Nerve Damage Guide: How Long Does It Take For A Nerve To Regenerate?

Written by Mary | Last Updated on 
June 10th, 2019 at 08:27 pm

Nerve injury can result is loss of sensation or problem with your muscles. This always leads to pain, a condition called “peripheral neuropathy”. To understand how the nerves repair and regenerate, you need to understand the types of nerve injuries.

Nerves are classified into three groups:

  1. Motor Nerves
  2. Sensory Nerves
  3. Autonomic Nerves.

One controls muscle movements, the other sends out information from and to the brain and the last one control different organs to regulate activities.

The large nerves in your leg are the same size as a pencil. This connection is made of tens of thousands of nerve fibers. Think of a telephone cable that carries the connection from one end to another.

The nerve fibers are arranged in fascicles. The ulnar and median nerves in the arm have sensory and motor fascicles that allow you to feel your hand during movement.

Nerve Regeneration Timeline

When it comes to never regeneration, the rate of recovery depends on how severely the nerve was injured. It the nerve was traumatized or bruised, then recovery rate is around 6 to 12 weeks. If the nerve was cut, the recovery rate is slower.

When the nerve has had a rest period of 4 weeks, the healing process begins and the nerve regenerates 1 mm/day. Since sensory nerves heal faster, full regeneration and recovery is expected to be within a year.

Motor nerves are a bit tricky in this matter. Their structure is quite different and is called “motor endplate”. The nerves join with the muscle and therefore, the damage is severe. When the motor endplate does not receive signals for 24 hours, the nerves die away.

Now that there’s no connection, the muscles can no longer be activated, which causes them to wither away. This is why motor nerves should be repaired within 12 hours, to avoid any lasting damage.

Until the time feeling returns to your sensory nerves, it is important to stay away from sharp and hot object. You might get injured and never feel the pain, which can cause the wound to fester. The same falls for the motor nerves.

Since you don’t have complete control over the muscles, it’s possible that you might develop abnormal postures. To make sure this does not happen, you can seek physiotherapy or hand therapy to maintain the feeling and action of movement while the nerves regenerate.

Nerve Recovery

Often people ask that how will they know that the damaged nerve is recovering. The healing process is not that unpleasant. It starts with a tingling feeling at the sight of the injury. As the nerve fibers grow back, you might feel light electrical shocks. As time passes, the feeling subside albeit slowly.

One thing you need to understand is that some nerves do not recover completely. You might have an odd feeling in your hands and legs after a nerve has been cut. The rate of recovery depends on various factors as followed:

  • Age: As you grow older, you body’s healing process slows down. So if you get a cut at an old age, you might never recover fully.
  • Mechanism of Injury: Damaged nerves due to a cut heal better than the ones from a crush.
  • Time of Recovery: The quicker the nerves are repaired, the faster they will regenerate.
  • Mechanism of Repair: The best and the fastest way to heal the nerves is through direct repair
  • Recovery According to Type of Nerve: Motor nerves heal at a slower rate compared to sensory nerves
  • Associated Injuries: If there is tension around the repair or the nerve is trapped under scar tissue, then the recovery rate is slow

Never Injury and Recovery

Degree of Nerve InjurySpontaneous RecoveryRate of RecoverySurgery
First

Neurapraxia

FullOccurs in days to 3 months after injuryNone
Second

Axonotmesis

FullRegenerates at the rate of 1 inch/monthNone
ThirdPartialRegenerates at the rate of 1 inch/monthNone or neurolysis
FourthNoneFollowing surgery at the rate of 1 inch/monthNerve repair, graft or transfer
Fifth

Neurotmesis

NoneFollowing surgery at the rate of 1 inch/monthNerve repair, graft or transfer
Sixth

(Mixed Injury)

Recovery and type of surgery depends on the injury itself and the combination of degrees of nerve injury

Let’s dissect the first and second degree of injury:

Neurapraxia

When the Neurapraxia nerve is damaged, the recovery takes just a few days, once the injury has been taken care of. The good news is that damage to this nerve does not cause lasting sensory or muscle problem.

Axonotmesis

When the Axonotmesis nerve is damaged, the recovery rate is slower. In order for the nerve to heal, it must reinnervate (get restored through surgical grafting) the skin or muscle. This nerve damage heals itself and grows at the rate of 1 inch per month. Hence, the recovery rate is much longer and requires extra care.

Third Degree Injury

Third degree nerve injury gets only partially recovered. Even this recovery depends on a few factors such as the severity of scarring and the success of the surgery. If the nerves are mismatched during the connection, then there are less chances of the nerve recovering. The nerve regenerates at the rate of 1 inch per month.

Fourth Degree Injury

Fourth degree nerve injury happens when the scar tissue is damaged deeply and the connection of other nerves is clocking recovering. The regeneration here begins a few weeks after the injury has had time to rest. The nerve regenerates at the rate of 1 inch per month.

Fifth Degree Injury

Fifth degree nerve injury is an injury that completely separates the nerve. In order to recover, the nerve must be repaired immediately through surgery. The nerve regenerates at the rate of 1 inch per month.

Sixth Degree Injury

Sixth degree nerve damage involves a combination of nerves. Since the damage is huge, the recovery and regeneration depends on how the deep the damage is and speedy surgery.

From all this you can conclude that that the regeneration rate of a damaged nerve depends on how deep the cut is: whether the nerve was severed or simply crushed. All in all, you are looking at months, possibly years in recovery.

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