|
Year |
2002 |
|---|---|
|
Question Number |
104 |
|
Category |
Hand |
Question
A 60 year-old woman who has had pain and numbness in the thumb, index, and long fingers underwent an uneventful open carpal tunnel release. Postoperatively, she reports complete resolution of her symptoms but now notes progressive thenar atrophy that was not present prior to surgery. What is the most likely cause of this finding?
1. Incomplete release of the transverse carpal ligament
2. Cervical radiculopathy
3. Unrecognized Martin-Gruber anastomosis
4. Unrecognized transligamentous motor branch of the median nerve
5. Median artery pseudoaneurysm
Figures
Answer (click for answer)
Preferred Answer: 4
The motor branch of the median nerve arises from the anterolateral side of the median nerve just as the nerve emerges from the carpal tunnel. The motor branch then curves radially and upward to enter the thenar musculature. There is however a significant anatomic variation concerning the median motor branch that may, in some cases, actually traverse the ligament. The risk to the nerve is minimized if the incision is made into the carpal tunnel on the ulnar side of the median nerve.
Reference: Hoppenfeld S Surgical Exposures in Orthopaedics: The Anatomical Approach, ed 2
Philadelphia, PA JB Lippincott 1994, pp162-163