Of the 326 patients undergoing SIJF, 1.2% (n = 4) underwent early surgical revision (<1 month). In each of those patients, one of the implants had been inadvertently placed into a sacral neuroforamen, causing postoperative neuropathic symptoms and requiring surgical repositioning of the implant. Late revision surgery (>1 month), performed in 2.8% (n = 9), was typically done to address pain, sometimes associated with poor implant position, with placement of additional implants in most cases. Signs of wound infection occurred in eight subjects overall, including deep wound infection requiring surgical washout (n = 1), drainage from wound treated with antibiotics (n = 3), redness treated with antibiotics (n = 3), and slow healing treated with antibiotics (n = 1). No subject had bony infection or implant removal for infection.
Combining data from three separate prospective studies allowed us to assess in more detail which patient groups may have a better chance of benefitting from conservative or minimally invasive surgical treatment of chronic SIJ pain. Our principal findings are that, within the patient cohort undergoing SIJF, two factors (current smoking and opioid use at baseline) predicted lower and two factors (higher patient age and longer duration of SIJ pain) predicted higher degrees of improvement in SIJ pain and pain-related disability. Older age also predicted higher improvements in quality of life (EQ-5D TTO). Even though one may argue that each of these differences may be of relatively modest clinical significance, it is important to note that they all reached statistical significance. Moreover, subgroups with smaller improvements after SIJF, such as smokers or opioid users, still displayed larger and clinically important improvements compared with patients in the NSM cohort. Another important difference between SIJF and NSM was that within NSM, we found no predictors of treatment outcome at all.
In the SIJF cohort, smokers showed reduced pain response (by 5.9 VAS points) and higher disability levels (by 4.4 ODI points) than nonsmokers. These results are consistent with previously published data describing a significant negative association between smoking and spine surgery outcomes.52
Patients using opioids at baseline also benefitted less from SIJF (by 6.4 VAS points and by 6.1 ODI points) when compared with opioid-naive patients. These findings add to the somewhat controversial discussion regarding opioids as part of LBP treatment overall, as current evidence suggests an absence of long-term superiority of opioids over placebo in the treatment of LBP, which has led some authors to call for avoiding any opioid use in LBP treatment.53,54 Opioid use may even increase the risk of recurrence of already existing depression as well as the risk of developing new onset depression.55
In the SIJF cohort, patients younger than 45 years displayed a reduced pain response (by 9.1 VAS points) compared with patients in the oldest age quartile. Whether young age reflects a true biologic effect or is a marker for more severe disability is not known, but our results suggest that SIJF should be discussed with greater caution in younger patients. However, our findings are in line with previously published reports on patients undergoing lumbar fusion surgery, which found that older patients were not at a higher risk of poor treatment outcomes.56
Within the SIJF cohort, we observed that patients in the third quartile of pain duration (3–6 years) had a larger improvement in pain. Also, patients in the fourth pain duration quartile (>6 years) had larger improvements in quality of life (EQ-5D). The significance of this finding is uncertain and is therefore the most difficult to integrate into decision-making during patient selection. However, as increased pain duration has been described to be a risk factor for poor treatment outcome in LBF,57 our contrasting results provide reassurance that in patients with long-standing pain originating from the SIJ, SIJF is a reasonable option.
Procedure-related safety was reasonable in our analysis, with a low rate of wound problems and a low surgical revision rate consistent with a previous report in the commercial setting.58
Minimally invasive SIJF is gaining increasing attention in spine surgery. Two different surgical approaches to SIJF have been reported. In the dorsal approach, which was not used in the trials evaluated in our analysis, a midline dorsal incision is made with dissection to the dorsal ligamentous recess followed by device placement. Stabilization is achieved through ligamentotaxis. Published outcomes from this approach are scant.59 In the lateral-to-medial approach, which was used in the trials analyzed by us, the implants transfix the SIJ. Published TTI studies include the three trials we summarized as well as retrospective case series,16–28 including some with 3-,26 4-,22 and 5-year24 follow-up, and comparative case series versus open SIJF.29–31 Three additional case series report good outcomes with hollow modular anchor screws60–62 and a recent small case series suggests good outcomes with an additional transfixing device.63 Minimally invasive SIJF using TTI was shown to not only improve the LBP component of SIJ pain but also the referred leg pain component.64 Because of differences in approaches, device design, acute impact on the joint, and long-term fusion strategies, it is unclear whether results from our analysis apply to other laterally transfixing devices or to devices placed via a dorsal approach.
