Study	Reason for exclusion
Acar 2012	Not participants with low back pain
Allen 2006	Not a randomised controlled trial
Bertocco 2002	Ultrasound as part of treatment package
Borman 2003	Not a randomised controlled trial
Brockow 1997	All groups had ultrasound – no control intervention
Charlusz 2010	Participants with acute low back pain
Chipchase 2003	Not a randomised controlled trial
Cloonan 1987	Not a randomised controlled trial
Draper 1993	Not a randomised controlled trial
Fiore 2011	Participants with acute low back pain
Foster 1999	Not a randomised controlled trial
Gorbunov 1997	Not a randomised controlled trial
Goren 2010	Participants with lumbar spinal stenosis
Greenough 2009	Not a randomised controlled trial
Gurer 2005	Ultrasound as part of treatment package
Haas 2004	Ultrasound as part of treatment package
Hamm 2003	Not a randomised controlled trial
Hurwitz 2002	Ultrasound as part of treatment package
Jia 2003	Ultrasound as part of treatment package
Kiralp 2009	Not a randomised controlled trial
Koes 1992a	Ultrasound as part of treatment package
Koes 1992b	Ultrasound as part of treatment package
Koes 1993	Ultrasound as part of treatment package
Koldas 2008	Ultrasound as part of treatment package
Kumar 2009a	Ultrasound as part of treatment package
Kumar 2009b	Ultrasound as part of treatment package
Kumar 2010	Ultrasound as part of treatment package
Leistner 1989	Not a randomised controlled trial
Li 2007	Ultrasound as part of treatment package
Lopes 2009	Not a randomised controlled trial
Morrisette 2004	Not a randomised controlled trial
Nordin 1999	Not a randomised controlled trial
Nwuga 1983	Participants with acute low back pain
Onel 1993	Not a randomised controlled trial
Pensri 2005	Not a randomised controlled trial
Poitras 2005	Not a randomised controlled trial
Poitras 2008	Not a randomised controlled trial
Roman 1960	Not a randomised controlled trial
Rush 1994	Not a randomised controlled trial
Sahin 2004	Not a randomised controlled trial
Santiesteban 1984	Participants with acute low back pain
Scott 2010	Not a randomised controlled trial
Si 2005	Not a randomised controlled trial
Tajali 2009	Not a randomised controlled trial
Tander 2005	Not a randomised controlled trial
Timm 1994	Ultrasound as part of treatment package
Tonev 2010	Ultrasound as part of treatment package
Unlu 2008	Participants with acute low back pain
Wagner 1995	Not a randomised controlled trial
Whitman 2006	Participants with lumber spinal stenosis; ultrasound as part of treatment package
Wiesinger 1997	Not a randomised controlled trial