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Neurosurgery. 2018 May 1;82(5):604-612. doi: 10.1093/neuros/nyx319.

Neurosurgical Randomized Controlled Trials-Distance Travelled.

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Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA.
Stanford Prevention Research Center, Department of Medicine, and Department of Health Research and Policy, Stanford University School of Medicine, and MetaResearch Innovation Center at Stanford (METRICS), Stanford, California.



The evidence base for many neurosurgical procedures has been limited. We performed a comprehensive and systematic analysis of study design, quality of reporting, and trial results of neurosurgical randomized controlled trials (RCTs).


To systematically assess the design and quality characteristics of neurosurgical RCTs.


From January 1961 to June 2016, RCTs with >5 patients assessing any 1 neurosurgical procedure against another procedure, nonsurgical treatment, or no treatment were retrieved from MEDLINE, Scopus, and Cochrane Library.


The median sample size in the 401 eligible RCTs was 73 patients with a mean patient age of 49.6. Only 111 trials (27.1%) described allocation concealment, 140 (34.6%) provided power calculations, and 117 (28.9%) were adequately powered. Significant efficacy or trend for efficacy was claimed in 226 reports (56.4%), no difference between the procedures was found in 166 trials (41.4%), and significant harm was reported in 9 trials (2.2%). Trials with a larger sample size were more likely to report randomization mode, specify allocation concealment, and power calculations (all P < .001). Government funding was associated with better specification of power calculations (P = .008) and of allocation concealment (P = .026), while industry funding was associated with reporting significant efficacy (P = .02). Reporting of funding, specification of randomization mode and primary outcomes, and mention of power calculations improved significantly (all, P < .05) over time.


Several aspects of the design and reporting of RCTs on neurosurgical procedures have improved over time. Better powered and accurately reported trials are needed in neurosurgery to deliver evidence-based care and achieve optimal outcomes.

[Indexed for MEDLINE]

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