Author's Note: As a current member of the Value-Based Benefits Subcommittee (VBBS) of the Oregon Health Evidence Review Commission (HERC), I provided the following information to the committee.
We should be very skeptical of the purportedly less invasive version of the already defrocked sacroiliac fusion surgery, "minimally invasive" sacroiliac joint fusion; and concerned this procedure simply represents the device manufacturer's attempt to find yet another new market.
When I began practice in 1981, surgeons held the staunch opinion that the sacroiliac joints did not move, nor were they a source of pain. Ten to 15 years later, spine surgeons agreed the sacroiliac joints acted as an important energy-transfer mechanism from the legs to the spine by stretching and allowing small movements (joint play).
Of course, the chiropractic and osteopathic professions had been aware of these small movements for many decades, as well as the positive clinical outcomes of manipulating the hypomobile (loss of normal joint play) or fixated SI joint.
In clinical practice, many is the time that the symptomatic or painful SI joint is actually hypermobile and compensating for the contralateral SI joint that has become hypomobile (fixated), commonly due to some traumatic event. Manipulating the hypomobile joint, restoring normal joint play and performing adjunctive physiotherapies to the painful hypermobile joint result in excellent outcomes.
Fusing Sacroiliac Joints: Inherent Complications?
The notion of fusing sacroiliac joints was first described in 1926 before the advent of instrumentation, with the first surgical materials being ceramic blocks.1 A few years later, rods and screws were utilized in an attempt to facilitate internal fixation (popular momentarily in the late 1990s), only to fall out of fashion as surgeons began to observe other problems and pains.
It is well-established that fusing any part of the spine results in other areas of the spine becoming overloaded in an attempt to compensate for the lack of motion caused by the fusion. The other non-fused areas can begin to degenerate (next-level / adjacent-level disease), instigating more long-term problems for the patient.
Spinal fusion is known to result in adjacent-level disease elsewhere in the spine, while at the same time lacking evidence of efficacy as a treatment for chronic low back pain.2-8 Why would we believe fusion of the sacroiliac joints for chronic pain would fare any better?
Actually, it doesn't, according to a study published in June.9 Germane to the concerns of biomechanical stressors elsewhere as a result of fusing one or both SI joints, this study of 469 patients noted, "The incidence of novel lumbar pathology in this population was 3.6% (n=17) at 90 days postoperatively and 5.3% (n=25) at 6 months." The investigators concluded; "The results of this study show that minimally invasive SI joint fusion could possibly carry higher risks of complications than previously stated." (Emphasis mine)
Joint Fusion vs. Conservative Care: Skewed Research?
To date, there is but one small (148 subjects) randomized, controlled trial concurrently comparing the outcomes after minimally invasive sacroiliac joint fusion and nonsurgical management (NSM) of chronic lower back pain with the presumption that the pain is coming from sacroiliac joint dysfunction.10 This RCT by Polly, et al., compared the outcomes of patients receiving either triangular titanium implants or nonsurgical treatment, presenting conspicuously superior outcomes in the implanted patients with sacroiliac joint dysfunction.
The manufacturer of the triangular titanium implants (SI-BONE) sponsored the study, with all of the authors having direct ties to this device manufacturer (with two, Drs. D. Cher and K. Wine, being employees of the company.) Other concerns regarding this study include:
Lack of sufficient detail in NSM treatments: Although the authors indicated that anti-inflammatory and pain medications, intra-articular SIJ steroid injections, physical therapy, and RFA of the sacral lateral nerve-root branches were administered in a stepwise fashion and tailored to each patient's needs, there is no indication these interventions were applied more than once each for immediate pain relief only.
Thus, it is misleading to indicate surgery was superior to NSM if the latter options were given for a limited time, rather than spread out over an extended period or even given prophylactically. Additionally, the authors indicate that 87 percent of their patients received "at least two" interventions in addition to the injections, but these additional applications were never specified.
Although "chiropractic" (meaning a singular modality / intervention, e.g., manipulation?) is mentioned as a known nonsurgical treatment, the nonsurgical management group in this study only received physical therapy. Furthermore, the specific treatment interventions utilized by the physical therapists were not specified.
Sacroiliac joint dysfunction / hypomobility vs compensatory hypermobility of the contralateral SI joint is many times the symptomatic or painful joint area, often with concomitant myofascial trigger points in the gluteal musculature. There is no mention or apparent recognition of this form of SI joint dysfunction in this study; nor the reality that manipulation of the hypomobile SI joint and adjunctive physiotherapies to the contralateral painful hypermobile SI joint and soft tissues often resolve this clinical entity.
Alternatively, if a therapist focuses only on the painful hypermobile SI joint, the typical mobilization techniques and rehabilitative exercises will at best, not resolve the problem, and at worst, exacerbate the pain and dysfunction.
