INSITE 1-year Results (Polly - Neurosurgery 2015) | SI-BONE

Clinical Data

INSITE 1-year Results (Polly - Neurosurgery 2015)

Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium Implants vs Nonsurgical Management for Sacroiliac Joint Dysfunction: 12-Month Outcomes

Polly DW, Cher DJ, Wine KD, Whang PG, Frank CJ, Harvey CF, Lockstadt H, Glaser JA, Limoni RP, Sembrano JN;
INSITE Study Group.
Neurosurgery. 2015;77:674-91. [Epub 2015 Aug 19].
DOI:10.1227/NEU.0000000000000988. PMCID: PMC4605280


Background: Sacroiliac joint (SIJ) dysfunction is a prevalent cause of chronic, unremitting lower back pain.

Objective: To concurrently compare outcomes after surgical and nonsurgical treatment for chronic SIJ dysfunction.

Methods: A total of 148 subjects with SIJ dysfunction were randomly assigned to minimally invasive SIJ fusion with triangular titanium implants (n = 102) or nonsurgical management (n = 46). Pain, disability, and quality-of-life scores were collected at baseline and at 1, 3, 6, and 12 months. Success rates were compared by using Bayesian methods. Crossover from nonsurgical to surgical care was allowed after the 6-month study visit was complete.

Results: Six-month success rates were higher in the surgical group (81.4% vs 26.1%; posterior probability of superiority >.0.9999). Clinically important (≥ 15 point) Oswestry Disability Index improvement at 6 months occurred in 73.3% of the SIJ fusion group vs 13.6% of the nonsurgical management group (P < .001). At 12 months, improvements in SIJ pain and Oswestry Disability Index were sustained in the surgical group. Subjects who crossed over had improvements in pain, disability, and quality of life similar to those in the original surgical group. Adverse events were slightly more common in the surgical group (1.3 vs 1.1 events per subject; P = .31).

Conclusions: This Level 1 study showed that minimally invasive SIJ fusion using triangular titanium implants was more effective than nonsurgical management at 1 year in relieving pain, improving function, and improving quality of life in patients with SIJ dysfunction caused by degenerative sacroiliitis or SIJ disruptions. Pain, disability, and quality of life also improved after crossover from nonsurgical to surgical treatment.



Some of the authors and study participants may be past or present SI-BONE employees, paid consultants, investors, clinical trial investigators, or grant recipients. This research was supported by SI-BONE. Dr. Polly and Dr. Sembrano are investigators on a clinical research study sponsored by SI-BONE. They have no financial interest in SI-BONE.

Author Information

Polly DW - Departments of Orthopedic Surgery and Neurosurgery, University of Minnesota, 2512 South 7th Street, Suite R200, Minneapolis, MN 55454

Cher DJ and Wine KD - SI-BONE, Inc.

Whang PG - Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, P.O. Box 14 208071, New Haven CT 06520-8071

Frank CJ - Integrated Spine Care, 601 North 99th Street, Suite 101, Wauwatosa, WI 53226

Harvey CF - Riverside Hospital, Kankakee, Illinois

Lockstadt H - Bluegrass Orthopedics & Hand Care, 3480 Yorkshire Medical Park, Lexington, KY 40509

Glaser JA - Medical University of South Carolina, 96 Jonathan Lucas St. CSB708 , Charleston, SC 29425

Limoni RP - Aurora BayCare Orthopedic & Sports Medicine Center, 1160 Kepler Drive, Green Bay, WI 54311

Sembrano JN - Department of Orthopaedic Surgery, University of Minnesota, 2450 Riverside Avenue South, Suite R200, Minneapolis, MN 55454

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