SI Joint Dysfunciton

1. SI Joint Dysfunciton Steven Garfin, M.D. Distinguished Professor and ChairDepartment of Orthopaedic Surgery, UCSD

2. Disclosures Medtronic NuVasive, Inc. Samumed SI Bone, Inc. Spinal Kinetics Stryker Symmetry Vertiflex AO Spine Benvenue Medical EBI Globus Medical Intrinsic Therapy Johnson & Johnson, DePuy Spine Magnifi Group

3. Burden of Disease: Utility Values High Asthma HIV+ Type 2 Diabetes Quality of Life SIJ Pain SI Joint Pain Hip osteoarthritis Lumbar stenosis Degenerative spondy Knee osteoarthritis Lumbar spondylosis Low Severe Parkinson's Ankylosing Spondylitis Cher D, Polly D, Berven S Med Devices Evid Res 2014

4. Function • Connects spine and pelvis • Transfers force • Opens during pregnancy (so it is “mobile”)

5. SI Joint • Large surface area • 1/4 – 1/3 synovial (anterior) • Cartilaginous surfaces • Strong ligaments • + Motions (multi-directions) < 4⁰ Can be arthritic

6. SI Joint – with age • Surfaces flat until puberty • Then ridges appear • 3RD and 4TH decade: elevations and depressions appear • Articular surfaces erode “Arthritic changes”

7. Innervation • Synovium and capsule contain unmyelinated nerve endings for pain and temperature • Anteriorly from L2-S2 ventral rami and sacral plexus • Posteriorly from L4-S4 dorsal rami Solomen, 1957 Nakegawa 1966 Ikeda, 1991 Grob, 1995 Could “sense” pain

8. Prevalence of SI Joint Degenerationin Asymptomatic AdultsEno, et al JBJS 2015500 consecutive pelvic CTs(no back or SI pain) • 65% SI DJD • 30% Substantial SI DJD • (91% by 80 yrs old)

9. 15-30% Component of LBP Prevalence of SI Joint Pain

10. Adjacent Segment Disease (ASD) • 75% 5-years post-fusion had radiographic SIJ degeneration1 • Post-L-S fusion2,3 • 32% definite SIJ pain • 29% likely SIJ pain 32-43% Symptomatic Post-Lumbar Fusion DePalma – Pain Med 2011 32% Katz 2003 35% Maigne 2005 43% DePalma 2011 40% Liliang 2011 Ha – Spine 2008 Katz – J Spine Disord Tech 2003 Maigne – Eur Spine J 2005

11. Patient Evaluation 60% 40% • Clinical History is Subtle • Pain usually inferior to L-5 • At or caudal to PSIS • Specific trauma or positional pain is rare • Pain with prolonged sitting (also with DDD)

12. Exam DISTRACTION PATRICK’S THIGH THRUST COMPRESSION GAENSLEN’S SACRAL THRUST At least 3 +

13. Radiologic Testing • X-rays, CT, MRI for abnormalities/asymmetry (often not helpful) • Fluoroscopic or CT guided SI Joint injection (pain relief)

14. SIJ Dx Injection • One injection that ↓↓’s at least 75% of pain • 2 injections where both ↓↓ at least 50% of pain

15. Non-Op RX • Physical therapy, manipulations/modalities • NSAIDs • Muscle relaxants • “Pelvic belt” • SI steroid injection No data to support

16. “Fusion” Candidate • SI Joint pain = chronic • SI Joint = primary pain generator (other primary causes ruled out) • + response to diagnostic injection(s)

17. Evidence Mixed for Open FusionAll Level IV • Published Clinical Evidence • 12 Articles • Describe a wide variety of procedures • Fibular allograft dowels • Screws, rods, plates • Anterior/posterior exposure • All retrospective case series • Total of 261 patients • Mixed results

18. Key MIS SI Joint Fusion Articles Level IIb Level I Level II Level II Post Long Fusion Open vs. MIS

19. Key MIS SI Joint Fusion Articles (cont.) Safety

20. Prospective, multi-center, RCT (INSITE) 2-year Results Polly, et al – Int J Spine Surg 2016 (39/44 crossed over) (39/44 crossed over)

21. INSITE 2-year Results Polly – Int J Spine Surg 2016 * Binary success/failure composite measure. Success if all criteria met: VAS SI joint pain reduction ≥20 points, no device-related SAEs, no neurological worsening, and no surgical re-intervention for SI joint pain.

