174 Comparison of Accuracy Between Image-Guided and Freehand EVD Bedside Placement in Association With Time Efficacy

INTRODUCTION: A common neurosurgical procedure is the placement of an external ventricular drain (EVD), often as a time-sensitive treatment for hydrocephalus and/or increased intracranial pressure (ICP). The etiology ranges from traumatic brain injury (TBI) to spontaneous intracranial hemorrhages (ICH), frequently causing change to ventricular anatomy, making them difficult targets. METHODS: Adult patients with bedside EVD placement for TBI or spontaneous ICH between October 2021 to December 2023 were retrospectively reviewed and dichotomized by electromagnetic image-guided or freehand EVDs. The primary outcome was the rate of suboptimal placement (defined by Kakarla score). The secondary outcomes were rates of multi-pass EVDs and procedural time. RESULTS: Of 44 patients included, median age was 59 years (IQR 44-66), and 59.1% were males. Median midline shift was different between image-guided (3.5mm [IQR 1.5-6.3]) and freehand (0mm [IQR0-5]) EVDs (p=0.0013). With image-guidance, 100% of cases were completed with one pass and optimally placed (Kakarla 1). With freehand placement, 73.5% of cases were completed with one pass, and 88.2% were optimally placed. Median procedural times were similar between image-guided (55 min [IQR 50-60]) and freehanded (60 min [IQR 48.8-89.3]) placement (p=0.71). ARR for suboptimal placement with image-guidance was 11.76%. For every 9 image-guided EVDs, 1 additional suboptimal EVD placement will be prevented (NNT=9). ARR for multiple passes with image-guidance was 26.5%. For every 4 image-guided EVDs, 1 additional patient will avoid multiple passes for EVD placement (NNT=4). CONCLUSIONS: Image-guidance in bedside EVD placement does not require more time in comparison to freehand EVD placement and is associated with fewer passes and higher accuracy.