8. Operative time (minutes).
| Study name | Comparison | Experimental group | Control group | SS_E | SS_C | P value | Results format |
| Al‐Salamah 2007 | Open vs closed (midline) | 43 (5.1) | 58 (4.5) | 192 | 188 | <0.0001 | Mean (SD) |
| Kareem 2006 | Open vs closed (midline) | 14.77 (3.42) | 23.38 (5.18) | 20 | 23 | <0.0001 | Mean (SD) |
| Hameed 2001 | Open vs closed (midline) | 27 (nr) | 49 (nr) | 37 | 40 | <0.05 | Mean |
| Mohamed 2005 | Open vs closed (midline) | 54.8 (3.66) | 63 (4.6) | 55 | 28 | nr | Mean (SD) |
| Jamal 2009 | Open vs closed (off‐midline) | 35 (nr) | 60 (nr) | 25 | 24 | <0.004 | Mean |
| Karakayali 2009 | Open vs closed (off‐midline) | 53.1 (20.4) | 89.3 (31.0) | 70 | 70 | <0.001 | Mean (SD) |
| Sheikh 2007 | Open vs closed (off‐midline) | 25 (5) | 45 (10) | 13 | 13 | nr | Mean (SD) |