Carpal Tunnel Syndrome
Treatment for compression of the median nerve at the wrist, including conservative care and surgery when necessary
What is carpal tunnel syndrome?
The carpal tunnel is a fixed space at the wrist, floored by the carpal bones and roofed by a strong ligament. Nine tendons and the median nerve pass through it, and there is no room to spare.
Anything that raises the pressure inside squeezes the nerve, since it is the softest structure there. Swelling of the tendon linings from repetitive gripping, fluid retention in pregnancy, an underactive thyroid, diabetes, rheumatoid disease and a previous wrist fracture all do this. In many people no specific cause is found and the tunnel is simply narrow.
The pressure is highest when the wrist is bent right forwards or back, which is the position most people sleep in, so the trouble concentrates at night. Compression that continues for long enough damages the insulating sheath of the nerve first and the fibres themselves later, and the muscle at the base of the thumb that the nerve supplies begins to waste.
What you might notice
- Numbness in the hand that wakes you at night
- Numbness in an area after a cut or a fracture
- A grip that has weakened
- Wrist pain that will not settle
How it is diagnosed
Your doctor maps out exactly which part of the hand is affected, since the median nerve supplies a specific territory and the pattern separates a problem at the wrist from one in the neck.
They tap over the tunnel and hold the wrist bent for a minute to see whether the trouble is reproduced, and press over the tunnel with the thumbs. They then look at the muscle bulk at the base of the thumb, comparing sides, and test its power, because wasting there is the finding that hurries a decision.
Nerve conduction studies measure how fast the signal crosses the wrist and grade the severity. They also confirm the level of the problem where the neck could be responsible. Blood tests for thyroid function and diabetes are checked when the cause is unclear.
Recovery
The wound in the palm is tender to pressure for a few weeks, and pressing through the heel of the hand, on a chair arm or a steering wheel, is uncomfortable for longer than the wound itself takes to heal.
Night-time symptoms usually go within days. Numbness that has been constant for a long time recovers more slowly, from the base of the fingers outwards, and can take a year, since nerve fibres regrow at about a millimetre a day. Some numbness may be permanent if the compression was severe and prolonged.
You use the hand for light activities immediately and stitches come out at around two weeks. Grip strength dips at first and returns over six to twelve weeks, sooner for desk work than for heavy manual work.
If it is left untreated
Mild intermittent compression can be watched. It often improves with a night splint and a change in how the hand is used, and the version that comes on in pregnancy usually resolves after delivery, so waiting is sensible there.
Sustained compression is different. The nerve fibres die back progressively, the muscle at the base of the thumb wastes, and pinching the thumb against the fingers becomes weak. Once that muscle has wasted, releasing the nerve stops further loss but the bulk and the fine grip may not return. The signs that the nerve is losing ground are the reason not to wait indefinitely.
Questions about carpal tunnel syndrome
Will a splint or an injection fix it?
A splint worn at night keeps the wrist straight while you sleep, which is when the pressure inside the tunnel is highest, and it settles mild cases well. A steroid injection into the tunnel gives relief that lasts months in most people and predicts a good result from surgery if it wears off. Neither reverses compression that has gone on long enough to damage the nerve fibres, and severe compression is treated by making room.
Open or endoscopic release, does it matter?
Both divide the same ligament and both relieve the nerve equally well in the long run. The endoscopic route leaves the palm skin intact, so tenderness in the heel of the hand settles a few weeks sooner and grip comes back faster, which matters for manual work or when both hands are being done. The open route gives a direct view of the nerve and is preferred where the anatomy may be unusual or there has been previous surgery.
Will the numbness definitely go?
Night-time waking and intermittent tingling usually go within days of the pressure being relieved. Numbness that has been constant for a year or more recovers slowly, over six to twelve months, as the nerve fibres regrow, and it may not come back completely. Wasting of the muscle at the base of the thumb often does not reverse. That is the reason your surgeon takes those particular findings seriously when timing the decision.
Other orthopaedics treatments
Replacement of a damaged knee joint to relieve persistent pain and improve mobility when conservative treatment is no longer enough
InpatientAssessment and treatment of ACL injuries, with rehabilitation or reconstruction considered based on activity and instability
InpatientTalk to a care coordinator about carpal tunnel syndrome
Leave a number and a care coordinator calls you back with what the treatment involves and which hospital it would be at. They book a consult only if you want one