BackgroundChronic subdural hematomas (cSDH) are one of the most common conditions requiring neurosurgical treatment. The reported recurrence after surgery is 3–21.5% with closed system drainage. In clinical practice, irrigation fluids at body temperature (37 °C) and at room temperature (22 °C) are routinely used in the evacuation of cSDH. Our hypothesis was that irrigation at body temperature might have more beneficial effects on coagulation and solubility of the chronic subdural hematoma than irrigation at room temperature. The aim of this study was to compare the effects of different intraoperative irrigation fluid temperatures on recurrence rates.MethodsThis was a retrospective study where we included all consecutive patients from a defined geographical area of western Sweden between September 2013 and November 2014. In the course of 6 months, we performed intraoperative irrigation at body temperature (37 °C, BT-group) during burr hole evacuation of chronic subdural hematoma. This was then compared with the previous 6-month period, when irrigation fluid at room temperature (22 °C, RT-group) was used. The primary endpoint was same-sided recurrence in need of reoperation within 6 months.ResultsRecurrence occurred in 11 of 84 (13.1%) patients in the RT-group compared with 4 of 88 (4.5%) in the BT-group (p = 0.013). There were no significant between-group differences regarding age, sex, duration of surgery, frequency of bilateral hematomas, hematoma density, and use of anticoagulant/antithrombotic therapy.ConclusionOur study demonstrates that intraoperative irrigation fluid at body temperature is associated with lower recurrence rates compared with irrigation fluid at room temperature. To investigate this further, a prospective randomized controlled trial has been initiated (clinicaltrials.gov, NCT0275235).Trial registrationClinicalTrials.gov Identifier: NCT0275235