Struggling to get medial pedicle spread with S1 TF ESI?

[DoctorInScrubs]

When doing an S1 TF ESI, I generally don't have problems finding the dorsal foramen. I will position my needle tip about 1-2 mm past the posterior aspect of the S1 vertebral body. My biggest challenge is that I struggle to get medial pedicular contrast spread with it instead often going laterally out the ventral foramen.

Any advice for how to reposition the needle in these circumstances to get better medial pedicle spread? What is the ideal target point on lateral imaging to get medial contrast spread?

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[lobelsteve]

If you are that far anterior you are going to skewer some roots. Try posterior epidural space at S1. Can always advance 1-2mm until flow goes where you hope it will go.

 

[bedrock]

When doing an S1 TF ESI, I generally don't have problems finding the dorsal foramen. I will position my needle tip about 1-2 mm past the posterior aspect of the S1 vertebral body. My biggest challenge is that I struggle to get medial pedicular contrast spread with it instead often going laterally out the ventral foramen.

Any advice for how to reposition the needle in these circumstances to get better medial pedicle spread? What is the ideal target point on lateral imaging to get medial contrast spread?

Several things to consider

1- start a full cm lateral and cm inferior to foramen (in a 5-10 degree ipsilateral oblique view) This way your final needle tip location will be both medial and superior to the S1 foramen.

2- put a 30 degree bend on the tip of your needle

If you do both, you’ll get good superior epidural spread >95% of the time.

 

[DoctorInScrubs]

Several things to consider

1- start a full cm lateral and cm inferior to foramen (in a 5-10 degree ipsilateral oblique view) This way your final needle tip location will be both medial and superior to the S1 foramen.

2- put a 30 degree bend on the tip of your needle

If you do both, you’ll get good superior epidural spread >95% of the time.

Thank you, I will try that. What is your needle target on your lateral view from that trajectory?

 

[RoloTomassi]

Do you do oblique trajectory or AP? Never had an issue getting medial flow with oblique trajectory, hub view 12 o'clock on the hole. On lateral I'm usually mid to anterior foramen. If you're anterior to sacral border that might be a factor. The injectate would have to flow retrograde to get to the ventral epidural space.

 

[DoctorInScrubs]

Do you do oblique trajectory or AP? Never had an issue getting medial flow with oblique trajectory, hub view 12 o'clock on the hole. On lateral I'm usually mid to anterior foramen. If you're anterior to sacral border that might be a factor. The injectate would have to flow retrograde to get to the ventral epidural space.

Yes, I do oblique ipsilateral 5-10 degrees. Do I need more?

Sounds like the unanimous recommendation is to have the needle a bit more posterior. I'll try that and share my results.

 

[RoloTomassi]

Yes, I do oblique ipsilateral 5-10 degrees. Do I need more?

Sounds like the unanimous recommendation is to have the needle a bit more posterior. I'll try that and share my results.

I would try one thing at a time. Try more posterior first then if still not having success, try more oblique. I usually go closer to 15. The foramen is on average closer to 25 degrees oblique but since it's so wide you don't have to be that oblique, and crest will limit you anyways.

 

[callmeanesthesia]

Saw this was just published. Basically Caudal ESI was equally effective vs TFESI for S1 radic due to L5-S1 disc herniation. Shorter fluoro times for the caudal. The abstract doesn’t specify though whether it was an L5-S1 or S1 TFESI.

Caudal epidural steroid injection versus transforaminal ESI for unilateral S1 radiculopathy: a prospective, randomized trial

AbstractObjective. Epidural steroid injections are frequently performed to manage radicular symptoms. Most research investigating the effectiveness of different

academic.oup.com

 

[bedrock]

Saw this was just published. Basically Caudal ESI was equally effective vs TFESI for S1 radic due to L5-S1 disc herniation. Shorter fluoro times for the caudal. The abstract doesn’t specify though whether it was an L5-S1 or S1 TFESI.

Caudal epidural steroid injection versus transforaminal ESI for unilateral S1 radiculopathy: a prospective, randomized trial

AbstractObjective. Epidural steroid injections are frequently performed to manage radicular symptoms. Most research investigating the effectiveness of different

academic.oup.com

Probably compared to an S1. I’d argue that if you’re using dex for both locations that you should stick with S1.

If willing to use depo then caudal with depo, likely provides equal to longer relief, vs S1 TFESI with dex.