Table 2:

Summary of characteristics of included studies

Number of patients	Included studies (n=61)
Cohort characteristics
Number of patients	22 335
Sex (%)
Male	14 071 (63%)
Female	8264 (37%)
Mean number of patients per study	366
Age at surgery (years)
Weighted mean	60·4 (SD 2·15)
Cohort geography
Asian	23 (38%)
North American	28 (46%)
European	10 (16%)
Study types
Prospective cohorts	4 (7%)
Retrospective cohorts	57 (93%)
Surgical indications *
Neurological dysfunction	49 (80%)
Intractable pain	20 (33%)
Spinal instability	12 (20%)
General oncological treatment	8 (13%)
Surgical approach (patients)
Patients for which approach is reported	9 834 (44·0%)
Anterior	808 (8·3%)
Posterior	8 090 (83·6%)
Combined	934 (9·7%)
Surgical intervention (patients) *
Patients for which intervention is reported	19 945 (89·3%)
Decompression with or without fusion	15 924 (79·8%)
Corpectomy	1 583 (7·9%)
Spondylectomy	299 (1·5%)
Tumour histology
Number of studies reporting histology	52 (85%)
Not reported	9 (15%)
Single tumour	24 (39%)
Multiple tumour	28 (46%)
Tumour histology type (patients)
Total patients for which histology is reported	9 984 (44·7%)
Lung	3 065 (30·7%)
Kidney	1 764 (17·7%)
Breast	1 582 (15·9%)
Prostate	1 411 (14·1%)
Other (not specified)	672 (6·7%)
Hepatobiliary	362 (3·6%)
Thyroid	337 (3·4%)
Colorectal	160 (1·6%)
Outcomes examined *
Survival	40 (66%)
Complications (any)	20 (33%)
Neurological function, ambulation, or mobility	10 (16%)
Non-home discharge or length of stay	4 (7%)
Health-related quality of life	1 (2%)

Data refer to studies and are given as n (%), unless otherwise stated.

^*Not mutually exclusive: patients could have more than one indication for surgery, surgical intervention, or outcome examined.