Outcomes of Intra-articular Steroid Injection Via Ultrasound Guidance Versus Fluoroscopic Guidance in the Sacroiliac Joint in Patients With Sacroiliitis

The sacroiliac joint (SIJ) is increasingly recognized as a contributor to low back pain (LBP), with epidemiological estimates attributing approximately 10-30 % of mechanical low back pain cases to SIJ pathology1. Anatomically, the SIJ is a synovial-type (inferior portion) or syndesmosis-type (superior portion) joint between the sacrum and the ilium, supported by substantial interosseous, posterior and anterior ligaments and innervated by dorsal sacral rami and lower lumbar dorsal rami2. Inflammatory involvement of the SIJ occurs in conditions such as axial spondyloarthritis and may also arise post-traumatically or degeneratively3.

NSAIDs and physical therapies are used to treat sacroiliitis. However, intraarticular corticosteroid injections administered locally to the SI joint might result in rapid and significant clinical improvements in extremely painful instances4,5. Fluoroscope guided (FL) is usually employed to increase the precision of this treatment, however CT and MRI have also been used in recent years. These imaging techniques have a number of drawbacks, such as radiation exposure, expense, and the need for suitable infrastructure6. A new alternative technique for guiding SIJ injection is ultrasound (US) guidance. The advantages of US-guided injection over FL include that it eliminates radiation exposure, is more accessible, and is less expensive when used alone. Additionally, the US permits "real-time" visualisation of the injectate distribution and needle tip during injection.7,8.

• Ultrasound-guided intra-articular steroid injection (Procedure), also known as Ultrasound-guided SI Joint Injection: Participants will receive intra-articular sacroiliac joint steroid injection under ultrasound guidance. A needle will be advanced under real-time ultrasound guidance to the sacroiliac joint, and 40 mg triamcinolone acetonide mixed with 1 mL 0.25% bupivacaine will be injected.

Primary outcomes

• Procedural success rate of sacroiliac joint injection [During the procedure]: Successful intra-articular deposition of steroid in the sacroiliac joint confirmed by the respective imaging guidance modality (ultrasound or fluoroscopy).

Secondary outcomes

• Oswestry Disability Index (ODI) Score [Baseline, 2 weeks, 1 month, and 3 months after the procedure]: The Oswestry Disability Index (ODI) is a validated patient-reported outcome measure used to assess disability related to low back pain. Scores range from 0 to 100, with higher scores indicating greater disability and worse functional status.

Sex: All, ages: 18 Years to 70 Years

Inclusion Criteria:

* Age 18-70 years
* Both sexes
* Clinical diagnosis of sacroiliitis

Exclusion Criteria:

* Prior SI joint injection in the past 12 months

  * Contraindication to corticosteroid injection (systemic infection, local infection, bleeding diathesis, uncontrolled diabetes with HbA1c >9%, allergy to contrast or steroid)
  * Radicular or neurogenic pain attributable to lumbar spine or hip pathology
  * Pregnancy or breastfeeding
  * Severe osteoarthritis or fusion of the SI joint on imaging
  * Systemic rheumatologic disease requiring systemic biologic therapy (unless stable for >6 months)