Nerve Compression, Microsurgery, and Soft Tissue Reconstruction
Core concepts
Nerve compression is diagnosed clinically and confirmed electrodiagnostically. Carpal tunnel syndrome presents with nocturnal paresthesias in the median distribution, thenar atrophy, and positive Phalen and Tinel signs; release the transverse carpal ligament while protecting the recurrent motor branch. Cubital tunnel syndrome affects the ulnar nerve at the medial epicondyle; examine for Froment and Wartenberg signs and first dorsal interosseous wasting, and remember that the nerve stretches with elbow flexion. Guyon canal compression spares the dorsal ulnar sensory branch.
Microsurgery fundamentals include magnification, atraumatic technique, and tension-free repair. Free flaps commonly used in the hand include the anterolateral thigh, radial forearm, and fibula. Replantation requires a sharp amputation, acceptable warm ischemia (under about six hours for muscle-containing parts), and favorable patient factors. Soft tissue reconstruction follows the ladder: secondary intention, skin graft, local flap, then free tissue transfer; Z-plasty addresses contracture bands.
Traps
Confusing carpal tunnel syndrome with cervical radiculopathy or diabetic neuropathy, missing a double crush, ignoring the dorsal sensory branch in Guyon lesions, and replanting a mangled digit without considering eventual function are classic pitfalls.
Rule of thumb
When compression is atypical, confirm with EMG/NCS. Before dividing the transverse carpal ligament, identify the recurrent motor branch, which branches radially and can be anomalous.