Entry Point Variation in the Osseous Fixation Pathway of the Anterior Column of the Pelvis—A Three-Dimensional Analysis

Abstract

Fractures of the superior pubic ramus can be treated with screw insertion into the osseous fixation pathway (OFP) of the anterior column (AC). The entry point determines whether the screw exits the OFP prematurely. This can be harmful when it enters the hip joint or damages soft tissues inside the lesser pelvis. The exact entry point varies between patients and can be difficult to ascertain on fluoroscopy during surgery. The aim of this study was to determine variation in the location of the entry point. A retrospective single center study was performed at a level 1 trauma center in the Netherlands. Nineteen adult patients were included with an undisplaced fracture of the superior pubic ramus on computer tomography (CT)-scan. Virtual three-dimensional (3D) models of the pelvises were created. Multiple screws were placed per AC and the models were superimposed. A total of 157 screws were placed, of which 109 did not exit the OFP prematurely. A universally reproducible entry point could not be identified. A typical crescent shaped region of entry points did exist and was located more laterally in females when compared to males. Three-dimensional virtual surgery planning can be helpful to identify the ideal entry points in each case.

Augmented reality-based surgical navigation of pelvic screw placement: an ex-vivo experimental feasibility study

“…Anchoring of implants is most important in poor bone quality and a significant issue in the development of surgical procedures. Here AR-navigated screws achieved this goal above expectation [ 25 – 27 ].…”

“…Published clinical results from a CT study show high variation in entry point positioning due to 14-38 mm variation in the horizontal plane and 9–15.9 mm in the vertical plane for the entry point in AC column screws [ 27 ]. The comparison of translational screw deviation between conventional technique 5.1 ± 3.0 mm, 2D-fluoroscopy based navigation 5.5 ± 3.0 mm, and 3D-fluoroscopy based navigation 4.7 ± 2.5 mm has also been examined before [ 9 ].…”

Augmented Reality-Based Surgical Navigation of Pelvic Screw Placement. Feasibility, Technique, and Limitations

“…Anchoring of implants is most important in poor bone quality and a signi cant issue in the development of surgical procedures. Here AR-navigated screws achieved this goal above expectation [25] [26] [27].…”

“…The perforation risk depends on the anatomic features of the respective pelvic region and the desired diameter of the screw to be placed in that anatomy. Together with the given system accuracy, it can now be determined whether the technique is suitable for the speci c surgical task [25] [26] [27] [28] [29].…”