The main strength of our analysis is that all three pooled studies were of high quality, used standardized enrollment and diagnostic criteria, and were rigorously monitored. The two RCTs were designed to directly estimate the clinical value of surgery compared with a nonsurgical treatment control group. However, certain limitations should be mentioned. First, because the study protocols of iMIA and INSITE allowed crossover from nonsurgical to surgical treatment after 6 months and the majority of patients made use of this option, long-term information for NSM (beyond 6 months) was not evaluated in our analysis. Nevertheless, while crossover prevented calculation of treatment ES after month 6, it allowed us to completely avoid early crossover, which has complicated interpretation of other surgery versus nonsurgery trials.65,66 Another limitation of our analysis is that all trials included were not blinded and therefore patient-specific expectations cannot be ruled out as potential confounders to overall outcome results. Nevertheless, the large observed ES suggest a true underlying effect. Finally, the fact that all three trials included in our analysis were industry-sponsored may be viewed by some as a limitation. However, industry-sponsorship is the norm in spine surgery device trials.67
Our pooled analysis suggests that the success of conservative management of SIJ pain is limited and difficult to predict. In contrast, improvements in pain, disability, and quality of life with minimally invasive SIJF were large; moreover, the extent of improvement was modestly associated with smoking, opioid use, patient age, and duration of pain. Procedure-related safety of SIJF was reasonable.Key PointsRecent evidence suggests that minimally invasive surgical treatment of pain originating from the sacroiliac joint (SIJ) may be a relevant alternative to frequently unsuccessful conservative management.We pooled data from the only existing prospective trials using triangular titanium implants to treat SIJ pain to identify predictors of treatment outcome.Minimally invasive surgical management produced significantly better outcome than conservative management.We found no predictors of outcome for conservative management of SIJ pain.For minimally invasive surgical management, we found that smoking and opioid use predicted poorer outcome, while higher patient age and longer duration of pain were associated with better outcome.
iMIA: D. Kools, G. Lesage, F. Martens, H. Keymeulen (Department of Neurosurgery, Onze-Lieve-Vrouw Hospital Aalst, Belgium); Y. Lecomte (Montegnée, Belgium); J. Dengler, S. Bayerl, J. Kopetzki (Department of Neurosurgery, Charité - Berlin, Germany); R. Pflugmacher, M. Webler, R. Bornemann, Tom Jansen (Department of Orthopedics and Traumatology, University Hospital Bonn, Germany); A. Mues (Hilden, Germany); A. Gasbarrini, C. Griffoni, S. Colangeli, R. Ghermandi (Instituto Ortopedico Rizzoli di Bologna, Bologna, Italy); D. Prestamburgo, F. Valli (Department of Orthopedics and Traumatology, Ospedale di Legnano, Italy); P. Gaetani, V. Silvani, M. Minelli, D. Adinolfi, M. Verlotta, A. Cattalani (Pavia, Italy); B. Sturesson, I. Dahlberg (Department of Orthopedics, Aleris, Ängelholm Hospital, Ängelholm, Sweden).
INSITE: John Swofford MD, John Cummings MD, James Cole MD, Elizabeth Pertile, Ellen Looney, Patti Hunker, Mary Anne Gfell (Indiana Interventional Pain and Community Hospital, Indianapolis, IN); Clay Frank MD, Jamie Edwards MD, Gordon Mortensen MD, Tracy Mente RN (Wheaton Franciscan Healthcare, Wauwatosa, WI); Scott Kitchel MD, Christopher Miller MD, Gregory Moore MD, Shawn Potts, Brett Barnes (Neurospine Institute, Eugene, OR); Robert Limoni MD, Nilesh Patel MD, Taylor Romdenne, Denise Barnes RN, Nicholas Peterson (Aurora BayCare Medical Center & Advanced Pain Management, Green Bay, WI); Harry Lockstadt MD, Elaine Wilhite MS, James Farris PA-C (Bluegrass Orthopaedics & Hand Care, Lexington, KY); Don Kovalsky MD, Laura Pestka RN, Cristy Newman (Orthopaedic Center of Southern Illinois, Mount Vernon, IL); Peter Whang MD, Donna Ann Thomas MD, Bethany Samperi, Stacey Lombardi (Yale University, New Haven, CT); Emily A. Darr MD, John A. Glaser MD, Laura Fields, Jennifer Philp, Monica Baczko (Medical University of South Carolina, Charleston, SC); Charles Harvey, MD, Jason Peterman PA-C, Karim Bouferrache MPAS PA-C, Lori Latham (Riverside Medical Center, Kankakee, IL); Pierce Nunley MD, Andrew Utter MD, Marcus Stone PhD, Norma Rivera, Monicah Jepkemboi, Anthony Juarez (Spine Institute of Louisiana, Shreveport, LA); Jonathan Sembrano MD, Ed Santos MD, David Polly MD, Charles Ledonio MD, Sharon Yson MD (University of Minnesota, Minneapolis, MN); Philip Ploska MD, Terry Price PA (Regenerative Orthopaedics and Spine Institute, Stockbridge, GA); Michael Oh MD, Gary Schmidt MD, Matthew Yeager (Allegheny General Hospital, Pittsburgh, PA); Merle Stringer MD, Douglas Stringer MD, Carolyn Henderson (Brain & Spine Center, Panama City, FL); Farshad Ahadian MD, Yu-Po Lee MD, Katie Lam (University of California, San Diego, CA); Gowriharan Thaiyananthan MD, Bryan Oh MD, Navid Farahmand MD, Tungie Williams (Basic Spine, Newport Beach, CA); William Rosenberg MD, Amy Akins RN BSN CCRC, Pamela McCann RN BSN, Jennifer Feeback CCRP (Midwest Division-RMC, LLC,-Research Medical Center, Kansas City, MO); Vikas Patel MD, Scott Laker MD, Venu Akuthota MD, Christopher Cain MD, Evalina Burger MD, Christopher Kleck MD, Claire Cofer, David Calabrese (University of Colorado, Aurora, CO); Mark C. Gillespy MD, Sherri Zicker RN (Orthopaedic Clinic of Daytona Beach, Daytona Beach, FL).
