gms | German Medical Science

Objectives/Interrogation: Our hypothesis is to define the relationship between vulnerable anatomic structures and knife edge of the instrument (Arthrex) in a cadaveric study. Vulnerable structures (ulnar artery, ulnar nerve, digital nerve 3rd and 4th web space, flexor tendons) will be within 10 mm of the knife edge when performing a ECTR using the Arthrex instrument in more than 50% of cadaveric specimens.

Methods: 18 specimens, 44% male, and 50% RHD and 50% LHD. The distance between the knife and the nerve for the 3rd web space showed the average distance when in neutral position 2.88 ± 2.18 mm increased to 4.22 ± 3.19 mm when the hand was in extension. When comparing the tip of the instrument to the nerve to the 4th web space, the distance averaged 5.1 ±1.88 mm when the hand was in neutral position, and increased to an average of 6.5 ±1.89 mm when the hand was in extension. The percentage of specimens with structures within 10 mm of the knife edge was statistically higher than expected 50% of specimens for the ulnar artery (P=0.027), the nerve for the 3rdweb space (p=0.031) and the nerve to the 4th web space (p=0.039), as well as both in extension (p=0.039), as determined by Fisher's exact test. An average of 2.6 passes of the knife to completely release the transverse ligament was documented.

Results and Conclusions: In conclusion, the data supported our hypothesis that in the majority of specimens the ulnar artery, commons digital nerves and are all less, and in many cases much less, than 10 mm from the knife edge of the instrument during a carpal tunnel release procedure. A relationship between the flexor tendons and the knife edge was not observed. In wrist extension, the distance from the tip of the knife to the common digital nerve for the 3rd and 4th web space increases, but is still less than 10 mm.