ABSTRACT
Scoliosis is an abnormal lateral curvature of the spine often accompanied by vertebralrotation. The most common form of scoliosis is adolescent idiopathic scoliosis (AIS). It isbelieved that there are several, separate causes of scoliosis all with a common end result which hinders experimental research design. Although abnormal spinal curves have been produced using several methods in a variety of species, none of the curves created mimic those seen in AIS. Consequently, there is no current animal model that can be used to study this problem. In recent years, it has been shown that removal of the pineal gland in young chickens results in the development of scoliosis and that the curves produced have many of the characteristics seen in patients with AIS. This model is receiving much attention as it has much potential for developing an understanding of a mechanism by which scoliosis might be produced at least in some cases of AIS and also as a model for studying scoliosis in general. While serum melatonin levels are significantly reduced in all chickens following pinealectomy, not all the chickens develop scoliosis. While there is much evidence to suggest that removal of the pineal gland with subsequent reduction in serum melatonin levels is the cause of the scoliosis, there remains some suggestion that it might be an artifact of the extensive surgery or reduced levels of another product of the pineal gland that might be responsible. Unfortunately, the phenomenon does not appear to be duplicated following pinealectomy in mammals but, nevertheless, an understanding of the reasons why this is so would provide a large step forward in the understanding of scoliosis in humans. A model to explain the process by which reduced levels of melatonin might produce scoliosis includes the involvement and connection of melatonin with growth hormone and its subsequent effect on bone growth within the vertebrae. This is a very dynamic area of research and one where there is possibly immediate clinical application accompanied by the potential to revolutionize thinking about the treatment methods for scoliosis.
