''Scoliosis is not that unusual, about 0.7% of the population have it!''
The simple answer: No one knows for certain.
For years and years research has been carried out to try and trace what triggers the development of Scoliosis in an otherwise perfectly healthy individual.
The Scoliosis Research Society is one of the better known researching institutions, yet even they can only describe it as a multifactoral disorder, where any number of elements may combine to contribute to idiopathic Scoliosis.
Some people believe in the Dr. Gary Young theory that suggests Scoliosis is a virus or bacteria that lies dormant or active along the spine. He says that these pathogens then create inflammation, which contorts and disfigures the spinal column. (For this reason, many people who use rods only find later the operation did not help, as the virus was still intact within the spine. This means if the virus activates again, it could take the rods and spinal cord out of alignment together!) As the virus progresses, it creates a greater disturbance to the bone and tissues. After several months or years of suffering from this bacterial-viral invasion, the back wearies from holding the body up and the tense muscles that have suffered from mal-adjusting to the problem, cause the person excruciating pain.
In fact patients who have used alternative treatments such as raindrop therapy find that after application the area around the curve gets very hot and angry looking, so indicating that this could be true.
Such activities as playing a lopsided instrument e.g. flute or violin can also compound any tendencies a person may have for developing Scoliosis.
However, for the time-being there is still no proven cause - only time will tell...