72 years, mean age: 33.3 +/- 14.4) referred to MR imaging of the inner ear, internal auditory canal and brainstem. All 3D T2-TSE studies were performed with a 1.5 T MR system. Imaging parameters used for 3DT2-TSE sequence were TR:4000, TE:150, and 0.70 mm slice thickness. A field of view of 160 mm and 256 x 256 matrix were used. The double rootlets of the abducens nerve and contralateral abducens nerves and their relationships with anatomical structures were searched in the subarachnoid space. RESULTS We identified 540 of 570 abducens nerves (94.7%) in its complete cisternal course with certainty. Seventy-two cases (25.2%) in the present study had double rootlets of the abducens nerve. In 59 of these cases (34 on the right side and 25 on the left) presented with unilateral double rootlets of the abducens. Thirteen cases presented with bilateral double rootlets of the abducens (4.5%). CONCLUSION An abducens nerve arising by two separate rootlets is not a rare variation. The detection of this anatomical variation by preoperative MR imaging is important to avoid partial damage of the nerve during surgical procedures. The 3DT2-TSE as a noninvasive technique makes it possible to obtain extremely high-quality images of microstructures as cranial nerves and surrounding vessels in the cerebellopontine cistern. Therefore, preoperative MR imaging should be performed to detect anatomical variations of abducens nerve and to reduce the chance of operative injuries.
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Affiliation(s)
- Alpay Alkan
- Department of Radiology, Inonu University School of Medicine, 44069 Malatya, Turkey.
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