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Ultrasound Guided Sacroiliac Joint Injection (Article for Doctors only)

Updated: Jan 2

Ultrasound Guided Sacroiliac Joint Injection  

Anatomy of the Sacroiliac Joint (SIJ):

The sacroiliac joint (SIJ) stands as a diarthrodial joint, featuring articular surfaces of the sacrum and ilium separated by a joint space enclosed within a fibrous capsule. Exhibiting synovial joint characteristics, particularly in the posterior and inferior aspects, the superior-posterior joint surface lacks a joint capsule and houses the interosseous ligament. The anterior joint capsule originates from the anterior sacroiliac ligament, while the posterior aspect encompasses stabilizing ligaments such as the posterior sacroiliac, sacrotuberous, and sacrospinous ligaments. Age-related degenerative changes manifest with the narrowing of the synovial cleft inferiorly, leading to fibrous ankylosis.

Muscular and fascial support for the SIJ is derived from various structures, including the gluteus maximus and medius, erector spinae, latissimus dorsi, thoracolumbar fascia, biceps femoris, piriformis and oblique muscles, and the transversus abdominis. Attachment points include the sacrotuberous ligament for the gluteus maximus, biceps, and piriformis, while the thoracodorsal fascia connects to the remaining muscle groups. The keystone configuration of the anteroposterior and superoinferior wedge-shaped sacrum, coupled with extensive muscular support, contributes to the SIJ's reduced mobility and heightened stability.

In terms of innervation, lateral branches of the L4-S2 nerve roots, along with contributions from S3 and the superior gluteal nerve, predominantly innervate the posterior SIJ. The anterior SIJ receives innervation from the L2-S2 segments. Both the synovial capsule and ligaments contain free nerve endings and mechanoreceptors, transmitting proprioceptive and pain sensations from the joint

Indications for SI Joint Injections: -

Sacroiliac Joint Intraarticular Injection can be done in the following conditions.


Assessment of pain relief following the injection of a local anaesthetic into the SI joint


Alleviation of pain associated with degenerative conditions or inflammation affecting the SI joints.

Contraindications for SI Joint Injections: -

Absolute Contraindications for SI Joint Injections:

1. Patient-reported or documented history of allergic reaction to cortisone injections.

2. Local malignancy.


Relative Contraindications for SI Joint Injections:

1. Coagulopathy or current/recent use of blood-thinning agents.

2. Pregnancy.

3. Systemic infection, septic joint, or osteomyelitis.

4. Diabetes Mellitus, Type II, with a history of poor glycemic control.

Advantages of ultrasound-guided (USG) sacroiliac joint (SIJ) injections

Following are the advantages of ultrasound-guided (USG) sacroiliac joint (SIJ) injections over fluoroscopy-guided SIJ injections are:


  • USG allows for visualization of soft tissue structures, such as nerves and vessels, which may reduce the risk of complications.

  • USG can be performed at the bedside, which may increase convenience and accessibility.

  • USG does not expose the patient or the operator to ionizing radiation, which may reduce the potential harm and cost.

How to Perform Ultrasound guided Sacroiliac Joint Injection -

  • Patient Position - The patient is placed in a prone position with a pillow supporting the abdomen to reduce lumbar lordosis.

  • Transducer Selection - To enhance penetration, particularly in obese individuals, a low-frequency curvilinear transducer is commonly employed.

  • Procedure - The transducer is positioned transversely at the lower sacrum (sacral hiatus level), and the lateral sacral edge is identified. Subsequently, the transducer is manoeuvred laterally and cephalad until the bony structure of the ileum becomes distinct. The gap observed between the medial border of the ileum and the lateral sacral edge serves as the visualization of the sacroiliac (SI) joint, with a focus on its inferior-most point. Using a 22-gauge needle, insertion begins at the medial end of the transducer, progressing laterally under direct ultrasound-guided vision until it enters the joint.

Alternative Technique -


PSIS Identification: -  

  • Locate the Posterior Superior Iliac Spine (PSIS).

  • Probe Placement in Transverse Plane:


Position the ultrasound probe in the transverse plane.

  • Guide the probe downward along the cleft between the iliac bone and sacrum, representing the homolateral SIJ.

Sacral Foramina Counting:

  • Count the sacral foramina, identified as breaks in the hyperechoic contour of the sacral wing.

  • Place the probe close to the second sacral foramen.

