Study protocol for a randomised controlled trial on the effect of local analgesia for pain relief after minimal invasive sacroiliac joint fusion: the ARTEMIS study

IntroductionChronic lower back pain is a common report in the general population. A dysfunctional sacroiliac joint (SIJ) is estimated to be responsible for one in five patients with lower back pain. Minimally invasive sacroiliac joint fusion (MISJF) is a surgical procedure to treat SIJ dysfunction. During the procedure, the SIJ is stabilised by implants inserted percutaneously under fluoroscopy guidance. Postoperatively, patients often report a lot of pain, which contributes to patients taking high doses of painkillers (opioids for example,) and preventing early mobilisation. In several orthopaedic procedures, intraoperative infiltration of the wound bed results in decreased consumption of analgesics, earlier mobilisation and shorter hospitalisation time. The aim of this study is to investigate the effectiveness of intraoperative SIJ infiltration with analgesia in reducing postoperative pain after MISJF.Methods and analysisWe will perform a two-centre, prospective, double-blind, randomised controlled trial to determine whether SIJ infiltration with 1.5–5 cc bupivacaine 0.50% is superior to 1.5–5 cc placebo (NaCl 0.9%) in reducing postoperative pain in patients after MISJF, and to determine whether bupivacaine significantly reduces opioid use in the direct postoperative period. Patients will be randomised with 1:1 allocation for either bupivacaine (intervention) or placebo SIJ infiltration. Postoperative pain will be measured by the Visual Analogue Scale pain score at entry and exit recovery, 2, 4, 6, 24 and 48 hours postoperatively.Ethics and disseminationThis is the first trial that investigates the effectiveness of intraoperative SIJ infiltration with bupivacaine 0.50% in reducing postoperative pain after MISJF. If intraoperative SIJ infiltration with bupivacaine 0.50% proves to be effective, this might have important clinical implications, such as postoperative analgesics (opioids for example,) consumption, earlier mobilisation and potentially shorter hospitalisation time.Trial registration numberNL9151.

Preoperative considerations

Sacroiliac joint fusion surgery is an option for patients whose sacroiliac joint pain has been refractory to conservative pain management. A good candidate for fusion surgery is one who has completed all appropriate nonsurgical management efforts, including physical therapy, intraarticular sacroiliac steroid injections, oral analgesics, and radiofrequency ablation of sacral nerve roots, without experiencing any improvement in pain. This chapter covers candidate selection, the two main surgical approaches used for this fusion surgery (open and minimally invasive), anticoagulation guidelines, and the risk of infection and complications. Before surgery it is very important to make sure the patient understands the risks of the surgery as well as the potential for success.

Biomechanics of a laterally placed sacroiliac joint fusion device supplemental to S2 alar-iliac fixation in a long-segment adult spinal deformity construct: a cadaveric study of stability and strain distribution

OBJECTIVE S2 alar-iliac (S2AI) screw fixation effectively enhances stability in long-segment constructs. Although S2AI fixation provides a single transarticular sacroiliac joint fixation (SIJF) point, additional fixation points may provide greater stability and attenuate screw and rod strain. The objectives of this study were to evaluate changes in stability and pedicle screw and rod strain with extended distal S2AI fixation and with supplemental bilateral integration of two sacroiliac joint fusion devices implanted using a traditional minimally invasive surgical approach. METHODS Eight L1–pelvis human cadaveric specimens underwent pure moment (7.5 Nm) and compression (400 N) tests under 4 conditions: 1) intact (pure moment loading only); 2) L2–S1 pedicle screw and rod with L5–S1 interbody fusion; 3) added S2AI screws; and 4) added bilateral laterally placed SIJF. Range of motion (ROM), rod strain, and screw-bending moment (S1 and S2AI) were analyzed. RESULTS Compared with S1 fixation, S2AI fixation significantly reduced L5–S1 ROM in right lateral bending by 50% (0.11°, p = 0.049) and in compression by 39% (0.22°, p = 0.003). Compared with fixation ending at S1, extending fixation with S2AI significantly decreased sacroiliac joint ROM by 52% (0.28°, p = 0.02) in flexion, by 65% (0.48°, p = 0.04) in extension, by 59% (0.76°, p = 0.02) in combined flexion-extension, and by 36% (0.09°, p = 0.02) in left axial rotation. The addition of S2AI screws reduced S1 screw-bending moment during flexion (0.106 Nm [43%], p = 0.046). With S2AI fixation, posterior L5–S1 primary rod strain increased by 124% (159 μE, p = 0.002) in flexion, by 149% (285 μE, p = 0.02) in left axial rotation, and by 99% (254 μE, p = 0.04) in right axial rotation. Compared with S2AI fixation, the addition of SIJF reduced L5–S1 strain during right axial rotation by 6% (28 μE, p = 0.04) and increased L5–S1 strain in extension by 6% (28 μE, p = 0.02). CONCLUSIONS Long-segment constructs ending with S2AI screws created a more stable construct than those ending with S1 screws, reducing lumbosacral and sacroiliac joint motion and S1 screw-bending moment in flexion. These benefits, however, were paired with increased rod strain at the lumbosacral junction. The addition of SIJF to constructs ending at S2AI did not significantly change SI joint ROM or S1 screw bending and reduced S2AI screw bending in compression. SIJF further decreased L5–S1 rod strain in axial rotation and increased it in extension.

Lateral fusion

Sacroiliac joint pain and dysfunction has increasingly been identified as an important pain generator in patients with chronic back pain or failed back surgery syndrome, and it is estimated to account for 15% to 30% of low back pain cases. Historically, fusion of the joint has been performed with an open posterior or posterolateral approach. Minimally invasive surgical (MIS) approaches were introduced in 2008, and since that time MIS posterior and lateral approaches have become common. Numerous medical device companies have marketed MIS systems, and evidence of their safety and efficacy is mounting. This chapter will detail lateral MIS approaches using fluoroscopic and navigation system guidance, as well as the posterolateral open approach, also known as the modified Smith-Petersen approach. Evidence for safety and efficacy of lateral sacroiliac joint fusion will also be discussed.