Table 1

Characteristics and outcomes of the studies included in the meta-analysis on the impact of operation details on hydrocephalus after decompressive craniotomy.

First author, Year	No.	Country	Study design	Primary disease	Main outcomes				Adjustment	Level of evidence (CEBM)
First author, Year	No.	Country	Study design	Primary disease	Case No. of hydrocephalus/distance to midline <25mm	Case No. of hydrocephalus/ distance to midline ≥25mm	Mean distance to midline in hydrocephalus group (cm), case No.	Mean distance to midline in no-hydrocephalus group(cm), case No.	Adjustment	Level of evidence (CEBM)
Honeybul & Ho, 201212	159	Australia	Retrospective observational cohort	TBI	–	–	2.4±1.1, 10	2.3±1.0, 73	Age, GCS, pupil reactivity, extracranial injury	2b
De Bonis et al, 201313	64	Italy	Retrospective observational cohort	TBI	15/32	4/32	–	–	Age, gender, hygroma, CSF infection, IVH	2b
Takeuchi et al, 20132	21	Japan	Retrospective observational cohort	HICH	8/14	2/7	2.17±0.47, 10	2.6±0.33, 11	Age, gender, GCS, IVH, midline shift	3b
Takeuchi et al, 201314	28	Japan	Retrospective observational cohort	CI	11/16	2/12	–	–	Age, gender, GCS, side, midline shift, infarct area, meningitis	3b
Wang et al, 201415	62	China	Retrospective observational cohort	TBI	–	–	3.4±1.1, 15	3.7±1.0, 47	Age, GCS, Fisher grade, midline shift, meningitis	2b
Wang et al, 201516	128	China	Retrospective observational cohort	CI	13/82	6/46	2.36±0.42, 19	2.31±0.48, 109	Age, duration from infarction to craniectomy, presence of SAH, preoperative GCS score	2b

No. - number, cm - centimeter, – - not reported, CEBM - Centre for Evidence-Based Medicine, GCS - Glasgow Coma Scale score, IVH - intraventricular hemorrhage, TBI - traumatic brain injury, HICH - hypertensive intracerebral hemorrhage, CI - cerebral infarction, CSF - cerebrospinal fluid, SAH - subarachnoid hemorrhage, 2b-3b - Studies were graded from level 1 (strongest evidence) to level 5 (weakest evidence)