22. INSITE 2-year ResultsSafety Profile Polly – Int J Spine Surg 2016 Adverse Events per Subject Frequency (first 180 days) • 1.5 iFuse vs. 1.3 NSM per subject (p=0.2253) Device- or Procedure-Related Adverse Event • 22 events: neuropathy (1), urinary retention (1), nausea/vomiting (2), atrial fibrillation (1), ipsilateral or contralateral SIJ pain and trochanteric bursitis (9), surgical wound problems (5), iliac fracture (1) and asymptomatic physical exam or radiographic findings (2). Revision Surgery • 3 iFuse subjects (3%) had a revision surgery through 2 years.

23. European Randomized TrialiFuse vs NSM103 pts/9 sites VAS ODI CM CM SIJ fusion SIJ fusion

24. (SIFI) Prospective, Single Arm, Multicenter 2-yr Results Duhon – Int J Spine Surg2016 172 patients, 26 US sites • Sustained clinical outcomes (VAS, ODI, QOL) • Radiographs show high rate (97%) of bony apposition (on at least 2 implants on both the iliac and sacral sides) 24pt mean improvement 53 pt mean improvement VAS SI Joint Pain ODI

25. 2-year ResultsQOL and Effectiveness Duhon et al. Patient Satisfaction (somewhat or very satisfied) 93.8% Opioid Use Reduction (% subjects using opioids, baseline to 2 year) 28.2%  Effectiveness Outcomes Quality of Life (QOL) via Short Form 36 (SF-36) p < 0.0001 for both PCS and MCS PCS = Physical Component Summary MCS = Mental Component Summary

26. SIFI 24-month ResultsSafety Profile Duhon et al. Device-related7 events • 3 Neuropathy related to malposition • 2 SI joint or buttock pain • 1 SI joint pain after fall assoc. with inadequate device placement • 1 Hip pain related to periosteal bone growth around implant Procedure-related 26 events • Buttock pain (2), foot pain related to anesthesia (1), iFuse impingement (3), nausea/vomiting, SI joint pain (5), SI joint pain due to inadequate stabilization (3), urinary retention (1), vascular injury (1), wound drainage/irritation/infection (6), wound numbness (1) Revision Surgery 8 cases (4.7%) • 2 – immediate postop new onset leg pain due to implant malposition. Resolved with slight repositioning. • 4 – minimal pain improvement, CT scan showed suboptimal implant placement (lower implants not sufficiently in the sacrum). Resolved with additional implants. • 1 – bilateral SIJ fusion, recurrent pain 6mo later; resolved with open SIJ fusion and additional implant. • 1 – subject had L4-S1 fusion 13mo post SIJ fusion, recurrent pain showed S1 screw touching implant. Resolved with additional non-iFuse device put across SI joint.

27. Consistent Prospective Study ResultsINSITE, iMIA, SIFI Sturesson – Eur Spine J2016 (iMIA 6mo) Polly – Int J Spine Surg2016 (INSITE 2yr) Duhon – Int J Spine Surg2016 (SIFI 2yr)

28. 11 Studies: Rapid and Sustained Pain Relief VAS

29. Systematic ReviewAll published cohorts of lateral approach joint-transfixing SIJ fusionMost cohorts (85%*) were treated with iFuse Implant System Heiney – Int J Spine Surg 2015 Gray line shows regression fit * 368 of 432 unique patients

31. SI Joint Fusion: Summary • SI joint is pain generator with relatively high prevalence • Correct diagnosis key (thorough SI joint exam, provocative tests, injections) • Treatment options • Conservative care • MIS SIJ Fusion option when conservative care fails • SI Joint pathology is an economic burden, cost effective options needed

32. In properly selected patients, MIS SI joint fusions have strong clinical evidence we are not doing enough • There is data Level I → IV • Peer review journals • Presentations – Academic Societies • Just because we have not paid attention to this in the past • The literature strongly supports getting our head out of the sand

33. Thank You