Posterior iliac screw rod for the treatment of unilateral unstable Denis I and II sacral fractures

Objective To explore the efficacy of posterior iliac screw rod for unilateral unstable Denis I and II sacral fractures. Methods Data of 50 patients with unilateral unstable Denis I, II sacral fractures treated from March 2016 to October 2018 were retrospectively analyzed. According to fixation methods, the patients were divided into posterior iliac screw rod group (Iliac screw rod group) and robot-assisted iliosacral screw group (Iliosacral screw group). There were 20 patients in the Iliac screw rod group, 13 males and 7 females, with an average age of 41.10±14.07 years (range, 22-76 years), and there were 5 cases of Denis type I and 15 cases of type II sacral fractures. All of them had anterior pelvic ring injuries, and according to pelvic Tile classification, there were 2 B1 type, 12 B2 type, 6 C1 type, and 3 cases of Gibbons grade II sacral nerve injuries. There were 30 patients in the Iliosacral screw group, 18 males and 12 females, with an average age of 44.70±13.35 years (range,16-78 years), and there were 6 cases of type I and 24 cases of type II sacral fractures. There were 2 cases of type B1, 20 cases of B2, 8 cases of C1 pelvic fractures, 4 cases combined with sacral nerve injuries including 3 cases of Gibbons grade II and 1 case of grade III. The patients’ age, operation time, amount of bleeding, times of fluoroscopy, postoperative Majeed score were compared by the independent t test. The quality of fracture reduction was compared by Chi-square test, and the postoperative Gibbons grade was compared by the rank sum test. Results All patients were followed up for 22.8 months (range, 12-40 months). In the Iliac screw rod group, the operation time was 41.40±7.30 min, intraoperative blood loss 105.00±61.94 ml, intraoperative times of fluoroscopy 19.10±7.33, and according to Mears and Velyvis valuation criterion, there were 9 cases of anatomical reduction, 10 cases of satisfactory reduction, and 1 case of unsatisfactory reduction, with the Majeed score of 84.25±8.29. There were 3 cases with Gibbons grade II sacral nerve injury, and 2 of them recovered to grade I. In the Iliosacral screw group, the operation time was 18.27±5.89 min, intraoperative blood loss 33.00±17.54 ml, intraoperative times of fluoroscopy 14.93±4.49, and according to Mears and Velyvis valuation criterion, there were 15 cases of anatomical reduction, 13 cases of satisfactory reduction and 2 cases of unsatisfactory reduction, with the Majeed score of 86.43±7.43. There were 3 cases with Gibbons grade II sacral nerve injury, and 2 of them recovered to grade I, and 1 case with grade III recovered to grade II postoperation. Compared to Iliosacral screw group, the Iliac screw rod group has longer operation time (t=-12.36, P<0.001), more blood loss (t=-6.04, P<0.001) and more intraoperative times of fluoroscopy (t=-2.50, P=0.016). There were no statistical differences for quality of fracture reduction (χ2=0.23, P=0.89), Majeed score (t=0.97, P=0.34), and the Gibbons grade (Z=-0.224, P=0.82) between the two groups. In the Iliac screw rod group, 1 patient had a unilateral superficial wound infection and 1 patient complained of discomfort because of the nail. In the Iliosacral screw group 1 patient had iatrogenic S1 neurological injury. Conclusion For the unstable sacral fractures, who are not suitable for iliosacral screw fixation, posterior iliac screw rod fixation is an effective alternative with similar clinical effect as robot assisted iliosacral screw fixation. Key words: Sacrum; Fractures, bone; Fracture fixation, internal; Surgical procedures, minimally invasive