Outcome of Accessory Rods and Ilic Fixation for Distal Augmentation of S1 Fixation

Lumbar fusion is a surgical procedure that can be utilized to treat a variety of painful and degenerative conditions in the lower back. The most common conditions that indicate the need for an L5 S1 fusion include low back disc degeneration (also known as spondylolisthesis), spinal fractures, recurrent disc herniation, scoliosis, lumbar canal stenosis, and instability resulting from failed spine surgery . The success rate of lumbo sacral fusion surgery is influenced by many factors. These include non-union, hardware breakage or loosening, discitis, osteoporosis, tumors, and pseudoarthrosis . Lumbosacral pseudarthrosis is one of the most common complications in L5 S1 fusion surgery. It is a strong indication for revision surgery if severe symptoms persist. The rate of pseudarthrosis increases based on several parameters, including the number of levels fused, the type of fusion, and medical risk factors for pseudarthrosis . There are various methods of revision. One such method involves the use of iliac screws in addition to lumbo sacral interbody fusion. This approach improves the outcomes of revision fusion surgery but still carries the risk of rod breakage . S2 alar-iliac (S2AI) screws have been described as another method, but they have some disadvantages like rod breakage, screw misplacement, breach of cortical bone, and injury to neurovascular structures. These structures include superior gluteal vessels, external iliac vessels, pudendal vessels, superior gluteal nerves, sciatic nerve, and sympathetic chain ganglia . Our theory proposes the use of an accessory rod, which offers the advantage of dual rod fixation with a low incidence of rod breakage. We also suggest the free-handed placement of the iliac screw in the iliac bone, which plays a significant role in improving the integrity of the fixation and simplifies the application process. Multiple-rod constructs could prevent rod breakage and pseudarthrosis while also lowering the revision rate. As a result, they could lead to a better clinical outcome than the 2-rod construct. This approach is based on the principle that increasing the number of rods in the construct can distribute the load more evenly, reducing the risk of rod breakage and pseudarthrosis. This, in turn, could lead to a lower revision rate and better clinical outcomes