Compressive effect and collapse behavior of three different transsacral implants in sacral fragility fractures - a retrospective analysis of 106 cases.

Purpose: The aim of this study were the retrospective evaluation of the compressive effect and complication rates of transsacral stabilization of osteoporosis-associated sacral fragility fractures in 106 patients using three different implants (6.0 mm sacral bar, n = 32; 7.3 mm screw, n = 26; 7.5 mm ISG-Rod System, n = 48) with regard to the image morphological and clinical-perioperative outcome.

Methods: For this purpose, the sacral width was determined preoperatively and postoperatively using multiplanar CT reconstructions and correlated with the measured bone density (HU). The results were compared with each other on an implant-specific basis.

Results: A significant compressive effect was found for all implants (6.0 mm sacral bar 7.1 ± 3.4 mm, 7.3 mm screw 6.9 ± 1.8 mm, 7.5 mm ISG-Rod System 8 ± 2.4 mm). No implant-specific difference in compression could be detected. Overall, the washers broke into the iliac cortex in 9% of cases. The subgroups did not differ significantly in this respect (6.0 mm sacral bar: 4 [13%], 7.3 mm screw 1 [1%], 7.5 mm ISG-Rod System (5 [10%], p = 0.581). A correlation between the degree of osteoporosis and the compressive effect could not be demonstrated. Significant implant-specific differences were found in the incision-suture time, with only ø0:39 ± 0:13 h required for implantation of the 7.5 mm ISG Rod System (6.0 mm sacral bar: ø1:09 ± 0:22 h, 7.3 mm screw: ø0:55 ± 0:20 h). The fluoroscopy time was significantly lower with the 7.3 mm screw (ø0:57 ± 0:23 min) and the 7.5 mm ISG Rod System (ø0:42 ± 00:17 min) than with the 6.0 mm sacral bar (ø1:36 ± 0:46 min).

Conclusion: A significant compressive effect was demonstrated with all three implants. No implant-specific complications or surgical site complications were identified in either the overall cohort or the subgroups. The 7.5 mm ISG Rod System shows advantages with regard to the duration of surgery and fluoroscopy.