Adjacent-level disease: Although the authors of this small RCT were quick to acknowledge that lumbar fusion, especially at the lumbosacral level, can result in stressors and pathology to the sacroiliac joints due to the biomechanical changes, they failed to consider the reverse also can occur. Fusing one or both SI joints will change the biomechanics in the low back, resulting in "novel lumbar pathology," as the June study validated.9
Specifically, fusing one SI joint will cause the contralateral joint to become hypermobile in an attempt to compensate for the surgically fixated joint, likely requiring that SI joint to be fused as well. Considering the lack of evidence supporting the efficacy of lumbar spinal fusion for the treatment of chronic low back pain, coupled with the reality of adjacent-level disease, it is unlikely fusing sacroiliac joints will fare any better.
Subjects with planned staged bilateral surgery: There is a brief reference to individuals who apparently underwent bilateral fusion of their sacroiliac joints, "most recent SIJ fusion to accommodate subjects with planned staged bilateral surgery." The assumption that both sacroiliac joints fell within the criteria as needing to be fused is rather aggressive. Could any of these bilateral fusion candidates be due to the stressors placed on the contralateral joint following the first fusion?
Bilateral fusion of the SI joints would likely have a profound biomechanical overloading effect on the lumbosacral regions. The question becomes, how will these patients fare 5-10-15 years later?
Most common adverse events in the SIJ fusion group included "back pain" (16.7 percent; n=17), "leg pain" (31.4 percent; n=32) and "pelvic pain" (47.1 percent; n=48) – precisely the chief complaints this surgery is designed to eliminate.
Intra-examiner reliability of the physical examination provocative tests were not very good and the selection of surgical candidates was somewhat subjective.
Lack of sufficient sham procedure: By the authors' own admission, despite the fact that sham procedures are rarely conducted in surgical clinical trials, the surgical patients experienced a multiplicity of stimuli other than the surgical implants themselves; and most likely adhered to post-intervention regimens to achieve recovery more strictly than the NSM cohort (surgical patients towing the line, the "Hawthorne effect"). In other words, the effect could not have strictly been attributed to the titanium implants themselves.
Unbalanced crossover numbers: A total of 35 patients were shown to cross over; only nine did not. There is no explanation as to why these numbers were so disparate. It is only by fortune of the large differences in outcomes between the two groups that the non-crossover cohort of just nine patients was not underpowered.
Unbalanced age groups: Although so many characteristics of the two experimental groups were generally matched at baseline, it appeared a greater proportion (17.4 percent) of NSM patients compared to SIJ fusion patients (9.8 percent) were over 65 years of age. This could have presented a disproportionate impediment to improvement of those patients receiving NSM.
Are Medicaid Patients in Your State Getting This Procedure?
Studies that support minimally invasive sacroiliac joint fusion have been single-center, case-based, with the exception of the small manufacturer-sponsored RCT whose issues I have reviewed above. It appears after providing this evidence-based information that my state of Oregon will not be funding this surgery for the Medicaid population.
Chiropractic colleagues across the nation should remain skeptical as to their states funding this surgical intervention for chronic low back pain until such time as higher-quality evidence is available supporting efficacy, incidence and severity of adverse events, as well as cost vs. benefit.
References
- Waisbrod H, Krainick JU, Gerbershagen HU. Sacroiliac joint arthrodesis for chronic lower back pain. Arch Ortho & Traumatic Surg, 1987;106(4):238-240.
- Brox JI, Sorensen R, Friis A, Nygarrd O, et al. Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercise in patients with chronic low back pain and disc degeneration. Spine, 2003;28(17):1913-21.
- Rivero-Arias O, Campbell H, Gray A, et al. Surgical stabilization of the spine compared with a programme of intensive rehabilitation for the management of patients with chronic low back pain: cost utility analysis based on a randomized controlled trial. BMJ, 2005;May 28;330(7502):1239.
- Fairbank J, Frost H, Wilson-MacDonald J, et al.; Spine Stabilization Trial Group. BMJ, 2005May 28;330(7502):1233. Epub May 23. Erratum in: BMJ, 2005 Jun 25;330(7506):1485.
- Abdu WA, Lurie JD, Spratt KF, et al. Degenerative spondylosis: does fusion method influence outcome? Four-year results of the spine patient outcomes research trial. Spine, 2009 Oct. 1;34(21):2351-60.
- Deyo RA, Mirza SK, Martin BI, et al. Trends, major medical complications, and charges associated with surgery for lumbar spinal stenosis in older adults. JAMA, 2010 April 7;303(13):1259-65.
- Mannion AF, Brox JI, Fairbank JCT. Comparison of spinal fusion and nonoperative treatment in patients with chronic low back pain: long-term follow-up of three randomized controlled trials. Spine J, 2013;13(11):1438-1448.
- Wang X, Wanyan P, Tian JH, Hu L. Meta-analysis of randomized trials comparing fusion surgery to non-surgical treatment for discogenic chronic low back pain. J Back Musculoskelet Rehabil, 2015;28(4):621-7.
- Schoell K, et al. Postoperative complications in patients undergoing minimally invasive sacroiliac fusion. Spine J, 2016 Jun 24 (epub ahead of print).
- Polly DW, et al. Randomized controlled trial of minimally invasive sacroiliac joint fusion using triangular titanium implants vs nonsurgical management for sacroiliac joint dysfunction: 12-month outcomes. Neurosurg, 2015;77(5):674-691.
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