Proximal junctional kyphosis (PJK) is a common post-operative radiographic finding after surgery for adult spinal deformity (ASD) patients. Although the clinical relevance of isolated PJK is unclear, PJK can progress to symptomatic proximal junctional failures which requires a large revision surgery. Currently, post-operative bracing with a thoracolumbosacral orthosis (TLSO) is common practice after spinal deformity surgery, however the efficacy of this in preventing PJK is unknown. This multi-center randomized control trial identified 84 patients undergoing thoracolumbosacral fusion for ASD and plans to study the efficacy of a novel post-operative TLSO in preventing the development of PJK as defined by the proximal junctional angle on 6-month post-operative X-rays.