Diminution of lower back pain has been a goal of lumbar surgery for degenerative conditions for many years. Spinal surgeons have been trying to optimize their diagnostic and surgical techniques in order to maximize pain reduction and minimize tissue trauma at the operative level while maximizing the longevity of the surgical construct. Lately, adjacent level issues have been a more highly debated issue. The adjacent level has been one of the reasons behind the introduction of the artificial lumbar disc. Other motion-sparing technologies have been developed and are under investigation or are in use nationally as well as internationally. Inter-spinous and pedicle-based posterior dynamic stabilization, nucleus replacement, annular repair techniques, and disc regenerative techniques are all examples of such technologies. Unfortunately there are a lot of unanswered questions. Among the many unresolved issues is that of adjacent level degeneration. While there are some published data on the incidence of adjacent level degeneration in spinal fusion surgery in the lumbar spine, there are no long-term Class I data. The preliminary results of prospective randomized FDA trials, which have included lumbar fusions as well as arthroplasty in similar cohorts of patients, are the closest we have to such data. However, prior to reaching any definitive conclusions, we need long-term results regarding the incidence of adjacent level disease and the possible beneficial effects of motion-sparing technologies.

The concept of pedicle screw instrumentation without attaining a fusion is one that in the past has been known for having complications and being fraught with hardware failure, loosening and “instability.” The role of pedicle-based dynamic stabilization and fixation without fusion has been more recently debated in the literature, and some authors have reported it as a viable technology for pain reduction and possible sparing of the adjacent levels. Such systems are thought to stabilize (to a physiologic range), rather than fuse or excessively restrict motion. Currently there are a number of pedicle-based dynamic stabilization systems that are either in use or under investigation worldwide. Given the paucity of long-term data regarding the outcomes of pedicle-based dynamic stabilization, we believe that identifying some of the potentially important variables and concepts can be of benefit to the future of this technique. In this symposium we discuss and expand on such concepts with experienced clinicians as well as researchers who have been studying these devices and techniques on a national and international level.

SAS Journal. Autumn 2007;1; 147–159. SASJ-2007-Symposium1