Inferior and Intra-/Peri-Articular Superior Sacroiliac Joint Injection Approaches Under Ultrasound Guidance to Treat Metastasis-Related Posterior Pelvic Bone Pain.

Abstract

Numerous mechanical and pathologic variables contribute to sacroiliac joint (SIJ) pain. The oncologic population has additional considerations, including tumor burden causing fracture, nerve compression, joint instability, and periosteal inflammation. Post-treatment changes may also restrict joint mobility, causing transitional pain. Currently, fluoroscopically guided SIJ injections, aimed at the inferior one third of the SIJ, are the gold standard for treatment but have only been described in the nononcologic population. Ultrasound (US) guidance may confer several benefits, including positioning, ease of procedure, lower costs, and, importantly, guidance to avoid neovascularization, metastatic disease, and other soft tissue structures. We aim to describe the advantages of US-guided SIJ injections for refractory malignant SIJ pain from extra-articular tumors. We then describe our technique and decision framework for accessing the superior or inferior SIJ in patients with metastatic sacroiliac pain. A retrospective review was performed on 5 patients with refractory malignant SIJ pain who underwent US-guided superior or inferior approach SIJ injection. Using imaging and outcomes, we developed a decision framework. Patients received either inferior or superior approach SIJ injections depending on location of tumor, extent of tumor invasion, and stability of the SIJ as per our framework. All patients reported improvement in pain and function without complications. We propose a decision framework for inferior vs. superior approach US-guided SIJ injections in the oncologic population with SIJ pain from metastases to the pelvis or sacrum. Having multiple techniques to approach the SIJ is important in the oncologic population, in whom metastatic tumor burden poses a technical challenge to performing these injections.