Recurrent episodes of micturition with expulsion of symphyseal plate screws following pelvic ring fixation: case report

BACKGROUND: Based on a computer-assisted literature search, this case is the first description of repeated loosening of metallic internal fixation implants after pelvic ring stabilization, associated with intravesical metal migration and micturition with expulsion of two bone screws. CASE PRESENTATION: A 62-year old woman was seen after the urinary expulsion of a 6.5 mm diameter cancellous screw. About seven years earlier, she had been hit by a motorcyclist while crossing the street. On admission at the time of the initial injury, thoraco-abdominal computerized tomography with intravenous contrast material revealed a bladder injury and pelvic ring fractures. An anterior-posterior type injury to the pelvic ring was diagnosed with symphyseal pubis disruption, and widening of the left sacroiliac joint with an associated sacral fracture. Explorative laparotomy revealed two bladder lacerations of both the posterior and the anterior bladder wall, which were repaired primarily. Orthopedic surgeons reduced the pelvis and stabilized it with two plates and screws. Seven years after the original injury, the patient presented with recurrent abdominal pain after expelling a screw into the toilet while urinating. Planar radiographs showed only five of the original screws remaining in the two symphyseal plates, and all screws appeared to have loosened when compared to the original fixation radiograph. CONCLUSION: This clinical report emphasizes the importance of symphyseal plate positioning and the sequelae of imprecise positioning, especially postero-superiorly adjacent to the Retzius space. The presence of protruding metal prominences, even smooth ones like a plate corner or screw head, might endanger the bladder. When using superior plates, imprecise contouring may lead to plate edge protrusion which could damage the bladder even long after application. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12891-015-0581-7) contains supplementary material, which is available to authorized users.