Carpal Tunnel Syndrome (CTS) is a common condition resulting from the compression of the median nerve as it passes through the narrow passageway in the wrist called the carpal tunnel. This nerve compression typically causes symptoms like pain, numbness, and tingling in the hand and fingers, often worsening at night. When conservative treatments such as wrist splinting or oral anti-inflammatories do not provide adequate relief, a targeted injection becomes a frequently recommended, non-surgical treatment option for managing these uncomfortable symptoms.
The Purpose and Composition of the Injection
The primary goal of a carpal tunnel injection is to deliver a potent anti-inflammatory medication directly to the site of nerve compression. This targeted approach is designed to reduce the pressure being exerted on the median nerve within the confined space of the carpal tunnel. The injection typically consists of a corticosteroid, such as triamcinolone or dexamethasone, combined with a local anesthetic like lidocaine or bupivacaine.
The corticosteroid serves as a powerful anti-inflammatory agent that works to decrease swelling in the surrounding tissues, especially the synovium and flexor tendons. By reducing this inflammation, the medication attempts to increase the available space for the median nerve, thereby relieving the pressure that causes the characteristic symptoms. The local anesthetic provides almost immediate, though temporary, pain relief and helps confirm correct needle placement.
The Injection Procedure and Immediate Aftercare
The carpal tunnel injection procedure is typically a quick, outpatient process that takes around 15 minutes. The patient is usually positioned with the palm facing up so the physician can access the injection site on the wrist. The skin over the wrist is thoroughly cleaned with an antiseptic solution to minimize the risk of infection.
A local anesthetic may be administered first to numb the skin and minimize discomfort. The use of ultrasound guidance is common and considered a best practice, as it allows the physician to visualize the median nerve, tendons, and arteries in real-time. This visualization is important for ensuring the needle is positioned safely and accurately adjacent to the median nerve but not directly into it or an adjacent blood vessel.
During the injection of the medication, the patient may feel a sensation of pressure or a brief, localized burning from the anesthetic, but the procedure is generally well-tolerated. Following the injection, a small bandage is placed over the site, and the patient is usually monitored briefly before leaving the clinic.
Immediate aftercare involves resting the wrist and hand for the first few hours, and then limiting activity for the next 24 to 48 hours. Patients are advised to avoid heavy lifting, repetitive hand movements, and strenuous activities during this initial recovery period. Temporary soreness at the injection site is normal and can often be managed with ice packs or over-the-counter pain relievers.
Anticipated Results and Duration of Relief
Patients often experience immediate pain relief or numbness shortly after the procedure due to the local anesthetic component. However, the full therapeutic effect of the corticosteroid takes longer to develop, typically providing noticeable symptom reduction within 3 to 7 days after the injection. Significant improvement in symptoms and function is generally seen within two to four weeks of the procedure.
The longevity of the relief provided by a carpal tunnel injection is highly variable among individuals, ranging from weeks to several months. For many patients, the injection can provide symptom improvement for up to six months, and in some cases, it may offer long-term resolution. Studies have shown that the injection may also reduce the need for surgery when assessed at one-year follow-up. If the initial injection provides a significant period of relief, this is considered a good prognostic sign, even if symptoms eventually return. Because repeated steroid exposure can potentially weaken tendons, physicians generally limit the number of injections to no more than one or two per year.
Potential Side Effects and When to Seek Medical Attention
Carpal tunnel injections are generally safe, but patients may experience some mild, temporary side effects. The most common is a temporary increase in pain or a “steroid flare” at the injection site, which can occur for one to three days as the local anesthetic wears off and the steroid begins to work. Other minor side effects include localized bruising, temporary skin discoloration, or a temporary increase in blood sugar levels for diabetic patients.
Rarely, more serious complications can occur, which makes careful monitoring following the procedure important. These rare events include infection at the injection site, localized fat or skin atrophy, or accidental injury to the median nerve or surrounding tendons. Immediate medical attention is necessary if a patient develops signs of infection, such as fever, chills, or expanding redness and swelling around the injection site.
If severe pain significantly worsens after the first 48 hours, or if there is new, persistent numbness, tingling, or weakness in the hand that was not present before the procedure, a physician should be consulted immediately.