“…Of all pain categories defined most recently by the European Pain Federation [ 1 ], most trials referred to chronic musculoskeletal pain, i.e., low back pain (4 trials) [ 52 , 55 , 64 , 68 ], knee osteoarthritis in obese patients (3 trials) [ 44 , 46 , 74 ], fibromyalgia (7 trials) [ 45 , 47 , 56 , 59 , 61 , 62 , 78 ], neck pain and stiffness (1 trial) [ 79 ], musculoskeletal pain or peripheral neuropathy due to cancer treatment (3 trials) [ 64 , 69 , 70 ], chronic headache or migraine (6 trials) [ 43 , 48 , 49 , 51 , 66 , 67 ], generalized chronic musculoskeletal pain (2 trials) [ 54 , 72 ], diabetic neuropathy [ 50 , 71 ], taxol-induced neuropathic pain [ 63 ], or abdominal pain (10 trials) [ 53 , 57 , 58 , 60 , 65 , 71 , 73 , 75 , 76 , 77 , 80 ]. A synthesis is provided in Table 2 ( Table 2 ).…”