Name of Procedure
- Blind and Ultrasound Guided Carpal Tunnel Injection
- Median Nerve Block
To inject medication into the carpal tunnel around the median nerve
Carpal tunnel syndrome
- Common contraindications
- Blood thinners – See ASRA based guidelines (and an abbreviated protocol) for managing various blood thinners pre and post procedure
As seen, the median nerve runs through the carpal tunnel.
Specific structures are relevant to the injection:
- Bounded superficially by the flexor retinaculum – You will likely puncture through this with your needle
- Medially and laterally the ulnar and radial arteries are not very far from your injection site.
- 25g x 1.5” hypodermic needle
- 3-5cc syringe with desired injectate (ie, 2mL 0.25% bupivacaine with 1mL 10mg dexamethasone)
- Alcohol prep pad and gauze pad or bandage
Landmarks and Patient Positioning
The patient can be laying supine or sitting with the arm resting comfortably on a flat surface with the palm face up.
- Identify your markers:
- Hold the patient’s fingers and ask him to flex at the wrist.
- Identify the palmaris longus tendon (blue).
- Identify an entry point 1cm distal to the wrist crease and 1cm medial to the tendon (towards the 5th finger) (red)
- Insert your 25g needle at roughly a 45 degree angle and pointing to the thumb
- Advance 1-2cm to your target end point (green)
- After confirming no paresthesia and negative aspiration, inject your desired medication.
This video provides a good overview, animations and two procedure techniques. Play the video below to start at the “usual” technique (described above). After the “usual” approach it will describe the “proximal” technique.
- Obtain a transverse view of the median nerve as shown in this video.
- Use an in-plane or out-of-plane approach to get the needle above and below the nerve and deposit your desired medication.
- If you see superficial infiltration you probably need to go just a bit deeper
- If the needle moves when the patient moves his/her fingers, then the needle tip might be in the tendon and should be repositioned..
- If there is extreme pain (especially in the median nerve distribution), reposition.
- Do NOT inject against resistance.
- Some people do not have a palmaris longus tendon. In this case just start 1cm lateral from the midline of the forearm, roughly where the tendon would be if it existed.
- Carpal Tunnel Injection – Everything You Need To Know – Dr. Nabil Ebraheim
- Youtube video review with technique description (video above)
- Carpal Tunnel Injections
- Technique description
- Diagnostic and Therapeutic Injection of the Wrist and Hand Region
- Overview of carpal tunnel syndrome and injection technique
- Carpal Tunnel Injections
- Thorough technique description and anatomy pictures.
- Ultrasound-Guided Peripheral Nerve Injection Techniques : American Journal of Roentgenology : Vol. 207, No. 3
- Carpal tunnel – Ultrasound-Assisted treatment | Arthroscopy of the upper limb
- Review of how ultrasound is used for for surgical intervention