Consequences of Nerve Damage and the Chances of Recovery

Causes of nerve damage

The causes of motor and sensory nerve damage are varied. This type of nerve damage usually results in what is called a peripheral nervous system problem, i.e., it affects a nerve segment that runs from the body toward the spinal cord. The central (central) part of the nervous system extends from the spinal cord to the brain.

Some common causes:

• Diabetes mellitus: Persistently high blood sugar over years can damage nerves. The consequence is diabetic peripheral neuropathy. This can cause pain, loss of sensation, numbness, itching and other symptoms.
• Injury: A nerve can be damaged in an accident; for example, nerve fibers can be injured in a severe bone fracture.
• Surgical complication: Nerve damage is a common surgical complication. For example, the surgeon may cut a nerve while removing a tumor, cyst or other structure. Sometimes the nerve is not physically severed but is still damaged — for example, surgical retractors or clamps press on the nerve or on the vessel supplying it, and it becomes damaged due to lack of oxygen. An example is prostate removal surgery, whose most common complication is nerve damage, resulting in erectile dysfunction and reduced urinary continence.
• Infections and inflammations: Some infections — for example Lyme disease or shingles — cause inflammation that can result in nerve damage, i.e., peripheral neuropathy.
• Autoimmune diseases: In some forms the immune system mistakenly identifies the nerve as an intruder and the defense system attacks and damages it.
• Toxic effects: Certain chemicals, such as alcohol, heavy metals or some medications (for example chemotherapeutic agents) can be toxic to nerves. The consequence is peripheral neuropathy.
• Vitamin deficiencies: Especially deficiency of B vitamins (B1, B6, B12) can cause nerve damage.
• Genetic disorders: Some genetic diseases, such as Charcot–Marie–Tooth disease, can be the cause.
• Tumors: As a tumor grows it can encroach on or surround nearby nerve fibers. This pressure or compression damages the nerve.
• Vascular disorders: Damage or occlusion of the vessels supplying the nerves can reduce their oxygen supply, leading to damage.

Symptoms of nerve damage

The symptoms of sensory and motor nerve damage depend on which peripheral nerves are affected and to what extent. Damage to sensory nerves leads to sensory problems (peripheral neuropathy), while damage to motor nerves causes difficulties in movement.

Symptoms of sensory nerve damage:

• Numbness or tingling: Especially felt in the hands and feet, often described as a “pins-and-needles” sensation.
• Pain: Sharp, burning, or throbbing pain, which is often worse at night.
• Sensitivity: Increased sensitivity to touch; even light touch can be painful.
• Changes in temperature sensation: Difficulty distinguishing between cold and heat. For example, the affected person may burn themselves because they do not sense the heat.
• Sensory loss: Reduced or lost sensation in certain parts of the body.

Symptoms of motor nerve damage:

• Muscle weakness: Muscles in the affected areas cannot function normally, leading to weakness.
• Muscle twitching: Involuntary twitching or cramping of the affected muscles.
• Muscle atrophy: Wasting of muscles due to inactivity or lack of use.
• Movement disorders: Lack of coordination and difficulty with fine motor skills.
• Paralysis: In severe cases, complete loss of movement of the affected limbs or body parts.

General symptoms:

• Coordination problems: Difficulty with fine motor skills, such as writing.
• Balance disorders: When sensory and motor nerves are damaged together, both coordination problems and balance disorders can occur.
• Chronic pain: Nerve damage can cause constant or recurring pain that can significantly affect quality of life.

The extent and type of peripheral nerve damage can be precisely determined with nerve conduction studies and electromyography (EMG).

What happens after nerve damage?

The peripheral nerve “tries to repair itself” after it is injured or cut!

The nerve fibers (axons) retract and “rest” for about one month; after that they begin to grow again.

The degree of nerve recovery varies between individuals. It can be said that it will never be 100% — that is, the pre-injury state does not fully restore.

The chance of recovery increases if, for example, the severed nerve ends are restored (sutured) by the surgeon.

If the nerve fiber is broken and the nerve ends separate because of the injury (and are not brought back together), the nerve fibers will try to grow and “find” the other end of the nerve. In many cases this does not succeed and the result is a nerve-end lump (neuroma). This is sensitive to impact or pressure and can be permanently bothersome in some cases.

