title: A cadaver study comparing spread of dye and nerve involvement after three different quadratus lumborum blocks.
abstract: BACKGROUND
  Posterior variants of abdominal wall block include the quadratus lumborum type I, quadratus lumborum type II and quadratus lumborum transmuscular blocks. Our objectives were to compare the spread of injectate and nerve involvement, after conducting blocks using ultrasound guidance in soft embalmed cadavers.
  
  
  METHODS
  After randomization, an experienced anaesthetist conducted three quadratus lumborum 1, three quadratus lumborum 2 and four transmuscular blocks on the left or right sides of five cadavers. All cadavers were placed in the lateral position and the quadratus lumborum muscle seen using a 3-9 MHz ultrasound probe placed in the flank. For each block, a 20 ml mixture of 17.75 ml water, 2 mls latex and 0.25 ml India ink was injected. The lumbar region and abdominal flank were dissected 72 h later.
  
  
  RESULTS
  We conducted 10 blocks. Two quadratus lumborum 1 and two quadratus lumborum 2 blocks were associated with spread of dye within the TAP plane. One quadratus lumborum 1 block spread to the deep muscles of the back and one quadratus lumborum 2 block dispersed within the subcutaneous tissue surrounding the abdominal flank. All transmuscular quadratus lumborum blocks spread consistently to L1 and L3 nerve roots and within psoas major and quadratus lumborum muscles.
  
  
  CONCLUSIONS
  Consistent spread to lumbar nerve roots was achieved using the transmuscular approach through the quadratus lumborum.
authors.affiliation: Centre for Anatomy & Human Identification, University of Dundee, Dundee, DD1 5EH, UK.
authors.forename: L
authors.initials: L
authors.lastname: Carline
authors.affiliation: Institute of Academic Anaesthesia, Ninewells Hospital & Medical School, Dundee, DD1 9SY, UK g.a.mcleod@dundee.ac.uk.
authors.forename: G A
authors.initials: GA
authors.lastname: McLeod
authors.affiliation: Centre for Anatomy & Human Identification, University of Dundee, Dundee, DD1 5EH, UK.
authors.forename: C
authors.initials: C
authors.lastname: Lamb
mesh_terms: D034861:Abdominal Wall / Q000294:innervation*; D002102:Cadaver; D004396:Coloring Agents; D006801:Humans; D009407:Nerve Block
chemical_list: D004396:Coloring Agents
keywords: anaesthesia; cadaver; regional; ultrasonography