C2 medial pedicle screw: a novel “in-out-in” technique as an alternative option for posterior C2 fixation in cases with a narrow C2 isthmus

Du, Yue-Qi; Yin, Yong; Qiao, Guangyu; Yu, Xinguang

doi:10.3171/2020.2.spine191517

Cited by 14 publications

(19 citation statements)

References 32 publications

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“…Pedicle screws insertion is the commonly used technique for C2 fixation. Pedicle screws are combined with C1 lateral mass screws to perform Goel-Harms technique, which is a widely used fixation technique in clinical practice [ 3 , 11 ]. The C2 pedicle screw can directly fix the isthmus and pedicle as a result of its long implant depth, good pull-out strength, and biomechanical stability [ 6 ].…”

Section: Discussionmentioning

confidence: 99%

“…Du et al and Lee et al have reported the medial “in–out-in” technique, which prevents VA injury by opening a window through the wall of the spinal canal to achieve multi-cortical tri-column fixation. Although no spinal cord injury has been reported, the screw entering the spinal canal poses a certain threat to the spinal cord [ 3 , 13 ]. Additionally, Goel performed the VA transposition technique, using two smaller screws for fixation.…”

Section: Discussionmentioning

confidence: 99%

“…Although no spinal cord injury has been reported, the screw entering the spinal canal poses a certain threat to the spinal cord [3,13]. Additionally, Goel performed the VA transposition technique, using two smaller screws for fixation.…”

Section: Discussionmentioning

confidence: 99%

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Application of C2 subfacetal screws for the management of atlantoaxial dislocation in patients with Klippel-Feil syndrome characterized by a narrow C2 pedicle and high-riding vertebral artery

et al. 2022

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Objective This study aims to investigate the clinical application and feasibility of C2 subfacetal screws in patients with Klippel-Feil syndrome (KFS), narrow C2 pedicles, and high-riding vertebral arteries (HRVAs). Methods The clinical data of seven patients with KFS, atlantoaxial dislocation, narrow C2 pedicles, and HRVAs treated with C2 subfacetal screws were analyzed in this retrospective study. The internal height, isthmus height, and pedicle width of C2 vertebra were measured using preoperative computed tomography (CT). Subfacetal screws were inserted for 7 patients (12 sides). The position and length of the screws were observed using postoperative CT. Intraoperative dura mater and vertebral artery (VA) injuries were recorded. Bone fusion was observed using follow-up CT. Results The internal height was 10.5 ± 3.2 mm, the isthmus height was 3.7 ± 1.8 mm, the pedicle width was 3.0 ± 1.4 mm, and the screw length was 19.7 ± 1.5 mm. All patients had HRVAs and narrow pedicles. No injury to the dura mater and vertebral artery (VA) occurred in this group of patients. Bone fusion was achieved in all patients during follow-up. Conclusions In patients with KFS, HRVA, and a narrow C2 pedicle, there is sufficient space below the C2 articular surface for screw insertion. When the pedicle is narrow and the C2 pedicle screw is not suitable for placement due to possible injury to the VA, subfacetal screws are a feasible alternative.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Application of C2 subfacetal screws for the management of atlantoaxial dislocation in patients with Klippel-Feil syndrome characterized by a narrow C2 pedicle and high-riding vertebral artery

et al. 2022

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“…This contrasts with the findings of the present study, which show that the cervical vertebrae in children between the ages of eight and 14 years were still growing. The C2 “in‐out‐of‐in” technique has been available for years (Du et al, 2020). For children with narrow pedicles and high vertebral artery spans, the screw length should be increased and the width decreased.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of 3.5 mm C2 pedicle screws in children: A computerized tomography analysis

