Sinus Lift Obtuse Angles, IMP6578-5 Description: Kramer-Nevins Sinus Lift Instrument (IMP6578) for OBTUSE angles with SMALLER Spoon blades width on one side compared to IMP6578. Spoon Blades Width (4 mm/5 mm). The botuse design will facilitat access to the mesial, distal, superior or inferior aspect. Designed to further separate the sinus lining from the bone, without fraying or tearing. IMP6578 or 6578