Carpal Tunnel syndrome refers to entrapment of the median nerve in the carpal tunnel. It is more commonly seen in females in third to fifth decade of the life.Carpal tunnel is a term used to denote a space present near the junction of forearm and hand. It is formed by carpal bones and is covered by a tough structure called as flexor retinaculum. The space contains some tendon and median nerve. If the space in the canal decreases or the content of canal increases, there is pressure over the median nerve leading to different symptoms.
Causes of Carpal tunnel syndrome:
- Idiopathic or no specific cause.
- Colles’s Fracture
- Cushing’s syndrome.
- Rheumatoid arthritis
- Acromegaly, amyloid disease
- Myxoedema,
- Tumors in the space.
- Diabetes Mellitus
- Pregnancy
- Sarcoidosis, SLE
Symptoms
- Aching and parasthesia in thumb , index, middle and 1/2 of ring finger
- worse at night
- forearm pain
- dropping things
- not always classical
Signs: A variety of clinical tests have been described to differentiate the carpal tunnel syndrome from other conditions.
- Hand normal looking
- If severe, thenar wasting, trophic ulcers
- weakness of thumb abduction
- Tinels sign -74% sensitivity, 91 % specificity. Gentle tapping over median nerve at the wrist in a neutral position. Positive if this produces paraesthesia or dysaesthesia in the distribution of the median nerve
- Phalens sign –61% sensitivity, 83% specificity. Elbows on the table allowing the wrists to passively flex. If symptoms provoked within 60 secs then positive
- Median nerve compression test – 86% sensitivity, 95% specificity* Elbow extended, forearm in supination, wrist flexed to 60 degrees, ,even digital pressure applied with one thumb over the carpal tunnel. Test positive if parasthesia or numbness within 30 secs
Differential diagnoses
- Cervical radiculopathy
- Spinal cord lesions - tumour, MS, syrinx
- Peripheral neuropathy- toxic, alcoholic, ureamic, diabetic
Investigations: Doctors would commonly do a Nerve conduction studies to confirm the diagnosis. It is a procedure done to study the rate of transmission of impulse acroos the nerves. In case of significant compression, the speed of the nerve impulse transmission gets delayed.
Management
Conservative- The initial management is usually conservative with doctors prescribing splints to immobilize your wrist joint and local corticosteroid injection. They may also suggest some local measures like limb elevation or wrapping your hand in a warm cloth before going to sleep. Certain medications like B complex vitamin and drugs like gabapentin have laos been shown to be beneficial.
Surgical-
Open Release: Failure of conservative management is an indication for release of transverse carpal ligament which forms the roof of the carpal tunnel.
Endoscopic release which was originally described by Okutso, Chow and Agee has-
- one or two incisions
- less scarring
- less pillar pain
- quicker return of strength and to work
- but anecdotal reports of disasters
- big learning curve
- time consuming, expensive
Possible complications:
- Tender hypertrophic scar pillar pain
- neuroma in palmar branch
- tenosynovitis / tendon adhesions
- bowstringing of tendons