Definition and Overview
Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment syndrome caused by compression of the median nerve that passes through the carpal tunnel in the wrist.
The carpal tunnel is a narrow tunnel at the front of the wrist, surrounded by the wrist bones and the flexor retinaculum, through which the median nerve and nine flexor tendons pass. When this space narrows or its contents increase, the median nerve is compressed.
The adult prevalence rate is approximately 3.8%, and it occurs approximately three times more frequently in women than in men. It is most commonly diagnosed in middle-aged women.
Causes and Pathophysiology
As pressure within the carpal tunnel increases, blood flow to the median nerve decreases, and continued pressure causes demyelination of the nerve and axonal damage. The causes of increased pressure within the carpal tunnel are as follows:
- Repetitive hand movements and use of vibrating tools (occupational exposure)
- Anatomical abnormalities of the wrist
- Systemic diseases: diabetes, hypothyroidism, rheumatoid arthritis, obesity, renal failure (dialysis patients)
- Pregnancy (edema due to fluid retention)
- Trauma: Deformity after wrist fracture
symptoms
Typical symptoms are numbness, paresthesia, and pain in the area innervated by the median nerve (thumb, index finger, middle finger, and radial half of the ring finger).
- Numbness at night: The most characteristic symptom is waking up with numbness in your hands during sleep, and it temporarily improves when you shake your hands or lower them vertically.
- Tinel's sign: Numbness appears when tapping the area where the median nerve runs in the wrist.
- Phalen's test: Numbness occurs when the wrist is held in maximum flexion for 60 seconds.
- In advanced cases: weakness and atrophy of the thenar eminence, impaired fine hand movements.
diagnosis
Nerve conduction study (NCS) is the standard diagnostic test for carpal tunnel syndrome. It is diagnosed by prolonged distal motor latency of the median nerve and decreased sensory nerve conduction velocity.
Clinically, typical symptoms and positive provocative test findings strongly suggest the diagnosis, but nerve conduction testing is used to assess severity and establish a treatment plan. Ultrasound examination is useful as an auxiliary diagnosis to confirm an increase in the cross-sectional area of the median nerve.
treatment
conservative treatment
In mild to moderate cases, conservative treatment is attempted first.
- Night wrist splint: Fixes the wrist in a neutral position to reduce pressure within the carpal tunnel. Effective in alleviating symptoms.
- Local steroid injection: Corticosteroid injection into the carpal tunnel is effective in relieving symptoms in the short term.
- Activity correction: limiting provocative movements, improving work environment
- Oral medications: NSAIDs (non-steroidal anti-inflammatory drugs), neuropathic pain medications are used as supplements.
surgical treatment
Surgical decompression is recommended if the patient does not respond to conservative treatment, has severe symptoms, or has muscle atrophy. Carpal tunnel release involves cutting the transverse carpal ligament to decompress the median nerve. Improvement of symptoms is reported in approximately 75-90% of patients after surgery.
Both open and endoscopic methods are performed, and the recovery period is somewhat shorter for the endoscopic method.
prognosis
The earlier treatment is started, the better the prognosis. If axonal loss is found on a nerve conduction test or if atrophy of the thumb muscle has progressed, it may take longer to fully recover after surgery. In diabetic patients, surgical results may be relatively poor.
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This information is provided for medical educational purposes and is not a substitute for individual medical care or treatment. If you have any symptoms, be sure to seek professional advice. Inquiries: Osang Neurosurgery 1599-5453 | osns.co.kr