Nerve Injuries in the Hand: A Comprehensive Guide to Understanding and Recovery

Introduction

Nerve injuries are common and multifaceted.  The nerve can be cut/severed, tractioned/pulled, crushed, or compressed. Nerve pain is usually reported as severe and can be described as burning, hot, electric, or shooting, with the experience of a loss of sensation, pins and needles, weakness and/or dropping things.

A Neuropraxia: is commonly used to describe temporary nerve damage, irrespective of whether the nerve damage comes from a crush, compression, or traction.  It falls under the broad category of peripheral neuropathies. Neurapraxia is the mildest form of peripheral nerve injury commonly induced by focal demyelination or ischemia of the nerve. The nerve impulses are blocked in the injured area. Motor and sensory conduction are partially or entirely lost. It can last an average of six to eight weeks before recovery.  Common conditions are: carpal tunnel syndrome and cubital tunnel syndrome.

Types and Causes of Nerve Injuries

Physical injury such as injury from car accidents, falls, sports, and medical procedures that can cut, stretch, crush, traction or compress nerves. Broken and/or dislocated bones can exert damaging pressure on nerves and slipped disks between the vertebrae can compress nerve fibres where they exit from the spinal cord.

Cut Nerves

• If the nerve is cut, the distal portion of the nerve (the part towards the periphery) dies.  This process is called Wallerian Degeneration.  The neural sheath remains intact (due to surgery), however the inside – the fibres that communicate information – deteriorates. The nerve cells (neurons) then start to regrow.  This process can sometimes take a month before regrowth begins.  The nerve grows at approximately 1mm a day, once the degeneration is complete.  This regrowth can be a lengthy process depending on where the nerve was severed initially.

Compressed / Crushed Nerves

• Compression of the nerve blocks the signals and communication. Symptoms include pins and needles, dropping objects and/or numbness.   Arthritis, prolonged pressure on a nerve or repetitive, forceful activities can cause ligaments or tendons to swell, which narrows or compresses the neural pathways.  The foramen or area where the nerve exists the spinal cord can also narrow and cause compression upon the nerve.  The symptoms can then be felt along way distal to the site of the compression.

Pulled / Traction of Nerves

• Significant trauma to the arm or leg, car accident, high fall or machinery accident can cause the nerve to be tractioned or avulsed from its original position.  Sometimes the pulling is just in side the neural sheath.  This has a significant impact upon the signal and communication of the nerve.  The axons and neurons are directly impacted and need time to recover.  The nerve remains in place but cannot transmit impulses, due to this severe trauma

Recognising Nerve Damage in the Hand and Fingers

Common Symptoms

• It is important to understand and recognise when a nerve may be damaged. Observational signs are skin dryness, or tightness.  An inability to feel objects properly and if sight was removed, may not be able to identify and describe the object.  A person may feel numbness, tingling, burning, electric or sharp pain as well.  

Nerve Conduction Studies

• A nerve conduction study is performed to determine the velocity, latency, and conduction of the nerve with respect to normal values.  It helps determine if there is a compression or other nerve dysfunction like demyelination.

Symptoms Specific to Finger Nerve Damage

• If a nerve, within the hand/fingers, has been cut there is a specific loss of sensation of everything distal to the laceration. The pain is reported to be electric initially, followed by a numbness or inability to feel pain.  
• A peripheral neuropathy may have more subtle signs of loss of sensation or sensation differing form the other side.  This is common in diabetics.  However, the first signs and symptoms will be within the feet before the hand as diabetic polyneuropathies are length-dependent.

Initial Recovery Steps

Immediate Care

After it has been identified and realised that a nerve has been injured, it is important to protect the nerve from further damage and rest the area of injury for the duration of the nerve repair phase of healing – the initial 3 weeks.

The first aid for a laceration of a nerve is to apply compression to stop bleeding, cover to protect from infection and support to prevent further damage and minimise pain.  

Post-Surgical Care

After a nerve has been surgically repaired, it will require sterile, nonstick dressings, light compression to prevent excessive swelling, scar management and sensory re-training needs to be commenced and addressed.  The sutures are usually removed at 10-14 days post-surgery.

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Hand Therapy and Nerve Rehabilitation

Therapy, treatment, and rehabilitation can expect the nerve to recover over time, only if the nerve cell itself has not died. The underlying causes of the nerve injury needs to be identified and resolved to allow the nerves recover or regenerate.

Nerve health and recovery can be improved with a healthy lifestyle such as maintaining optimal weight, eating a balanced diet, and correcting any vitamin deficiencies.  Smoking should be avoided as it constricts the blood vessels that supply the nutrients to the peripheral nerves and can worsen neuropathic symptoms.

