Intravascular injection with SIJ injection that looks like "spider" appearance?

[DoctorInScrubs]

I have had this happen multiple times. I will feel like I am in the joint. Then on the lateral fluoro view, I look like I am about halfway between the posterior and ventral aspect of the sacrum. So I try to advance the needle a bit further with resistance against bone. Then when I inject contrast, it looks like very clear vascular flow that almost looks like spider legs leaving from my bevel.

Has this happened to anybody else? What vessel or vessels am I injecting into? I also know many people who don't do live contrast or any contrast at all for SIJ injections.

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[pmrmd]

You’re in the bone. Pull back a hair and you’ll get your arthrogram.

 

[Taus]

Bone marrow biopsy. I see it a few times a year. Somewhat interesting is that it is usually pretty painful when I inject the contrast.

 

[Drd105]

Bone marrow biopsy. I see it a few times a year. Somewhat interesting is that it is usually pretty painful when I inject the contrast.

I get it in osteoporosis

 

[DoctorInScrubs]

You’re in the bone. Pull back a hair and you’ll get your arthrogram.

Bone marrow seems reasonable. Is the intraarticular bone surface more cancellous than along the posterior sacrum making it easier to pierce the bone surface? Often times, I will feel the cortical bone of the sacrum surface and then adjust the bevel and walk in.

 

[SSdoc33]

You’re in the bone. Pull back a hair and you’ll get your arthrogram.

Yup.

NBD. Just pull back and inject.

Also, with SIJ, don't kill youself just to get a good arthrogram. If you are close, just inject and live to fight another injection. Outcomes will be the same anyway

 

[GlowInTheDark]

And to add what others have said, textbook description of most SI injection is 2/3 volume in joint, 1/3 outside.

 

[DoctorInScrubs]

Thanks for everybody's thoughts. I feel like this sometimes happens when I am trying to advance my needle tip more anterior in the lateral view. How far past the posterior sacrum do you consider "acceptable" needle position?

I would think that as long as I am somewhere past the posterior aspect of the sacrum, I should be in the joint space or in periarticular tissue. I usually use a 10 degree cephalad tilt when doing an SIJ. So my entry point isn't likely to be at the very bottom of the sacrum where the SIJ moves more ventral.

 

[pastafan]

And to add what others have said, textbook description of most SI injection is 2/3 volume in joint, 1/3 outside.

Especially when injection volume exceeds SI joint 2.5 ml max volume.