Carpal Tunnel Injection

About this injection

Carpal tunnel syndrome (CTS) is caused by compression of the median nerve as it passes through the carpal tunnel at the wrist. It is the most common peripheral nerve entrapment syndrome, causing numbness, tingling, and pain in the thumb, index, middle, and radial half of the ring finger.

Corticosteroid injection into the carpal tunnel reduces inflammation around the median nerve, relieving pressure and improving symptoms. It is a highly effective treatment — particularly for mild to moderate CTS — and can provide relief lasting weeks to months. For some patients, a single injection produces sustained long-term improvement.

Dr Hasham performs carpal tunnel injection using anatomical landmark technique, approaching the carpal tunnel via the ulnar side of palmaris longus tendon at the wrist crease. The procedure is quick, well tolerated, and does not require sedation or general anaesthetic.

Conditions treated

• ✓Carpal tunnel syndrome — idiopathic (the most common type)
• ✓Pregnancy-related CTS — often resolves after delivery but injection can provide relief
• ✓CTS associated with hypothyroidism, rheumatoid arthritis, diabetes
• ✓Occupational CTS from repetitive wrist flexion/extension
• ✓CTS in patients awaiting surgical decompression

Symptoms

• —Numbness and tingling in the thumb, index, middle, and ring fingers (median nerve distribution)
• —Symptoms worse at night — waking from sleep with numb hands
• —Shaking the hand relieves symptoms (flick sign)
• —Weakness and clumsiness of grip and fine motor tasks
• —Pain at the wrist radiating into the forearm
• —Thenar muscle wasting in severe or longstanding cases

Assessment & diagnosis

Phalen's test (sustained wrist flexion for 60 seconds reproducing symptoms) and Tinel's sign (tingling on percussion over the carpal tunnel at the wrist) support the diagnosis. Nerve conduction studies confirm the diagnosis and severity — mild to moderate CTS is most amenable to injection.

Treatment options

What happens on the day

1. Clinical assessment — Phalen's test, Tinel's sign, grip strength, sensory testing
2. Patient seated with wrist supinated and slightly extended over a rolled towel
3. Palmaris longus tendon identified (patient opposes thumb and little finger)
4. Injection site marked ulnar to palmaris longus at the proximal wrist crease
5. Skin cleaned with antiseptic
6. Needle inserted at 30–45° to skin, directed distally into the carpal tunnel
7. Paraesthesia in the median nerve distribution — needle repositioned slightly
8. Corticosteroid injected — should flow freely without resistance
9. Needle withdrawn, pressure applied
10. Patient asked to flex and extend fingers to distribute the medication

Injection technique

The injection is performed ulnar to the palmaris longus tendon (or at the midline if palmaris longus is absent — present in ~85% of people) at the proximal wrist crease. The needle is angled 30–45° distally into the carpal tunnel. If paraesthesia is felt in the median nerve distribution, the needle is withdrawn slightly to avoid intraneural injection. Methylprednisolone 40mg or triamcinolone 20mg in 1ml is used without local anaesthetic to avoid temporary nerve numbness.

Risks & side effects

• —Median nerve injury — rare with correct technique; avoid intraneural injection (reposition if paraesthesia felt)
• —Flexor tendon injury — needle should not meet solid resistance
• —Post-injection flare — temporary wrist discomfort for 24–48 hours
• —Infection — rare
• —Temporary blood glucose elevation in diabetic patients
• —Incomplete or short-lived relief — suggests more severe compression requiring surgery

Aftercare

• ✓Normal hand use is possible immediately
• ✓Avoid heavy lifting for 24 hours
• ✓Symptoms may temporarily worsen for 24–48 hours before improving
• ✓Effect typically develops over 1–2 weeks
• ✓Wear a night splint to maintain the benefit
• ✓If no improvement after 6 weeks, or symptoms return rapidly, surgical decompression should be considered

Frequently asked questions