Surgery in Nerve Disorders – Overview

The goal of surgery is to preserve or restore nerve function. Whether an operation is appropriate depends on the exact diagnosis, the extent of the damage, and the course of the condition.

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1. Decompression and Neurolysis

What happens?

The nerve is surgically exposed and released from pressure or adhesions. Two main techniques are used:

Examples:

• Carpal tunnel release:
  The transverse carpal ligament is divided to reduce pressure on the median nerve. In most cases, this is a pure decompression; neurolysis is rarely required.
• Cubital tunnel surgery:
  The ulnar nerve at the elbow is exposed. Often, a combination of decompression and neurolysis is performed. A transposition (moving the nerve to the front) is only needed in special situations, such as instability or recurrent compression.

Goal: Relieve pressure and restore the nerve’s mobility.

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2. Nerve Transposition

Example:

• In rare cases, the ulnar nerve at the elbow is moved to the front if, despite decompression and neurolysis, it remains unstable or shifts across the bone during movement.

Goal: Protect the nerve from renewed injury and reduce irritation.

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3. Nerve Transfer

What happens?

During a nerve transfer, healthy neighboring nerves or small bundles of fibers (called fascicles) are carefully redirected so they can take over an important function that was lost because of the injured nerve. Only part of the donor nerve is used, so its main task remains intact.
You can imagine it a bit like redirecting traffic: if the main road is blocked, a side street can be connected in such a way that cars still reach their destination. In the same way, the redirected nerve fibers help restore signals for movement or sensation that would otherwise be lost.

Examples:

Oberlin transfer:

A portion of the ulnar nerve is redirected to a branch of the musculocutaneous nerve to restore elbow flexion through the biceps muscle. This is a standard procedure in brachial plexus injuries.

Mackinnon-Oberlin transfer:

A variation in which an additional fascicle from the median nerve is transferred to the branch for the brachialis muscle. In this way, both biceps and brachialis are reinnervated, leading to stronger elbow flexion.

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Somsak transfer (Radial → Axillary):

A motor branch of the radial nerve (e.g., to the triceps) is transferred to the axillary nerve to restore shoulder abduction via the deltoid muscle. This procedure is mainly used in brachial plexus injuries or isolated axillary nerve lesions.

Applications in tetraplegia:

S-PIN Nerve Transfer – Supporting Hand Opening:

After a spinal cord injury in the neck region, many people with tetraplegia can still move their arms but have difficulty opening the hand and releasing objects.
With an S-PIN nerve transfer, surgeons reroute a small motor branch in the forearm to muscles that normally extend the fingers. This allows signals from nerves that are still under brain control to reach muscles that could no longer be activated.
Over time, some patients may regain a degree of finger extension. This can make it easier to open the hand, let go of objects, and perform certain daily tasks more independently.
The procedure cannot restore normal hand function, but it may provide helpful improvement in specific movements and contribute to greater usefulness of the hand in everyday life.

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Brachialis to Anterior Interosseous Nerve (AIN) Transfer – Regaining Thumb and Finger Function:

Sometimes, after certain nerve or plexus injuries, people can still bend the elbow but are no longer able to bend the thumb or the tip of the index finger. This makes it very difficult to pinch, hold, or pick up small objects.
In this operation, a small branch of the nerve that normally supplies the brachialis muscle (one of the elbow flexors) is redirected and connected to the anterior interosseous nerve. This target nerve normally controls the fine bending of the thumb and index finger.
As a result, when the patient activates the brachialis muscle, part of that nerve signal is rerouted to the thumb and index finger muscles. With intensive training, the brain learns this new “wiring,” so that a more precise pinch grip becomes possible again.
The aim of the transfer is not to restore full hand strength, but to improve fine motor skills and make everyday tasks such as buttoning clothes, writing, or using a phone easier.

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Special note:

• The patient must actively learn this new control pathway. The brain has to “relearn” that a nerve originally responsible for another movement now activates a new one.
• Nerve transfers are mostly used in complicated nerve injuries, for example when the brachial plexus is affected and a direct repair is not possible. In some cases, they are also used in people with tetraplegia (paralysis of all four limbs after a spinal cord injury). Here, still functioning nerves from the spinal cord can be “redirected” to muscles that have lost their control, so that at least some important movements can be regained.

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4. Nerve Grafting (Nerve Transplantation)

What happens?

In a nerve graft, a gap between the ends of an injured nerve is bridged with a piece of nerve tissue taken from another part of the body. This “nerve graft” serves as a kind of biological guide rail through which new nerve fibers can grow. Over time, the regenerating fibers can use this pathway to reconnect with the target muscle or skin area.
Only small, less critical sensory nerves are usually taken as grafts, so that no important function is lost at the donor site.

How does it work?

Usually, a sensory nerve, which is not essential for motor function, is taken – typically the sural nerve from the lower leg. This graft is sutured between the healthy ends and serves as a “biological bridge” through which new nerve fibers can grow.

When is it used?

• In fresh nerve transections, when a gap has to be bridged.
• In cases of neuromas or scarred segments that must be removed and can no longer serve as a pathway for regeneration.
• Particularly common in brachial plexus injuries, where entire nerve sections may need to be replaced.

Special note:

• Harvesting the donor nerve leads to a small area of numbness on the skin (e.g., along the outer edge of the foot), which is usually not very disturbing.
• Regeneration is slow: about 1 millimeter per day. This means it takes many months before functions begin to return – and often some limitations remain, even if improvements are achieved.

