See the Hand injections - General section and also the Handout on Carpal Tunnel Syndrome
Beware
- Flexor tendons
- Median nerve
- Superficial veins
Anatomy
Proximal wrist flexion crease
5mm ulnar to palmaris longus
Palpate digital flexor tendons as the fingers flex and extend
The Median nerve is radial to Palmaris longus, between this tendon and the FCR tendon
Use of Carpal tunnel Injections:
A good response to a cortisone injection can:
- Help differentiate between:
- Compressive neuropathy eg CTS and other types of neuropathy eg Diabetic.
- Carpal tunnel syndrome and Cervical spondylosis and the degree to which each condition contributes to a particular patients symptoms in a double crush syndrome
- Act as a positive prognostic indicator for a good subsequent response to a carpal tunnel decompression. If a patient does not improve with an injection I would be very reluctant to recommend surgery.
- In late stages of Pregnancy
Carpal tunnel injection is not a useful test unless a clear end point can be identified.
- ie Complete resolution of symptoms, ability to sleep.
- In severe cases of late CTS when numbness is constant and patients may not still be waking from sleep
injection of cortisone is not such a useful test.
Technique:
1 ml Celestone + 1 ml Lignocaine
Mark entry site with finger nail
Clean with alcohol swab then no touch technique
Pass needle through skin quickly with the needle bevel parallel with nerve and then inject a small amount of fluid just under the skin.
Wait 20 – 30 seconds then gently advance the needle while getting the patient to gently flex and extend their fingers.
Continue injecting.
If fluid bulges the skin and fat it is superficial to the deep fascia. ie too superficial.
When the flexor tendons can be felt moving against the end of the needle the needle is deep enough.
If the needle moves with finger ROM it is in the tendon!!! and should be moved.