“The objective of this systematic review was to assess the effectiveness of spinal manipulations as a treatment option for cervicogenic headaches…There are few rigorous RCTs testing the effectiveness of spinal manipulations for treating cervicogenic headaches. The results are mixed and the only trial accounting for placebo effects fails to be positive. Therefore, the therapeutic value of this approach remains uncertain.” Paul Posadzki PhD, MSc, BSc, and Edzard Ernst MD, PhD, FMedSci, FSB, FRCP, FRCPEd, Headache (7th June 2011)