title: Clival Screw Placement in Patient with atlas assimilation: A CT-based feasibility study.
abstract: Clival screw and plate fixation technique is an alternative or supplement to the occipitocervical instrumentation. However, no report has clarified the applied anatomy of clivus in patients with atlas assimilation (C1A), especially for clival screw fixation. Therefore, we measured the parameters of clival lengths, widths, putative screw lengths, clival-cervical angel and foramen magnum diameters on CT images in a cohort of 81 C1A patients and patients without C1A. The clivus showed a rectangular shape in 96.3% (78/81) of C1A patients, and a normal-like triangle shape in 3.7% (3/81) of C1A patients. The intracranial clival length decreased 13% (37 mm) in C1A patients, the extracranial clival length 14.8% (24.1 mm), the clival-cervical angle 6.2% (122.3°) and the superior screw length 11.3% (14.1 mm), the sagittal diameter of foramen magnum 16% (28.0 mm), respectively. There was no significant difference in the widest or narrowest clival width, or the middle screw length, or the transverse diameter of foramen magnum between groups. The inferior clivus was feasible for an average 9.7-mm-length screw placement in C1A patients, while not in patients without C1A. The present study characterizes clivus of C1A patients with an unnormal-like rectangular shape, and confirmes a screw placement at the inferior clivus.
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Hospital of Orthopaedics, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), 111 Liuhua Road, Guangzhou, China.
authors.forename: Wenhan
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Zucheng
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Jianting
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Qingan
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Hospital of Orthopaedics, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), 111 Liuhua Road, Guangzhou, China.
authors.forename: Zenghui
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000328:Adult; D001863:Bone Screws; D003388:Cranial Fossa, Posterior / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery; D005260:Female; D005539:Foramen Magnum / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012887:Skull Fractures / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed