Minimally Invasive vs. Open Sacroiliac Joint Fusion: A Comparison of Outcomes in Propensity Matched Cohorts

Presented at SMISS Annual Forum 2013
By David Polly, Jr. MD
With Charles Ledonio MD, Marc Swiontkowski MD, Nathaniel Slinkard MD,

Disclosures: David Polly, Jr. MD A; DOD, SRS, POSNA. E; University of Minnesota. Charles Ledonio MD E; Globus Medical, Marc Swiontkowski MD None, Nathaniel Slinkard MD None,

Introduction: The sacroiliac joint (SIJ) is implicated as a source of chronic low back pain in 15 to 30% of patients. The mainstay of therapy for disorders of the sacroiliac joint has been nonoperative management, including rest, nonsteroidal anti-inflammatory agents, and physical therapy. When these modalities fail, SIJ fusion may be recommended. Open anterior approach to the SIJ is the most common technique for SIJ fusion with plates & screws. Recent advances in intraoperative imaging guidance have led to minimally invasive (MIS) techniques using ingrowth coated fusion rods. These implants are being utilized more frequently due to the observed advantages of decreased morbidity, shorter hospital stay and surgical time. The purpose of this study is to compare the operative process measures and Oswestry Disability Index (ODI) outcomes associated with both techniques. Study Design: retrospective study of a prospectively collected dataset.

Materials & Methods: Retrospective chart review was performed of patients who underwent SIJ fusion with a minimum of 1 year follow-up. Specifically, operative process measures and ODI scores were compared between MIS and the open anterior approach technique of SIJ fusion. Patients were matched via propensity score adjusting for age, sex, BMI and preoperative ODI scores. Student’s t-test was used to compare the means and verify propensity score matching.

Results: From 2006 to 2011, 63 patients underwent SI joint fusions. Open technique was performed for 36 patients and 27 patients underwent MIS. After propensity score matching, 44 patients were included in the analysis: 22 open and 22 MIS. Male:female ratios were 5:17 for open and 9:13 for MIS. 11 of 22(50%) in the open group had a history of spine surgery and 14 of 22(64%) in the MIS group. All patients had SIJ dysfunction confirmed by SIJ injection and failed non-operative treatment. Mean age, BMI, preoperative ODI and gender distribution did not differ significantly between the two groups (p>0.05). The open group had significantly more blood loss, requiring transfusions for 3 patients; the MIS group had no transfusions. Length of surgery and length of hospital stay were significantly shorter in the MIS group compared to the open group. The postop ODI score did not differ significantly between the two groups.

Conclusion: In this propensity matched cohort study, statistically significant decreases were noted in EBL, length of hospital stay and surgery for minimally invasive SIJ fusion compared to the open technique. Comparative effectiveness of SI joint fusion techniques reveals similar ODI outcome scores between the two groups.