| Investigator | Country | Year | No. | Mean Follow up | CS % | Satisfied % | Dissatisfied % |
| Rex LO [4] | Sweden | 1998 | 1152 | 38 m | 59.8 | 97.5 | 2.5 |
| Gossot D [5] | France | 2003 | 125 | 46 m | 86.4 | 92 | 8 |
| Lardinois [7] | Swiss | 2002 | 37 | 34 m | 72 | 95 | 5 |
| Herbst F [19] | Austria | 1994 | 270 | 36 m | 67.4 | 93.3 | 6.7 |
| Chiou TS [32] | Taiwan | 1999 | 91 | 22 m | 97 | 87 | 13 |
| Durate J [33] | Brazil | 1998 | 140 | 30 m | 5 | 96.5 | 3.5 |
| Lai Y [34] | China | 1997 | 72 | 18 m | 98.6 | 78 | 22 |
| Wali M [35] | Saudi Arabia | 2003 | 22 | 25 m | 12 | 94 | 6 |
| Katara A [36] | Singapore | 2006 | 25 | 23 m | 80 | 100 | 0 |