 Using angled 2-mm Kerrisons hypertrophied ligamentum flavum, the superior facet of S1 and L5 was resected increasing the dimensions for the foramen passed lateral to medial and medial to lateral without further compromise. 
Using angled 2 - mm Kerrisons hypertrophied ligamentum flavum , the superior facet of S1 and L5 was resected increasing the dimensions for the foramen passed lateral to medial and medial to lateral without further compromise .