Anatomy of neurovascular structures around the carpal tunnel during dynamic wrist motion for endoscopic carpal tunnel release.
OBJECTIVE
The purpose of this study is to investigate the anatomic relationship between neurovascular structures and the transverse carpal ligament (TCL) so as to avoid complications during an endoscopic carpal tunnel release procedure.


METHODS
Fresh cadaver hands from seven men and 12 women (age range, 48-74 yr) were used. The neurovascular structures just over and under the TCL were meticulously dissected under loupe magnification. Several anatomic landmarks were calculated (average length of the TCL; average distance between the TCL distal margin and the neurovascular structures; and average lengths of the superficial palmar arch, ramus communicantes, recurrent motor branch, and palmar cutaneous branch of the median nerve). The ulnar neurovascular structure was studied with the wrist positioned in neutral, ulnar flexion, and radial flexion.


RESULTS
The anatomic relationships between the TCL and vascular and neural structures were measured. The ulnar neurovascular structures usually passed just over ulnar to the superior portion of the hook of the hamate. However, in 11 hands, a looped ulnar artery coursed 1 to 4 mm radial to the hook of the hamate and continued to the superficial palmar arch. The looped ulnar artery migrates on the ulnar side of Guyon's canal (-2-2 mm radial to the hook of the hamate) with the wrist in radial flexion (of the wrist). During ulnar flexion of the wrist, the ulnar artery shifts more radially beyond the hook of the hamate (2-7 mm).


CONCLUSIONS
It is appropriate to transect the ligament over 4 mm apart from the lateral margin of the hook of the hamate without placing the edge of the scalpel toward the ulnar side. We would also recommend not transecting the TCL in the ulnar flexed wrist position to protect the ulnar neurovascular structure. The proximal portal could be made just ulnar to the palmaris longus tendon to spare the neurovascular structures in the proximal portion of the TCL.
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Jae Taek
JT
Hong
Sang Won
SW
Lee
Seung Ho
SH
Han
Byung Chul
BC
Son
Jae Hoon
JH
Sung
Choon Keun
CK
Park
Chun Kun
CK
Park
Joon Ki
JK
Kang
Moon Chan
MC
Kim
D000368:Aged; D002102:Cadaver; D002348:Carpal Bones / Q000033:anatomy & histology / Q000294:innervation; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008022:Ligaments / Q000033:anatomy & histology*; D008297:Male; D008475:Median Nerve / Q000033:anatomy & histology*; D008875:Middle Aged; D017535:Ulnar Artery / Q000033:anatomy & histology*; D014459:Ulnar Nerve / Q000033:anatomy & histology*; D014953:Wrist / Q000033:anatomy & histology* / Q000294:innervation