The surgeon I went to for evaluation of my L45 spondylolisthesis invited me to attend a meeting where other surgeons would be discussing the kinds of surgeries done for this problem. Most of it was understandable but when they started talking about ALIFs, PLIFs, and TLIFs, I confess I got lost and tuned out. Now I'm looking back at my notes and thinking if you could explain these terms to me, then I might be able to understand what was said about my case in particular.
It sounds like you understand your diagnosis but need some help explaining the surgical procedures and approaches used when treating this problem. As you probably know, L4-L5 describes the segment of your lumbar spine that is involved. Spondylolisthesis is a term to mean vertebral slippage. Spondyl = vertebra and olisthesis = slip. Because of a fracture in the supporting column of the vertebral bone, the main vertebral body has slipped forward away from the back half of the vertebra. The result is a pulling, traction pressure on the nerve tissue and neurologic symptoms. X-rays taken from a side view show characteristic changes that identify this condition. Nerve tissue is highly sensitive so a shift of this type usually causes significant low back and/or leg pain. The pain is worse when extending the spine because the shift in the bone is the greatest in this position. Forward flexion moves the vertebra back toward a more neutral position, which takes pressure off the spinal nerves. When rest, improved postural alignment, and exercises don't help, then surgery to stabilize the segment may be needed. Fusion is the most successful surgery. But there are different ways to do a spinal fusion. Different techniques can be used along with different approaches. For example, an anterior approach means the surgery is done from the front, posterior approach from the back, and lateral or transforaminal from the side. Often a combination of two different directions gives the surgeon the angle needed to avoid tissue trauma and potential problems or complications. Interbody fusion means they remove the disc and replace it with a metal cage filled with bone chips. Screws are often used to hold everything together and in place until healing and complete fusion occurs. Surgeons have been using various fusion techniques for many years now. Research and study have improved fusion techniques. Many procedures can be done with minimally invasive methods to spare spinal muscles and prevent major complications such as bleeding or nerve damage. The goal is to use the least invasive procedure possible while getting the most stable long-term results for each patient.