A Comparison of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Microdiscectomy for Lumbar Disc Herniation in the Korean: A Meta-Analysis

Table 2

Risk of bias assessment of the nonrandomized studies.

Studies	Selection	Comparability	Exposure	Total Quality score
Jeong (2006)	2	2	1	5
Lee (2006)	2	2	3	7
Kim (2007)	2	1	1	4
Lee (2009)	2	2	1	5
Lee (2017)	2	2	2	6
Ahn (2016)	2	2	2	6
Choi (2016)	2	2	1	5