Table 2.

EMBASE search strategy

1	Clinical trial/
2	Randomized controlled trial/
3	Randomization/
4	Single blind procedure/
5	Double blind procedure/
6	Crossover procedure/
7	Randomi?ed controlled trial$.tw.
8	Rct.tw.
9	Random allocation.tw.
10	Allocated randomly.tw.
11	(allocated adj2 random).tw.
12	Double blind$.tw.
13	Single blind$.tw.
14	((treble or triple) adj blind$).tw.
15	1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14
16	Case study/
17	Case report.tw.
18	Abstract report/ or letter/
19	16 or 17 or 18
20	15 not 19
21	methods paper.mp.
22	protocol.mp.
23	exp study design/
24	study design.mp.
25	trial design.mp.
26	21 or 22 or 23 or 24 or 25
27	20 and 26
28	exp surgery/
29	surgical.mp.
30	surgeon$.mp.
31	operative.mp.
32	surger*.mp.
33	re-operation.mp.
34	reoperation.mp.
35	28 or 29 or 30 or 31 or 32 or 33 or 34
36	27 and 35
37	limit 36 to yr=“2005—Current”