caa a22 4500 445835133 CHVBK 20180317145328.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1007/s00586-011-1893-4 doi (NATIONALLICENCE)springer-10.1007/s00586-011-1893-4 The options of C2 fixation for os odontoideum: a radiographic study for the C2 pedicle and lamina anatomy [Elektronische Daten] [Xian-zhong Meng, Jia-xin Xu] Introduction: Patients with os odontoideum always present instability in atlantoaxial joint and need atlantoaxial fixation. C2 pedicle or laminar screws fixation has proven to be efficient and reliable for atlantoaxial instability. However, os odontoideum is a congenital or developmental disease, featured with anomalous bony anatomies. The anatomic measurements and guidelines for C2 pedicle screw placement in general population tends to differ with those of os odontoideum patients, for whom C2 pedicle screws are often needed. The option and techniques of C2 fixation are still challenging and yet to be fully explored. Material and methods: We recruited 29 adult patients with os odontoideum and measured the dimension of C2 pedicle and lamina for each patient to examine how well do they match with the screws anatomically. In order to access the intra-observer reliability and inter-observer repeatability of the measurements, the intraclass correlation coefficient (ICC) was also calculated. Results: The results for reliability of the CT measurements showed excellent intraobserver (ICC=0.95 and 0.96) and interobserver correlation coefficient (ICC=0.93). The diameter and length of C2 pedicle were found to be 6.06±1.37 and 24.05±2.54mm, while the corresponding figures of C2 laminar were 6.95±0.82 and 25.60±2.18mm, respectively. In the measurements, all 29 cases had suitable diameter (larger than 5.5mm) for C2 laminar screw (the laminar diameters ranged from 5.52 to 8.82mm). In C2 pedicle measurements, the diameters of the 29 cases were from 3.50 to 9.86mm, while 20 pedicles (34.5%) in 14 cases were less than 5.5mm in diameter. Six had bilateral small pedicles where the diameter was less than 5.5mm. Conclusion: Anatomically, we found laminar screw is a better match in comparison with pedicle screw for C2 fixation in os odontoideum. The options for C2 fixation should be made based on careful preoperative imaging and thorough consideration. Preoperative reconstructive CT scan can offer great assistance for the choice of fixation in os odontoideum by revealing the anatomy of the C2 pedicles in detail. Springer-Verlag, 2011 Os odontoideum pedicle screw nationallicence Laminar screw nationallicence C2 fixation nationallicence Meng Xian-zhong Department of Spine, Hebei Medical University Third Hospital, No. 139, Zi-qiang Street, 050051, Shijiazhuang, Hebei, China aut Xu Jia-xin Department of Spine, Hebei Medical University Third Hospital, No. 139, Zi-qiang Street, 050051, Shijiazhuang, Hebei, China aut European Spine Journal Springer-Verlag 20/11(2011-11-01), 1921-1927 0940-6719 20:11<1921 2011 20 586 https://doi.org/10.1007/s00586-011-1893-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00586-011-1893-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Meng Xian-zhong Department of Spine, Hebei Medical University Third Hospital, No. 139, Zi-qiang Street, 050051, Shijiazhuang, Hebei, China aut NATIONALLICENCE 700 1- Xu Jia-xin Department of Spine, Hebei Medical University Third Hospital, No. 139, Zi-qiang Street, 050051, Shijiazhuang, Hebei, China aut NATIONALLICENCE 773 0- European Spine Journal Springer-Verlag 20/11(2011-11-01), 1921-1927 0940-6719 20:11<1921 2011 20 586 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer