Table 7

Analysis of effect size, heterogeneity, and ANOVA testing of difference by type of endoscopy.

	Type of Endoscopy	Number of Studies Included in This Analysis	Effect Size	Lower Limit	Upper Limit	Higgins I ² Statistic of Heterogeneity	Variance	Standard Error	Number of Patients
Oswestry Disability Index	Combined outside-in and Interlaminar	1	0.9805	0.9749	0.9848	0.0000	0.0000	0.0025	124
	Interlaminar approach	20	0.9567	0.9403	0.9732	0.0000	0.0001	0.0084	2940
	Biportal UBE endoscopy	9	0.9299	0.8954	0.9645	0.0000	0.0003	0.0176	960
	Transforaminal outside-in	51	0.9044	0.8803	0.9285	0.0000	0.0002	0.0123	8198
	Transforaminal inside-out	5	0.8967	0.8468	0.9467	0.0000	0.0007	0.0255	962
	ANOVA Q test random effects with separate estimates of T ²				Sig < 0.0001		Total patient samples		13,184
VAS back	Biportal UBE endoscopy	4	0.8943	0.8470	0.9416	0.0000	0.0006	0.0241	336
	Interlaminar approach	10	0.8336	0.7687	0.8984	0.0000	0.0011	0.0331	794
	Transforaminal outside-in	22	0.7775	0.6964	0.8586	0.0000	0.0017	0.0414	3990
	Transforaminal inside-out	1	0.8300	0.6435	0.9235	3.9883	0.0045	0.0673	14
	ANOVA Q test random effects with separate estimates of T ²				Sig = 0.093		Total patient samples		5134
VAS leg	Combined outside-in and interlaminar	1	0.9660	0.9562	0.9736	0.0000	0.0000	0.0044	124
	Interlaminar approach	20	0.9331	0.9106	0.9556	0.0000	0.0001	0.0115	2914
	Biportal UBE endoscopy	10	0.9271	0.9008	0.9534	0.0000	0.0002	0.0134	1002
	Transforaminal outside-in	48	0.9112	0.8880	0.9345	0.0000	0.0001	0.0119	7954
	Transforaminal inside-out	6	0.8912	0.8544	0.9281	0.0000	0.0004	0.0188	1111
	ANOVA Q test random effects with separate estimates of T ²				Sig <0.00001		Total patient samples		13,105

ANOVA, analysis of variance; Sig, significance level of 95% CI; UBE, uniportal biportal endoscopy; VAS, visual analog scale.