Transitional segment

[onechance]

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If some one has a lumbarized sacral vertebral body, i.e 6 lumbar vert bodies, and pt has
L4 dermatomal pain, what level would you give the TFESI?

On the other hand, if some one has sacralized lumbar vert body, i.e 4 lumbar vert bodies: and pt has L5 distribution pain: what level do you offer TFESI.

Other scenario...if you are planning ablation of medial branch and some one has lumbarized sacral vert body with 6 lumbar vert bodies....what would be the nomenclature for the MB nerve on the 6th vert body?

Thanks so much.

 

[deleted185747]

You always count from the top down. Thus, the "L6 MB" is actually S1 lateral branch. The dermatomes don't change levels just because the bone is malformed.

Your L4 TFESI would be done in the standard fashion, counting the vertebra from the top down.
It's usually safe to assume 12 T spine segments.

 

[nvrsumr]

There are prefixed and post fixed brachial and lumbarsacral plexuses in a small but significant percentage. It would be interesting to see if there is a correlation with transitional segments and dermatomal patterns.

 

[specepic]

Are you ordering or doing the injection? Why not just put the med where the pathology is on the MRI? Was there an MRI?

 

[buddy 2004]

Agree with above, that even if there are extra or fewer bones present, the main nerves are constant. So in the first case, start counting the spinal nerves from the upper lumbar area and proceed as usual once you have the nerve you are looking for. If there is an extra lumbar segment, this would be S1, not L6.

However, you have to look at the numbering system on the MRI report as well. Often the radiologist says "the lowest segment is considered L5", which changes things. In this case, do your own counting and remain internally consistent between procedures.

You could also be conservative with the blocks and do minimal levels, or even do the old fashioned SNRB with lidocaine. Patient are understanding of difficult anatomy once you start saying "this bone normally isn't supposed to be there..." or they had a chiropractor tell them about it.

 

[onechance]

Are you ordering or doing the injection? Why not just put the med where the pathology is on the MRI? Was there an MRI?

Just brushing up on anatomy......dont have a pt.... yet.
Thanks for your inputs, appreciate it.

 

[NEPain]

Do an interlaminar<g>

 

[DOctorJay]

Our radiologist tells us to count from C2 down (he teaches for ISIS).

 

[SIIMS]

Ahh, the transitional segment, took me the longest time to wrap my brain around

Don't bother counting from C2, you might be there for 30 minutes, just start caudal, look at MRI and then correlate to plain film. Count how many segments up from the trans. segment your pathology is on MRI then on x-ray ident. trans. segment and move up accordingly. Key is to know which disc is herniated and then put your medicine how you would normally put it.

Many articles (counting from C2, iliolumbar ligament best seen on T1 attaches to L5, etc.)

Wether you call it partially lumbarized or sacralized the key is just explain and be consistent. Eg., "patient has a transitional segment, to clarify radiologist calls this S1, for the purposes of my injection the herniated disc is between L5 which is the first fully formed normal appearing lumbar vertebrae and the trans. segment, again labeled S1 on the patients MRI report" This way everyone who reads your procedure or clinic note is clear.

Seen surgeons operate wrong level b/c of trans. segment but in the end game there job is a lot harder then ours b/c there work will be there for everyone to see

Most of the time b/c the trans. segment's TP is partially fused to sacrum the disc above is the one to herniate. Sometimes sneaking in for a TFESI is hard but most of the time there is an adequate window.

 

[onechance]

Very helpful!! Thanks.

On a side note, how about medial branch blocks, and RFA. If there is a L5 well developed vert body, and there is a lumbarized sacral vert body followed by sacral ala. how does the nomenclature go in this situation.

 

[lobelsteve]

Very helpful!! Thanks.

On a side note, how about medial branch blocks, and RFA. If there is a L5 well developed vert body, and there is a lumbarized sacral vert body followed by sacral ala. how does the nomenclature go in this situation.

It goes however you want it to go. You just need to add a comment to your dictation clearly stating what you considered to be L5 and S1 and to make it apparent to another doc what levels you are referring to. Also saving pic on dicom or to chart is best.

 

[DOctorJay]

To clarify we don't count down under fluoro it's off the MRI scout or plane films.

 

[SIIMS]

Very helpful!! Thanks.

On a side note, how about medial branch blocks, and RFA. If there is a L5 well developed vert body, and there is a lumbarized sacral vert body followed by sacral ala. how does the nomenclature go in this situation.

Agree with lobelsteve,

Of note, I almost never do facet injections or target mbb's to the facet between the transitional segment and the sacrum, if you look at these under MRI they are often very rudimentary joints that barely look like facet joints.

Many articles on symptomatic facet joints contralateral and one level superior to a transitional segment that has a unilateral articulation with its TP to the sacrum.

 

[NEPain]

I also often see a large transverse process at a lumbarized segment that "articulates" with the sacrum. Injecting that pseudo-articulation often gets good relief.

 

[PMR 4 MSK]

I also often see a large transverse process at a lumbarized segment that "articulates" with the sacrum. Injecting that pseudo-articulation often gets good relief.

I've done that a few times with variable results.