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5. Muscle and Tendon Transfer

What happens?
If a nerve can no longer recover, or if regeneration would take too long, healthy muscles or tendons can be repositioned so they take over the lost movement. The surgeon redirects a muscle that still works well and connects it in such a way that it can perform the task of the paralyzed muscle.
You can imagine it like reassigning a helper: one muscle changes its “job” and takes over the function that has been lost. This way, important movements – for example, lifting the hand or bending the elbow – can often be regained, at least in part.

Examples:

• Foot drop correction:
  A muscle that normally turns the foot inward is rerouted so it can lift the foot.
• Finger and thumb extension:
  A functioning tendon in the forearm is redirected to allow finger or thumb extension (e.g., after radial nerve injury).
• Shoulder function: In selected cases, muscles are repositioned to improve movement or stability of the shoulder.

Applications in tetraplegia:

In people with spinal cord injuries affecting arm and hand function, muscle and tendon transfers can make everyday movements possible again. For example, muscles that still work for wrist or elbow motion can be redirected to help close the hand or move the thumb. Even if normal function cannot be restored, these operations can provide a more useful grasp and allow patients to perform daily tasks more independently.

ECRL to FDP Transfer – Supporting Finger Flexion:

After certain spinal cord injuries, people can often still extend the wrist but cannot bend their fingers into a fist. Without this movement, it is very difficult to grasp or hold objects.
In an ECRL to FDP transfer, the tendon of a functioning muscle that normally extends the wrist – the extensor carpi radialis longus – is re-routed and connected to the tendons that bend the fingers – the flexor digitorum profundus.
This means that when the patient tries to extend the wrist, the force is redirected to help flex the fingers. With training, the brain learns to use this movement for gripping.
The goal is not to bring back normal hand function, but to allow the hand to close again and make grasping everyday objects easier.

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Brachioradialis to Flexor Pollicis Longus Transfer – Helping the Thumb Move Again

Sometimes after a spinal cord injury or nerve damage, people can bend the elbow but cannot bend the thumb tip anymore. This makes it very hard to pinch, hold, or pick up objects.
In a BR to FPL transfer, the tendon of a working muscle in the forearm – the brachioradialis, which normally helps bend the elbow – is connected to the tendon of the flexor pollicis longus, the muscle that bends the thumb.
This way, when the patient activates the brachioradialis, the force is redirected to the thumb muscle. With training, the movement pattern can be relearned: instead of just bending the elbow, the patient can now also bend the thumb and pinch objects.
The goal is to restore a more useful pinch grip, so that everyday tasks like holding utensils, picking up small items, or using a phone become easier again.

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Special note:

• After the operation, the patient must learn to use the new movement actively through training.
• These procedures mainly aim to improve daily function, even if the original nerve function does not return.

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Requirements for Surgery

• Accurate diagnostics: Various methods may be used, such as nerve ultrasound, electrophysiological studies, or MR neurography, depending on the individual situation.
• Timing: Some nerves can recover spontaneously, others cannot – the duration of damage is decisive.
• Prior treatment: Conservative methods (physiotherapy, occupational therapy, splints, electrotherapy) should be considered first.
• Individual decision: Benefits and risks must always be carefully weighed with the treating specialist.

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After Surgery

Recovery does not end with the operation – in fact, the real work often begins afterwards.

Physiotherapy and occupational therapy:

These therapies are an essential part of recovery after nerve surgery – regardless of the exact procedure.

• After decompression or neurolysis: Therapy helps the nerve glide freely again, maintains mobility of the joints, and prevents muscles from becoming stiff while the nerve recovers.
• After nerve transpositions: Since the nerve is moved to a more protected or favorable position, therapy supports smooth movement, prevents scar-related adhesions, and maintains function while the nerve recovers.
• After nerve transfers: Training is crucial so that the brain learns to use the new nerve pathway for the new function.
• After nerve grafting: Exercises keep the affected limb flexible during the slow process of nerve regeneration, which can take many months.
• After muscle or tendon transfers: Patients must learn how to activate the muscle in its new role and integrate the movement into everyday life.

In all cases, physiotherapists and occupational therapists support mobility, prevent stiffness, and guide patients step by step in practicing movements until the nervous system adapts.

Follow-up examinations:

Time and patience:

Everyday benefit as main goal:

Even if the original function cannot be fully restored, the aim is to achieve practical improvements that make daily life easier and increase independence.

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Summary

Surgery may be necessary in nerve disorders when conservative treatments are not sufficient. Options range from nerve decompression to complex nerve, muscle, and tendon transfers. The choice of procedure depends on the type of injury, the timing, and the individual circumstances.

It is important to understand that these operations do not usually restore the original condition of the nerve or muscle. Instead, the goal is to relieve pressure, restore continuity, or create new functional connections so that useful movements become possible again.

Aftercare plays a decisive role: physiotherapy and occupational therapy support the training of new functions, while follow-up examinations (such as EMG or ultrasound) help monitor the regeneration process. Nerves grow back very slowly – visible improvements often appear only after many months.

With patience, structured therapy, and realistic expectations, surgery can help improve everyday abilities and increase independence, even if complete recovery is not possible.

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Legal Notice

The procedures described here are provided as general information only. They do not replace medical examination or individual treatment planning. The treating specialist decides whether surgery is appropriate in each individual case.

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Disclaimer: The information provided on this page is for general informational purposes only and does not constitute medical advice. It is not a substitute for personal consultation, examination, or treatment by a physician or other qualified healthcare professional. No guarantees of healing or cure are made. While we strive for accuracy and completeness, we cannot guarantee that all content is up to date or free from errors, and we accept no liability for any inaccuracies.