prox humeral fx with arm/hand weakness

[PMR 4 MSK]

A case for residents:

68 yo female presented with 12 day-old proximal humeral fx. Ortho saw pt 1 week post-injury, ordered CT, and followed-up yesterday. Humeral head has comminuted fx and dislocated. He wants to take her to surgery today, but wants to know the neurological state of the arm, as the humeral head is sitting in the vicinity of the brachial plexus and she has arm weakness.

Right arm is diffusely ecchymotic and edematous. PT is morbidly obese, BMI 45. She has no appreciable shoulder abduction, painfully weak elbow flexion and extension, no thumb or index finger flexion, weakness of finger abduction, but normal wrist and finger extension.

EMG showed no response to stimulation of the median motor nerve to the APB at the wrist or elbow, and no response to the FPL or PT with stim at the elbow. Median sensory showed no response. Ulnar motor showed normal distal latency and amplitude, but no response proximally, above or below the elbow, possibly due to edema and/or obesity. Radial motor shows normal distal onset and amplitude, no response again at the elbow or above it. Radial and ulnar sensory studies were normal. Ulnar F-waves borderline normal, most were a little over the upper limit of normal

Erb's point stimulation was deferred due to the fracture and pain.

Needle exam showed normal insertional activity and no positive sharp waves or fibrillations in any muscle. There were no MUAPs from the Deltoid, PT, FPL, APB or OP. There were normal MUAPs, with normal size, morphology and recruitment of the tricep, bicep, IP, FCU and FDIM.

What do you tell the orthopod in terms of his question - what is the neurological function of this arm? How do you explain the findings?

How would you assist in the post-op rehabilitation of this patient?

For bonus points - How do these findings affect what surgery he might do?

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[RUOkie]

Great case.

Once there are responses, would you like the old men and women to join in the discussion?

 

[pmr4life]

PMR 4 MSK,
Interesting case. Long time lurker, first time poster. I had to chime in because I really like the cases that are posted up here. Granted, I haven't done a formal EMG rotation yet, so bear with me.
First off, more questions than answers.
Concerning her intial injury: did she have a fall, MVA, bungee accident? Also, what is the rest of the neurological exam (just to be absolutely sure there is no cord involvement in this slightly older than 20 y/o female)?
I feel it naturally to split your findings into 2 lesions, proximal and distal. Unfortunately, I cannot completely trust elbow flexion/extension strength secondary to her humeral fracture. Hence, lack of shoulder abduction = C5/6, upper trunk, axillary lesion. In order for lesion localization, what was her serratus anterior strength? Spinati would be poor choice 2/2 distal attachment on humerus.
Secondly, I would think about the distal findings. Weak thumb/finger flexion = C8/T1, lower trunk, lower cord, median, AIN lesion. Since no NCS response of median nerve at wrist, is it safe to say poor/no APB strength? This would at least get me to a Median lesion. However, with the weak finger abduction, she likely has a Lower Trunk/cord lesion primarily affecting the median innervated muscles.
Concerning her EMG findings, it is likely too early for completeness of Wallerian degeneration and fibs/PSW's to appear; hence, making the needle exam useless in lesion localization at this time period.
Concerning the orthopod's questions: What does he want to know in terms of neuro function? As far as prognosis, poor to good, depending on the intactness of endoneural tube for peripheral nerve regeneration. A repeat EMG at 3-4 weeks post-injury would at least help with determining location and axonal involvement. As far as assisting in post-operative rehabilitation: usual physiatry stuff to prevent contractures/ROM loss. F/u in office in a few weeks for EMG. Start PT/OT when stable post-op. Assess function when pain subsiding.
As far as what surgery? No idea, leaving that answer for others.

 

[SSdoc33]

