Focus Issue: Introduction
Progressive deformity or degenerative instability requiring a fusion concentrates forces on the remaining motion segments; therefore, the patient has the potential for developing subsequent adjacent disc degeneration and/or junctional deformity. Limited surgery and motion-preserving techniques are potentially advantageous but may be only for a period of time before adjacent segments wear out and necessitate further treatment. Elderly patients with comorbidities or compromised bone who require surgical intervention are exposed to high rates of postoperative medical and implant-related complications. The preoperative evaluation and medical postoperative care of adult spine deformity patients require careful consideration with special attention directed to the cardiovascular and pulmonary systems. Adult spinal deformity has different characteristics from adolescent idiopathic scoliosis, demanding a new classification system and requiring new surgical techniques, especially for the correction of any sagittal plane deformity.
All these components of adult spine deformity are explored in this issue of Spine. In addition, three debates emphasize the typically difficult decisions that confront spinal deformity surgeons: whether or not a patient with comorbidities is an operative candidate and what is the best proximal, and what is the best distal extent of the fusion. While the answers to these questions are not absolute or for that matter even easily determined, the debaters have given the reader excellent insights into the related factors that must be accounted for from the time of preoperative surgical planning to the actual surgical procedure. It should be noted by the reader that the debaters were required to support their assigned positions even if it would not be their preferred choice. We hope the readers enjoy this issue of Spine. We have attempted to be comprehensive in our approach to the considerations in addressing adult spine deformity.