Assessing Nerve Injuries, Part 1

In my years of clinical practice and teaching, I’ve found that some of the most perplexing cases massage therapists encounter involve persistent nervous system pain problems. While many practitioners feel confident addressing typical musculoskeletal complaints, nerve-related conditions often present unique challenges that require a deeper understanding of neuroanatomy, pathophysiology, and appropriate treatment approaches.

Here we focus on assessment and evaluation; in the next installment, we’ll delve into treatment approaches for addressing these complex conditions. Assessing nerve injuries is critical for developing an effective treatment plan because it helps identify the specific type and location of the injury, allowing for targeted interventions. A thorough assessment also ensures that contraindications are recognized and appropriate referrals are made when necessary, preventing further complications.

Understanding nerve injuries and their healing processes is crucial for massage therapists who work with clients experiencing neuropathic pain (pain in the nervous system).

The Foundation: Nerve Structure and Function

Before discussing nerve injuries, let’s do a quick refresh on nerve tissue structure and function. Nerves are not just simple conducting wires but complex organs composed of numerous specialized tissues working together. The basic functional unit is called the axon, a long cellular extension that conducts electrical signals. These can be surprisingly long—a single sciatic nerve axon extends from the spinal cord all the way to the toes. Many axons are wrapped in myelin sheaths that increase signal transmission speed, while unmyelinated axons conduct signals more slowly.

Multiple axons bundle together in groups called fascicles, surrounded by three distinct connective tissue layers: the endoneurium surrounding individual nerve fibers, the perineurium encasing fascicles, and the epineurium forming the outer nerve sheath (Image 1). This hierarchical organization is crucial for understanding injury mechanisms and healing processes, as damage to different layers results in distinct types of injuries.

Exploring Nerve Injury

Nerve injuries fall along a spectrum of severity with three main classifications that help us understand both prognosis and appropriate treatment approaches. The mildest form, neuropraxia, represents a temporary nerve conduction functional block without structural damage to the axon itself.

Common examples of neuropraxia include Saturday night palsy, a condition where someone wakes up with arm numbness after falling asleep with their arm draped over a chair (compressing the radial nerve). A similar example would be a carpenter experiencing hand tingling after working overhead (compressing the ulnar nerve). These symptoms typically resolve within hours to days once compression is removed, though repeated episodes can lead to chronic issues.

Axonotmesis represents the next level of severity, involving structural damage to the axon while preserving the surrounding connective tissue framework. This impairment occurs in crush or severe compression injuries and, in some cases, acute muscle strain. Recovery typically takes several months as the axon regenerates along its original path, guided by the intact connective tissue sheaths.

The most severe form, neurotmesis, involves complete nerve transection. While massage therapists don’t directly treat acute neurotmesis, we may work with clients during post-injury rehabilitation. Understanding this condition allows us to recognize healing complications and work effectively with other health-care professionals in postoperative care.

Time Factor: Acute vs. Chronic Injuries

The duration of nerve dysfunction profoundly influences both the treatment approach and prognosis. Acute nerve injuries, like brachial plexus compression from a seat belt in a car accident, often present with dramatic symptoms—immediate numbness, pain, and weakness. However, with prompt therapeutic intervention, including massage therapy, these symptoms often resolve completely over weeks to months.

Chronic nerve injuries present differently, as seen in a dental hygienist who develops gradual hand numbness and weakness over the years due to occupational positions. These cases often involve compression at multiple sites, requiring a comprehensive treatment approach that investigates various potential injury locations in the upper extremity.

Factors seemingly unrelated to mechanical compression, such as stress, poor nutrition, and consumption of alcohol or caffeine, can aggravate chronic nerve conditions. Successful treatment must address both the mechanical nerve irritation and necessary lifestyle modifications.

A particularly challenging aspect of nerve injury is nociplastic pain—pain arising from altered pain processing despite no clear evidence of tissue damage. Individuals with nociplastic pain can be dismissed by health-care professionals who may attribute the condition to psychosomatic symptoms if the diagnostic tests are unrevealing (or poorly read). These untreated clients typically experience widespread hypersensitivity to both painful and nonpainful stimuli, with pain often spreading beyond the original site.

Nerve Compression vs. Tension Stress

Nerve injuries typically result from either compression or tension forces. The symptoms of compression and tension injuries can be identical, but the treatment approach differs. Let’s look at compression injuries in greater detail.

Compression injuries depend on two critical factors: the amount of compression force applied and the duration of that compression. This relationship explains why brief but intense compression might cause less damage than moderate compression maintained over a long period. We commonly see this principle in conditions like carpal tunnel syndrome, where the median nerve is compressed at the wrist (Image 2). Compressive forces are not high, but they are applied over a period of time. The gradual onset of symptoms also results in prolonged healing.