PMR 4 MSK,
Interesting case. Long time lurker, first time poster. I had to chime in because I really like the cases that are posted up here. Granted, I haven't done a formal EMG rotation yet, so bear with me.
First off, more questions than answers.
Concerning her intial injury: did she have a fall, MVA, bungee accident? Also, what is the rest of the neurological exam (just to be absolutely sure there is no cord involvement in this slightly older than 20 y/o female)?
I feel it naturally to split your findings into 2 lesions, proximal and distal. Unfortunately, I cannot completely trust elbow flexion/extension strength secondary to her humeral fracture. Hence, lack of shoulder abduction = C5/6, upper trunk, axillary lesion. In order for lesion localization, what was her serratus anterior strength? Spinati would be poor choice 2/2 distal attachment on humerus.
Secondly, I would think about the distal findings. Weak thumb/finger flexion = C8/T1, lower trunk, lower cord, median, AIN lesion. Since no NCS response of median nerve at wrist, is it safe to say poor/no APB strength? This would at least get me to a Median lesion. However, with the weak finger abduction, she likely has a Lower Trunk/cord lesion primarily affecting the median innervated muscles.
Concerning her EMG findings, it is likely too early for completeness of Wallerian degeneration and fibs/PSW's to appear; hence, making the needle exam useless in lesion localization at this time period.
Concerning the orthopod's questions: What does he want to know in terms of neuro function? As far as prognosis, poor to good, depending on the intactness of endoneural tube for peripheral nerve regeneration. A repeat EMG at 3-4 weeks post-injury would at least help with determining location and axonal involvement. As far as assisting in post-operative rehabilitation: usual physiatry stuff to prevent contractures/ROM loss. F/u in office in a few weeks for EMG. Start PT/OT when stable post-op. Assess function when pain subsiding.
As far as what surgery? No idea, leaving that answer for others.

id like to see an obese 68 y/o woman bungee jumping. stranger things have happened, i suppose.

 

[pmr4life]

SSdoc33,
As a physiatrist, I am absolutely certain your autobiography would be filled with an abundance of "Ripley's Believe It or Not" material...many of which start, "I was just walkin' along, doc.....

 

[PMR 4 MSK]

PMR 4 MSK,
Interesting case. Long time lurker, first time poster. I had to chime in because I really like the cases that are posted up here. Granted, I haven't done a formal EMG rotation yet, so bear with me.
First off, more questions than answers.
Concerning her intial injury: did she have a fall, MVA, bungee accident? Also, what is the rest of the neurological exam (just to be absolutely sure there is no cord involvement in this slightly older than 20 y/o female)?
I feel it naturally to split your findings into 2 lesions, proximal and distal. Unfortunately, I cannot completely trust elbow flexion/extension strength secondary to her humeral fracture. Hence, lack of shoulder abduction = C5/6, upper trunk, axillary lesion. In order for lesion localization, what was her serratus anterior strength? Spinati would be poor choice 2/2 distal attachment on humerus.
Secondly, I would think about the distal findings. Weak thumb/finger flexion = C8/T1, lower trunk, lower cord, median, AIN lesion. Since no NCS response of median nerve at wrist, is it safe to say poor/no APB strength? This would at least get me to a Median lesion. However, with the weak finger abduction, she likely has a Lower Trunk/cord lesion primarily affecting the median innervated muscles.
Concerning her EMG findings, it is likely too early for completeness of Wallerian degeneration and fibs/PSW's to appear; hence, making the needle exam useless in lesion localization at this time period.
Concerning the orthopod's questions: What does he want to know in terms of neuro function? As far as prognosis, poor to good, depending on the intactness of endoneural tube for peripheral nerve regeneration. A repeat EMG at 3-4 weeks post-injury would at least help with determining location and axonal involvement. As far as assisting in post-operative rehabilitation: usual physiatry stuff to prevent contractures/ROM loss. F/u in office in a few weeks for EMG. Start PT/OT when stable post-op. Assess function when pain subsiding.
As far as what surgery? No idea, leaving that answer for others.

Now this is the kind of thinking and research that one should aspire to in residency! You are well on your way to a promising career.

She fell on ice, landed on the arm. There is no evidence for cord damage - LE and LUE are good.

Exactly true about the proximal weakness. Due to fx and pain, one cannot trust the strength exam. The complete lack of abduction, however, is quite concerning, especially to the orthopod.

Serratus Anterior is normal.

She has a median nerve lesion, but no apparent lower trunk lesion. The reason for the abductor weakness is weakness of flexion - inability to stabilize the fingers to abduct with full strength. The hand is complex and weakness of any part often gives other parts weakness due to destabilization.

I told the ortho that at this point, it appears she has a complete lesion of the median nerve, but it is really too early to tell if she wil get any recovery. If he was really ambitious and had vascular surgeon with him, he could explore the median nerve proximally, but he's more concerned about getting her arm back in one piece.

The reason for no denervation potentials (fibs/PSWs, increased IA) are, of course, due to it being too early. Ideally one waits until 3 weeks post injury to see these waveforms, but they may come in earlier.

