Munis IONM Coulmn Today!

Cochlear Nucleus, Acounstic Overstimulation and Plasticity:
Recently received manuscript for review from one of my old postdoctoral lab, it is the work I have done during early 2000s at the

Uconn Health Center. Dr.Kent Morest with whom I worked as a senior Postdoctoral fellow one of the Pioneer's and stalwart in the Auditory Anatomy and Physiology field, I was delighted when he called me to review the paper, that he did not forget my work and contributions, I had already reviewed the manuscript and sent it back with my reviews and critics. It was quite interesting work where we looked at the various cellular, synaptic changes at the ultrastructural level using Electron Microscopy. Hope to see the paper coming out soon, 

but thought to mention that the field of "Synaptic Nests" in cochlear nucleus is quite an interesting model to study neuronal plasticity.

-- Smaller Things in Intraoperative Neuromonitoring, could make real differences in terms of safety, good care and less invasiveness??. 

Yes or no: I guess I hear you say Yes, my answer is a great Yes.

Many of the Neuromonitoring professionals and Techs advise sub-dermal needle electrodes for recording EMGs (free running and triggered EMGs). 

One of the reason they will give you is the guidelines, the neuromonitoring society guidelines say so?
Other reasons they will give is needles are effective because it goes deeper into the muscle and picking up potentials with ease!.


The most important aspect of an electrode is 1.Sensitivity and 2. Specificity?.
From these two aspect, needle seems to be sensitive to pickup potentials, is that right or it is more specific, I think it is the former.

So, if it is sensitive, while recording EMGs does sensitivity matter or Specificity matter?.The electrodes regardless of needle or surface electrode is placed on the belly of a muscle group you want to record EMGs, meaning at the center of a muscle groups selected, for example at the belly of Deltoid or Tibialis Anterior, where most innervation of the nerve root is established by anatomical and physiological studies.

If the nerve innervation on a given muscle group is diffused in nature, where is the sensitivity question arises here to use Needle?.


So, sticky pads are good to pickup EMGs from more surface area than the needle, being specific to that muscle group is important here?. If the surface area is prepared well, sticky pads works as good as needle, it is less invasive and least chances of localized burning or infection.
Would you rather use sticky pad or Needle.......


to be Continued...!!!!
@5.54pm 4/2/2010

Sticky is my preference due to the above said reasons, however,  sub-dermal needles must be used in the following conditions!. 
1.When the patient is too Old, where the skin is not smooth and other skin conditions
2.When the patient is too young, like infants and children's pediatric cases!
3.when the wrist or ankle is found with some casting?, use needle
4.In trauma or most emergency cases, where there is not much time to prepare skin for surface electrodes, needle is quick and quite faster to prepare

Todays Column:
04/28/2010

1. I have some questions about Facet Screw testing?
2. Posterior Cervical pedicle screw testing?.

Can someone write here what kinds of criteria such as stimulus strength, acceptable ranges of impedence and warning criteria to be used for these two less frequently used tests?.
..............................................................almost two months no one answered! Yikes, I will do my best to answer them soon!.

06/19/2010
Release of Tethered Cord Procedure and NeuroMonitoring!.
I had done many of these procedures mostly in young children's, as young as 16month, it is one of the most challenging procedures, especially when the patient has multiple disorders with Tethered cord problems.
I had some interesting observations, one of the patient was 16 month and the other 4 years old. First patient did not have identifiable SSEP waveforms both in upper and lower extremities, whereas the EMGs and TrEMGs tested for release of Tc was of great use to the surgeon, the surgeon is more concerned about cutting the nerves in this case than asking for any changes in SSEPs, infact, surgeon asked for SSEPs and EMGs along with nerve root tests?. No motor test was scheduled by surgeon. In the 4y Old child, upper extremity SSEPs were very well formed with good amplitude and latencies, though little widened waveform with first wave appears bit delayed, the uppers were very good to compare it to the lowers. Lower SSEPs were poor (perhaps relates to the patient's other conditions I believe!), but the signals had delayed latencies in lower extremities, amplitudes were not distinct like the typical beginning, raising phase and falling phase, after signal phase, it was rather diffuse and broadened waveform.
I am interested to hear from anyone else who routinely perform IONM on pediatric patients about their experiences, problems and troubleshooting steps?.
1.At what age the SSEPs are distinct and identifiable in order to interpret the signals to the surgeon?
2.At what age the TcMEPs can be tested and will be able to get some appreciable signals?
3. Can you do motors on such as 1 to 2 year old
4. Are there any special subdermal needle's for such tender scalps?
5. If there is a stent in the brain done few weeks or months before release of tethered cord procedure, is it a contraindication of any SSEP or TcMEPs test at all?. Though one must navigate to put the needle electrodes carefully away from stent area?, what if the stent is on your way, right on the spot where you have to put your C3 or C4 electrodes or others?.
6. what is the stim parameters for your TrEMGs on tethered cord release tests?.
as usual, I may or may not see an answer from others, but visit back, I will do my own diligence and fill these columns.
Check out today's interesting article on Tethered cord procedure in articles section?.
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Todays column: 12032010
Posterior Cervical Fusion and Pedicle screws testing on the cervical levels?: I do not find much reference on Pubmed, not even on google search?. Is there someone familiar with this procedure and can you write to me about the purpose, significance, risks and benefits of Posterior Cervical fusion?