Anatomical landmarks for safer carpal tunnel decompression: an experimental cadaveric study

Area of Science:

• Anatomy
• Surgical Procedures

Background:

• Carpal tunnel syndrome is a common surgical outpatient presentation.
• Surgical treatment involves dividing the flexor retinaculum, risking damage to nerves and vessels.
• Identifying anatomical landmarks is crucial for safe decompression.

Purpose of the Study:

• To characterize the anatomical extent of an avascular area in the flexor retinaculum.
• To identify anatomical landmarks for safer carpal tunnel decompression.
• To protect the recurrent branch of the median nerve and superficial palmar arch during surgery.

Main Methods:

• Dissection of 13 Sri Lankan cadavers.
• Measurement of anatomical structures using a vernier caliper.
• Identification of an avascular area within the flexor retinaculum.

Main Results:

• The recurrent branch of the median nerve was typically a single trunk (76.9%) and extra-ligamentous (84.6%).
• Mean distances from the distal border of the transverse carpal ligament (TCL) to the recurrent branch and superficial palmar arch were 7.75 mm and 11.48 mm, respectively.
• A mean avascular area width of 11.10 mm proximally and 7.09 mm distally was identified on the TCL.

Conclusions:

• Recommend incision along the radial border of the extended ring finger for carpal tunnel decompression.
• Avoid extending incisions beyond 8.16 mm proximally and 7.75 mm distally from TCL borders.
• An identified avascular area on the TCL can minimize intraoperative bleeding.