The reason for the shoulder abduction weakness is axillary neuropathy due to the dislocation - axillary nerve not uncommonly damaged. Again, too early to tell if this will recover.

Post-op rehabilitation will depend partly on return. Initial phase is pain and edema control, ROM preservation and stretching. 2nd phase is strengthening via active contraction or via NMES. 3rd phase is functional use.

Repeat EMG is likely indicated, but I would wait several weeks to see what function comes back and incorporate that into the prognosis and plans for rehab - e.g. is the focus on restoration or compensation?

As for the surgery, given the comminuted dislocation fx, the head is smashed and needs to be replaced. This would call for a hemiarthroplasty. However, the lack of deltoid function means she still wont have abduction. Wiuthout the median nerve, she also lacks good distal function, especially thumb.

The surgeon was hoping instead he could do a reverse total shoulder, but the deltoid is out, so this wont work. So he is left with hemiarthroplasty and hoping for the best, with possible revision later, should the deltoid come back.

 

[SSdoc33]

Now this is the kind of thinking and research that one should aspire to in residency! You are well on your way to a promising career.

She fell on ice, landed on the arm. There is no evidence for cord damage - LE and LUE are good.

Exactly true about the proximal weakness. Due to fx and pain, one cannot trust the strength exam. The complete lack of abduction, however, is quite concerning, especially to the orthopod.

Serratus Anterior is normal.

She has a median nerve lesion, but no apparent lower trunk lesion. The reason for the abductor weakness is weakness of flexion - inability to stabilize the fingers to abduct with full strength. The hand is complex and weakness of any part often gives other parts weakness due to destabilization.

I told the ortho that at this point, it appears she has a complete lesion of the median nerve, but it is really too early to tell if she wil get any recovery. If he was really ambitious and had vascular surgeon with him, he could explore the median nerve proximally, but he's more concerned about getting her arm back in one piece.

The reason for no denervation potentials (fibs/PSWs, increased IA) are, of course, due to it being too early. Ideally one waits until 3 weeks post injury to see these waveforms, but they may come in earlier.

The reason for the shoulder abduction weakness is axillary neuropathy due to the dislocation - axillary nerve not uncommonly damaged. Again, too early to tell if this will recover.

Post-op rehabilitation will depend partly on return. Initial phase is pain and edema control, ROM preservation and stretching. 2nd phase is strengthening via active contraction or via NMES. 3rd phase is functional use.

Repeat EMG is likely indicated, but I would wait several weeks to see what function comes back and incorporate that into the prognosis and plans for rehab - e.g. is the focus on restoration or compensation?

As for the surgery, given the comminuted dislocation fx, the head is smashed and needs to be replaced. This would call for a hemiarthroplasty. However, the lack of deltoid function means she still wont have abduction. Wiuthout the median nerve, she also lacks good distal function, especially thumb.

The surgeon was hoping instead he could do a reverse total shoulder, but the deltoid is out, so this wont work. So he is left with hemiarthroplasty and hoping for the best, with possible revision later, should the deltoid come back.

this is exactly why EMGs are cool. you actually have to think. you could do 1000 brachial plexopathy EMGs, and every one will be a puzzle. it can be complicated, and I have seen so many poorly done EMGs that it makes me sick (usually from poorly trained neurologists). but i tend to look forward to my "EMG" day more than any other day in the week. this is the last thought in your mind when you are sitting in the corner of the EMG roon as a PGY-2 ready to pull out your eyelashes with boredom.....

 

[RUOkie]

this is exactly why EMGs are cool. you actually have to think. you could do 1000 brachial plexopathy EMGs, and every one will be a puzzle. it can be complicated, and I have seen so many poorly done EMGs that it makes me sick (usually from poorly trained neurologists). but i tend to look forward to my "EMG" day more than any other day in the week. this is the last thought in your mind when you are sitting in the corner of the EMG roon as a PGY-2 ready to pull out your eyelashes with boredom.....

+1!

(although I do EMGs every day )

 

[PMR 4 MSK]

Yeah, sometimes it gets a little repetitive with all the "R/O CTS" but the academic hunt of where the lesion is in these more complicated cases make you really have to know your anatomy and physiology. They make doing EMG more mentally rewarding.

 

[kstarm]

I just got done going through the whole thread, and found it great. Thanks for posting!