Stratification of Sacroiliac Joint Pain Patients and the Efficacy of Ultrasound-Guided Injection Treatment: A Retrospective Study

INTRODUCTION: Sacroiliac joint (SIJ) pain is a significant contributor to low back pain and affects patients´ quality of life. This study aims to (1) stratify patients with SIJ pain based on their clinical history and imaging findings, (2) evaluate the efficacy of ultrasound-guided injection techniques for pain management, and (3) identify predictors of pain relief. Materials and methods: ​A retrospective observational study was conducted at the chronic pain unit (CPU) of a tertiary hospital, with 75 patients diagnosed with SIJ pain who underwent ultrasound-guided injection treatment between February 2021 and August 2024. Patients were stratified into different groups based on their clinical diagnoses and imaging findings. Pain intensity was assessed using the numeric rating scale (NRS) at baseline, 48 hours, one week, and three months postprocedure. A logistic regression model was applied to assess associations between predictive variables in univariate analysis and the likelihood of significant early pain reduction (≥70%). Variables were iteratively removed if p > 0.10, with the final model retaining predictors with p ≤ 0.05.​ Results:​ A cohort of 75 patients underwent 127 ultrasound-guided SIJ injections. Pain reduction of ≥50% was observed in 57.3% of patients at 48 hours postprocedure, declining to 34.7% at three months. SIJ pain and normal magnetic resonance imaging (MRI) ​significantly increased the likelihood of early pain reduction (OR = 5.13, 95% CI: 1.01-26.13, p = 0.049), and the presence of metabolic disorders (defined as the presence of diabetes mellitus and/or obesity) decreased the likelihood of early pain reduction (OR = 0.28, 95% CI: 0.09-0.95, p = 0.040). The median time to reintervention was 21 months. Metabolic disorders (HR = 2.72, p = 0.010) and cardiovascular comorbidities (hypertension, cardiac diseases, cerebrovascular diseases, peripheral arterial disease) (HR = 2.64, p = 0.011) were associated with a higher risk of earlier recurrence of pain, suggesting a role of systemic health in limiting treatment durability. The complication rate was low (2.67%), consisting only of transient sensory disturbances, with no major adverse effects identified. CONCLUSIONS: Ultrasound-guided SIJ injections provided early pain reduction, with a complication rate of 2.67% limited to transient, self-limited sensory changes. Predictive factors, such as the presence of metabolic disorders, offer insights into patient selection and individualized treatment planning. A clinical diagnosis supported by a positive response to diagnostic injection may be sufficient to confirm SIJ-related pain, although further investigation is needed to elucidate the underlying cause.