Surgical Correction of Distal Junctional Kyphosis

Abstract

Distal junctional kyphosis (DJK) is defined as the development of a kyphotic angulation over 10 degrees below a fusion construct and has been described as a complication of the treatment of adolescent idiopathic scoliosis, Scheuermann kyphosis, adult spinal deformity, and cervical deformity. There are some inherent risk factors to DJK: multilevel fusions, damage to the midline soft tissues including interspinous/supraspinous ligaments, T5-T12 thoracic kyphosis, T11-L2 thoracolumbar kyphosis, and increased mismatch between cervical lordosis and T1 slope. A 53-year-old male presented with cervicalgia, inability to sustain horizontal gaze, and kyphosis-enabled forward head posture. He underwent C3-T1 posterior decompression and fusion as treatment for cervical myelopathy 18 months prior. Neurologic examination was normal, with appreciable protrusion of the T1 vertebral spinous process. Surgery was initiated through subperiosteal exposure of C2-T6, followed by removal of previously set instrumentation, placement of new screws, and posterior column osteotomies of selected segments. Final steps involved compression across excised portions, locking pedicle screws, and a multirod insertion after closure of the posterior column osteotomies by compression maneuvers. Correction for DJK encompasses sagittal alignment restoration, a stable construct, and a good biological environment for healing. Failure of DJK realignment can occur if the patient's ligaments deteriorate distal to the construct or fractures develop in vertebral bodies at the lowest instrumented vertebra or lowest instrumented vertebra +1. One year after surgery, the patient's condition improved, evidenced from both patient self-report and a standing posture radiograph.

Keywords: Adolescent idiopathic scoliosis; Adult spinal deformity; Cervical deformity; Distal junctional kyphosis; Lowest instrumented vertebra; Posterior column osteotomies; Scheuermann kyphosis; Thoracic kyphosis; Thoracolumbar kyphosis.