Radic vs LTN palsy

[PMR 4 MSK]

49 yo male present to ortho with cc R shoulder pain. In the Hx, neck and R arm pain noted along with R hand tingling. Exam showed benign neck, neuro and shoulder exam except for scapular winging with wall press. Pt sent for EMG.

I did the EMG and it showed acute denervation of the serratus anterior - 2+ fibs and PSW's, decreased recruitment. I did not do NCS to serratus as I've previously done due to coming to believe NCS is unreliable for this nerve/muscle. needle and NSC of rest of shoulder girdle and arm unremarkable - supraspinatus, trapezius, deltoid, triceps, biceps, PT, FDIM, APB, etc. Only finding was serratus denervation. Sensories and motors all normal - median, ulnar, radial, LAC, MAC.

Ortho also ordered MRI C-Spine, images attached, showing HNP right C5-6 and C6-7.

Pt then sent to me for rehab, my findings the same as above.

My questions for all:

Are the HNP's responsible for the serratus findings - i.e. is this radicular or LTN palsy? If radicular, why no arm findings. Obviously there could be nerve root irritation without damage, but isolated LTN palsy is unusual.

How would you treat? Pt currently c/o of only intermittent neck and arm pain, mainly with overhead activities and intermittent numbness. He also notices weakness with overhead activities on the right.

He is a mechanic and avid hunter who lives to shoot bows and guns. Would you restrict him from shooting for now?

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[RUOkie]

Are the HNP's responsible for the serratus findings - i.e. is this radicular or LTN palsy? If radicular, why no arm findings. Obviously there could be nerve root irritation without damage, but isolated LTN palsy is unusual.
Probably not, especially if the paraspinals were neg. You could consider a transforaminal ESI for diagnostic reasons. I probably would not do this with the hx you gave. Isolated LTN palsies are not that unusual. I see it about every 2-3 years(600 EMG/yr), but usually I am lucky and the c-spine imaging does not confuse the issue. Although I do agree with ordering the MRI. This could be related to his bowhunting, but I don't think it has been reported as such.
How would you treat? Pt currently c/o of only intermittent neck and arm pain, mainly with overhead activities and intermittent numbness. He also notices weakness with overhead activities on the right.
Compensatory strategies, NMES to the Serratus, and scapular stabilization without overfatigue.
He is a mechanic and avid hunter who lives to shoot bows and guns. Would you restrict him from shooting for now?
Get him a crossbow permit until his scapular mechanics are normal. If his recruitment was good, follow clinically. If he does not improve, repeat the EMG in 12 weeks.

Great case. See above.

 

[Ludicolo]

From a pure EMG standpoint, can’t call this a radic. You need at least 2 muscles (same root, different peripheral nerve innervation) abnormal. Of course, you can have one of them there sensory radiculopathies as well. And theoretically you could be tweaking the fibers of the LTN as the C6 or C7 nerve roots exit the foramen.

Curious – on exam, did he have a positive Spurlings (which could indicate root compression), or did he have reproduction of symptoms with looking down and away from the affected limb? That position would cause traction on the LTN, and perhaps reproduce symptoms. Overhead activities also can stretch the LTN.

Agree w/ RUOkie - isolated long thoracic neuropathies aren’t that uncommon. It is (by nomenclature) a long nerve, with multiple possible sites of compression or traction. I know there are a few case reports specific to archery and shooting related LTN. Should also consider Parsonage-Turner, although clinically less likely.

Conservative management, repeat EMG in 3 months, and then probably again in another 3 months. Recovery can be prolonged, sometimes taking a year or more. I would avoid hunting. Not only does he run the risk of reinjuring the nerve, he also runs the risk of messing up his shoulder given his unstable scapula. If he must hunt, not sure if you can teach him how to modify his technique. Maybe he could hunt with a scapular winging brace, but most of my patients don't like them.

