Methods, surgical tools and a surgical system for performing spinal fixation using a lateral trans-psoas approach through a vertebral body into the disc space between that vertebral body and an adjacent vertebral body are provided. The approach, tools and system are adapted for use in fixing the L-5 and S-1 vertebral bodies. It should be understood that the methods and tools described can also be used for disc fusion where insertion proceeds from an inferior vertebral body to a superior vertebral body, and also cases where the fusion occurs across multiple disc spaces fusing more than two vertebrae.