"A trans-foraminal modified approach to a Ponte type osteotomy." A trans-foraminal modified approach to a Ponte type osteotomy. We use this trans-foraminal osteotomy (TFO) for larger and less flexible curves. This approach allows for resection of the entire facet joint and ligamentum flavum. In the figure, notice a wide bone resection has been carried out while preserving the midline osteo-ligamentous complex. The tip of the suction is resting on the dura. In idiopathic cases, the ligamentum flavum can be left behind after resection of the facet joint.