Internal Fixation of Posterior Pelvic Ring Injuries Using Iliosacral Screws in the Dysmorphic Upper Sacrum

[Introduction][1] The correct usage of preoperative and intraoperative imaging allows fixation of posterior pelvic ring injuries with safely positioned iliosacral screws in the setting of sacral dysmorphism. [Step 1: Preoperative Planning][2] Obtain CT reformats along the longitudinal axis of the sacrum to determine the orientation and diameter of the osseous corridor for selection of the ideal screw size, length, and trajectory. [Step 2: Patient Positioning][3] Proper positioning enables reduction and accurate iliosacral screw placement. [Step 3: Fracture Reduction][4] Reduction of the posterior pelvic ring confers stability; if closed reduction is unsuccessful, proceed with open reduction. [Step 4: Identification of the Entry Point][5] The entry point for an iliosacral screw into the upper sacral segment of a dysmorphic pelvis lies more posterior and caudal on the outer table of the posterior ilium than does a transsacral screw; adjust the entry point on the basis of inlet and outlet fluoroscopic views. [Step 5: Drilling Technique][6] Insert a stout cannulated drill bit of 4.5 to 5 mm (depending on the core diameter of the intended iliosacral screw) over the Kirschner wire and drill it into the sacral body under fluoroscopic guidance, in accordance with the preoperative plan. [Step 6: Screw Insertion][7] With the guidewire in the ideal position, measure the screw length off the inserted guidewire and advance a tap into the pathway; insert the screw and verify its position on the inlet, outlet, and lateral sacral views. [Results][8] Understanding the three-dimensional anatomy of the posterior pelvic ring is essential to successful reduction and fixation of unstable pelvic injuries with use of percutaneous iliosacral screws. [Indications][9] [Contraindications][10] [Pitfalls & Challenges][11] [Introduction][1] The correct usage of preoperative and intraoperative imaging allows fixation of posterior pelvic ring injuries with safely positioned iliosacral screws in the setting of sacral dysmorphism. [Step 1: Preoperative Planning][2] Obtain CT reformats along the longitudinal axis of the sacrum to determine the orientation and diameter of the osseous corridor for selection of the ideal screw size, length, and trajectory. [Step 2: Patient Positioning][3] Proper positioning enables reduction and accurate iliosacral screw placement. [Step 3: Fracture Reduction][4] Reduction of the posterior pelvic ring confers stability; if closed reduction is unsuccessful, proceed with open reduction. [Step 4: Identification of the Entry Point][5] The entry point for an iliosacral screw into the upper sacral segment of a dysmorphic pelvis lies more posterior and caudal on the outer table of the posterior ilium than does a transsacral screw; adjust the entry point on the basis of inlet and outlet fluoroscopic views. [Step 5: Drilling Technique][6] Insert a stout cannulated drill bit of 4.5 to 5 mm (depending on the core diameter of the intended iliosacral screw) over the Kirschner wire and drill it into the sacral body under fluoroscopic guidance, in accordance with the preoperative plan. [Step 6: Screw Insertion][7] With the guidewire in the ideal position, measure the screw length off the inserted guidewire and advance a tap into the pathway; insert the screw and verify its position on the inlet, outlet, and lateral sacral views. [Results][8] Understanding the three-dimensional anatomy of the posterior pelvic ring is essential to successful reduction and fixation of unstable pelvic injuries with use of percutaneous iliosacral screws. [Indications][9] [Contraindications][10] [Pitfalls & Challenges][11] [1]: #sec-10 [2]: #sec-11 [3]: #sec-12 [4]: #sec-13 [5]: #sec-14 [6]: #sec-15 [7]: #sec-16 [8]: #sec-17 [9]: #sec-19 [10]: #sec-20 [11]: #sec-21