Fig. 4.

The percentage drain insertion per clinical team over the period of 2009 to 2016. The % drain usage in each clinical team is plotted per year. Data points on the graph were omitted if the clinical team performed fewer than three CSDH drainage procedures in that year. Only one clinical team (team 8) convincingly adopted the practice of using subdural drain in 2010, following the publication of the Santarius et al. trial in September 2009. The practice was variable amongst the other clinical teams between 2010–2013. Following the audit of drain usage from January 2009 to January 2014, and subsequent presentation to the Morbidity and Mortality meeting in Spring 2015, there was a notable increase in % drain use by the majority of the clinical firms in 2015