Sagittal alignment correlates with the C1-C2 fixation angle and functional outcome after posterior atlantoaxial fixation for traumatic atlantoaxial instability

✓ The authors placed titanium mesh cages to achieve posterior atlantoaxial fixation in five patients with atlantoaxial instability caused by rheumatoid arthritis or os odontoideum. A mesh cage packed with autologous cancellous bone was placed between the C-1 posterior arch and the C-2 lamina and was tightly connected with titanium wires. Combined with the use of transarticular screws, this procedure provided very rigid fixation. Solid fusion was achieved in all patients without major complications. The advantages of this method include more stable fixation, better control of the atlantoaxial fixation angle, and reduced donor-site morbidity compared with a conventional atlantoaxial arthrodesis in which an autologous iliac crest graft is used.

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Unstable odontoid fractures: technical appraisal of anterior extrapharyangeal open reduction internal fixation for irreducible unstable odontoid fractures. Patient series

Journal of Neurosurgery: Case Lessons ◽

10.3171/case21501 ◽

2021 ◽

Vol 2 (20) ◽

Author(s):

Sushil Patkar

Keyword(s):

Open Reduction ◽

Facet Joint ◽

Open Reduction Internal Fixation ◽

Atlantoaxial Instability ◽

Rigid Fixation ◽

Atlantoaxial Joint ◽

Fracture Fragment ◽

Odontoid Fractures ◽

Atlantoaxial Fixation ◽

Displaced Fracture

BACKGROUND Displaced odontoid fractures that are irreducible with traction and have cervicomedullary compression by the displaced distal fracture fragment or deformity caused by facetal malalignment require early realignment and stabilization. Realignment with ultimate solid fracture fusion and atlantoaxial joint fusion, in some situations, are the aims of surgery. Fifteen such patients were treated with direct anterior extrapharyngeal open reduction and realignment of displaced fracture fragments with realignment of the atlantoaxial facets, followed by a variable screw placement (VSP) plate in compression mode across the fracture or anterior atlantoaxial fixation (transarticular screws or atlantoaxial plate screw construct) or both. OBSERVATIONS Anatomical realignment with rigid fixation was achieved in all patients. Fracture fusion without implant failure was observed in 100% of the patients at 6 months, with 1 unrelated mortality. Minimum follow-up has been 6 months in 14 patients and a maximum of 3 years in 4 patients, with 1 unrelated mortality. LESSONS Most irreducible unstable odontoid fractures can be anatomically realigned by anterior extrapharyngeal approach by facet joint manipulation. Plate (VSP) and screws permit rigid fixation in compression mode with 100% fusion. Any associated atlantoaxial instability can be treated from the same exposure.

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Is Initial Posterior Atlantoaxial Fixation and Fusion Applying Bilateral C1–2 Transarticular Screws and C1 Laminar Hooks Reliable for Acute Pediatric Atlantoaxial Instability?

Spine ◽

10.1097/brs.0000000000003259 ◽

2020 ◽

Vol 45 (4) ◽

pp. 244-249

Author(s):

Xiang Guo ◽

Zhao Han ◽

Qunxiang Chen ◽

Jun Yang ◽

Fei Chen ◽

...

Keyword(s):

Atlantoaxial Instability ◽

Atlantoaxial Fixation ◽

Laminar Hooks

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3D-Customized Guiding Template for Posterior Fixation in Complex Atlantoaxial Instability—Preliminary Experiences of National Cheng Kung University Hospital

Journal of Neurological Surgery Reports ◽

10.1055/s-0039-1695795 ◽

2020 ◽

Vol 81 (01) ◽

pp. e20-e27

Author(s):

Yi-Yun Chen ◽

Liang-Chun Chao ◽

Jing-Jing Fang ◽

E-Jian Lee

Keyword(s):

Three Dimensional ◽

University Hospital ◽

Atlantoaxial Instability ◽

Posterior Fixation ◽

Screw Insertion ◽

Anatomical Abnormality ◽

Spine Model ◽

Atlantoaxial Fixation ◽

3D Printed ◽

Complex Cases

Objective Atlantoaxial fixation is technically demanding and challenging, especially in cases with anatomical abnormality. The purpose of this study is to report the effectiveness of the three-dimensional (3D)-customized guiding template for placement of C1 and C2 screws in cases with abnormalities. Method Two patients with anatomical abnormality and one without were included. The preoperative computed tomography (CT) image was analyzed using our software. The entry point, trajectory, and depth of the screws were designed based on these images. Templates with screw guiding cylinders and cervical spine model were created. In operation, guiding templates were applied directly to the laminae. Drilling, tapping, and screwing were performed through the cylinders. To evaluate the accuracy, deviation of the screw axis from the preplanned trajectory was measured on postoperative CT. A classification system was taking to evaluate the pedicle screw insertion. Results In complex cases, one of C2 screws has grade 2 deviation, and two has grade 1. There was no deviation in screws of C1. All patients achieved symptoms free after 6 months follow-up. Conclusion Although 3D-printed template for atlantoaxial fixation still has limitation in complex cases, it has been proved usefulness and makes the most difficult and dangerous spinal posterior fixation easy to achieve.

