Radiculopathy - Nerve Recruitment - Nerve Regeneration

[Realitycheck]

So what I have read is that nerve injury at the root usually heals nominally. I have improved nominally, regaining some strength and movement, as the 4 month maximum recovery period has pretty much expired since the injury occurred. I did read this one article that states the following. I was looking for confirmation about the extent that it is possible, as there are a lot of nerves in my arm that could theoretically pick up the slack.

 

Denervation also causes “territorial invasion” Every gardener knows what this means. For example, when a bed of

roses dies, the weeds move in to take over. Whenever muscle cells lose their nerve supply, adjacent surviving nerve

axons send sprouts to invade the deprived sector and take over, enlarging their territory. Sprouting distorts the normal

pattern of muscle contraction (and are seen in electromyography as “Giant waves”.

© iSTOP - Institute for the Study and Treatment of Pain - 2002

 

If a nerve root became damaged and is providing only limited recruitment of the muscle, could a neighboring nerve start branching out into that muscle? Is there another mechanism that enables improvement?

[zule]

I don’t know about this subject, but I think that we can help you in the forum to look up about it if you can provide us more information.

 

For example:

How much time ago did you suffer the injury?

Was the injury in the spinal cord or in the arm itself?

In what way the injury has been improving in the time?

Some other data provided by the doctors who have treated the lesion…

[Realitycheck]

The injury happened about 4 months ago. 2 months ago, it was treated. There was also a tumor inside the protective layer of the spinal cord which had started to erode the nerve. They removed about 95% of the tumor. While in the hospital, I could not lift my arm, deltoid and biceps were very weak. After rehabbing it for a while, I can lift my arm up, but progress has slowed down and strength gains are very slow if at all.

[zule]

I have found this

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=recruitment,nerve&rid=spinalcord.section.2960#2967

“It must be remembered, however, that nearly all muscles receive innervation from more than one spinal cord segment. Consequently, unless both the spinal cord segments supplying the recorded muscle are involved, and all the AHCs within them are destroyed, the CMAPs are more likely to be of low amplitude than to be unelicitable. Also, the CMAP amplitudes in these instances are affected by the duration of the lesion, particularly if the latter is incomplete. This is because a variable number of the denervated muscle fibers in the recorded muscle will be reinnervated by sprouts arising from intramuscular axons whose cell bodies in the spinal cord were not injured. Under these circumstances, although the number of motor axons supplying the recording muscle remains severely reduced, the number of innervated muscle fibers in the recorded muscle that can respond to nerve stimuli increases. As a result, the CMAP responses, which for the first few months after onset of symptoms were quite low, will slowly begin to increase in amplitude.”

AHCs: alpha motor neurons

CMAP: muscular action potential

 

As you can move your arm, both spinal cord segments weren’t destroyed. And spreading of nerves take a long time. So, I think you could be in the stage in which the cells have practically been reinnervated but muscles have still to recuperate more. I think that your arm will continue improving, but slowly.

[Realitycheck]

Thank you for your help. That is good to know.

 

This just happened to show up in the news today.

 

http://news.yahoo.com/s/afp/20080107/ts_afp/healthneurologyspineinjurydrugs

 

Brain says to spine 'heal thyself': study

 

PARIS (AFP) - Tiny nerves crisscrossing the spine can bypass crippling injuries recently written off as irreversible, scientists reported in a study published Monday.

 

Experiments conducted on mice at the University of California in Los Angeles showed for the first time that the central nervous system can rewire itself to create small neural pathways between the brain and the nerve cells that control movement.

 

This startling discovery could one day open the way to new therapies for damaged spinal cords and perhaps address conditions stemming from stroke and multiple sclerosis, according to the study.

 

Normally, the brain relays messages that control walking or running via neural fibers called axons.

 

When these long nerves are crushed or severed -- in a road crash or sports accident, for example -- these lines of communication are cut, resulting in reduced movement or paralysis.

 

"Not long ago, it was assumed that the brain was hard-wired at birth and that there was no capacity to adapt to damage," explained neurobiologist Michael Sofroniew, who led the research.

 

But the new findings add to a growing evidence of the brain's remarkable capacity to reorganise in response to injury "in ways that were not thought possible," he told AFP.

 

Sofroniew compared the axons to major freeways running from the brain to the lower spinal cord.

 

"When there is a traffic accident on the freeway, what do drivers do? They take shorter surface streets," he said.

 

In the same way, the short nerves found up and down the spinal cord, called propriospinal connections, set up alternate routes.

 

"These detours aren't as fast or direct, but still allow drivers to reach their destinations," he said, completing the metaphor.

 

In the experiments, Sofroniew and his colleagues blocked half of the long axon nerve fibers in mice in different places, and at different times, on either side of the spinal cord, paralysing the animals' hind legs.

 

They left untouched the spinal cord's core, which contains the shorter nerves.

 

Astonishingly, most of the mice regained control of their legs within eight weeks, albeit with less mobility than before.

 

When the researchers blocked then shorter propriospinal nerves, the mice were once again paralysed, proving that they had been responsible for the recovered mobility.

 

The challenge for medicine will be finding ways to enhance and harness this spontaneous neural rewiring to help heal spinal cord injuries.

 

Up to now, most experts believed that the only way for injured patients to walk again was to regrow the long axon, but it has been extremely difficult to get these damaged "highways" to regenerate more than a short distance.

 

"The next goal is to determine how to maximise the process through the right kind of rehabilitation and training, and to test whether there are any forms of pharmacologic stimulation that might help as well," said Sofroniew.

 

More than a quarter of million people in the United States suffer from spinal cord injury, with some 10,000 new cases every year, according to epidemiological studies. Worldwide, the rate of new cases is between 15 and 40 cases per million every year.