Additional Sacroplasty Does Not Improve Clinical Outcome in Minimal-Invasive Navigation-Assisted Screw Fixation Procedures for Non-Displaced Insufficiency Fractures of the Sacrum.

STUDY DESIGN: Prospective single-center cohort study (non-inferiority study).

OBJECTIVE: To compare clinical results of navigation-assisted screw fixation (NSF) to those of NSF with additional sacroplasty (NSF+SP) for immobilizing non-displaced insufficiency fractures of the sacrum.

SUMMARY OF BACKGROUND DATA: Navigation-assisted screw fixation 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 non-displaced sacral insufficiency fractures surgically treated using 3D-fluoroscopy for 3D-real-time-navigation and post-instrumentation screw control in form of NSF (I) or NSF+SP (II) were enrolled. SP was performed only in absence of transforaminal or central fractures. Outcome parameters were post-surgical pain relief determined by visual analogue scale (VAS), post-surgical improvement of disability evaluated using the Oswestry-Disability-Index (ODI), and length of post-surgical hospital stay.

RESULTS: In two groups of 26 individuals, each, a total of 124 insufficiency fractures of sacral vertebrae were surgically treated. Post-operative pain-level decrease was comparable in both groups (5.3 vs. 5.4 VAS points). Extent of post-operative disability-score improvement (53.4 vs. 57.7 ODI points) led to successful remobilization after similar durations of post-surgical 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.

CONCLUSIONS: This comparative study indicates non-inferiority 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.