SIFI: Harry Lockstadt, MD, Elaine Wilhite, MS, James Farris, PA-C (Bluegrass Orthopaedics and Hand Care, Lexington, Kentucky); Don Kovalsky, MD, Cristy Newman, Laura Pestka, RN (Orthopaedic Center of Southern Illinois, Mount Vernon, Illinois); Cheng Tao, MD, Jackie Makowski, Toni Kelly (Spine and Neuro Center, Huntsville, Alabama); S. Craig Meyer, MD, Vicki Jones, Michelle Vogt (Columbia Orthopaedic Group, Columbia, Missouri); Scott Kutz, MD, Linda Thompson, RN, BSN, FNP (Mercy Medical Research Center, Springfield, Missouri); Dimitriy Kondrashov, MD, Irina Kondrashov (SF Spine Group, San Francisco, California); Andy J. Redmond, MD, Jennifer Piazza, MS, Laurie Doredant, Beth Short, BSN, MS, Jessica Mayfield, RN (Precision Spine Care, Tyler, Texas); CL Soo, MD, Julie White, MBA, Kallena Haynes (Medical Research International, Oklahoma City, Oklahoma); Bradley Duhon, MD, Amber Pfister (Neurosurgical and Spine Specialists, Parker, Colorado); Ali Mesiwala, MD, Stephanie Bose, RN (Southern California Center for Neuroscience and Spine, Pomona, California); Leonard Rudolf, MD, John Thibodeau Jr RN (Alice Peck Day Memorial Hospital, Lebanon, New Hampshire); Kevin Stevenson, MD, Logan Mahoney, LPN (Piedmont Orthopaedic Complex, Macon, Georgia); Fabien Bitan, MD, Stephanie Gomez (Manhattan Orthopaedics, New York City, New York); John Stevenson, MD, Ana Marichal (The Orthopaedic Institute, Gainesville, Florida); Donald Sachs, MD, Robin Cambron, MSN, MBA, RN, Missy White, Ana Colburn, RN, Sally Raiden, RN, MSN (Center for Spinal Stenosis and Neurologic Care, Lakeland, Florida); Abhineet Chowdhary, MD, Tina Fortney, RN, BSN (Overlake Hospital Medical Center, Bellevue, Washington); Gowriharan Thaiyananthan, MD, Tungie Williams (BASIC Spine, Orange, California); Michael Oh, MD, Gary Schmidt, MD, Matthew Yeager (Allegheny General Hospital, Pittsburgh, Pennsylvania); David Wiles, MD, Susan Maye, RN, MS (East Tennessee Brain & Spine, Johnson City, Tennessee); Michael Hasz, MD, Carrie Califano (Virginia Spine Institute, Reston, Virginia); William Rosenberg, MD, Pamela McCann, RN, BSN (Midwest Division-RMC, LLC,-Research Medical Center, Kansas City, Missouri); Jeffrey D. Coe, MD, Julia Coe, Marlene Coe (Silicon Valley Spine, Campbell, California); Jed Vanichkachorn, MD, Jessica Lynch (Tuckahoe Orthopaedics Associates, Richmond, Virginia); Mark C. Gillespy, MD, Sherri Zicker, RN (Orthopaedic Clinic of Daytona Beach, Daytona Beach, Florida); Ralph Rashbaum, MD, Shannon Rusch, BA, CCRC (Texas Back Institute, Plano, Texas); Emily A. Darr, MD, John A. Glaser, MD, Laura Fields, Monica Baczko (Medical University of South Carolina, Charleston, South Carolina).
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