Improving outcomes in adult spinal deformity surgery

Proximal junctional kyphosis and failure are important complications in reconstructive spine surgery. The impact of proximal junctional pathology on health status is variable, and junctional failure may involve compromise of neural and physical function, and may require revision surgery. The risk factors for proximal junctional kyphosis include multilevel fusion to the sacrum, malalignment of the spine, choice of upper instrumented vertebra, magnitude of realignment, bone and muscle quality, tension band integrity and characteristics of the unfused spine. The pathophysiology of proximal junctional pathology involve fracture and bony failure, ligamentous and soft tissue failure, and combined bone and soft tissue failure. Prevention of proximal junctional pathology is an important goal, and has a significant impact on improving the outcomes and durability of spinal reconstructive surgery. Prevention strategies are derived from an understanding of the underlying causes of junctional pathology. Preoperative planning to determine optimal post-operative alignment, and intraoperative strategies to achieve that alignment are important for prevention of junctional pathology. Preoperative preparation of the patient with optimization of bone quality, extensor muscle strength and body mass index may prevent junctional complications. Surgical strategies including anterior column load sharing and posterior augmentation of fixation are useful for prevention of junctional pathology. Cement augmentation at the upper instrumented vertebra, with possible inclusion of the next cephalad vertebra may be protective of bone failure. Ligamentoplasty and preservation of the tension band may be protective of soft tissue failure. Proximal junctional pathology remains an important complication in spinal reconstructive surgery. Understanding the factors associated with proximal junctional pathology including the mechanisms underlying junctional kyphosis, and awareness of the strategies for avoidance of junctional pathology will empower the surgeon to reduce the risk of post-operative junctional kyphosis and lead to improved outcomes in adult spinal deformity surgery.