“…Of the 21 included studies involving 2695 LPCs, 2 studies were randomized controlled trials (87 LPCs), 21,22 with most designs being observational: 11 retrospective (1324 LPCs) 19,20,[23][24][25][26][27][28][29][30][31] and 8 prospective (1304 LPCs). [32][33][34][35][36][37][38][39] Eight studies were performed in the United States 19,20,23,25,30,32,33,35 ; seven studies in Australia, 21,22,26,27,34,36,38 three studies in Italy, 24,29,37 one each in India and Iraq, 31,39 with one not specified.…”