Table 1.

Summary of analysis results

Variable	No. of studies	Population		MD or OD or HR (95% CI)	p-value	Heterogeneity
		MIS	OS			I2 %	p-value
Operative time	10	271	305	−35.23 (−73.36 to 2.91)	0.07	96	<0.00001
Operative bleeding	10	271	305	−562.59 (−776.97 to −348.20)	<0.00001	94	<0.0001
Instrumented levels	5	125	120	−0.05 (−0.75 to 0.66)	0.89	72	0.006
Transfusions	5	119	122	0.26a) (0.15 to 0.45)	<0.00001	50	0.09
Postoperative bed rest	2	48	44	−1.60 (−2.46 to −0.74)	0.0003	0	0.90
Length of stay	6	170	220	−3.08 (−4.50 to −1.66)	0.001	89	<0.00001
Complications	9	244	287	0.60a) (0.37 to 0.96)	0.03	6	0.38
Reinterventions	3	66	73	0.65a) (0.15 to 2.84)	0.57	0	0.93
Change in pain	4	102	93	−0.74 (−2.41 to 0.94)	0.39	88	<0.0001
ECOG grading	2	57	48	−0.25 (−0.68 to 0.18)	0.26	0	0.50
Tokuhashi	5	128	118	−0.52 (−2.08 to 1.05)	0.41	85	<0.0001
Frankel	3	104	160	1.00 (0.60 to 1.68)	1.0	0	0.40
ASIA Scale	2	37	40	0.53 (0.21 to 1.37)	0.19	36	0.21
Survival	2	61	43	0.81b) (0.56 to 1.16)	0.25	0	0.37

MIS, minimally invasive surgery; OS, open surgery; MD, mean difference; OD, odds ratio; HR, hazard ratio; CI, confidence interval; ECOG, Eastern Cooperative Oncology Group; ASIA, American Spinal Injury Association.

^a)Indicates OR.

^b)Indicates HR.