Table 2.

Summary of included studies

Author	Design	Location	Cohort	Indications	Procedure	MIS			OS
						Cohort	Mean age (yr)	Primary lesion	Cohort	Mean age (yr)	Primary lesion
H_uang et al. [25] (2006)	Retrospective observational	Thoracic	46	Intractable back pain and/or neurological deficit	MIS: MASS; OS: traditional OS	29	58	Breast (6); lung (5); hepatoma (4); others (14)	17	57	Breast (3); lung (1); hepatoma (2); others (11)
Fang et al. [28] (2012)	Retrospective observational	Thoracic; lumbar	41	Acute progressive neurological deficits, intractable pain, impending fracture of the vertebral body	Posterior total en bloc spondylectomy; mini-open corpectomy	24	56.6	Gastric (1); lung (5); rectal (0); thyroid (4); prostate (3); lymphoma (0); liver (1); colon (0); breast (6); unidentified (4)	17	51	Gastric (2); lung (5); rectal (1); thyroid (1); prostate (0); lymphoma (1); liver (3); colon (1); breast (2); unidentified (1)
Lau and Chou [29] (2015)	Retrospective observational	Thoracic	49	Spinal cord compression	MIS: complete posterior-approach transpedicular corpectomy with expandable cage reconstruction of anterior spinal column; OS: traditional OS	28	59.5	Lung (3); breast (5); renal/bladder (2); others (14)	21	55.8	Lung (6); breast (2); renal/bladder (6); others (11)
Miscusi et al. [30] (2015)	MIS group: prospective cohort; OS group: retrospective cohort	Thoracic	42	Myelopathy (excluded patients with neurological deficit greater than 24 hr+modified Bauer Score >2)	MIS: minimally invasive laminotomy/laminectomy+percutaneous stabilization; OS: open laminectomy or laminotomy+stabilization	23	58.4	Lung (7); breast (6); myeloma (4); kidney (1); melanoma (3); others (2)	19	57.8	Lung (8); breast (6); kidney (2); prostate (2); ovary (1)
Hansen-Algenstaedt et al. [31] (2017)	Prospective observational	Thoracic; lumbar	60	Intractable pain and/or neurological deficit	MIS: central small incision with circumferential decompression and percutaneous pedicle screw system; OS: standard open	30	61,8	Breast (14); prostate (3); lung (5); thyroid (1); others (7)	30	60.2	Breast (4); prostate (8); lung (3); thyroid (4); others (11)
Kumar et al. [26] (2017)	Prospective observational	Thoracic; lumbar	45	Neurologic deficit; spinal instability	MIS: posterior instrumentation; OS: posterior instrumentation	27	62	Lung (7); breast (3); GI (2); renal (2); prostate (1); others (12)	18	65	Lung (5); breast (5); GI (1); renal (0); prostate (5); others (2)
Hikata et al. [32] (2017)	Retrospective observational	Thoracic; lumbar	50	Neurologic dysfunction; intractable pain	MIS: percutaneous screw and rod placement+neural tissue decompression fixation; OS: open pedicle screw placement and decompression+fixation	25	63.6	Lung (7); breast (3); prostate 4; kidney (2); lymphoma (2); liver (1); others (6)	25	60.2	Lung (2); prostate (0); breast (4); lymphoma (1); liver (3); others (15)
Saadeh et al. [33] (2019)	Matched retrospective	Cervical; thoracic; lumbar	40	Intractable pain	MIS: hybrid MIS transpedicular; OS: open transpedicular	20	56.4	Breast (4); lung (4); colon (2); renal (2); squamous (2); others (6)	20	60.3	Breast (4); lung (4); colon (2); renal (2); squamous (2); others (6)
Morgen et al. [27] (2020)	Non-blinded randomized controlled parallel-group trial	Thoracic; lumbar	49	Back pain and/or neurological impairment; MSCC between T5–L3	MIS: MASS; OS: traditional OS	23	65.9	Lung (3); breast (9); prostate (4); unidentified (4); renal (2); pancreatic (1); melanoma (0); thyroid (0); lymphoma (3); others (0)	26	67.6	Lung (6); breast (7); prostate (1); unidentified (1); renal (3); pancreatic (0); melanoma (1); thyroid (1); lymphoma (0); others (3)
Zhu et al. [15] (2021)	Retrospective observational	Thoracic; lumbar	154	Progressive paralysis due to spinal cord compression or intolerable back pain as a result of the instability of pathologic fracture	Minimally invasive spine surgery; traditional OS	49	53.84	Lung (9); breast (12); kidney (7); liver (2); thyroid (3); myeloma (3); colorectal (1); unknown (3); prostate (2); nasopharynx (3); uterus (1); others (3)	105	54.10	Lung (19); breast (18); kidney (8); liver (12); thyroid (4); myeloma (4); colorectal (4); unknown (9); prostate (4); nasopharynx (5); uterus (2); others (16)

MIS, minimally invasive surgery; OS, open surgery; MASS, minimal access spinal surgery; GI, gastrointestinal; MSCC, metastatic spinal cord compression.