The carpal tunnel is a narrow canal in the wrist through which the median nerve passes. When it is compressed, tingling and numbness appear and, as it progresses, loss of strength in the hand.
The symptom that brings almost every patient in is the same: tingling in the hand that wakes them at night, above all in the thumb, index and middle fingers, forcing them to shake the hand or hang it out of the bed for relief. In time comes clumsiness with fine tasks — doing up a button, holding a cup, writing — and objects dropping from the hand unintentionally. It is one of the most frequent consultations in hand surgery, and also one of the latest to arrive.
The surgery is straightforward: the ligament forming the roof of the tunnel is opened and the nerve stops being compressed. It takes less than half an hour, it is a day case and it is done under local anaesthesia. What is not straightforward is recovering the nerve when it has been compressed for too long. With prolonged compression, wasting of the muscle at the base of the thumb appears, and at that point the operation stops the progression and relieves the pain, but strength and sensation no longer come back completely. Hence the insistence on coming early.
It usually helps when there is
- Tingling or numbness at night in the thumb, index and middle fingers.
- Needing to shake the hand to relieve the symptoms.
- Clumsiness with fine tasks or objects dropping from the hand.
- Symptoms persisting despite a night splint and changes of activity.
- A nerve conduction study confirming the compression.
Worth discussing first if
- Mild, intermittent symptoms, which may respond to conservative treatment.
- Pregnancy, where the problem usually resolves after the birth.
- Uncontrolled hypothyroidism, diabetes or rheumatoid arthritis, which make it worse.
- Atypical symptoms, which may be due to compression in the neck.
- Expecting full recovery when wasting is already established.
None of these rules the procedure out on its own; all of them change the conversation.
Before and during surgery
Not every case needs surgery from the outset.
Conservative treatment
A night splint keeping the wrist neutral, adjustment of activities and control of the associated conditions. It is the first step in mild cases.
Injection
Corticosteroid inside the tunnel. It relieves temporarily and has diagnostic value, but it does not resolve the underlying problem.
Surgical release
Division of the ligament compressing the nerve, through an open approach with a short incision. It is the definitive treatment and highly effective.
Operate before the wasting
The decision depends not only on how much it bothers you but on what stage the nerve is at. While the symptoms are intermittent and nocturnal, the nerve is irritated but intact, and release restores function almost completely. When the numbness is constant and wasting appears at the base of the thumb, there is already structural damage: surgery halts the progression and relieves the pain, but recovery is partial. That is why putting it off is not advised.
The technique aims for a complete release of the ligament through the shortest incision possible. What defines success is not the size of the wound but that the division is complete: an incomplete release leaves symptoms and means reoperating, which is the most frequent cause of failure.
The nerve branches in the area are protected, in particular the one supplying sensation to the palm, injury to which produces a painful, persistent scar. And the hand is mobilised from the first day: the wrist is not immobilised, because that only produces stiffness.
What the process is like
It is one of the simplest procedures in the catalogue.
Consultation
Examination of sensation, strength and the specific manoeuvres, and assessment of wasting at the thumb. Other causes are ruled out.
Investigation
Electromyography and nerve conduction study, which confirm the diagnosis and its severity. They are the basis of the indication.
Surgery
As a day case, under local anaesthesia and in under half an hour. You walk out with your hand free, with no splint.
Follow-up
Stitches out at ten to twelve days. Movement from the first day and reviews at one month and three months.
Week by week
Relief at night is usually the first thing and it comes quickly.
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Days 1 to 7
The night-time tingling disappears in the first days in most cases. Discomfort at the scar. The fingers are moved from the first day.
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Weeks 2 to 4
Stitches out. Gradual use of the hand for everyday activities. No lifting and no leaning on the palm.
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Weeks 6 to 12
Grip strength recovers. The discomfort on pressing the base of the palm — frequent and temporary — gradually settles.
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Months 3 to 12
Sensation recovers gradually, and it can continue for months if the compression was long-standing.
Risks, and what is not promised
Those of any minor surgery — infection, haematoma — and the specific ones: discomfort on pressing the base of the palm for weeks or months, which is frequent and almost always temporary; a tender scar; an incomplete release that leaves symptoms and means reoperating; injury to a sensory nerve branch, infrequent but bothersome; and, exceptionally, complex regional pain syndrome.
When the compression was long-standing, recovery of sensation is slow and may remain incomplete. If there was already wasting of the muscle at the base of the thumb, pinch strength does not fully recover: surgery halts the damage, it does not reverse it.
It is not promised that the hand will be as it was before the symptoms started if you come late. What is promised, in the great majority of cases operated in time, is that the night-time tingling disappears and that the nerve stops being damaged. These risks are reduced by a timely indication and a complete release. They are not eliminated. The ones that apply to your case are set down in writing in the informed consent.
The information on this page is for guidance and does not replace an in-person medical consultation. Medical practice is an obligation of means, not of result.
The questions we are asked most about carpal tunnel
In mild, recent cases, yes: a night splint keeping the wrist straight, adjusting the activities that provoke it and controlling associated conditions such as hypothyroidism or diabetes.
If the symptoms persist despite that, or if there is already constant numbness or loss of strength, conservative treatment is not going to resolve it.
Sustained compression damages the nerve progressively. First the tingling becomes constant, then loss of sensation appears and finally wasting of the muscle at the base of the thumb.
At that stage surgery halts the progression and relieves the pain, but strength and sensation no longer come back fully. That is why putting it off is discouraged.
The night-time tingling, usually the most bothersome part, disappears in the first days in most cases. It is the most immediate relief this surgery gives.
Recovery of sensation in the fingers is slower and can take months if the compression was long-standing.
Office work, between one and two weeks. Work demanding grip strength or the use of tools, between four and eight weeks.
What limits you most during that period is the discomfort on pressing the base of the palm, which is normal, does not indicate a problem and settles over the weeks.
Question not answered here? There are more answers in the frequently asked questions.