Clinical signs of compression injuries often include nocturnal symptoms that wake the client, positional aggravation, and gradual progression of symptoms over time, with numbness and tingling that follows specific nerve distributions.

The most common nerve compression signs and symptoms include:

• Burning sensation—Some individuals may feel burning or heat sensations

• Loss of coordination—In severe cases, clients experience difficulty with coordination

• Numbness and tingling—Pins and needles sensations or a feeling of the limb falling asleep

• Pain—Manifests as dull, aching pain in the affected area or as sharp, radiating pain like sciatica

• Problems with positional awareness—Trouble sensing their position in space

• Radiating symptoms—Pain, numbness, or tingling may radiate into an arm or leg, depending on the location of the compressed nerve

• Sensitivity—Increased sensitivity to touch or pressure in the compressed nerve region

• Weakness—Muscle weakness is common, especially in the arms or legs

Nerve tension injuries occur when nerves experience excessive elongation or traction (Image 3). The symptoms of nerve tension injury can be identical to those for nerve compression injuries. Neural tension injuries often manifest acutely, as in sports injuries, where a nerve gets suddenly overstretched.

Anatomical variations can also increase nerve tension susceptibility. A typical example is the presence of a cervical rib in the neck, which is a bony extension of the transverse process of the C7 vertebra and usually has a fibrous attachment to the first rib. When present, the brachial plexus courses over the top of the cervical rib, causing traction injuries to the brachial plexus (a form of thoracic outlet syndrome).

Sensitization Process: Peripheral to Central

When nerve tissue is injured, a complex cascade of changes begins both locally and systemically. Local tissue injury initiates peripheral sensitization—a process where nerve endings become more sensitive to stimuli, their activation thresholds lower, and they begin releasing inflammatory chemicals. While these changes initially serve protective functions, they can become problematic when they persist beyond the typical healing time frame.

Several key signs and symptoms characterize peripheral sensitization:

• Heat sensitivity—Pain typically worsens with heat application

• Hyperalgesia—Increased sensitivity at or close to the site of tissue damage

• Inflammatory signs—Redness and swelling may be present in the affected area

• Localized pain—Often confined to a discrete area of tissue damage

• Nocturnal pain—Often present or more noticeable at night

• Normal movements become painful—Previously painless activities may cause discomfort

• Pain quality—Often described as burning, deep, or achy

• Reduced pain threshold—Might be decreased at the injury site

In cases of peripheral sensitization, these symptoms and signs are typically confined to the tissue involvement or nerve distribution area.

Acute nerve injuries often present with dramatic symptoms. However, with prompt therapeutic intervention, including massage therapy, these symptoms often resolve completely. 

In central sensitization, more expansive body areas are affected, representing an even more complex phenomenon involving changes in the central nervous system. The brain and spinal cord begin processing pain signals differently, leading to expanded receptive fields and reduced pain thresholds. Clients may experience enhanced pain responses, develop mirror symptoms in unaffected areas, and notice significant emotional and cognitive impacts on their pain perception. Understanding these sensitization processes helps explain why some clients continue experiencing pain long after apparent tissue healing.

Several key symptoms and indicators characterize central sensitization:

• Allodynia—Pain caused by ordinarily nonpainful stimuli, such as light touch or clothing

• Disproportionate pain—Pain more intense than expected with the nature and extent of injury or pathology

• Cognitive difficulties—Poor concentration, memory problems, and brain fog

• Fatigue—Frequent reports of fatigue and unrefreshing sleep

• Heightened sensitivity to various stimuli—Includes light, sound, smell, and touch

• Hyperalgesia—Increased sensitivity to painful stimuli

• Mood changes—Anxiety and depression are frequently involved

• Temporal summation of pain—Increased pain perception with repeated stimulation or exposure

• Widespread pain—Pain that is diffuse, less defined, and often affects multiple body regions

Peripheral sensitization also frequently occurs before and, if not appropriately treated, can lead to central sensitization. Peripheral and central sensitization can co-occur, so it is essential to watch for these differences.

Treatment

Massage treatment for nerve injuries employs two main approaches: addressing mechanical causes of nerve irritation and using manual therapies to treat injuries, impingement, and peripheral and/or central sensitization. Mechanical approaches focus on the specific forces causing nerve compression or tension. For compression injuries, treatments aim to reduce compressive forces on the nerve by working on adjacent soft tissues, while avoiding direct pressure on the nerve. Neural tension injuries require improving nerve mobility through neural mobilization techniques, which are most effective after treating surrounding tissues (Image 4).

The second installment of this series will delve into various aspects of nerve injury treatment, offering insights and techniques most effective in managing nerve impairments and optimizing recovery.