anterior scalene and pec minor block

[nvrsumr]

I have a patient referred by their surgeon for the above blocks as a dx test for TOS.

These are just an intramuscular injections that I will perform with US guidance.

Any pearls on technique? Dose? Etc?

Thank you.

The patient is a WC adjuster I work with so dont really want to get into the whole is TOS real rabbit hole.

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[drf]

I usually do anterior and middle scalene blocks for this. Straight probe. Start as if I were doing a supraclavicular block. Trace the plexus cephalad a couple of centimeters then use a 1.5 in 27g to go into the two muscles on either side of the plexus. Lat to medial for middle scalene and med to lat for anterior scalene. 2-3 ml bupivicaine each, making sure it stays in the muscle and doesn't spread to plexus.

If it helps I inject 25-40 units of Botox into each. I probably have about 3-4 pts who get the Botox every 3-4 months.

 

[drf]

I haven't done a pec minor injection. If I were to do one I would most likely scan over ribs 3-5 looking for a new muscle deep to the pec major heading towards the coracoid and inject as laterally as feasible before it becomes tendon.

 

[lobelsteve]

In most patients with nonspecific thoracic outlet syndrome (TOS), there are no indicated procedures. An anterior scalene block can be performed to anesthetize the anterior scalene muscle and to relieve pressure from the brachial plexus. Thus, this type of block is diagnostic but also may be therapeutic.

The anterior scalene block is a potentially dangerous procedure because the plexus can be injured directly in the process; however, its reliability, accuracy, and safety may be improved with the use of electrophysiologic guidance to verify needle tip placement.

Jordan and Machleder believe that a negative response to this block excludes a surgical treatment option, while a positive response predicts which patients should benefit from surgical decompression.[11]

In a study of patients being tested for neurogenic TOS, Torriani et al concluded that diagnostic injection of anesthetic into the anterior scalene muscle can be safely performed with ultrasonographic guidance.[12] The investigators administered injections to 26 patients with suspected neurogenic TOS, reporting technical success (ie, anterior scalene muscle identification, intramuscular needle placement, and intramuscular medication delivery) in all procedures, with no major complications occurring. They concluded that this was a well-tolerated diagnostic test.

http://emedicine.medscape.com/article/316715-workup#a0722


If using US please take lots of pics of your probe location and save images.

 

[nvrsumr]

Good info. I will present the botox option as well if a good response. Do you bill as a plexus block?

 

[drf]

I bill as trigger point since I specifically try to not anesthetize plexus.

It takes about 1 minute. Fast and easy.

 

[epidural man]

I usually do anterior and middle scalene blocks for this. Straight probe. Start as if I were doing a supraclavicular block. Trace the plexus cephalad a couple of centimeters then use a 1.5 in 27g to go into the two muscles on either side of the plexus. Lat to medial for middle scalene and med to lat for anterior scalene. 2-3 ml bupivicaine each, making sure it stays in the muscle and doesn't spread to plexus.

If it helps I inject 25-40 units of Botox into each. I probably have about 3-4 pts who get the Botox every 3-4 months.

I've done it both ways - just the anterior, and the anterior + middle. The times I have had a brachail plexus block I have injected both muscle bellies.

I am surprised at how often the plexus runs IN the belly of the anterior scalene so be careful - but I guess that goes without saying.

 

[drf]

If you see another plexus running in the anterior scalene, save the pic and post!