The term flat-back syndrome has been used to describe symptoms resulting from distraction instrumentation into the lower lumbar spine or sacrum and other factors that may aggravate the loss of lumbar lordosis include thoracolumbar kyphosis, fixed thoracic kyphosis, hip flexion contractures, and pseudoarthrosis, although loss of lumbar lordosis may occur with modern segmental implant systems if precautions to preserve lumbar lordosis ore not taken loss of lumbar lordosis with forward inclination of the trunk, inability to stand upright, and back pain. The aim of this paper is to review the leterature to determinate couses and clinical presentation of Flat-Back-Syndrome.