A neuroma is a disorganized, tangled growth of nerve tissue that forms after a nerve has been damaged; it is not a cancerous tumor. This condition develops when the body attempts to repair a nerve injury, resulting in a clump of regenerating nerve fibers that fail to reconnect properly with the nerve’s far end. Neuromas are a frequent source of chronic, severe pain in the hand and upper extremity, often following a deep cut, crush injury, or surgical procedure. The tissue growth itself is rarely visible from the skin’s surface.
Anatomy and Types of Hand Neuromas
The formation of a neuroma occurs when a peripheral nerve is severed or severely injured. Inside a healthy nerve, axons—the long, slender projections that transmit electrical signals—are neatly bundled within a protective nerve sheath made of connective tissue. When this structure is disrupted, the proximal nerve end attempts to sprout new axons to bridge the gap and find its target.
When regenerating axons are impeded from re-entering the distal segment, they grow in a chaotic, disorganized manner, mixing with scar tissue and connective cells to form a mass called a traumatic neuroma. A common form is the stump or amputation neuroma, which forms at the end of a nerve following the surgical removal of a finger or part of the hand.
Another classification is the neuroma-in-continuity, where the nerve remains physically intact but the internal structure is damaged, resulting in a focal swelling or thickening along the nerve’s path. The presence of this tangled mass, which contains sensitive nerve endings, leads to the chronic pain that patients experience.
Recognizing the Pain and Sensory Changes
The discomfort associated with a hand neuroma is characterized by a distinctive and intense quality of neuropathic pain. Patients often describe an electric shock sensation that shoots through the hand or finger, or a deep, relentless burning feeling. This sensation is frequently triggered by direct pressure or contact over the site of the neuroma itself.
The hyper-sensitivity can manifest as allodynia, which is pain experienced from a stimulus that should not normally be painful, such as the light touch of clothing. Another common symptom is hyperalgesia, where a mildly painful stimulus produces a disproportionately severe pain response.
Neuromas are commonly found along the digital nerves in the fingers, often after fingertip injuries or amputations. They can also occur following surgeries in the wrist, such as carpal tunnel release, if a small sensory branch is accidentally damaged. The specific location of the pain often directly corresponds to the path of the injured nerve, allowing doctors to narrow down the source of the problem. The pain signals from this damaged nerve tissue can sometimes lead to a more generalized pain condition in the limb.
How Doctors Visualize the Condition
Neuromas are typically not visible as a distinct lump on the surface of the skin, though a small, tender mass may occasionally be felt, especially in the fingers. Doctors rely on a physical examination paired with specialized imaging to confirm the diagnosis and pinpoint the neuroma’s precise location and size. A traditional physical examination often involves the Tinel’s sign test, where the physician gently taps over the suspected nerve path, eliciting a tingling or electric shock sensation that radiates into the hand or fingers.
For internal visualization, high-resolution ultrasound is frequently the first-line diagnostic tool because it is non-invasive and cost-effective. The ultrasound can show the neuroma as a focal, hypoechoic swelling along the nerve, sometimes appearing as a bulbous mass at the nerve end. This imaging technique also allows for a “sono-Tinel sign,” where the ultrasound probe is used to compress the neuroma, directly reproducing the patient’s pain to confirm the lesion’s identity.
Magnetic Resonance Imaging (MRI) is another common method used for a more detailed view, particularly for larger or deeper neuromas. The MRI can clearly show the characteristic fusiform swelling of a nerve or a bulbous mass at a nerve ending.
Options for Managing and Treating Neuromas
Managing a neuroma begins with conservative approaches aimed at reducing the nerve’s irritation and sensitivity. Non-surgical options include physical therapy, which may involve nerve desensitization techniques and scar massage to improve tissue mobility. Medications, such as certain anti-seizure or antidepressant drugs, are often prescribed to help modulate the nerve pain signals.
Diagnostic nerve blocks, involving local anesthetic injected near the neuroma, can provide temporary relief and confirm the exact nerve causing the pain. Therapeutic injections, often containing a steroid, may also be used to reduce inflammation and symptoms. If conservative measures fail to provide adequate relief, surgical intervention becomes the next step.
The goal of surgery is to excise the painful neuroma tissue, a procedure called neurectomy, and manage the remaining nerve end to prevent recurrence. Advanced techniques include implanting the nerve stump into a nearby muscle or bone (transposition) or placing a protective nerve cap over the nerve end. For a small gap, the surgeon may perform a nerve repair using a nerve graft to bridge the defect.