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CaliforniaMD, Neurologist (MD)
Category: Neurology
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Experience:  board certified neurologist
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What does left superficial peroneal sensory distal latency

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What does left superficial peroneal sensory distal latency normal with diminished amplitude mean on my emg report? This was the only question on an otherwise normal emg/ncv study. No lumbar radiculopathy or peroneal nerve entrapment at the fibular head. However, My symptoms are chronic Postero-inferior fibula subluxation at fibular head and I had a left ankle arthroscopy for synovitis and scarring along the anterolateral gutter with thickening of the anterior inferior tibiofibular ligament creating an impingement done 8/31/2011. When my fibula is subluxed I have nerve sensations all the way down the left leg. When if is adjusted by chiropractor and braced afterwards the nerve sensations calm down but then at the distal end of fibula I still have sensations anterior between fibula and tibia. Trying hard to get ankle stability and trying to rule in and out anything that pertains to this area.
Adding my history,  I had L-5-S1 microdisectomy in 2002 with associated foot drop for 2-3 months but have done much rehab over these past 10 years and back is great but this one area of lower leg is still getting my attention. In fact I'm glad to have just done an EMG/NCV to prove that this wasn't all in my back but a more local problem which the Physiatrist stated in his EMG report that "the diminished superficial peroneal sensory amplitude is of doubtful clinical significance, possibly related to local injury".
I'm just trying to rule in and out all possible situations pertaining to my left lower leg/ankle. Oh by the way the ankle MRI before surgery was all normal except for what I mentioned above, and a knee MRI completely normal in all categories. Just trying to be helpful
Submitted: 4 years ago.
Category: Neurology
Expert:  CaliforniaMD replied 4 years ago.

it suggests that the axon (the nerve) is not as healthy as it could be but the impulses travel well if "conduction velocity" is fine.

some nerve fibers could have been damaged because of the injury (foot drop -- peroneal nerve when abnormal, it causes foot drop).

Customer: replied 4 years ago.
Thank you for your reply. Is there anything that can or cannot be done about the slight nerve problem from what I have told you? Or anything I have missed in diagnostic workups? I will met with my ankle orthopaedic specialist for a follow-up in a week and will be sharing all this info with him and discuss the high ankle pain/sensations with him again.
Expert:  CaliforniaMD replied 4 years ago.

the sensation is probably due to the mononeuropathy. MRI and EMG are appropriate evaluations.

unfortunately, other than good nutrition, physical therapy if appropriate and patience nothing else can be done about axonal loss.

stabilizing the joint -- as you have been - is very important.

if pain or unpleasant sensations are dominant features, a nerve block or corticosteroid injection to reduce inflammation can be considered before oral medications are tried.

you're welcome.
CaliforniaMD and other Neurology Specialists are ready to help you
Customer: replied 4 years ago.

This is a followup question to CaliforniaMD if possible. Pertaining to your last reply to me on the Superficial Peroneal Nerve, my local doctor had no hesitation ordering an injection under ultrasound guidance when I saw him after I had shared the information you gave me on our last conversation. So I assume I don't have to repeat the last question/answer session if this request is picked up by another doctor online because the new person is able to read what has already be shared.
Anyhow, where would the corticosteroid injection normally be given in the leg for the superficial peroneal nerve? Or is this something the radiologist determines himself upon examining me. I really do not know where the supposed nerve fibers are damaged as per our previous conversation.
And is there any different type of reaction to this injection by the nerve than I could normally expect like I've had into my wrist, shoulder joint before?


Optional Information:
Gender: Female
Age: 51

Expert:  CaliforniaMD replied 4 years ago.

a radiologists would inject where they are told to inject. they don't diagnose the problem per se.

yes, tissue reaction is expected to be similar.

the location of damage of the nerve in the leg is determined by doing nerve conduction inch by inch.

i'm not sure if the proper way to approach it is to inject it in the leg before location of the problem is known -- by EMG.

Customer: replied 4 years ago.
thank you for your advice. I will contact the doctor that did the EMG and inquire if he knows already or needs a retest for the specific location of the nerve damage.
Thanks for bringing this to my attention as I certainly do not want to have this injection in the wrong place. I would never have thought about this without your help.
Much appreciation.
Upon your receipt of this message I will accept your last answer.
Expert:  CaliforniaMD replied 4 years ago.

hi again,

superficial peroneal nerve problems typically happen at the fibular head -- just slightly below & near the outer part of the knee because the nerve travels there superficially.

here are my thoughts:

you had the EMG done by a physiatrist & he should know where the abnormality is. moreover, most physiatrists perform corticosteroid injections.

if it's already ordered to be done by radiology, the physiatrist and the radiologist should either talk or your PCP should put PM&R's EMG findings in the referral.

what you mentioned in your original paragraph is probably nerve entrapment, and while corticosteroid shots tend to help the symptoms often return. shots can be repeated typically every 3 months; if they are done more often they can weaken the tissues, esp. tendons and ligaments.

all my best. hope you feel better.

Customer: replied 4 years ago.
I really appreciate your extra thoughts. The reason my primary Physiatrist is not doing the injection is that he wanted ultrasound guided injection which is only done in the Spokane area by one specific radiologist.
What is the difference between nerve entrapment and what you described in earlier conversation about axon(nerve) fiber possible damage, or are they similar or same?
I get the nerve problems right where you describe the injection would normally go below/outer part of knee. But sometimes that area can feel more or less fine but then the nerve sensations(such as cold, tingling or pain) can localize more around ankle/foot.
A very specific area is the peroneal tendons as they come down and around the fibula and one other spot possibly the extensor digitorum longus muscle just medial of fibula as fibula get close to skin. Does my nerve of question affect these areas as I can get a lot of pain right below the distal fibual bone on lateral ankle?
So another question is, would one shot up by fibula head also help the peroneal tendon area around distal fibula or does a dose of medicine need to be put in two locations?

Also I am not going to be overly expecting of the shot to do anything. I've lived with this problem for 10 years and now finely have the details about the problem. I just wanted to try one shot to see if it could help so that I could progress better in p/t with my exercises to correct some of my biomechanical dysfunction of the lower leg and lateral ankle.
without so much transient nerve problems.

Thank you for your reply! Kim
Expert:  CaliforniaMD replied 4 years ago.

when the nerve gets entrapped, it is being squeezed and this affects all vital functions of the axons (nerve fibers). so indeed the reason for the axonal amplitude loss on your EMG can very well be caused by the scar tissue pinching; the fewer the normal axon fibers, the smaller the amplitude.

superficial peroneal nerve comes off common peroneal nerve (along with deep peroneal nerve).

common peroneal supplies sensation to part of the upper side of the calf and peroneal nerve and then continues as lateral branch to lower calf and part of upper foot. so you have these symptoms along the course of the nerve, sometimes more proximal (upstream), sometimes more distal (downstream).

the injection next to the knee would be at the source of the problem. there's a fair chance that it will improve if your symptoms are not more or less constant.

Customer: replied 4 years ago.
Sir, I went to accept your answer and close this discussion on this subject and the computer wanted me to pay another $58 fee like I had paid last week with the original question. I had signed up for the subscription with a 30 day free trial before asking this follow up question and I'm in the dark as to why I am being told I will be charged this again.In fact I had signed up with your invitation so to speak to do so. If I had known this, I may not have asked my question.
Irregardless, I am very pleased and had intended to leave a good tip but this upsets me with your customer service dept and I will call them on Monday to find out what is up before accepting the answer.
If you have insight, feel free to reply but I need to get this straight before paying anything.
Again please accept my apologies for a delay in accepting your very thorough and most appreciated answers.

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