title: Plexus brachialis strain and compression deformation in the costo-axillary-brachial region: a cadaveric study.
abstract: OBJECTIVE
  The aim of this study was to clarify the role of different mechanisms in nerve injury during arm abduction positions. The tasks were to determine the strain deformation of the plexus brachialis during arm abduction, to measure the pressures in the neurovascular bundle in the cervico-costoclavicular-axillary area, and evaluate the histological changes of nerve after the stretch test.
  
  
  METHODS
  During the cadaveric study on 7 specimens 7-20 h after death, strain deformation of plexus brachialis as well as compression deformation caused by the surrounding structures of the neurovascular bundle were investigated in the arm abduction position of 0°, 90°, 12°, 150°, and 180°. One nerve sample was studied histologically after 15% stretch on the bench.
  
  
  RESULTS
  The relative strain deformation of 3%-23% was documented during 0° to 180° abduction tests. The strain deformation from 0° to 90° was significant (P<0.001). The mean pressure change in the bundle was 13.6 mm Hg at 90°, 53.7 mm Hg at 120°, 73.4 mm Hg at 150°, and 89.0 mm Hg at 180° arm abduction. An increase in pressure was significant in the intervals: 0°-90° (P<0.001), 91°-120° (P<0.001), 121°-150° (P<0.001) and 151°-180° (P<0.05).
  
  
  CONCLUSIONS
  Nerve traction and tissue compression arising during the arm abduction above 90° were found to be sufficient to induce lesions in neural bundles of the plexus brachialis.
authors.affiliation: Department of Anesthesiology, Riga Stradins University, Latvia. edgars.vasilevskis@inbox.lv
authors.forename: Edgars
authors.initials: E
authors.lastname: Vasilevskis
authors.forename: Sandra
authors.initials: S
authors.lastname: Skuja
authors.forename: Irina
authors.initials: I
authors.lastname: Evansa
authors.forename: Eva
authors.initials: E
authors.lastname: Steina
authors.forename: Anna Sondore
authors.initials: AS
authors.lastname: Pīlipa
authors.forename: Grigorijs
authors.initials: G
authors.lastname: Vābels
authors.forename: Uldis
authors.initials: U
authors.lastname: Teibe
authors.forename: Haralds
authors.initials: H
authors.lastname: Jansons
authors.forename: Valērija
authors.initials: V
authors.lastname: Groma
authors.forename: Indulis
authors.initials: I
authors.lastname: Vanags
mesh_terms: D001917:Brachial Plexus / Q000648:ultrastructure*; D002102:Cadaver; D006801:Humans; D046529:Microscopy, Electron, Transmission; D009408:Nerve Compression Syndromes / Q000209:etiology* / Q000473:pathology*; D013180:Sprains and Strains / Q000209:etiology* / Q000473:pathology*