Do nerves grow back after injury or not?

[jostpuur]

I've understood that if somebody gets paralyzed as result of injury to the spine, then there is no change of recovery if the injury has been bad enough. (Recovery can occur if the injury is sufficiently mild.) When I've asked about why don't the nerves grow back, I've learned that it simply is the case that they don't grow back.

But then I see stuff like this: http://www.guardian.co.uk/science/2008/oct/08/medicalresearch.germany First double arm transplant patient recovering well

Doctors said there were good indications of nerve growth in the arms but it could take up to two years for Merk to relearn how to use his hands.

If nerves grow back to arms, then why not the the spine too?

 

[Astronuc]

Peripheral nerves do regenerate. I know this from personal experience - after I sliced into my left thumb. Initially there was numbness around the deep cut. After a couple of years or so, the feeling had more or less completely returned.

Then there is this:

Regeneration
Most of the cells in the human body have the ability to repair themselves after an injury. If you cut your finger, often you have a visible laceration for a few days or weeks, followed by the formation of a scar. In time, you may not be able to tell that the cut had occurred. This indicates that skin cells regenerate, just like cells in the blood vessels, organs and many other tissues. Peripheral nerves (nerve fibers outside the brain and spinal cord), such as those located in your fingertips, also regenerate, although this process is different from that in the skin and other organs.

For years, scientists have focused on the big mystery: "Why doesn't the central nervous system regenerate?" This question is even more perplexing because we know that central nerves in lower animal species CAN regenerate. There are no definite answers to this mystery yet, but scientists are exploring the questions in many ways.

http://www.spinalcord.org/news.php?dep=17&page=94&list=1179

 

[quicknote]

I would say that the answer to this question is not a simple yes or no. It is a complex process that depends on various factors such as the severity and type of injury, the location of the injury, and the individual's overall health and healing ability.

Firstly, it is important to understand that nerves do have the ability to regenerate and repair themselves to some extent. This process, called nerve regeneration, involves the regrowth of damaged nerve fibers and the reconnection of these fibers to the appropriate target cells. However, this process is not as efficient or as fast as other types of tissue regeneration in the body.

In the case of spinal injuries, the chances of nerve regeneration and recovery depend on the extent of the damage to the spinal cord. If the injury is severe enough to completely sever the spinal cord, then the chances of recovery are very slim. This is because the spinal cord is the main pathway for nerve signals to travel from the brain to the rest of the body. If this pathway is damaged, then the signals cannot reach their destination and the body cannot function properly.

On the other hand, if the injury is not severe enough to completely sever the spinal cord, then there is a possibility for nerve regeneration and recovery. This is because the spinal cord contains a type of cell called glial cells, which can help support and guide the regrowth of damaged nerve fibers. However, this process is slow and may not fully restore the function that was lost due to the injury.

In the case of the double arm transplant patient mentioned in the article, the nerves in the arms were not completely severed, allowing for the possibility of nerve regeneration and recovery. However, it is important to note that this is a rare and complex procedure, and the patient will still need to undergo extensive rehabilitation and therapy to relearn how to use his hands.

In conclusion, while nerves do have the ability to regenerate and repair themselves to some extent, the extent of recovery after injury depends on various factors. In cases of severe spinal injuries, the chances of recovery are slim, but in other cases, nerve regeneration may occur with proper treatment and rehabilitation. More research is needed to fully understand the process of nerve regeneration and to develop more effective treatments for spinal injuries.