Our literature and database review identified 6 unique devices that can be used by spine surgeons and pain management physicians for MIS (percutaneous) posterior SIJF (Table 1). Although it is becoming increasingly5 common for pain management physicians and physiatrists to perform percutaneous SIJF at the bedside using a posterior approach, our search yielded only 2 studies (one meta-analysis and one clinical trial) pertaining to performance of this procedure by non-surgeons. Additionally, because spine surgeons most commonly use other approaches, there is only one study describing the implementation of the posterior allograft approach by surgeons.7
This is in contrast to the performance of other MIS SIJF techniques by spine surgeons, who often employ lateral (most common), posterolateral, and combined approaches by using a 11 unique FDA approved SIJF devices and a total of 33 devices overall (including those not featured in the peer-reviewed, published literature)3. In contrast to devices used in the posterior allograft approach, which have only been described in the 3 aforementioned studies, over 10 unique devices used in the lateral and posterolateral MIS SIJF approaches by spine surgeons have been described in numerous reports throughout the literature. For example, Titanium Triangular Implants manufactured by SI-Bone are used by spine surgeons in MIS lateral SIJF and have been described in 118–18 retrospective case series (level 4 evidence), 219, 20 prospective cohort studies (level 2 evidence), 221, 22 additional prospective studies (level 1 evidence) and 2 safety analyses.3 Overall, the lateral approach is performed only by spine surgeons and encompasses the strongest body of evidence and largest number of devices3 relative to any other approach. Other studies23–25 describing the utility of MIS lateral SIJF using devices such as SImmetry include 2 case series (level 4 evidence) and one prospective cohort study (level 2 evidence). Furthermore, studies describing these lateral approaches report notable improvements in ODI, decreased opioid usage, and improved functionality with minimal complications following MIS lateral SIJF.25–27 MIS SIJF performed by spine surgeons using posterolateral devices has also been associated with favorable, albeit less robust, outcomes. For example, a retrospective study (n = 24) describing MIS placement of Medtronic’s posterolateral fusion device reported statistically significant reduction in low back pain and leg pain scores postoperatively.28 Overall, the lateral and posterolateral approaches to MIS SIJF have become increasingly popular over the last decade and can provide pain relief for patients with SI-related LBP when conservative management fails.3
Additionally, in 2008, Wise7 and Dall contributed to the limited body of evidence regarding the posterior allograft approach with a prospective study of 13 patients. They reported no significant complications, an 89% fusion rate at 6 month follow-up, and a statistically significant reduction in LBP visual analog scale (VAS) scores.3, 7 Despite these results, there is currently no FDA approved device for posterior allograft SIJF on the market.3
As such, when interventional pain management specialists or physiatrists perform posterior percutaneous SIJF, they are doing so with devices that are not yet FDA approved. Despite this fact, one advantage of the posterior approach for non-surgeons is that it avoids critical neurovascular structures that are otherwise encountered in the lateral and oblique approaches.29 In the first peer-reviewed, published review on the performance of MIS SIJF by non-surgeons, which appeared in the International Journal of Spine Surgery in June 2021, Lee et al.29 conducted a systematic review that identified 10 studies on MIS posterior SIJF. However, this study does not include any evidence that would help delineate a clear-cut stance on the role of pain management physicians in performing MIS SIJF for refractory SI disease and/or LBP. In fact, one of the studies included in Lee et al.’s review is that published in 2008 by Wise and Dall, a study which describes 13 patients undergoing posterior allograft SIJF performed by spine surgeons.3, 7, 29 Additionally, 3 other studies included in Lee et al.’s review describe posterolateral (or other) approaches performed by spine surgeons.30–32 The 2 studies describing posterolateral devices were featured in the prior systematic review by Himstead et al., while the 3rd was not included in that prior review because it described an atypical distraction-arthrodesis technique (as opposed to typical fusion or arthrodesis).3 However, the remaining 6 studies included by Lee et al.29, which feature reports on the performance of MIS posterior SIJF by pain management physicians, are each non-peer reviewed abstracts that were presented at pain management conference meetings. For example, Patterson and colleagues presented their case series at the California Society of Interventional Pain Physicians (CASIPP) annual meeting, held in November 2018, while Mann et al. presented on MIS posterior SIJF at The American Society of Pain and Neuroscience (ASPN) annual meeting in July 2019. Altogether, because each of the 6 studies cited by Lee et al.29 are conference abstracts as opposed to peer-reviewed publications, they cannot be used to inform guidelines on the role of non-surgeons in the MIS SIJF treatment algorithm for patients with SI joint disease.
Aside from this study, the only other study investigating the role of pain management physicians in performing MIS SIJF for SI joint disease is a clinical trial featured on ClinicalTrials.gov, termed the PainTEQ study. Led by a pain management physician principal investigator, the PainTEQ study is a prospective, multi-site, single arm study designed to collect patient reported outcomes data following the MIS posterior SIJF procedure in 100 patients with SI disease.33 The study began enrolling patients in early 2020 and is expected to reach completion by March 2022.33 Until data from this study is subject to peer-review and ultimately published, there is no peer-reviewed evidence available within the medical literature on conduct of MIS SIJF by non-surgeons and therefore no way to assign levels of evidence for the purpose of formulating recommendations on the role of non-surgeons in performing MIS posterior SIJF. By contrast, there are multiple MIS SIJF approaches performed by spine surgeons – as well as multiple studies investigating each approach – which have been assigned varying levels of evidence (highlighted in the present review) that have factored into recommendations made regarding the indications for MIS SIJF performed by spine surgeons.
Furthermore, this contrast in available levels of evidence may be interpreted in light of the Position Statement offered by the American Association of Neurological Surgeons (AANS) and Congress of Neurological Surgeons (CNS) on “arthrodesis of the spine by the non-spine surgeon”.5 This Position Statement, set forth by the Joint Section on Disorders of the Spine and Peripheral Nerves in August 2021, emphasizes the fact that neurosurgeons and orthopaedic spine surgeons have completed extensive surgical training, rendering them experts in the diagnosis and treatment of disorders requiring instrumentation of the spine or changes to its biomechanics.5 Furthermore, it stipulates that “non-surgeon spine practitioners…are valuable members of the spine care team” who can play an instrumental role in the diagnosis and treatment of various spinal pathologies, but who should not engage in operative measures (such as SIJF) that alter the biomechanics of the spine. In summation, the Position Statement maintains that pain management physicians and physiatrists have not undergone the training necessary to properly handle complications associated with spinal instrumentation or to perform the calculated decision-making necessary to achieve optimal surgical stabilization of the spine.5 Above all, the AANS and CNS emphasize the prioritization of best care practices and patient safety in situations where clinicians must manage surgical diseases of the spine.