This investigation attempts to define the contributing factor in postoperative brachial plexus palsy by means of a correlative anatomical and clinical study. Tension recording along the brachial plexus was made on nine fresh cadavers by means of a spring guage placed in series with the nerve plexus. Increasing nerve tension or stretch was observed with the arm in progressive abduction. In 39 patients affected by this neurological defect as reported in the literature, hyperabduction of the arm was also noted in the majority of instances. Excessive nerve stretch is believed to be an important causal factor. Observations of brachial plexus tension, with reference to various arm position outlined in this study, may serve as a guide in the prevention of this paralytic disability.
Jack H. M. Kwaan, Irving Rappaport. Postoperative Brachial Plexus PalsyA Study on the Mechanism. Arch Surg. 1970;101(5):612–615. doi:10.1001/archsurg.1970.01340290068015