Level Requirements for Regional Anesthesia.

The anesthetic level required depends on the surgical procedure. Dermatomal level requirements for a selection of operations:

• T4–5: upper abdominal surgery

• T6–8: intestinal, gynecologic or renal surgery

• T10: transurethral resection of the prostate, hip or inguinal hernia surgery

• T12: lower extremity surgery with a thigh tourniquet

• L1: Knee surgery

• L2–3: Foot surgery

• S2–5 (saddle block): perineal surgery, hemorrhoidectomy