Minimally Invasive Sacroiliac Joint Fusion: 2-Year Radiographic and Clinical Outcomes with a Principles-Based SIJ Fusion System

William W Cross1, Arnold Delbridge2, Donald Hales3, Louis C Fielding4, *
1 Mayo Clinic Rochester, Minnesota, MN 55905, United States
2 Cedar Valley Medical Specialists PC Waterloo, Iowa, IA 50704, United States
3 Northern Arizona Orthopaedics Flagstaff, Arizona, AZ 86001, United States
4 Tahoe Labs, LLC 1057 Montgomery St., San Carlos, California, 94070, United States

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Creative Commons License
© 2018 Cross et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Tahoe Labs, LLC, 1057 Montgomery St., San Carlos, California 94070, United States; Tel: +1 206-953-9839; Fax: +1 650-585-6307; E-mail:



Sacroiliac joint (SIJ) degeneration is a common source of low back pain (LBP). Minimally invasive (MI) SIJ fusion procedures have demonstrated meaningful clinical improvement. A recently developed MI SIJ fusion system incorporates decortication, placement of bone graft and fixation with threaded implants (DC/BG/TF).

Patients and Methods:

Nineteen patients who had MI SIJ fusion with DC/BG/TF were enrolled at three centers. Fusion was assessed in CT images obtained 12 and 24 months postoperatively by an independent radiographic core laboratory. LBP was assessed using a 0-10 numerical pain scale (NPS) preoperatively and at 12 and 24 months postoperatively.


At 12 months, 15/19 patients (79%) had bridging bone across the SIJ, and at 24 months 17/18 patients (94%) available for follow-up had SIJ fusion. Of the patients with bridging bone 88% had fusion within the decorticated area, with solid fusion in 83%. A significant reduction in NPS scores was demonstrated, representing a 73% reduction in average low back pain.


The patients in this series demonstrated significant improvement in LBP. Fusion rates at 24 months demonstrate promise for this system, which utilizes the established orthopedic principles of DC/BG/TF to achieve arthrodesis. Further study is warranted to demonstrate comparative fusion rates for different implant systems.

Keywords: Sacroiliac joint, Sacroiliac fusion, Decortication, Minimally invasive, Fusion, Radiographic fusion, Bridging bone, Low back pain.