GAP43 and carpal tunnel syndrome: There was no difference in the percentage of PGP+ IENF containing GAP-43 between patients with CTS classified as regenerators and non-regenerators both before (median [IQR] regenerators 8.3% [25.6%]); non-regenerators 18.5% [28.8%], Mann Whitney U test p = 0.332) and after surgery (regenerators 12.0% [40.3%]; non-regenerators 18.0% [43.8%], Mann Whitney U test p = 0.748, Fig 1D).