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.

The Feasibility of Anterior Occipital Condyle Screw for the Reconstruction of Craniovertebral Junction: A Digital Anatomical and Cadaveric Study of a Novel Technique

“…14,28,29 Similarly, clival screw and plate fixation was also reported as a feasible technique for craniovertebral reconstruction in anatomy. 30 However, both these surgical methods have some disadvantages. There are some complications and risks of aforementioned methods including 1) the inner structure of clivus was the epencephalon and foramen magnum which contains medulla oblongata and it may be injured when inserting the clival screw.…”

The Feasibility of Anterior Occipital Condyle Screw for the Reconstruction of Craniovertebral Junction: A Digital Anatomical and Cadaveric Study of a Novel Technique

“…And en bloc resection is a popular operation method for upper cervical reconstruction, which has been reported achieved desired clinical e cacy [6,12,13]. Similarly, clival screw and plate xation was also reported as a feasible technique for craniovertebral reconstruction in anatomy [14].…”

Cervical Alignment of Patients with Basilar Invagination: A Radiological Study

“…In our previous research, the characteristics of the cranial-cervical spinal canal 16 , the thickness of the occipital bone 17 , and the anatomic feature of clivus with atlas assimilation 32 were investigated in patients with congenital malformation in CVJ region. The present study described the cervical curvature and the ROMs of relative parameters in BI patients, supplementing the lack of the morphological feature of cervical alignment in this population.…”