Don’t know nothing about crossbows. I’m a city dweller. I only hunt cockroaches.

 

[RUOkie]

Don't know nothing about crossbows. I'm a city dweller. I only hunt cockroaches.

Lots of bowhunters around here. If LTN injuries have been reported with archery, then bowhunting would likely be worse. Many bowhunters intentionally use high tension recurve bows (the recurve is more challenging than a compound, but you need high tension for a clean kill) around here which are real hard to draw. It would be real bad for the shoulder to hunt with a LTN injury.

Crossbows are usually not legal during bowhunting season since they are so much easier to shoot. You need a special permit for medical reasons here in OK. I fill out 20-30 crossbow permits each year during deer season for my disabled patients. And I'm originally a city dweller, and have never (and will never) hunted!

 

[SSdoc33]

Lots of bowhunters around here. If LTN injuries have been reported with archery, then bowhunting would likely be worse. Many bowhunters intentionally use high tension recurve bows (the recurve is more challenging than a compound, but you need high tension for a clean kill) around here which are real hard to draw. It would be real bad for the shoulder to hunt with a LTN injury.

Crossbows are usually not legal during bowhunting season since they are so much easier to shoot. You need a special permit for medical reasons here in OK. I fill out 20-30 crossbow permits each year during deer season for my disabled patients. And I'm originally a city dweller, and have never (and will never) hunted!

the others stole my thunder. i think i read that an isolated long thoracic neuropathy is the most common finding in brachial plexopathies. i have seen it myself several imes as well. they do make a brace/harness for your scapula if there is significant winging. cant say ive seen it work all that well, however

 

[PMR 4 MSK]

Thanks for the replies.

Spurling's was negative.

The surgeon who referred the patient asked me what causes LTN palsy. "Damned if I know" was my reply.

We will see how he does after PT.

 

[latinman]

Good Case. Quick question: Was needle EMG of the paraspinals carried out? I didn't see it mentioned in your case.

 

[drusso]

Any possible history of tick-borne illness? He hunts, spends time out-doors, etc? Brachial plexitis in the context of Lyme/tick borne illness has been reported...

 

[PMR 4 MSK]

Good Case. Quick question: Was needle EMG of the paraspinals carried out? I didn't see it mentioned in your case.

Yes, normal

Any possible history of tick-borne illness? He hunts, spends time out-doors, etc? Brachial plexitis in the context of Lyme/tick borne illness has been reported...

Interesting thought. I'll try to ask him at the next visit.

 

[Gauss]

I had a parsonage turner case with only LTN and suprascapular nerve involvement. MRI of the shoulder was interesting, atrophy and edema of both supraspinatus and infraspinatus.
Waiting to see if he improves

 

[RUOkie]

^^^
nice quote in the sig

 

[dc2md]

PMR 4 MSK,
Excellent case!! Let us know how he progresses.


Here's a quick Archives of PM&R article I found:

Arch Phys Med Rehabil. 1992 Jan;73(1):87-90.
Long thoracic neuropathy from athletic activity.

Schultz JS, Leonard JA Jr.

Department of Physical Medicine and Rehabilitation, University of Michigan Medical Center, Ann Arbor 48109-0042.

Abstract

Four cases of long thoracic mononeuropathy associated with sports participation are presented. Each patient developed shoulder pain or dysfunction after an acute event or vigorous activity, and demonstrated scapular winging consistent with serratus anterior weakness. The diagnosis was confirmed with electromyography in each case. It is suggested that the athletic activity caused a stretch injury to the long thoracic nerve. Conservative management, consisting of range of motion exercises for the shoulder and strengthening of the serratus anterior muscle, resulted in a favorable outcome in all patients.

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And another article about surgical decompression that the surgeon might like to see:

BMC Musculoskelet Disord. 2007; 8: 25.
Microneurolysis and decompression of long thoracic nerve injury are effective in reversing scapular winging: Long-term results in 50 cases