Purpose
The use of percutaneous Kirschner wires for
fixation of unstable fractures of the distal radius has been widely accepted as
the least invasive procedure. However, the injury to the superficial branch of
the radial nerve (SBRN) is common. Our purpose in this study was to develop a
reliable technique to avoid damaging the SBRN.
Methods
Twenty cadaver forearms were dissected to identify
the SBRN distribution, and 18 forearms were used to undergo placement of three
Kirschner wires (KW-A, KW-B, and KW-C). The KW-A, KW-B, and KW-C were driven in
the frontal plane into the distal radius, and KW-A and KW-C through the tip of
radial styloid process at different angles. The SBRN distribution and its
relationship with the KW insertion were identified. Fifty-three patients with
unstable distal radius fractures were fixed with external fixator and augmented
with 1–3 KW, and the injury rates of SBRN were evaluated.
Results
We found a blind region of the SBRN bound
by its first bifurcations into radial and ulnar branches and the line crossing
the tip of the styloid process. The mean distance of the three wires (KW-A,
KW-C, and KW-B) to the closest nerve branch was 4.5, 4.4, and 3.4 mm,
respectively. The injury of SBRN occurred in two of 53 patients.
Conclusion
The injury rate of the SBRN can be
effectively reduced when the Kirschner wire is placed along the curve AB and as
in proximity to the TRSP as possible under fluoroscopic guidance. Our pinning
technique is therefore reliable and practical.