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Introduction: Typical stabilisation of pelvic open book injuries consists of plate fixation of the symphysis. No previous literature has been published about the evaluation of screw placement and their trajectory with four oblique 4.5 mm screws using a four-hole plate in symphysis diastasis. The aim of this study was to define insertion points and angles of trajectory for crossed screw placement regardless of any plate design based on an analysis of three-dimensional computed tomography data sets., Methods: One hundred human pelvic CT data sets were collected. Unilateral and bilateral placements of crossed 4.5 mm screws were simulated. Primary outcome measure was successful simulated screw placement without cortical breach. Secondary outcome measures included the anatomical measurements of the screw positions., Results: Simulated screw placement of two oblique screws on each side of the pubic symphysis without cortical breach was achieved in all (100 %) cases. There were a total of 400 screw simulations. Medial screws were longer, lateral screws had higher coronal angles, and the distance between both screws was higher on the right side (p < 0.001 each). The lengths of the right lateral, right medial, left lateral, and left medial screws were 44.9, 65.8, 45.4, and 67.4 mm, respectively. The sagittal angles to the dorsal surface area of the pubic rami were 10.5°, 11.1°, 9.0°, and 11.0°. The coronal angles to the vertical axis of the symphysis measured 39.5°, 16.0°, 33.8°, and 16.8°. The distances between these screws and the medial edge of the pubic crest were 33.5, 8.6, 29.5, and 7.3 mm. Furthermore, certain sex- and side-related differences were noted., Conclusions: This series provides results about the feasibility and a detailed anatomical description of crossed screw placement. This is of special interest in pelvic surgery for choosing the entry points, safe screw channel parameters, and trajectories.

With rapid advancement in surgical techniques and improvement in implant materials, rate of internal fixation for pubic symphyseal disruption in rotationally and vertically unstable pelvic ring injuries has increased. Among various modes of implant failure, screw/plate breakage and loosening are common complications following unstable fixation. Migration of loose screws into the urinary bladder has been reported as an extremely uncommon complication of pubic symphyseal plating. Here we present a case report of a 52-year-old female who presented with asymptomatic passage of screws in her urine following migration into the bladder, 2 years after symphyseal plating for pubic diastasis in an anteroposterior compression pelvic ring injury.

We report a case of right ureter injury in an 11-year-old girl after a percutaneous iliosacral screwing with non-computer-assisted fluoroscopic guidance. The indication was a pelvic ring fracture, C1-1 in the Tile modified AO classification (J Am Acad Orthop Surg. 1996;4:143-151). The mechanism was a ski accident. A percutaneous iliosacral screwing was performed to stabilize the right iliac wing fracture. Twelve days after the initial trauma, a right ureter tear was highlighted, just opposite the fourth lumbar vertebra. Uneventful spontaneous healing of the ureteral injury site occurred following double J-stent catheterization., (Copyright © 2012 Elsevier Inc. All rights reserved.)