Pronator teres syndrome vs CTS + AIN

[PMR 4 MSK]

39 yo female with 1 year of left arm weakness and numbness, unknown etiology. Not worsening over time. Pain is elbow, forearm and palm, numbness is median nerve and forearm. Strength grossly normal except APB and she cannot bend DIP index. Sensory testing normal except paresthesias in a median nerve distribution. No neck pain. Reflexes normal.

Median motor - 4.7 (<4.2 nl) ms distal onset, 3.5 (>5.0) mV amplitude, 47 (>50) m/s NCV in forearm.
Ulnar motor - 3.1 ms (<3.3) distal onset, 6.7 (>3.0) mV amplitude, 53 forearm NCV, 64 across elbow (>50).

Median sensory orthodromic 2.7 (<2.5) ms, 15 (>10) mcV
Ulnar sensory orthodromic 2.5 ms, 18 mcV
Radial sensory orthodromic 2.5 ms, 12 mcV

Needle normal deltoid, triceps, biceps, pronator teres, FPL, FPS and FDIM.

PQ showed 2+ fibs and 3+ PSW, normal amplitudes, some dispersion, poor recruitment. FPL not sure I was in it due to lack of recruitment. APB showed 1+ PSW, slightly reduced recruitment.

PT syndrome or CTS + AIN? I voted PT syndrome.

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[Ludicolo]

Any positive CTS provocative maneuvers? How about a Tinel's sign over the pronator teres?

PT syndrome seems to fit well. Although I'm a little surprised at the severity of findings in the pronator quadratus, given the other mild findings.

 

[PMR 4 MSK]

Any positive CTS provocative maneuvers? How about a Tinel's sign over the pronator teres?

PT syndrome seems to fit well. Although I'm a little surprised at the severity of findings in the pronator quadratus, given the other mild findings.

Negative Tinel's and Phalen's at carpal tunnel, neg Tinel's over PT.

 

[RUOkie]

I agree with PT syndrome or certainly a Ligament of Struthers/Lacertus Fibrosis as possibilities. He needs an MR or US of the elbow/forearm and to see a hand surgeon.

 

[PMR 4 MSK]

I agree with PT syndrome or certainly a Ligament of Struthers/Lacertus Fibrosis as possibilities. He needs an MR or US of the elbow/forearm and to see a hand surgeon.

Hand surgeon sent him to me for EMG .

I suggested elbow/proximal forearm MRI. Surgeon did xray - no abnormalities at elbow.

Anyone ever do inching of the median nerve in the forearm? One surgeon has asked me to do it a few times. It takes needle stim in the proximal forearm, and I'm not certain if it is valid to do.

 

[RUOkie]

I have tried to do an inching study unsucessfully but without needle stim (the pt. refused). I made the mistake of doing my entire EMG and then going back to try the inching and the pt. said "no way". If you are going to use needle stim, I would use it for ALL the stimulations to minimize your variables. Thus, it becomes much more painfull.

Honestly, all of the proximal Median neuropathies I have seen have ended up being explored with the exception of one guy who had intraoperative compartment syndrome of the arm during a parotid tumor removal (BP cuff and the sheet was tied too tight)

 

[Ludicolo]

Tried it a couple times during fellowship. It was cool and all, but I didn’t find it all that helpful in the grand clinical scheme of things. I think needle EMG, at least in the case you describe, is sufficient with regards to localization.

Do you still inch? My hand surgeon colleagues don’t find it necessary, given the utility of ultrasound and MRI these days.

 

[RUOkie]

I inch for the Ulnar N. The surgeons are always happy since they can decrease their incision length. But we have NO MSK US in our area (ie:200mile radius), and I'm taking the course in June. I wonder if my workup will change afterward. We'll see.