Analgesic Effect of Sacral Submultifidus Block as an Adjunct to Sacroiliac Joint Injection

will receive SIJ Injection Alone ) , will receive SIJ Injection Alone :The sacroiliac joint will be identified under real-time ultrasound guidance. low- frequency curvilinear transducer is used, The transducer is placed transversely over the lower part of the sacrum (at the level of the sacral hiatus), and the lateral edge of the sacrum is identified. Then the transducer is moved laterally and cephalad till the bony contour of the ileum is clearly identified. The cleft seen between the medial border of the ileum and the lateral sacral edge represents the SI joint, and the inferior-most point is targeted. needle is then inserted at the medial end of the transducer and advanced laterally under direct vision in plane with the ultrasound beam, Following skin infiltration with a small volume of local anesthetic (e.g., lidocaine 1%), a 22-25G spinal needle 50mm block needle (SONOTAP, Pajunk , Geisingen ,Germany ),will be advanced toward the inferior third of the sacroiliac j

receive SIJ Injection \& Sacral Submultifidus Block). group B (intervention group: will receive SIJ Injection \& Sacral Submultifidus Block).:2.Sacral Submultifidus Block (group A and group B): After completion of the SIJ injection, patients in the intervention group will receive an ultrasound-guided sacral submultifidus block (device used is GE healthcare model LOGIQ P7). A low-frequency curvilinear transducer will be placed longitudinally over the sacrum to identify key anatomical landmarks, including the median sacral crest, intermediate sacral crest, and overlying multifidus muscle. A 22G block needle will be inserted using an in-plane technique in a cranial-to-caudal or lateral-to-medial direction, targeting the fascial plane between the multifidus muscle and the underlying sacral lamina. After careful aspiration to exclude intravascular placement, 8 mL of local anesthetic (e.g., bupivacaine .25%) combined with 8 mg dexamethasone ( 2 ml) and the total volume will b