Study	Reason for exclusion
Amudsen 1982	Not RCT
Anderson 1993	No randomisation.
Carr 2003	Patients were pregnant.
Celestini 2005	No contrast for lumbar supports.
Garg 1992	Not RCT
Hamonet 1993	Not RCT
Iwamoto 2004	No contrast for lumbar supports.
Jellema 2002	No contrast for lumbar supports.
Jonai 1997	Not RCT
Langford 2005	Magnet, no lumbar support
Larsson 1980	No contrast for lumbar supports.
Marty 1998	No contrast for lumbar support.
Monticone 2004	No contrast for lumbar supports.
Spratt 1993	No contrast for lumbar support.
Thompson 1994	Not RCT
Toda 2002	No randomisation
Wassell 2000	No randomisation.