Table 1: Characteristics of randomized controlled trials of minimally invasive surgery (MIS) versus conventional open surgery for cervical and lumbar discectomy included in the meta-analysis

Trial	Patient characteristics		Treatment arm; no. of patients and description of treatment		Duration of follow-up, wk
Trial	Mean age, yr	Male sex, %	MIS	Open surgery	Short term	Long term
Cervical discectomy
Soliman et al., 2013⁴⁴	44	48.0	37; microendoscopic discectomy and fusion	33; conventional anterior cervical discectomy and fusion	–	121
Ruetten et al., 2008⁴⁵	34	43.0	100; full-endoscopic cervical posterior foraminotomy	100; conventional anterior cervical discectomy and fusion	26	104
Ruetten et al., 2009⁴⁶	36	NR	60; full-endoscopic anterior cervical decompression	60; conventional anterior cervical discectomy and fusion	26	104
Kim et al., 2009⁴⁷	63	54.3	22; tubular posterior discectomy or foraminotomy	19; open posterior discectomy or foraminotomy	26	104
Lumbar discectomy
Arts et al., 2009¹³ and 2011⁴⁸	53	41.5	167; tubular discectomy	161; conventional microdiscectomy	26	104
Brock et al., 2008⁴⁹	61	51.0	66; tubular discectomy	59; conventional microdiscectomy	1	–
Franke et al., 2009⁵⁰	60	44.0	52; microscope-assisted percutaneous nucleotomy	48; conventional microdiscectomy	26	52
Garg et al., 2011⁵¹	71	37.5	55; microendoscopic discectomy	57; conventional open discectomy	26	52
Huang et al., 2005⁵²	68	39.5	10; microendoscopic discectomy	12; conventional open discectomy	–	82
Righesso et al., 2007⁵³	47	43.9	21; microendoscopic discectomy	19; conventional open discectomy	26	104
Ruetten et al., 2008⁵⁴	42	43.0	100; endoscopic interlaminar and transforaminal discectomy	100; conventional microdiscectomy	26	104
Ryang et al., 2008⁵⁵	53	38.0	30; minimal access trocar microdiscectomy	30; conventional microdiscectomy	–	69
Shin et al., 2008⁵⁶	40	42.0	15; microendoscopic discectomy	15; conventional microdiscectomy	1	–
Teli et al., 2010⁵⁷	66	39.5	70; microendoscopic discectomy	72; conventional microdiscectomy	26	104

Note: NR = not reported.