“…For the primary outcome, sensory block duration, 20 studies were judged to have a low risk of bias [35, 38, 39, 42, 45, 56, 59, 65, 76, 81, 82, 92–94, 107, 110, 113, 115, 116], 61 studies had some risk of bias [33, 34, 36, 37, 43, 47, 48, 52, 55, 57, 58, 61, 67, 68, 70, 71, 73–75, 77–80, 83–85, 87–91, 95–106, 108, 109, 111, 114, 117–123, 125–131] and 4 studies were at high risk of bias [41, 63, 86, 124].…”