A new technical contribution for ultrasound-guided injections of sacro-iliac joints.

INTRODUCTION Sacroiliac joint (SIJ) represents a difficult location for local therapies, as intra-articular injections may be hard to execute, especially in particular conditions such as chronic inflammatory diseases. However, in selected patients, local therapies may be considered. Some recent studies demonstrated the feasibility of ultrasound (US)-guided injection of SIJ, but still a complete explanation and definition of the technique is needed. MATERIALS AND METHODS Seven patients, four males and 3 females, affected by mono or bilateral sacroiliitis entered the study. Each patient received 40 mg of acetonide triamcinolone for each SIJ, intra articular (IA) US-guided injection. The technical originality proposed in this study consists in the spinal needle insertion in the middle of the cranial long side of the linear transducer with an orientation of about 10 degrees, determining shorter needle insertion for reaching joint space and consequently probably granting lesser pain and traumatism for patients. RESULTS A total of 22 injections was performed. The longer follow-up time obtained was 18 months in 3 patients. All patients reached at least a 6 month follow-up. All patients reported an amelioration in pain that lasted for at least 6 months. No systemic adverse events were reported or observed. Complete visualization of SIJ and of needle placement was performed by US imaging, while compound proper injection was also visualized by Color-Doppler US imaging. DISCUSSION Actually, sacroiliac joint intraarticular injections are often performed under fluoroscopy or Computerized Tomography guidance. Such techniques present several limitations, especially for repeated injections, such as the use of ionizing radiations, the need of a contrast agent and the direct and indirect costs connected. US guidance in IA SIJ injections may represent an easily repeatable imaging technique for needle placement and a precious tool for detecting inflammatory activity of the joint.