When stability of the spine is a concern, fusion is accepted as the gold standard to maintain spine stability and pain relief. After a proper rigid fixation procedure of the spine (aiming to fusion), the end-result is decreased pain and disability levels, at the expense of a less mobile spine. High mortality and morbidity rates specific to fusion techniques (especially in elderly people with comorbidities), painful postoperative period, the risk of failure (non-union), and accelerated degenerative changes adjacent to fused spinal segments are the major disadvantages of the fusion surgery.
In gross/overt instability cases, such as patients with trauma or some congenital defects, the need for fusion surgery is quite clear. However, patients with degenerative conditions such as lumbar stenosis, degenerative spondylolisthesis, degenerative scoliosis, painful degenerative disc disease and annular rupture with or without lumbar disc herniation, overt instability is actually rare. In those cases, the degree of instability is low, and can be termed as segmental, or sometimes “micro” instability. Those patients with degenerative segmental instability do not need a fusion surgery most of the time. Sometimes, just a well-constructed exercise program, weight loss and occupational preventions may be sufficient. Sometimes, the intrinsic stabilization capacity of spine is more severely disturbed, and some sort of stabilization procedure may be necessary to support/restore stability of the spine. In those cases, a fusionless, i.e., motion-preserving spine stabilization is the solution of choice. Today arthroplasty, soft stabilization, semi-rigid stabilization and dynamic stabilization techniques offer a viable alternative to fusion surgery. These techniques solve instability problem in a less invasive way (than that of the fusion surgery) without disturbing biomechanics of the spine and eliminating the problems specific to fusion. Thus, it is our strong belief that fusion surgery is an over-treatment for most of the degenerative cases, and should be kept as the last resort. Instead, motion-preserving techniques should be accepted as the first-line treatment in degenerative spinal instability, when internal fixation of the spine is indicated. In summary, motion-preserving spine stabilization systems has been developed to eliminate the major disadvantages of fusion, and we believe that they will be the future of spine surgery.