title: Three different approaches to Transversus abdominis planeblock: a cadaveric study.
abstract: OBJECTIVE
  The transversus abdominis plane (TAP) block is a new technique for providing analgesia to the anterior abdominal wall. There is ongoing debate regarding access point for TAP block. The aim of this cadaveric study was to compare the spread of 40 mL of dye using three different approaches to TAP: subcostal , via the mid-axillary and via the lumbar triangle of Petit (LTOP).
  
  
  METHODS
  Injection of black dye into the TAP was performed for each hemi-abdominal wall of 13 embalmed human cadavers by using 3 different access points: subcostal (9 hemi-abdomens), mid-axillary (9) and LTOP (8). This was followed by dissection to determine the extent of dye spread and nerve involvement in the dye injection. The shapes of the dye were traced onto clear plastic, which was then photographed. These digital photographs were loaded into the mathematical software programme Matlab, and the outline of the dye spread was digitised using a piecewise cubic spline, enabling the shapes to be plotted on a graph and the areas to be calculated.
  
  
  RESULTS
  The area of the dye spread for subcostal, mid-axillary and LTOP was 85.1 (T7-L1), 58.9 (T10-L1) and 77.9 cm² (T10-L1), respectively. There was statistically significant difference between area of dye spread between subcostal and mid-axillary approach (p<0.01).
  
  
  CONCLUSIONS
  This dye injection study in a cadaver model indicates that subcostal approach is associated with a larger area of spread of dye than the mid-axillary approach. Dye injected through subcostal, mid-axillary and LTOP approaches demonstrated different nerve involvement.
authors.affiliation: Department of Anaesthesia, St James's University Hospital, Beckett St, Leeds, United Kingdom. z.millan@leeds.ac.uk
authors.forename: Zoka
authors.initials: Z
authors.lastname: Milan
authors.forename: Dominic
authors.initials: D
authors.lastname: Tabor
authors.forename: Patricia
authors.initials: P
authors.lastname: McConnell
authors.forename: James
authors.initials: J
authors.lastname: Pickering
authors.forename: Mitko
authors.initials: M
authors.lastname: Kocarev
authors.forename: Frances
authors.initials: F
authors.lastname: du Feu
authors.forename: Sarah
authors.initials: S
authors.lastname: Barton
mesh_terms: D034861:Abdominal Wall / Q000294:innervation*; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D004396:Coloring Agents / Q000008:administration & dosage; D006801:Humans; D009407:Nerve Block / Q000379:methods*
chemical_list: D004396:Coloring Agents