Needle Insertion:

  • Insert a 22G, 9 mm spinal needle (Spinocan) at the medial side of the probe.

  • Utilize an in-plane free-hand technique.

Confirmation of Needle Penetration:

  • Confirm needle penetration through the Posterior Sacroiliac Ligament (PSL) into the SIJ.

Colour Doppler Activation:

  • Activate a Color Doppler (CD) box and position it over the SIJ.

  • Monitor the spread of the injected solution, ensuring it stays below the PSL throughout the procedure.

Solution Injection:

  • Administer the entire solution under direct ultrasound visualization.

  • Reposition the needle tip as necessary.

Limitations of Ultrasound-Guided SIJ Injection:

Limitations of sacroiliac joint injection compared to fluoroscopy-guided sacroiliac joint injection are as follows -

  1. Periarticular Injection Risk:

  2. Contrast Agent Arthrography not possible:

  3. Intravascular Injection Detection:


Advanced Reading -

History and Development of USG Guided Sacroiliac Joint Injection

The following Researchers have contributed to the Development of ultrasound-guided Guided Sacroiliac Joint Injections -

Pekkafahli et al. 2003 -

  • Explored the feasibility of ultrasound-guided SIJ injections.

  • Reported a 76.7% overall success rate in 60 cases.

  • Identified a steep learning curve, with success improving from 60% to 93.5% over 30 injections.

Klauser et al. 2008:

  • Investigated ultrasound-guided SIJ injections using cadavers and patients.

  • Defined upper and lower puncture sites based on sacral foramen levels.

  • Achieved 80% correct intra-articular needle placement in cadavers and 100% success in patients.

Perry et al. 2016.

  • Assessed the accuracy of ultrasound-guided SIJ injections using a cadaveric model.

  • Found 88.2% success in achieving intra-articular injections.

  • Highlighted ultrasound's capability to visualize extra-articular spread, aiding redirection for accurate injections.

Soneji et al. 2016

  • Compared fluoroscopy and ultrasound guidance for SIJ injections in patients with SIJ arthritis.

  • Concluded that ultrasound-guided injections with fluoroscopic confirmation are comparable in accuracy and efficacy to fluoroscopy alone.

  • Emphasized the similarity in outcomes for chronic low back pain secondary to SIJ arthritis.

References -

  1. Pekkafahli MZ, Kiralp MZ, Başekim CC, Silit E, Mutlu H, Oztürk E, Kizilkaya E, Dursun H. Sacroiliac joint injections performed with sonographic guidance. J Ultrasound Med. 2003 Jun;22(6):553-9. doi: 10.7863/jum.2003.22.6.553. PMID: 12795552.

  2. Klauser A, De Zordo T, Feuchtner G, Sögner P, Schirmer M, Gruber J, Sepp N, Moriggl B. Feasibility of ultrasound-guided sacroiliac joint injection considering sonoanatomic landmarks at two different levels in cadavers and patients. Arthritis Rheum. 2008 Nov 15;59(11):1618-24. doi: 10.1002/art.24204. PMID: 18975358.

  3. Perry JM, Colberg RE, Dault SL, Beason DP, Tresgallo RA 3rd. A Cadaveric Study Assessing the Accuracy of Ultrasound-Guided Sacroiliac Joint Injections. PM R. 2016 Dec;8(12):1168-1172. doi: 10.1016/j.pmrj.2016.05.002. Epub 2016 May 10. PMID: 27178376.

  4. Soneji N, Bhatia A, Seib R, Tumber P, Dissanayake M, Peng PW. Comparison of Fluoroscopy and Ultrasound Guidance for Sacroiliac Joint Injection in Patients with Chronic Low Back Pain. Pain Pract. 2016 Jun;16(5):537-44. doi: 10.1111/papr.12304. Epub 2015 May 19. PMID: 25988390.

  5. Chang, Wei-Han MD; Lew, Henry L. MD, PhD; Chen, Carl P.C. MD, PhD. Ultrasound-Guided Sacroiliac Joint Injection Technique. American Journal of Physical Medicine & Rehabilitation 92(3):p 278-279, March 2013. | DOI: 10.1097/PHM.0b013e318278d108

  6. Todorov P, Batalov A. A comparative study between ultrasound guided and landmarks guided intraarticular sacroiliac injections in spondyloarthritis patients. Arch Clin Exp Orthop. 2020; 4: 001-008.

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