Healing time for nerve damage

The regeneration time depends on how severely the peripheral nerve is damaged and the type of injury.

A severed nerve rests for about 4 weeks after the injury, then begins to grow. For this reason you will not feel substantial improvement in the first weeks after nerve damage. Usually the situation changes gradually over several months, with progressive improvement and return of sensation and motor abilities.

The chance of recovery is best in cases where the continuity of the nerve has not been broken. In such cases improvement is usually expected within 2–3 months.

Nerve regeneration is a very slow process! A nerve fiber grows by roughly 1 mm per day, and some experts believe it to be even slower. Therefore a lengthy recovery period should be expected after nerve injury.

Sensory nerves are more resilient than motor nerves and can regain sensation months or even years after the injury.

There is a time limit for motor nerve recovery. This is due to the structure called the “motor endplate,” where the nerve connects to the muscle. If the motor endplate does not receive nerve impulses for more than 18–24 months, it degenerates and the muscle can no longer be activated by the nerve. At this point the muscle loses its function and essentially becomes nonfunctional.

Treatments that stimulate nerve regeneration

Electrotherapy

As mentioned in the previous section, preventing damage to the motor endplate is fundamentally important for regaining motor function. After nerve injury the electrical muscle stimulation of the affected muscles should be started as soon as possible.

Electrical stimulation acts not only on the muscle but also on the nerve fiber — the stimulus traveling from the muscle toward the center has a stimulating effect on nerve regeneration as well.

In central damage (central paralysis) a good quality muscle stimulator is sufficient.

In peripheral nerve damage (peripheral paralysis) a device that also provides denervated current treatment is required.

The electrical treatment must be maintained until the motor nerve's regeneration again reaches the given muscle. Without electrical muscle stimulation the condition of the muscles cannot be maintained!

• You can find devices suitable for treating muscles affected by central nerve damage by clicking here.
• Devices suitable for treating muscles affected by peripheral nerve damage can be found by clicking here.

Haastert-Talini K, Grothe C. Electrical stimulation for promoting peripheral nerve regeneration. Int Rev Neurobiol. 2013;109:111-24. doi: 10.1016/B978-0-12-420045-6.00005-5. PMID: 24093609.

Laser therapy

Researchers have found evidence that laser therapy helps peripheral nerve regeneration. This improves motor functions.

Click here to find appropriate softlaser devices.

Muniz XC, de Assis ACC, de Oliveira BSA, Ferreira LFR, Bilal M, Iqbal HMN, Soriano RN. Efficacy of low-level laser therapy in nerve injury repair-a new era in therapeutic agents and regenerative treatments. Neurol Sci. 2021 Oct;42(10):4029-4043. doi: 10.1007/s10072-021-05478-7. Epub 2021 Jul 22. PMID: 34292450.

Vacuum therapy

The device designed to treat nerve damage after prostate surgery is the Rehabi PVT penis trainer. This is a vacuum device recommended for every patient who has undergone prostate surgery.

How can you tell if the nerve is recovering?

During regeneration the affected area gradually recovers. Initially quite uncomfortable and tingling sensations occur. You may experience sensations similar to electric shocks along the growing nerve fibers. The location of these complaints shifts gradually away from the trunk as the nerve heals and grows. Eventually the unpleasant sensations cease and sensation in the area returns to normal.

Can a damaged nerve fully recover?

In practice, damaged nerves never fully recover. The degree of recovery depends on many factors:

• Age: As age advances the body becomes less efficient at self-repair.
• Mechanism of injury: Nerve injuries from cuts have a better chance of recovery than those caused by compression.
• Time since injury: The sooner treatment begins the better the outcome may be.
• Type of nerve: Sensory nerves recover better than motor nerves.
• Associated injuries: Sometimes the healing nerve becomes trapped in scar tissue at the injury site, which significantly worsens the chance of recovery. Laser treatment of the injured area improves scar tissue quality — laser treatment results in less but stronger scar tissue (by increasing collagen production).
  Laser treatment of the injured area can prevent pathological scar formation.