PROCEDURE: Extensor Carpi Radialis Brevis to Anterior Interosseous Nerve Transfer.
Donor Nerve: Extensor carpi radialis brevis nerve branch of the radial nerve.
Recipient Nerve: Anterior interosseous nerve of the median nerve.
Nerve Coaptation: End-to-end.
Exposure and Dissection:
- A lazy-S volar incision is made in the proximal-forearm, about 12cm in length.
1. Incise skin and dissect through subcutaneous tissue.
Median Nerve Decompression and Exposure:
2. In the distal portion of the incision, the radial vessels are identified and the radial sensory nerve is identified. The pronator teres tendon is located between these two structures.
Extensor Carpi Radialis Brevis to Anterior Interosseous Nerve Transfer:
3. A step-lengthening tenotomy of the pronator teres tendon is performed at this level.
4. Moving proximally in the forearm, the median nerve is identified just medial to the radial vessels.
5. The deep head of the pronator teres is divided to expose the median nerve.
6. The anterior interosseous nerve is identified as the major branch coming off of the median nerve on the radial side.
7. There is a cleavage plain between the anterior interosseous nerve and the median nerve that allows for the proximal neurolysis of the anterior interosseous nerve for additional length.
8. The anterior interosseous nerve is stimulated to confirm that it is not functioning.
9. The nerve to the extensor carpi radialis brevis (ECRB) is then identified by following the radial sensory nerve proximally and observing the nerve branch takeoff of the smaller nerve to the ECRB. This nerve is stimulated to confirm function.
10. The donor nerve, ECRB, is divided distally.
11. The ECRB nerve is transposed towards the anterior interosseous nerve (AIN).
12. The recipient nerve, AIN, is divided proximally.
13. The nerve repair is completed with no tension on the repair through full range of movement of the extremity.