The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion
Objective To determine the ideal Atlas (C1) lateral mass screw placement and trajectory using the intersection between the lateral mass and inferomedial edge of the posterior arch as an easily identifiable and reproducible medial reference point. Selection of an ideal entry point and trajectory of C...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Korean Spinal Neurosurgery Society
2021-06-01
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| Series: | Neurospine |
| Subjects: | |
| Online Access: | http://www.e-neurospine.org/upload/pdf/ns-2040814-407.pdf |
| _version_ | 1797329973826027520 |
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| author | Torphong Bunmaprasert Watcharapong Puangkaew Nantawit Sugandhavesa Wongthawat Liawrungrueang K. Daniel Riew |
| author_facet | Torphong Bunmaprasert Watcharapong Puangkaew Nantawit Sugandhavesa Wongthawat Liawrungrueang K. Daniel Riew |
| author_sort | Torphong Bunmaprasert |
| collection | DOAJ |
| description | Objective To determine the ideal Atlas (C1) lateral mass screw placement and trajectory using the intersection between the lateral mass and inferomedial edge of the posterior arch as an easily identifiable and reproducible medial reference point. Selection of an ideal entry point and trajectory of C1 lateral mass screw insertion can help to minimize neurovascular injuries. While various techniques for screw insertion have been proposed in the past, they all require extensive dissection of the C1 lateral mass, which can cause profuse bleeding. Methods Ninety-three 3-dimensional computed tomography reconstructed images of C1 lateral masses in adult patients were utilized to simulate the placement of C1 lateral mass screws via 4 entry points and 2 trajectory angles referencing off of a medial reference point using Vero’s VISI 17 software. The safety during screw insertion simulation, as well as the screw length, were evaluated. Results We found that C1 lateral mass screws could be safely placed bilaterally at 3 mm lateral to the reference point in both 0° and 15° medial screw angulation without violation of the cortex. The 15° medial angulation allowed for longer (18 mm) screws than the 0° angulation. Conclusion We recommend starting C1 lateral mass screws 3 mm lateral to the intersection between the lateral mass and inferomedial edge of the posterior arch at a 15° medial angulation. |
| first_indexed | 2024-03-08T07:13:05Z |
| format | Article |
| id | doaj.art-f480da6606a74df5bc035427646a7c44 |
| institution | Directory Open Access Journal |
| issn | 2586-6583 2586-6591 |
| language | English |
| last_indexed | 2024-03-08T07:13:05Z |
| publishDate | 2021-06-01 |
| publisher | Korean Spinal Neurosurgery Society |
| record_format | Article |
| series | Neurospine |
| spelling | doaj.art-f480da6606a74df5bc035427646a7c442024-02-03T02:10:29ZengKorean Spinal Neurosurgery SocietyNeurospine2586-65832586-65912021-06-0118232833510.14245/ns.2040814.4071151The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw InsertionTorphong Bunmaprasert0Watcharapong Puangkaew1Nantawit Sugandhavesa2Wongthawat Liawrungrueang3K. Daniel Riew4 Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Department of Orthopaedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Department of Orthopedic Surgery, NewYork-Presbyterian Och Spine Hospital/Columbia University Irving Medical Center, New York, NY, USAObjective To determine the ideal Atlas (C1) lateral mass screw placement and trajectory using the intersection between the lateral mass and inferomedial edge of the posterior arch as an easily identifiable and reproducible medial reference point. Selection of an ideal entry point and trajectory of C1 lateral mass screw insertion can help to minimize neurovascular injuries. While various techniques for screw insertion have been proposed in the past, they all require extensive dissection of the C1 lateral mass, which can cause profuse bleeding. Methods Ninety-three 3-dimensional computed tomography reconstructed images of C1 lateral masses in adult patients were utilized to simulate the placement of C1 lateral mass screws via 4 entry points and 2 trajectory angles referencing off of a medial reference point using Vero’s VISI 17 software. The safety during screw insertion simulation, as well as the screw length, were evaluated. Results We found that C1 lateral mass screws could be safely placed bilaterally at 3 mm lateral to the reference point in both 0° and 15° medial screw angulation without violation of the cortex. The 15° medial angulation allowed for longer (18 mm) screws than the 0° angulation. Conclusion We recommend starting C1 lateral mass screws 3 mm lateral to the intersection between the lateral mass and inferomedial edge of the posterior arch at a 15° medial angulation.http://www.e-neurospine.org/upload/pdf/ns-2040814-407.pdfatlantoaxial fixationc1 lateral mass screw fixationisolated medial referenceinferomedial edge of posterior c1 archmediolateral trajectorycraniocaudal trajectory |
| spellingShingle | Torphong Bunmaprasert Watcharapong Puangkaew Nantawit Sugandhavesa Wongthawat Liawrungrueang K. Daniel Riew The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion Neurospine atlantoaxial fixation c1 lateral mass screw fixation isolated medial reference inferomedial edge of posterior c1 arch mediolateral trajectory craniocaudal trajectory |
| title | The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion |
| title_full | The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion |
| title_fullStr | The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion |
| title_full_unstemmed | The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion |
| title_short | The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion |
| title_sort | intersection between lateral mass and inferomedial edge of the c1 posterior arch a reference point for c1 lateral mass screw insertion |
| topic | atlantoaxial fixation c1 lateral mass screw fixation isolated medial reference inferomedial edge of posterior c1 arch mediolateral trajectory craniocaudal trajectory |
| url | http://www.e-neurospine.org/upload/pdf/ns-2040814-407.pdf |
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