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. 2023 Feb;15(2):563-571.
doi: 10.1111/os.13535. Epub 2022 Oct 11.

Comparison of Perpendicular to the Coronal Plane versus Medial Inclination for C2 Pedicle Screw Insertion Assisted by 3D Printed Navigation Template

Chao Wu  1   2 , Jiayan Deng  2 , Qing Wang  3 , Danwei Shen  2 , Binwei Qin  3 , Tao Li  1 , Xiangyu Wang  1 , Baifang Zeng  1   3
Affiliations

Comparison of Perpendicular to the Coronal Plane versus Medial Inclination for C2 Pedicle Screw Insertion Assisted by 3D Printed Navigation Template

Chao Wu et al. Orthop Surg. 2023 Feb.

Abstract

Objective: C2 pedicle screw insertion is very important in posterior upper cervical surgery. The traditional screw placement technique requires us to consider both medial inclination and cephalad angle, it is difficult to operate intraoperatively. This paper is to explore a novel method of C2 pedicle screw placement compared with traditional C2 pedicle screw.

Methods: A total of 44 patients diagnosed with atlantoaxial fracture or instability from May 2018 to November 2020 were involved in this retrospective study, and they were divided into C2-PPS group (perpendicular to the coronal plane C2 screw, 24 patients) and C2-TPS group (traditional C2 pedicle screw, 20 patients). The diameter of the maximum tangential circle, distance between geometric center and median sagittal plane and screw length of PPS and TPS were measured based on the 3D model of C2, respectively. Then the 3D printed navigation templated were designed and manufactured by 3D printing to assisted the PPS and TPS placement, respectively. The surgical time and radiation exposure times during operation were recorded; the post-operative grading criteria, deviation of screw entry point and deviation of screw angle of two groups were evaluated, respectively.

Results: A total of 48 screws were inserted in the C2-PPS group, and 40 screws were inserted in the C2-TPS group. There were 46 screws with grade 0 (95.8%) in the PPS group and 31 screws with grade 0 (77.5%) in the TPS group, (P = 0.03). The radiation exposure times in the C2-PPS group and C2-TPS group were 4.7 ± 1.5 and 7.8 ± 3.8, respectively, (P = 0.045). The deviations of screw entry point in the C2-PPS group and C2-TPS group were 1.2 ± 0.8 mm and 3.2 ± 1.3 mm, respectively; the deviations of screw angle in the C2-PPS group and C2-TPS group were 2.1 ± 1.6° and 4.8 ± 2.0°, respectively, (P = 0.000). The diameters of the maximum tangential circle in the C2-PPS group and C2-TPS group were 5.5 ± 1.0 mm and 5.3 ± 0.9 mm, respectively. The distances between the geometric center and median sagittal plane in the C2-PPS group and C2-TPS group were 15.4 ± 2.3 mm and 18.0 ± 3.3 mm, respectively; The screw lengths in the C2-PPS group and C2-TPS group were 25.9 ± 3.2 mm and 27.6 ± 3.7 mm, respectively, (P = 0.000).

Conclusion: Eighty percent of C2-PPS corridor can accommodate a 3.5 mm diameter screw, and with an average screw length of 26 mm. Navigation templates assisted the C2-PPS placement is less surgical time, less radiation exposure times, more safe and more accurate than C2-TPS.

Keywords: Axis; Navigation templates; Pedicle screw.

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Figures

Fig. 1
Fig. 1
Acquisition of the trajectory of C2‐PPS and C2‐TPS. (A) Plane A was defined as a plane parallel to the upper edge of the C2 pedicle; (B) Plane C was defined as the median sagittal plane based on the 3D model of C2, the red circle show the maximum tangent circle of C2‐PPS and “D” represent the diameter of the circle; (C) The corridor of C2‐PPS is shown by red columns, and the center of the red columns represent the screw entry point of C2‐PPS, and the “distance” show the linear distance from entry point to the plane C; (D) “L” show the length of PPS based on the axial CT image of C2; (E) Plane B was formed by bilateral midpoint of superior and inferior articular processes, and root of dens C2; (F) Plane C was defined as the median sagittal plane based on the 3D model of C2. The green circle show the maximum tangent circle of C2‐TPS and “D” represent the diameter of the circle; (G) The corridor of C2‐TPS is shown by green columns, and the center of the green columns represent the screw entry point of TPS, and the “distance” show the linear distance from entry point to the plane C; (H) “L” show the length of TPS based on the axial CT image of C2
Fig. 2
Fig. 2
Design of the navigation template. (A) The navigation template for PPS is closely attached to C2; (B) Sketch of the navigation template for C2‐PPS; (C) The navigation template for TPS is closely attached to C2; (D) Sketch of the navigation template for TPS
Fig. 3
Fig. 3
The surgical procedure. (A) Lateral border of the C1‐C2 articulation was exposure; (B) The navigation template for C2‐PPS is closely attached to C2; (C) Two K‐wires with diameter of 2.0 mm were inserted; (D) Remove K‐wires and confirm the entry point pf C2‐PPS; (E), Screw with diameter of 3.5 mm were placed along the trajectory of C2‐PPS; (F), The screw and rod system is fixed of C2‐TPS group; (G) The navigation template for C2‐TPS is closely attached to C2; (H) The screw and rod system is fixed of C2‐TPS group
Fig. 4
Fig. 4
(A–H) Intraoperative and postoperative images of a 45‐year‐old female patient with an axis fracture in C2‐PPS group; (A, B), Intraoperative fluoroscopy of Kirschner wires were inserted; (C, D) Intraoperative fluoroscopy of screws were inserted; (E, F), Postoperative anteroposterior and lateral X‐ray; (G), Axial view of postoperative CT (Grade 0); (H), Sagittal CT 3 months postoperatively. (I–L), Intraoperative and postoperative images of a 41‐year‐old male patient with an axis fracture in C2‐TPS group; (I, J), Postoperative anteroposterior and lateral X‐ray; (K, L) Axial view of postoperative CT show a screw penetrated bone cortex greater than 2 mm, without any symptoms (Grade 0)
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References

    1. De Iure F, Donthineni R, Boriani S. Outcomes of C1 and C2 posterior screw fixation for upper cervical spine fusion. Eur Spine J. 2009;18(Suppl 1):2–6. 10.1007/s00586-009-0981-1 - DOI - PMC - PubMed
    1. Xu R, Bydon M, Macki M, et al. Biomechanical impact of C2 pedicle screw length in an atlantoaxial fusion construct. Surg Neurol Int. 2014;5(Suppl 7):S343–6. 10.4103/2152-7806.139664 - DOI - PMC - PubMed
    1. Tsuji T, Chiba K, Horiuchi Y, Urabe T, Fujita S, Matsumoto M. Atlantoaxial stabilization using C1 and C2 laminar screw fixation. Asian Spine J. 2017;11(2):314–8. 10.4184/asj.2017.11.2.314 - DOI - PMC - PubMed
    1. Ma W, Feng L, Xu R, et al. Clinical application of C2 laminar screw technique. Eur Spine J. 2010;19(8):1312–7. 10.1007/s00586-010-1447-1 - DOI - PMC - PubMed
    1. Hong X, Dong Y, Yunbing C, Qingshui Y, Shizheng Z, Jingfa L. Posterior screw placement on the lateral mass of atlas: an anatomic study. Spine. 2004;29(5):500–3. 10.1097/01.brs.0000113874.82587.33 - DOI - PubMed