A normal spine is structurally balanced for optimal flexibility and has gentle front-to-back inward and outward curves that work in harmony to keep the body’s center of gravity aligned over the hips and pelvis. The cervical spine (neck) and lumbar (lower) spine both have a lordosis,  an inward  or concave curve, while the thoracic (middle) spine has a kyphosis, an outward or convex curve. Together these curves form a gentle S.

Spinal deformity is caused by abnormal curvature of the spine putting it out of alignment. When the abnormal curvature is seen from the side (a front-to-back imbalance) it is called sagittal imbalance, and includes the conditions of kyphosis, lordosis, and spondylolisthesis resulting in flatback syndrome and chin-on-chest or dropped head syndrome. When seen from the back (a side-to-side imbalance) it is called scoliosis. While scoliosis can be caused by conditions such as cerebral palsy, muscular dystrophy, and a broad spectrum of conditions (acquired or secondary scoliosis), the cause of most scoliosis is unknown (idiopathic scoliosis). Spinal deformity affects individuals in every age and demographic group, but the prevalence increases with age as many causes are affected by degenerative conditions. 

Spinal deformity has a significant and measurable impact on health-related quality of life, including pain, function, self-image, mental health, work status, and disability. Prevalence of disease, utilization of healthcare resources, impact of disease on health-related quality of life, and cost of care are useful tools for measuring the burden of deformity on our population and on our healthcare economy. The purpose of this chapter is to provide information on the burden of spinal deformity on patients and on our healthcare system.

Adult spinal deformity is a broad diagnostic classification that includes idiopathic scoliosis as well as de novo or degenerative curves, which often result in coronal and/or sagittal plane decompensation. Sagittal plane malalignment is an increasingly recognized cause of pain and disability.1

Prevalence

The prevalence of spinal deformity has been reported at a wide range depending on the type of deformity and age. Congenital scoliosis has been reported at 100 in 100,000 persons,2 with acquired deformity as high as 68,000 in 100,000 persons.3  (Reference Table 2B.1.0 PDF CSV)

• 1. Joseph SA Jr, Moreno AP, Brandoff J, et al. Sagittal plane deformity in the adult patient. J Am Acad Orthop Surg. 2009:17(6):378-88.
• 2. Hedequist D, Emans J: Congenital scoliosis: a review and update. J Pediatr Ortho 2007:27:106-116.
• 3. Schwab F, Dubey A, Galez L, et al. Adult scoliosis: prevalence, SF-36, and nutritional parameters in an elderly volunteer population. Spine 2005:30:1082-1085.