Minimally invasive internal fixator for unstable pelvic ring injuries with a pedicle screw-rod system: a retrospective study of 23 patients after 13.5 months

PurposePelvic ring fractures are challenging injuries and require effective treatment due to the frequently compromised patient condition. The aim of this study was to evaluate the outcome of unstable pelvic ring injuries treated with a minimally invasive pedicle screw-rod system.MethodsRetrospective analysis was performed for patients with an unstable pelvic ring injury that were treated with a minimally invasive anterior internal pelvic fixator (INFIX) with or without a posterior pedicle screw-rod fixator (6/2012-4/2015). The quality of reduction was evaluated by the Tornetta and Matta criteria and the clinical outcome was evaluated by the Majeed scores. Further evaluation included the operation time, intraoperative blood loss, and complication rate.ResultsA total of 23 patients (12 males and 11 females) with a mean age of 37.6years (range 10-65years) and a follow-up of 13.5months (6-27months) were evaluated. The Tile classification showed 13 type B (B1=6, B2=4, and B3=3) and 10 type C (C1=7 and C2=3) fractures. Mean operation time and intraoperative blood loss were 24.8min (20-30min) and 20.4ml (16-29ml) for an anterior INFIX (n=13), and 60min (45-70min) and 150ml (115-168ml) when combined with a posterior pedicle screw-rod fixator (n=10). Quality of reduction was excellent in 13, good in 6, and fair in 4 patients, with no signs of heterotopic ossification. Clinical results after 6months were excellent in 14 patients, good in 6, fair in 2, and poor in 1. Unilateral thigh paresthesia was seen in 2 patients which resolved after implant removal.ConclusionsThe INFIX appears to be a safe and minimally invasive surgical technique which can effectively be combined with posterior pedicle screw-rod fixation. It also can be applied for the definitive treatment of vertically and/or rotationally unstable pelvic ring injuries, especially in severely compromised patients with a high mortality risk.