Minimally Invasive Sacroiliac Joint Fusion: Posterior Graft Implant vs. Lateral Arthrodesis with Compression Screw Hardware at a Pain Management Center.

Background: The sacroiliac joint (SIJ) is a frequently overlooked source of lower back pain (LBP), contributing to 15-30% of cases. Nonoperative treatments such as NSAIDs, physical therapy, and SIJ injections have limited effectiveness on LBP. When conservative measures fail, SIJ fusion is recommended, with minimally invasive techniques showing better outcomes than traditional open surgery. However, there is no clear agreement on the optimal approach for SIJ fusion.

Objectives: This study aims to evaluate the outcomes of minimally invasive SIJ fusion performed by a single surgeon, comparing the lateral and posterior approaches to another in terms of pain relief, functional improvement, and procedure durability.

Study design: A retrospective comparative study.

Setting: A single pain management center at the Interventional Pain Institute, where patients underwent SIJ fusion between April 2020 and May 2024.

Methods: A total of 115 patients who underwent minimally invasive SIJ fusion and met the inclusion criteria were included in the study. Patients were assessed before and after the procedure for pain using the Visual Analog Scale (VAS), functional outcomes using the Oswestry Disability Index (ODI), opioid consumption, sleep quality, and procedure durability. Statistical comparisons between the lateral and posterior approaches were performed using the chi-square (c²), Fisher's exact test, and t-test as appropriate, while durability was analyzed with the Kaplan-Meier curve and log-rank test.

Results: The average follow-up duration was 11.3 ± 5.8 months. Lateral SIJ fusion demonstrated longer procedural durability compared to the posterior approach, with greater improvements in VAS pain scores (66.3% vs. 53.8%, P = 0.017), ODI functional outcomes (45.0% vs. 30.7%, P = 0.002), higher rates of sleep improvement (83.9% vs. 61.0%, P = 0.006), and lower recurrence rates (12.5% vs. 28.8%, P = 0.031). At the last follow-up, most patients (79.1%) maintained their improvements.

Limitations: This study is limited by its retrospective design, its single-center setting, and the lack of randomization between the lateral and posterior approaches.

Conclusion: Both the lateral and posterior approaches to minimally invasive SIJ fusion were beneficial. However, the lateral approach used in our study demonstrated superior outcomes in the areas of pain relief, functional improvement, and procedure durability. Further multicenter prospective studies with larger patient populations are recommended to confirm these findings.