Back Muscles Holding the Bone Graft The back muscles connected to the transverse processes create tension when placed back into position over the bone graft on the posterolateral area. This tension holds the graft in place during the healing process. Further Reading: Posterolateral Gutter Spine Fusion Surgery Related Articles Posterolateral vs. Interbody Fusion: The Two Main Approaches to Spinal FusionAfter Posterolateral Gutter Fusion Surgery: Risks and Complications Related Videos Posterolateral Gutter Fusion Surgery VideoPosterolateral gutter fusion is a type of spinal fusion surgery during which the spine is approached from a midline incision in the back. Interbody Spine Fusion Surgery VideoSee how an interbody spine fusion is designed to be a less invasive way of obtaining a spinal fusion. Spinal Compression Fracture VideoCompression fractures occur most often in the thoracic and lumbar sections of the spine and can be caused by traumatic injury or as a result of osteoporosis.