[Minimally invasive stabilization of posterior pelvic ring injuries with a transiliac internal fixator and two iliosacral screws: comparison of outcome].

PURPOSE OF THE STUDY A comparison of radiological and clinical results between dorsal pelvic segment stabilization with a transiliac internal fixator (TIFI) and that with two iliosacral screws (IS). MATERIAL AND METHODS In this prospective study, both the TIFI and the IS group had 32 patients. The majority of injuries were assessed as type C1.3 because only patients with a high-energy mechanism of injury were included. Radiological results were evaluated according to the Matta scoring system and clinical outcome using the Majeed score and the Pelvic Outcome Score. Categorical data were evaluated by the two-sided Fisher's exact test or Pearson's χ2 test and continuous data by Student's t-test. A test result with p<0.05 was considered statistically significant. RESULTS In the TIFI group, the mean posterior displacement was 2.2 mm, in the IS group it was 1.9 mm (p=0.58542). The pelvic outcome scores in the TIFI group were: excellent, 28%; good, 12%; fair, 48.0%; and poor, 4 %; in the IS group they were: excellent, 11.1%; good, 22.2%; fair, 66.7%; and poor, 0.0% (p=0.51731). The Majeed scores were as follows: excellent, 56.0%; good, 16.0%; fair, 20.0%; poor 8.0 % for the TIFI group and excellent, 50.0%; good, 27.8%; fair, 11.1%; and poor, 11.1% for the IS group (p=0.70187). Within the total, average Majeed score was 80.64 points in TIFI, 80.67 in IS (p=0.99654). In a sub-analysis of unilateral transforaminal fractures (Pohlemann type II), the average score for TIFI was 82.8 points and only 53.5 points for IS; the differences were statistically significant (p=0.04517). No intraoperative complications were associated with TIFI and one injury to the superior gluteal artery (3.1%) and two iatrogenic neurological injuries with IS (6.3%; p=0.23810). In the TIFI group, the fixator was removed without complications. In the IS group, post-operative wound bleeding following screw removal occurred in three patients (20.0%; p=0.22414), complete extraction of screws and washers was successful only in seven patients (46.7%), washers were left in situ in six patients (40.0 %) and IS removal was not possible in two patients (13.3%). The difference in complications between the groups was highly significant (p=0.00220). DISCUSSION The results of our study are in agreement with those of the relevant studies published recently as well as with the outcomes of transiliac plate fixation reported in the literature. TIFI implantation is preferred in transforaminal and central sacral fractures because, unlike iliosacral screws, it carries a low risk of excessive compression of the sacral foramina and iatrogenic neurological injury. There were no significant differences in clinical and radiological findings between TIFI and IS procedures. Only in unilateral transforaminal fracture the TIFI stabilization had better outcome, as shown by the Majeed score. The IS fixation was associated with a higher rate of complications not only in primary implantation, but also at implant removal. CONCLUSIONS The TIFI technique is superior to the IS procedure in fixation of unilateral transforaminal fractures and provides a reasonable alternative to the existing types of minimally invasive fixation.