AUTHOR=Greuter Ladina , Hejrati Nader , Soleman Jehuda 

TITLE=Type of Drain in Chronic Subdural Hematoma—A Systematic Review and Meta-Analysis

JOURNAL=Frontiers in Neurology

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2020.00312

DOI=10.3389/fneur.2020.00312

ISSN=1664-2295

ABSTRACT=Background: 
Chronic subdural hematoma (cSDH) is one of the most common neurosurgical diseases, while burr-hole drainage is the most frequently used surgical treatment. Strong evidence exists that subdural drain (SDD) placement reduces recurrence rates. The insertion of a subperiosteal drain (SPD) was shown to lead to similar recurrence rates and less complications than SDD. The aim of this study is to provide a systematic review of the literature and conduct a meta-analysis of studies comparing SPD with SDD. 
Methods:
Pubmed and Embase databases were searched using a systematic search strategy to identify studies on drain location up to December 2019. Primary outcome measure was recurrence, while secondary outcome measures were drain misplacement, morbidity, mortality, and clinical outcome. Besides randomized controlled trials (RCT), we included non-randomized prospective cohort studies, as well as retrospective cohort studies. A fixed effect model was used if low heterogeneity (I2<50%) was present, otherwise a random effect model was used. 
Results:
Following removal of duplicates, we screened 1109 articles of which ten articles were included in our qualitative and quantitative analysis. One study was an RCT, three were non-randomized prospective cohort studies, and the remaining articles were retrospective cohort studies.  In these ten articles, 1553 patients were treated with SPD and 1782 patients with SDD. Comparing the recurrence rate of cSDH a significant difference was found between SPD and SDD insertion (11.9% and 12.3%; RR 0.8, 95% CI 0.67-0.97, I2=0%, z=-2.27 p=0.02). SPD had significant lower rates of drain misplacement and parenchymal injuries (1.2% and 7.8%; RR 0.17, 95% CI 0.07-0.42, I2=0%, z=-3.4, p=0.0001), as well as morbidity (6.4% and 8.2%; RR 0.65, 95% CI 0.5-0.84, I2=44.5%, z=-3.32 p=0.0009). Mortality rates (5.0% and 4.6%; RR 0.83, 95% CI 0.6-1.14, I2=0%, z=-1.2, p=0.25) and favorable clinical outcome (89.6% and 88.9%; RR 1.1, 95% CI 0.89-1.24, I2=54.2%, t=0.98, p=0.40) were comparable in both groups. 
Conclusion:
The insertion of SPD in cSDH showed lower rates of recurrence, drain misplacements and parenchymal injuries, as well as overall morbidity, while clinical outcome and mortality were comparable to SDD. Therefore, the insertion of SPD after surgical drainage of cSDH should be encouraged.