Steroid injection vs surgery for carpal tunnel syndrome

Carpal tunnel syndrome occurs when the median nerve is compressed as it passes through the narrow tunnel at the wrist. The typical symptoms are tingling, numbness and pain in the thumb, index and middle fingers, often worse at night, with weakness or clumsiness in more advanced cases.

Treatment options therefore aim either to reduce swelling and pressure temporarily, as with splints and steroid injection, or to enlarge the tunnel permanently, as with surgery.

A small amount of corticosteroid and local anaesthetic is injected into or near the tunnel, usually in a clinic. The medicine reduces swelling around the nerve. Many people notice improvement over a few days, with night symptoms often settling first. For some, the improvement lasts months; for others, symptoms return sooner.

Possible effects include temporary soreness, a flare in pain, skin lightening at the injection site and, rarely, infection or injury to the nerve. A good response also supports the diagnosis, though a poor response does not exclude it. Repeat injections are limited because the benefit tends to reduce and steroids can affect tendons.

Under local anaesthetic, usually as a day case, the surgeon divides the transverse carpal ligament, which forms the roof of the tunnel, through an open or keyhole (endoscopic) approach. Night-time symptoms often improve rapidly, while numbness and weakness can take longer to recover and may not recover fully if the nerve has been compressed for a long time.

Risks include scar tenderness, stiffness, infection, nerve injury and, in a small number of cases, persistent or recurrent symptoms. Return to light activity is usually quick, with heavier use of the hand restricted for a few weeks.

Primary care guidance generally starts with a night splint for mild to moderate symptoms and considers a corticosteroid injection when splinting is not enough or when quicker relief is wanted. Referral for surgery is considered for severe symptoms, thumb muscle wasting or weakness, or when conservative treatment has not worked, with nerve conduction studies sometimes used to confirm the diagnosis and severity.

The decision weighs the likelihood that the injection will give a lasting result against the risk of continuing nerve compression, since delaying surgery in severe cases can lead to permanent damage.

• Occasional tingling, mostly at night, for a short time: try a night splint and ask a clinician about an injection if symptoms persist.

• Symptoms in pregnancy: splint and expect improvement after birth; discuss options with your midwife or GP.

• Constant numbness, weak grip, dropping objects, or thin thumb muscle: ask for specialist review, as surgery is likely to be advised.

• Injection helped for a few months and symptoms are returning: discuss surgery rather than repeating injections indefinitely.

• Other conditions such as diabetes or thyroid disease: treating them can also help symptoms.

Carpal tunnel syndrome is not always caused by typing; many causes contribute, including pregnancy, diabetes and inherited factors. Surgery is also not a last resort only for desperate cases; it is a sound option for persistent symptoms. And an injection is not a permanent cure for most.

Another misconception is that delaying surgery has no downside. Prolonged compression can cause lasting numbness and weakness.