Ultrasound-guided flexor tendon sheath (FTS) block for digital analgesia in the emergency department: A case report.

A 26-year-old male presented to the emergency department (ED) with a penetrating injury to his fourth digit requiring analgesia for removal of an extruding metal foreign body. An ultrasound (US)-guided flexor tendon sheath (FTS) block was performed on the volar surface of the hand near the distal palmar crease using an out-of-plane approach with in-plane longitudinal confirmation of needle placement. Anesthetic placement was verified by a "horseshoe" appearance of the anesthetic surrounding the FTS. The patient achieved complete analgesia within five-minutes following the administration of the local anesthetic. This case highlights the efficacy and feasibility of US-guided FTS blocks as a viable alternative for digital anesthesia in the emergency setting.