Scar Management

• Proper care of the scar is crucial to prevent hypersensitivity. This can be especially debilitating and limits the ability to pick up objects.  Desensitisation exercises, compression, stretches, massage, and wearing a silicone product can aid in scar healing.  It is also important to ensure the scar is not raised and is aesthetically pleasing

Active Joint Movement

• Active joint movement is started initially to ensure all joints remain mobile in anticipation of nerve recovery.  Exercise and active joint movements are essential as they improve blood flow to the damaged nerve and in turn deliver more blood, oxygen, and nutrients to far-off nerve endings.  They improve muscle strength, joint integrity, and limits muscle atrophy.  Controlled exercises are commenced within the first 10-14 days. It is vital to ensure that all joints continue to move through their full range, preparing them for re-innervation.

Strengthening Post Nerve Injury

• A graded strengthening program is typically introduced with signs of nerve recovery.  The muscles are strengthened proximally to distally, in the order or re-innervation. If the nerve has been compressed then the strengthening is more general and involves all the muscles innervated by that specific nerve that was injured.  As it can take time for a nerve to recover and return to function, it is integral to continue to strengthen all muscles surrounding the injury to ensure when the nerve does return there is no strength deficit due to neglect and deconditioning.

Motor and Sensory Nerve Retraining Techniques

• As the nerve recovers, maintaining the brain connections and brain space is essential. Techniques like laterality, imagery, and mirror therapy exercises are be beneficial. As this is a complex form of rehabilitation, therapists need to provide detailed guidance and information booklets to patients to achieve the best outcomes.  
• Sensory re-training is also essential to help keep the pathways and somatosensory cortex occupied with input of signal while the peripheral signals recover.

Nerve Glides

• Nerve glides are a form of treatment that gently stretches irritated nerves, with the goal of improving range of motion and reducing pain. They also glide the internal nerve within its neuronal sheath.  This frees up the nerve communication and reduces pain.

Monitoring Nerve Recovery and Ensuring Safety

Monitoring Recovery

• Hand therapists will conduct a series of tests to track the nerve growth and recovery to measure progress.  Motor and sensory nerves are tracked with a battery of tests including: manual muscle testing of specific nerve regrowth, monofilament testing, grip and pinch strength measurements, questionnaires (neuropathic pain scale), nerve conduction studies, Moberg’s test, Sollerman’s test of functional return, and nine-hole peg test

Safety Measures

• When your peripheral sensation is compromised, it’s crucial to rely on visual cues and common sense. Avoid prolonged gripping and exposure to hot objects to prevent burns or blisters.

Symptoms of Nerve Recovery

Nerves recover with a myriad of different symptoms.  It is important to educate and understand the different situations of normal nerve recovery to provide comfort and re-assurance to the patient.

Sharp, shooting, electric pains are normal signs of nerve recovery.  The signal should extend to the farthest distal nerve ending.   It is the body’s way of communicating the direction of where to travel.

The scar should become less sensitive as a sign of recovery.  The muscles will progressively get re-innervated and show approximately where nerve growth is up to.  The sensation will also gradually return and more depth of feeling be experienced.

A gentle Tinnel’s test along the line of the injured nerve can help find the location of where the nerve growth is up to.  When tapped it will send shooting pains to the tip of the nerve and be extra sensitive.

Frequently Asked Questions

Is Burning a Sign of Nerve Healing?

Yes, burning sensations can be a sign of nerve healing. You may experience sharp shooting or burning pain. These symptoms are common in nerve pain and are generally considered positive indicators of recovery, especially if the nerve has been severed and surgically repaired.

What Does Nerve Damage in the Thumb Specifically Look Like?

Nerve damage to the thumb is common with either a knife laceration or the result of nerve compression in the wrist from Carpal Tunnel Syndrome.  It is reported to have difficulty manipulating and grasping objects due to loss of sensation and weakness.  Pins and needles and numbness especially at night is also described.  Burning, electric and knife-like pain are common pain descriptors of thumb nerve damage.

How Long Does It Typically Take for a Cut Nerve to Heal?

The expected timeframe for a cut nerve to heal is roughly four weeks for the axonal degeneration to occur and then it depends on where the laceration was. It is approximately 1mm a day. For example, if the cut nerve is at the thumb base then a distance of 100mm is approximately 100 days after the initial4 weeks.  Nerve growth can also slow down as it gets closer to the destination site.

Conclusion

Nerve injuries tend to be complicated in nature and understanding that both the peripheral symptoms need to be addressed as well as the central changes.   It is important to seek understanding of the nerve condition presenting and how the nerve recovers.  A timely intervention is critical to ensure the nerve recovers without any adverse effect.  

Professional and tailored information regarding the specific nerve injuries is highly recommend to achieve the best results from a nerve injury.