Peripheral Nerve: Trauma and Surgery for Peripheral Nerves

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Peripheral Nerve:  Trauma and Surgery for Peripheral Nerves




Guest:  Dr. Abhay Varma – Neurosurgery

Host:  Dr. Linda Austin – Psychiatry


Dr. Linda Austin:  I’m Dr. Linda Austin, talking, today, with Dr. Varma, who is Assistant Professor of Neurosurgery here, at MUSC.  Dr. Varma, let’s talk about surgery of the peripheral nerves.  Now, the peripheral nerves are those that go from the spinal cord out to the arms and legs.  So, what are some examples, then, of some of the conditions of trauma that you need to repair in a surgical practice?


Dr. Abhay Varma:  We see trauma of peripheral nerves in all age groups, starting from even newborns.  We sometimes see what is called brachial plexus injury, or obstetrical brachial plexus injury that results from pulling of the arm during delivery.  It can lead to injury to the nerves that run from the neck down into the arm.


Dr. Linda Austin:  Where is the brachial plexus?


Dr. Abhay Varma:  The brachial plexus is located above the collar bone.  I’m sure most people understand what the collar bone is.  In that small area just above the collar bone, it runs from the neck down into the arm.  During birth, if the arm is stretched excessively for whatever reason, it can lead to pulling or tearing of the nerves running from the neck to the arm, causing weakness in the baby’s arm.


Dr. Linda Austin:  How do you repair that in a baby?


Dr. Abhay Varma:  Initially, we like to wait and see if it improves on its own; in many cases, it improves on its own.  But, if by three or five months we see that there is a persistent weakness, we recommend exploration to see what’s going on.  Before that, we like to get nerve conduction studies done to see what nerves are intact.  But, ultimately, the best is to explore if the baby is not showing signs of full and spontaneous improvement.  We can repair it by using the baby’s own nerves from the legs, where small pieces of nerves are taken from sensory nerves in the legs and they’re used to repair the injured nerves in the brachial plexus.


Dr. Linda Austin:  Can there be brachial plexus injuries in adults as well?


Dr. Abhay Varma:  It can happen, definitely.  It can follow auto accidents or any kind of accident where there was stretching or pulling of the arm.  It can also follow gunshot injuries, or stab injuries to that area on the body.


Dr. Linda Austin:  So then, basically, is the technique the same?  You harvest a nerve from the leg and actually move it up to where you have a problem and stitch it back into place?


Dr. Abhay Varma:  Yes.  We would need to harvest a nerve if the gap between the two ends of the injured nerve is so big that we cannot bring the two ends together without any tension.  So, if the gap is big, we would need to harvest a nerve.  But if, sometimes, like, following a stab injury where there’s a sharp weapon used to produce a clean cut in the nerve, the two ends can be brought together and we can repair the nerve without having to harvest another nerve from the body.

Dr. Linda Austin:  That sounds like very delicate surgery.


Dr. Abhay Varma:  It’s done under microscope and good training.


Dr. Linda Austin:  What’s the longest that those procedures can take, let’s say, in a baby with a brachial plexus injury?


Dr. Abhay Varma:  In some of the centers which are doing these surgeries on a regular basis, they have reported their operative time as close to two hours.  Otherwise, it can take anywhere from four to six hours, depending on the severity of injury and the complexity of repair.


Dr. Linda Austin:  And I would guess that’s likewise in an adult, after a motor vehicle injury or something like that.


Dr. Abhay Varma:  Yes.  It also depends on how badly scarred that area is.  If there’s extensive scarring in that area, one has to very meticulously and carefully cut through the scar to identify the nerves and identify the cut ends of the nerves before you can do any kind of repair. 


Dr. Linda Austin:  Now, you mentioned that, in trauma, like an accident, sometimes there’s stretching of the nerve while other times, actually, the nerve can be torn.  If there is just stretching, what do you do?  How do you repair that?


Dr. Abhay Varma:  It depends on what parts of the nerves are stretched and torn during the accident.  If there is stretching of just axons and the outer layers are intact, it may be possible for the axon to grow spontaneously.  By axon, I mean, the conducting part of the nerve through which the impulses are conducted.  It may be possible for it to grow back on its own without requiring any surgical intervention.  However, if there’s severe stretching which leads to not only disruption of the axon, or the conducting part of the nerve, but also the outer layers, which kind of provide a sheath around the axons, then the axons may not be able to repair or grow on their own.  This may need surgical intervention with some kind of repair, a primary repair, where you don’t need a graft, or a repair using a graft.


Dr. Linda Austin:  How do you evaluate this before you take the patient to surgery?


Dr. Abhay Varma:  There are different ways of evaluating it.  The most important is the clinical evaluation.  There’s no substitute for a good clinical exam, where you carefully examine the patient.  A careful clinical examination can tell you the level of the injury and its severity.  We also have newer techniques, MRI imaging, for example, which can help us diagnose a nerve injury and see if there’s any evulsion of the nerve from this point where it’s coming off the spinal cord. 


Dr. Linda Austin:  Evulsion, meaning?


Dr. Abhay Varma:  Tearing of the nerve as it comes off the spinal cord.  We also have electrophysiological studies where we study the conduction through the nerves and the condition of the muscles that these nerves supply.  That helps us know the severity of the injury and what the prognosis is.  If the muscle is completely destroyed because it’s been a long standing injury, and even if you repair the nerve, it’s unlikely that the muscle would recover, we can tell the patient beforehand.


Dr. Linda Austin:  Dr. Varma, thank you very much.


Dr. Abhay Varma:  You’re welcome.


If you have any questions about the services or programs offered at the Medical University of South Carolina or if you would like to schedule an appointment with one of our physicians, please call MUSC Health Connection:  (843) 792-1414.


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