Guyon’s canal decompression

• Incision and exposure
  • Make a longitudinal or gently curved incision over the ulnar aspect of the volar wrist, centered over the pisiform
  • Incise skin and subcutaneous tissue
  • Identify and protect the superficial branches of the ulnar nerve and cephalic vein (if encountered)
• Dissection and identification of Guyon’s canal
  • Incise the palmar carpal ligament, the superficial roof of Guyon’s canal
  • Identify the ulnar nerve and artery entering the canal lateral to the pisiform
  • Carefully separate the ulnar nerve from the artery—they may share a fibrous sheath
• Decompression
  • Divide the roof of the canal (palmar carpal ligament and, if needed, distal aponeurotic fascia of hypothenar muscles)
  • Extend the release proximally and distally to fully decompress the nerve
  • The nerve bifurcates in the canal:
    • Superficial branch (sensory)
    • Deep motor branch (dives deep through the hypothenar muscles)
  • Release fascial bands overlying the deep motor branch as it travels deep to the hook of hamate and into the hand
  • Be cautious to avoid injury to the ulnar artery, especially in trauma or aneurysmal cases
• Tendon transfers
  • correct claw fingers
    • possible grafts include ECRL, ECRB, palmaris longus
    • tendons must pass volar to transverse metacarpal ligament in order to flex the proximal phalanx
    • attach with either a two or four-tailed graft to the A2 pulley of the ring and small fingers
  • restore power pinch
    • Smith transfer using ECRB or FDS of ring finger
  • restore adduction of small finger
    • transfer ulnar insertion of EDM to A1 pulley or radial collateral ligament of the small finger

https://www.youtube.com/watch?v=qnH3lXa74LY&ab_channel=WUSTLLearnSurgery