To re-investigate the success rate of Ultrasound guided sacroiliac joint steroid injection in depositing the drug inside the joint capsule (confirmed by contrast spread in fluoroscopy) and if there is a difference in clinical outcome between injections done strictly inside the joint and injections done periarticular.

An IV cannula will be inserted, and basic ASA monitors applied, then the patients will be positioned in prone position. After disinfection of the skin, Ultra sonography will be used to Guide Needle Placement in SIJ (the hypoechoic cleft between the surface of the sacrum and the ilium) under complete a sepsis as the technique previously described in the literature.

A low frequency (2-5 Hz) curvilinear transducer will be used in a sterile cover, the posterior superior iliac spine, lateral borderof sacrum, and ilium will be identified in transverse orientation. Subsequently, the probe will be moved caudally until the superior part of the posterior SIJ is identified. The SIJ will be traced caudally until the distal third of the SIJ is visualized as evident by the flat contour of the iliac crest and the presence of the second sacral foramen on the medial aspect of the sacrum.

After local anesthetic infiltration of skin and subcutaneous tissues using Lidocaine 1%, a 21-gauge spinal needle will be advanced from a medial to lateral direction using an in-plane technique. After reaching the joint, a total volume of 4 ml of injectate will be injected which consists of: 1 ml 40 mg of methylprednisoloneacetate (Depo-Medrol®, Pfizer), 2 ml Lidocaine 2%, 1 ml Iohexol (Omnipaque 300®, GE Healthcare).

Control fluoroscopy

After injection of the drug and withdrawal of the needle, a antero-posterior fluoroscopy image will be obtained and recorded for the injected joint to detect the spread pattern of the contrast and whether its pre-dominantly intra or periarticular. (N.B: Periarticular injection is any injection done near the joint as evidenced by US but on fluoroscopy no contrast is detected inside the joint). Then a sterile patch will be applied to the puncture site and patient discharged to the recovery room for follow-up for 30 minutes before discharge to home.

Measurement tools

• Total number of intraarticular and periarticular drug injections as evidenced by contrast spread in fluoroscopy.
• Patient's pain score rated from 0-10 (Numeric Pain Rating Scale, NRS) before the procedure, 10 minutes after the procedure (in the recovery room), 1 week and 1 month post-procedure.
• Demographic data (including age, sex, BMI, ASA score).
• Limitation of physical functioning as measured by the Oswestry Disability Index (ODI) at 1 month after the procedure .
• Procedure-related variables (time, complications, patient satisfaction.

Inclusion Criteria:

• Subject has sacroiliitis (acute or chronic) by history.
• Failed conservative therapy eg. bed rest, anti-inflammatory medications and physical therapy for at least 6 weeks.

Exclusion Criteria:

• Subject has BMI above 35 kg/m2
• Coagulopathy.
• Renal or Hepatic Failure.
• Current Pregnancy or actively pursuing pregnancy.
• Known allergy to local anesthetic or steroids.
• Infection at site of needle placement or SIJ infection.
• Prior surgical procedures involving the SIJ.
• Previous surgical Fixation involving the lumbar spine.