Fluoroscopically guided anterior atlantoaxial transarticular screws: a feasibility and trajectory study using CT-based simulation software

Abstract

BACKGROUND CONTEXT: Anterior transarticular screw (ATAS) fixation has been suggested as a viable alternative to posterior stabilization. However, we are not aware of previous reports attempting to establish the usefulness of specific fluoroscopic landmark-guided trajectories in the use of ATAS, and we could find no reference to it in a computerized search using MEDLINE. PURPOSE: To determine the anatomic feasibility of ATAS placement using defined fluoroscopic landmarks to guide screw trajectory. STUDY DESIGN: Evaluation using three-dimensional screw insertion simulation software and 1.0-mm-interval computed tomographic scans. PATIENT SAMPLE: Computed tomographic scans of 100 patients including 50 men and 50 women. OUTCOME MEASURES: Incidence of violation of the vertebral artery groove of C1 and C2, the spinal canal, and the atlanto-occipital joint and screw lengths and lengths of C1 and C2 purchase. METHODS: Four screw trajectories were determined: promontory screw (PS), single central facet (CF) screw, and medial (MF) and lateral (LF) double facet screws. Placement of a 4.0-mm screw was simulated using defined fluoroscopic landmarks for each trajectory. The previously mentioned outcome measures were evaluated and compared for the four trajectories. This study was not supported by any financial sources, and there is no topic-specific potential conflict of interest with this study. The disclosure key can be found on the CONCLUSIONS:Our results suggest that it may be possible to place ATASs without violating the vertebral artery groove, spinal canal, or the atlanto-occipital joint by using the described entry points, trajectories, and fluoroscopic landmarks. Ó

A Review of the Diagnosis and Treatment of Atlantoaxial Dislocations

“…It provides a safer and more appropriate environment with high fusion rates and only minor complications for challenging cases such as patients with osteolysis in infectious or tumorous conditions, aberrant vertebral artery, and/or narrow pars interarticularis. 83 However, there are concerns about safe screw dimension, insertion, and trajectory. One study analyzed the feasibility of anterior transarticular screw fixation in 100 patients and recommended reliable fluoroscopic landmarks with minor complications and threshold lengths of C1 purchase screws during this procedure.…”

Feasibility and trajectory study of anterior transarticular crossing screw placement for atlantoaxial joint instability: a cadaveric study and description of a novel technique

“…Two years later, the same team performed a biomechanical study and confirmed the effectiveness of this technique in atlantoaxial stabilization [4]. Since then, some modification in surgical techniques using minimally invasive or percutaneous surgical procedures have been reported [5][6][7][8][9][10].…”

An Infantile Alantoaxial Dislocation with Patent Foramen Ovale Managed with Titanium Cabling and Allogenic Bone Grafts

“…This approach offers a securer and extra suitable milieu with high fusion rates and negligible hitches for difficult cases like in patients with osteolysis in infectious or tumorous disorders, aberrant vertebral artery, and/or narrow pars interarticularis. 1 , 8 , 50 However, safe screw dimension, insertion, and trajectory are the major short comings with the approach. 1 …”