Ultrasound in Carpal Tunnel Syndrome
- Έρση Καραχαλιά
- Aug 25
- 3 min read
What is Carpal Tunnel Syndrome
Carpal Tunnel Syndrome (CTS) is the most common entrapment neuropathy of the upper limb, affecting approximately 5% of the general population. It occurs more frequently in women and mainly affects individuals aged 40–60. The carpal tunnel is a narrow anatomical space at the wrist through which the median nerve passes along with tendons and blood vessels, surrounded by bones and ligaments. When the median nerve is compressed within this narrow canal, it becomes inflamed and gradually degenerates.
Causes and Risk Factors
The exact cause of nerve compression is less commonly identified and, when present, usually relates to an injury in the area. More often, it is attributed to a combination of predisposing factors along with repeated wrist extension and flexion movements. Conditions and circumstances that increase the likelihood of developing CTS include:
Wrist arthritis
Diabetes mellitus
Hypothyroidism
Obesity
Pregnancy and postpartum period
Chronic kidney disease
Additionally, manual labor or hobbies that involve intense wrist use increase the risk of CTS.
Symptoms
In the early stages, patients typically experience:
Numbness, burning, or pain in the hand, primarily in the first three fingers
Symptoms that are often worse at night but improve with movement
As the condition progresses:
Symptoms may occur with hand fatigue and eventually become persistent
Weakness in performing everyday hand movements
Muscle atrophy
CTS can significantly impact daily life, especially in younger individuals or those who work extensively with their hands or at a computer.
Diagnosis
Traditionally, diagnosis is based on medical history, clinical examination, and primarily neurophysiological tests such as electromyography (EMG). EMG is highly specific and sensitive for diagnosing neuropathies, but is expensive, often uncomfortable for patients, and not immediately available since it is performed in a laboratory by a specialized physician.
In recent years, ultrasound has emerged as a particularly useful and complementary tool for both diagnosis and monitoring of disease progression.
The Role of Ultrasound
Ultrasound is a simple, painless, quick, and cost-effective examination without radiation exposure. It allows the physician to visualize the anatomy of the carpal tunnel in real time.
With ultrasound, it is possible to evaluate:
Thickness, morphology, and echogenicity of the median nerve: In CTS patients, the nerve is usually swollen with reduced echogenicity, parameters that can be measured precisely. Anatomical variations, such as a bifid median nerve, can also be detected, which may predispose to degeneration.
Anatomy of surrounding structures: Ultrasound visualizes tendons, the transverse ligament, and any abnormalities (e.g., cysts, osteophytes, tumors) that may compress the nerve.
Nerve vascularization and dynamics: In some cases, increased blood flow or reduced nerve mobility during wrist flexion-extension can be observed, or the artery may course through the nerve, predisposing to compression.
Therapeutic guidance: Ultrasound can guide corticosteroid injections safely and effectively.
Evaluation of previous interventions: By comparing parameters before and after a procedure, residual compression or scar tissue formation can be identified.
Ultrasound not only assesses nerve function like EMG but also reveals the nerve’s anatomical structure and surrounding tissues in real time. Its value lies in three key aspects:
Immediate diagnosis: Provides quick insight into whether the nerve is swollen or hypoechoic and if there is any anatomical cause of compression.
Non-invasive nature: Painless, without radiation exposure, and well tolerated, unlike EMG, which can often cause discomfort.
Complementary value: Does not replace EMG, which provides specific functional information, but enhances it, giving a more complete picture.
Studies have shown that combining EMG and ultrasound increases diagnostic accuracy and helps optimize treatment planning.
Benefits of Early Diagnosis
For the patient, ultrasound translates into faster diagnosis, less discomfort, and better treatment planning. It does not replace traditional neurophysiological testing but complements it. Together, these tests provide a comprehensive view of both the function and anatomy of the median nerve.
Carpal Tunnel Syndrome can significantly affect quality of life, but with early diagnosis and appropriate therapeutic strategy, outcomes are excellent. Ultrasound is a modern, reliable, and patient-friendly tool that adds significant value to neurological practice.