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Relationship between the atlantodental interval and T1 slope after atlantoaxial fusion in patients with rheumatoid arthritis

BMC Surgery ◽

10.1186/s12893-020-00900-x ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Byeong Jin Ha ◽

Yu Deok Won ◽

Je Il Ryu ◽

Myung-Hoon Han ◽

Jin Hwan Cheong ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Sagittal Alignment ◽

Multivariate Logistic Regression Analysis ◽

Atlantoaxial Instability ◽

Atlantoaxial Fusion ◽

T1 Slope ◽

Significant Difference ◽

Cervical Sagittal Alignment ◽

Before And After ◽

Atlantodental Interval

Abstract Background Atlantoaxial fusion has been widely used for the treatment of atlantoaxial instability (AAI). However, atlantoaxial fusion sacrifices the motion of atlantoaxial articulation, and postoperative loss of cervical lordosis and aggravation of cervical kyphosis are observed. We investigated various factors under the hypothesis that the atlantodental interval (ADI) and T1 slope may be associated with sagittal alignment after atlantoaxial fusion in patients with rheumatoid arthritis (RA). Methods We retrospectively investigated 64 patients with RA who underwent atlantoaxial fusion due to AAI. Radiological factors, including the ADI, T1 slope, Oc-C2 angle, cervical sagittal vertical axis, and C2–C7 angle, were measured before and after surgery. Results The various factors associated with atlantoaxial fusion before and after surgery were compared according to the upper and lower preoperative ADIs. There was a significant difference in the T1 slope 1 year after surgery (p = 0.044) among the patients with lower preoperative ADI values. The multivariate logistic regression analysis showed that the preoperative ADI (> 7.92 mm) defined in the receiver-operating characteristic curve analysis was an independent predictive factor for the increase in the T1 slope 1 year after atlantoaxial fusion (odds ratio, 4.59; 95% confidence interval, 1.34–15.73; p = 0.015). Conclusion We found an association between the preoperative ADI and difference in the T1 slope after atlantoaxial fusion in the patients with RA. A preoperative ADI (> 7.92 mm) was an independent predictor for the increase in the T1 slope after atlantoaxial fusion. Therefore, performing surgical treatment when the ADI is low would lead to better cervical sagittal alignment.

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The Role of Transverse Connectors in C1-C2 fixation for Atlantoaxial Instability: Is It Necessary? A Biomechanical Study

World Neurosurgery ◽

10.1016/j.wneu.2020.04.247 ◽

2020 ◽

Vol 140 ◽

pp. e212-e218

Author(s):

Teng Li ◽

Chao Ma ◽

Yue-Qi Du ◽

Guang-Yu Qiao ◽

Xin-Guang Yu ◽

...

Keyword(s):

Biomechanical Study ◽

Atlantoaxial Instability ◽

C2 Fixation

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Atlantoaxial Fixation for Basilar Invagination without Obvious Atlantoaxial Instability (Group B Basilar Invagination): Outcome Analysis of 63 Surgically Treated Cases

World Neurosurgery ◽

10.1016/j.wneu.2016.11.093 ◽

2017 ◽

Vol 99 ◽

pp. 164-170 ◽

Cited By ~ 32

Author(s):

Atul Goel ◽

Prashant Sathe ◽

Abhidha Shah

Keyword(s):

Basilar Invagination ◽

Atlantoaxial Instability ◽

Outcome Analysis ◽

Atlantoaxial Fixation ◽

Group B

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Subaxial Sagittal Alignment After Atlantoaxial Fixation Techniques

Journal of Spinal Disorders & Techniques ◽

10.1097/bsd.0000000000000144 ◽

2015 ◽

Vol 28 (1) ◽

pp. E49-E55 ◽

Cited By ~ 16

Author(s):

Shigeki Oshima ◽

Hideki Sudo ◽

Manabu Ito ◽

Kuniyoshi Abumi

Keyword(s):

Sagittal Alignment ◽

Fixation Techniques ◽

Atlantoaxial Fixation

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C1-C2 screw fixation in the patient with anomalous course of vertebral artery: Case report

Vojnosanitetski pregled ◽

10.2298/vsp160622143i ◽

2019 ◽

Vol 76 (5) ◽

pp. 555-558 ◽

Cited By ~ 1

Author(s):

Drazen Ivetic ◽

Goran Pavlicevic ◽

Branislav Antic

Keyword(s):

Case Report ◽

Vertebral Artery ◽

Screw Fixation ◽

Atlantoaxial Instability ◽

Complicated Structure ◽

Neurological Improvement ◽

Degenerative Disorders ◽

Translaminar Screw ◽

Atlantoaxial Fixation ◽

Alternative Fixation

Introduction. The atlantoaxial complex is a very complicated structure and open reduction of C1-C2 subluxation is very demanding. Atlantoaxial instability may result from the traumatic, inflammatory, neoplastic, congenital or degenerative disorders. Anatomy of the vertebral artery is essential for surgical approach and sometimes the placement of C2 pedicle screw is not possible. In these instances, the translaminar screw placement in C2 can provide an alternative fixation point in C2, without threatening injury to the vertebral artery. Case report. We presented 54- year-old patient with cervical myelopathy according to traumatic atlantoaxial subluxation. Computed tomography angiography showed a bilateral vertebral artery anomaly of ?high-riding? type. The patient was operated and the posterior C1-C2 screws fixation was used. Due to the vertebral artery anomaly C2 screws were translaminary inserted. Complete reduction of C1-C2 subluxation and excellent neurological improvement were achieved. Conclusion. Surgical treatment of C1-C2 subluxation is very challenging. Many techniques of atlantoaxial fixation have been developed. The use of C2 translaminar screw is an alternative method of fixation in the treatment of atlantoaxial instability, especially in cases with the vertebral artery anomaly.

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