Chen

Cen

et al. 2022

Clinical Anatomy

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There have been no studies with large sample sizes on growth of the pedicle of C2 in children. In the present study we measured the pedicle of C2 through computed tomography (CT) imaging in children aged less than 14 years and evaluated the suitability of the 3.5‐mm screw for the pedicle in such children. The study was conducted on CT morphometric images of 420 children in our hospital between June 2018 and June 2020. The width (D1), length (D2), height (D3), inclination angle (α), and tail angle (β) of the C2 pedicle were measured. One‐way analysis of variance and Student's t test were used for statistical analyses. The least‐square method was used to analyze the curve fitting the trend of anatomical change in the pedicle. The largest degree of goodness of fit determined the best‐fitting curve. The size of the pedicle of C2 increased with age. The median ranges of D1, D2, D3, α, and β were 3.312–5.431 mm, 11.732–23.645 mm, 3.597–8.038 mm, 32.583°–36.640°, and 24.867°–31.567°, respectively. The curves fitting the trends of D1 and D3 were power functions, whereas D2 was fitted by a logarithmic curve. However, no curve fitted α or β. A 3.5‐mm screw can be placed in the pedicle of C2 in children aged more than 1 year. The growth and development trend of this pedicle can provide an anatomical reference for deciding on posterior cervical surgery and for selecting and designing pedicle screws for children.

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“…Routt et al suggested iliosacral screw insertion into the sacral isthmus region required avoidance of IOI to reduce the risk of damage to the adjacent neurovascular structures 12 . Du et al recommended the C2 pedicle screw IOI to provide multicortical 3-column rigid xation in the patients with basilar invagination and atlantoaxial dislocation 13 . Ramesh et al proposed anterior column lag screw IOI in the xation of acetabular fractures to provide rigid stability and minimize the surgical duration, radiation exposure, and intra-operative complications 14 .…”

Section: Discussionmentioning

confidence: 99%

How to avoid the posterosuperior femoral neck screw in-out-in intraoperatively: The application of the 150° oblique tangential fluoroscopic view

Zhang

Tang

2022

Preprint

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Objective: This study investigates the application of the 150° tangential fluoroscopic projection as a novel fluoroscopic view to detect the posterosuperior screw in-out-in (IOI) in the inverted triangle cannulated screws fixation of femoral neck fractures.Methods: A retrospective analysis was conducted including 33 patients with femoral neck fractures enrolled from April to November 2021. All patients underwent closed reduction and internal fixation with inverted triangular cannulated screws under intra-operative C-arm fluoroscopy. The posterosuperior femoral neck screw position (whether in-out-in and the distance to the femoral neck cortex) was evaluated from the standard anteroposterior (AP), lateral view, and tangential view images. Postoperative computed tomography (CT) scan results are considered the gold standard for detecting the femoral neck screw locations.Results: Of 33 patients, no femoral neck screws were found to be placed IOI under the standard AP and lateral views. The tangential view revealed the posterosuperior screw was IOI in 8 patients, whereas the average distance between the posterosuperior screw and the posterior femoral neck cortex was 2.73±1.06 mm under the standard lateral view. Postoperative CT verified that posterosuperior screw was placed IOI in these 8 patients. In the other 25 patients, the average distance between the posterosuperior screw and the posterior femoral neck cortex was 5.48±1.26 mm under the standard lateral view and 2.76±1.08 mm under the tangential view, with a statistically significant difference between the two groups (p<0.05). Post-operative CT demonstrated that the femoral neck screws were completely contained in the femoral neck in these 25 patients.Conclusions: Intra-operative tangential view of 150° can effectively identify the posterosuperior screw IOI in the inverted triangle cannulated screws fixation of femoral neck fractures. Based on our study, we highly recommend the tangential view as a routine intraoperative fluoroscopic angle to avoid the posterosuperior screw IOI.

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C2 medial pedicle screw: a novel “in-out-in” technique as an alternative option for posterior C2 fixation in cases with a narrow C2 isthmus

Cited by 14 publications

References 32 publications

Application of C2 subfacetal screws for the management of atlantoaxial dislocation in patients with Klippel-Feil syndrome characterized by a narrow C2 pedicle and high-riding vertebral artery

Application of C2 subfacetal screws for the management of atlantoaxial dislocation in patients with Klippel-Feil syndrome characterized by a narrow C2 pedicle and high-riding vertebral artery

Feasibility of 3.5 mm C2 pedicle screws in children: A computerized tomography analysis

How to avoid the posterosuperior femoral neck screw in-out-in intraoperatively: The application of the 150° oblique tangential fluoroscopic view

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