Carpal Tunnel Syndrome
Carpal tunnel syndrome is the most common entrapment neuropathy, resulting from compression of the median nerve within the carpal tunnel at the wrist and causing numbness, tingling and pain in the thumb, index, middle and half of the ring finger. Treatment is graded by severity: conservative methods such as splinting and injection in mild cases, and carpal tunnel release surgery in resistant or advanced cases.
Última actualización: 2026-06-07
Definition
Carpal tunnel syndrome is the most common entrapment neuropathy and develops when the median nerve is compressed within the carpal tunnel on the palm side of the wrist. The carpal tunnel is a narrow channel formed by the wrist bones and the transverse carpal ligament (flexor retinaculum); the median nerve and the flexor tendons that bend the fingers pass through it. Increased pressure within the tunnel compresses the median nerve and produces the characteristic symptoms.
Causes and Risk Factors
A substantial proportion of cases develop without an obvious cause (idiopathic). Known risk factors include female sex (more commonly affected), the 40-60 age range, repetitive and forceful wrist movements, certain systemic diseases (diabetes, hypothyroidism, rheumatoid arthritis, amyloidosis), pregnancy (a form related to hormones and fluid retention that usually resolves after delivery), obesity and wrist trauma (for example a distal radius fracture). Masses within the carpal tunnel (ganglion cyst, lipoma) and anatomical variations such as a narrow tunnel can also be responsible.
Symptoms
Early on there is numbness and tingling in the thumb, index, middle and the median-supplied half of the ring finger. Symptoms typically worsen at night, may wake the patient from sleep and can be relieved temporarily by shaking the hand (the flick sign). Pain may radiate from the wrist to the forearm and sometimes the shoulder. As the condition progresses there may be constant numbness, reduced grip strength (difficulty opening jar lids), impaired fine motor skills and dropping objects. In advanced disease, wasting of the muscles at the base of the thumb (thenar atrophy) may develop. Symptoms are often bilateral.
Diagnosis
Diagnosis is based primarily on the clinical history and examination. Examination uses the Phalen test (provoking symptoms by holding the wrist flexed), the Tinel sign (tingling in the median nerve distribution on percussion over the carpal tunnel) and the Durkan (carpal compression) test; in advanced disease, thenar atrophy and weakness of thumb abduction may be found. Electromyography (EMG) and nerve conduction studies are the main tests used to confirm the diagnosis, grade the severity (mild, moderate, severe) and assist with the differential diagnosis. Ultrasound can assess the thickness of the median nerve. The differential diagnosis should include cervical radiculopathy (C6), pronator syndrome and de Quervain's tenosynovitis.
Medical (Conservative) Treatment
Conservative treatment is the first choice in mild-to-moderate cases with short-duration symptoms. A splint that holds the wrist in a neutral position (particularly worn at night) can reduce symptoms. A corticosteroid injection into the carpal tunnel provides several months of relief in many patients. Non-steroidal anti-inflammatory drugs (NSAIDs) and nerve-gliding exercises can be supportive. Pregnancy-related cases often resolve spontaneously after delivery. If conservative treatment is tried for a period without response, or if the condition is moderate-to-advanced, surgery comes into consideration.
Surgical Treatment: Carpal Tunnel Release
Carpal tunnel release surgery is performed in cases that do not respond to conservative treatment or are at a moderate-to-advanced stage. In the procedure the transverse carpal ligament (flexor retinaculum) is divided to enlarge the carpal tunnel and relieve the pressure on the median nerve. There are two main techniques: in open surgery the ligament is divided under direct vision through a small incision in the palm; in endoscopic surgery the division is performed with the guidance of a camera inserted through a smaller incision, and recovery can be faster. The procedure can often be performed under local anaesthesia as a day case. Surgery markedly reduces or eliminates symptoms in most patients; however, if thenar atrophy has developed in advanced disease, strength may not fully return. Possible side effects include temporary palm pain, scar tenderness and, rarely, nerve or vessel injury.
Prognosis and Recovery
Recovery after carpal tunnel release surgery is usually gradual; numbness and tingling decrease quickly in most patients, but in advanced cases nerve recovery may take months. Use of the hand begins early, while heavy lifting and strenuous activities are restricted for a time. Early intervention gives better results before permanent nerve damage and muscle wasting develop. Recurrence after surgery is rare. Ergonomic adjustments, control of risk factors and the use of a splint when needed help to prevent recurrence. Outcomes vary from person to person and cannot be guaranteed in advance.
Referencias
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:546-552.
- Winn HR, ed. Youmans Neurological Surgery. 6th ed. Saunders; 2011:2427-2439.
- American Academy of Orthopaedic Surgeons. Management of Carpal Tunnel Syndrome Evidence-Based Clinical Practice Guideline. AAOS; 2016.
- Padua L, Coraci D, Erra C, et al. Carpal tunnel syndrome: clinical features, diagnosis, and management. Lancet Neurol. 2016;15(12):1273-1284.
Este artículo es informativo y no sustituye un examen médico. Las decisiones de diagnóstico y tratamiento son individuales.