Additional Sacroplasty Does Not Improve Clinical Outcome in Minimally Invasive Navigation-Assisted Screw Fixation Procedures for Nondisplaced Insufficiency Fractures of the Sacrum

STUDY DESIGN: Prospective single-center cohort study (noninferiority study). OBJECTIVE: To compare clinical results of navigation-assisted screw fixation (NSF) to those of NSF with additional sacroplasty (NSF + SP) for immobilizing nondisplaced insufficiency fractures of the sacrum. SUMMARY OF BACKGROUND DATA: NSF for sacral insufficiency fractures is a new, technically demanding procedure requiring surgical skills and experience. Up to date, controversies exist about the benefit of additional sacroplasty in surgically stabilized insufficiency fractures of the sacrum. METHODS: From February 2011 to May 2017, all individuals with immobilizing nondisplaced sacral insufficiency fractures surgically treated using 3D-fluoroscopy for 3D-real-time navigation and postinstrumentation screw control in the form of NSF (I) or NSF + SP (II) were enrolled. SP was performed only in absence of transforaminal or central fractures. Outcome parameters were postsurgical pain relief determined by visual analog scale, postsurgical improvement of disability evaluated using the Oswestry Disability Index, and length of postsurgical hospital stay. RESULTS: In 2 groups of 26 individuals, each, a total of 124 insufficiency fractures of sacral vertebrae were surgically treated. Postoperative pain-level decrease was comparable in both groups (5.3 vs. 5.4 visual analog scale points). Extent of postoperative disability score improvement (53.4 vs. 57.7 Oswestry Disability Index points) led to successful remobilization after similar durations of postsurgical hospital stay (9.3 vs. 9.6 days). Minimum clinically important differences of outcome parameters were not reached in the comparison of study group results. In procedures with SP, no major complications occurred, in those without SP, no specific complications were observed. CONCLUSION: This comparative study indicates noninferiority of NSF compared to NSF + SP for sacral insufficiency fractures, and could not confirm clinical advantages of additional SP concerning pain relief, improvement of fracture-related disability, or time from surgery to discharge. Therefore, additional sacroplasty is not recommended to enhance the clinical benefit for patients receiving image-guided sacral screw fixation. LEVEL OF EVIDENCE: 2.