Background and Goal of Study: 
Blinded spinal anaesthesia (SA) remains a gold standard. Alternatively, a preliminary ultrasound (US) scan may improve safety and efficacy1, but a few anaesthetists currently perform it (lack of understanding of spinal sonoanatomy1 using poor US imaging low-frequency sonography2, S). A miniature automated ultrasound-based system (MAUBS), as anatomical structure tracker, might be a solution for Dura mater (D) location during SA. The MAUBS (Accuro™, Rivanna™) principle is to detect first the facet joins in the US field, measure their depth and then, fuse (SpineNav3D™ technology) with a 3D spine anatomical model (Fig1) for real-time 3D lumbar navigation to facilitate needle insertion.We report a preliminary case-series comparing MAUBS data against BW 2D S and depth measurement on the needle. 
Materials and methods: 
Ten patients (orthopaedic surgery) were included (2.5ml HB bupi 0.5% + Suf 5µg SA with 90 vs 150mm long 25G Witacre needle). The Fig. 1 displays the 4 steps methodology regarding the multimodal D depth assessment (steps 1-3) and verification on SA needle (step 4). 
Results and discussion: 
SA always succeeded. The patients´ data and results about technique are listed in Table. The individualization of three distinct patterns (spinous process, vertebral laminae and facet joint with D) was always possible whatever the US technology was. The Fig. 2 displays the respective individual depth measurements regarding facet joint and D. Finally the intra-individual inter-measurement comparison confirmed the measures´ similarity between the technologies. 
Conclusion: These conclusive results encourage the study of the MAUBS learning curve and its impact on SA practice.
 References: 
1. Br J Radiol 2012; 85: e262-e269 2. Med Ultrason 2014; 16: 356-63

An original miniature automated ultrasound-based system for spinal anesthesia against usual sonography: preliminary case-serie