Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 PPP three to 18 months after thoracotomy	7	499	Odds Ratio (M-H, Random, 95% CI)	0.52 [0.32, 0.84]
2 PPP three to six months after cardiac surgery	2	116	Mean Difference (IV, Random, 95% CI)	−0.76 [−1.73, 0.21]
3 PPP three to twelve months after breast cancer surgery	18	1297	Odds Ratio (M-H, Random, 95% CI)	0.43 [0.28, 0.68]
3.1 Paravertebral block	6	419	Odds Ratio (M-H, Random, 95% CI)	0.61 [0.39, 0.97]
3.2 Intravenous lidocaine	2	97	Odds Ratio (M-H, Random, 95% CI)	0.24 [0.08, 0.69]
3.3 Multimodal block	4	402	Odds Ratio (M-H, Random, 95% CI)	0.76 [0.32, 1.77]
3.4 Local infiltration	6	379	Odds Ratio (M-H, Random, 95% CI)	0.29 [0.12, 0.73]
4 PPP three to eight months after caesarean section	4	551	Odds Ratio (M-H, Random, 95% CI)	0.46 [0.28, 0.78]
5 Pain score three to six months after caesarean section	2	110	Std. Mean Difference (IV, Random, 95% CI)	0.14 [−0.34, 0.61]
6 PPP three to 55 months after Iliac crest bone graft	3	123	Odds Ratio (M-H, Random, 95% CI)	0.20 [0.04, 1.09]
7 PPP six to 12 months after amputation	2	108	Odds Ratio (M-H, Random, 95% CI)	0.53 [0.21, 1.33]
8 PPP six to 12 months after laparotomy	2		Odds Ratio (M-H, Random, 95% CI)	Totals not selected
9 PPP three to 12 months after hernia repair	2		Odds Ratio (M-H, Random, 95% CI)	Totals not selected
10 Pain score three months after prostatectomy	2	150	Std. Mean Difference (IV, Random, 95% CI)	0.06 [−0.26, 0.38]
11 SF-36 bodily pain score at three to six months after hysterectomy	3	297	Mean Difference (IV, Random, 95% CI)	1.70 [−1.06, 4.46]