Scoliosis is a complex three-dimensional deformity of the spinal column that causes structural changes in the three planes of the spine (frontal, sagittal and transverse plane) and may occur in all vertebral segments.

The word “scoliosis” comes from the Greek for “crooked” (scolios).

Scoliosis viewed from the frontal plane exhibits a (partially) fixed lateral deviation of the spinal column with deformation of the vertebral bodies. In the transverse plane, a rotation of the vertebrae about their own axis is observed around the apex of the scoliosis, and torsion (spiraling) of the spinal column also occurs in this area.

In the sagittal plane the physiological curves (kyphosis and lordosis) are changed, with an increase or decrease in kyphotic or lordotic curvature depending on the type of scoliosis present.

Due to the rotation, the costal hump may be on the convex side of the spinal curve and the costal concavity may come to be on the opposite (concave) side. Lateral deviation of the spinal column cannot be completely compensated, either passively or actively. In cases of progressive lateral deviation of the spine, the vertebral segments stiffen progressively. A distinction is made between structural scoliosis with deformation and rotation of the vertebral bodies that cannot be completely compensated actively and passively and a purely functional scoliosis. Functional scoliosis is mainly seen in cases of postural damage, e.g. different leg lengths. In such cases, the scoliosis is not fixed and can be adjusted in a prone position.

From a morphological standpoint, the increasing malposition of the vertebral bodies results in structural changes in all vertebral body elements (vertebral bodies, spinous processes, transverse and arch processes, pedicles, and uncovertebral joints).

Body planes and directional terms

Scoliosis

Scolioses by groups

Idiopathic scoliosis

80-90% of all scolioses are termed “idiopathic.” (Greek: idios = self, pathos = suffering, disease). This refers to a form of scoliosis for which the cause and pathogenesis has not been explained to date. Idiopathic scoliosis is a three-dimensional spinal deformity, the pathogenesis of which remains unknown to date.

The three-dimensional quality of scoliosis refers fact that the changes it brings about occur in the three planes of the body, the frontal, sagittal, and transverse planes. Lateral deviation is observed in the frontal plane. A rotation of the vertebrae in the affected segments about their own axes as well as torsion, a screw-shaped turning of the spinal column, occurs in the transverse plane. An additional change is observed in the sagittal plane, which may alter the typical physiological lateral contours of the spinal column curvatures (kyphosis and lordosis). Scolioses of the thoracic spine frequently feature a flattening of the sagittal profile with the formation of a thoracic flat back. Scolioses in the transitional thoracolumbar spine region often feature a kyphosing (humpback) in the area. The deformation of the spinal column leads to structural changes in the mobile segments with changes in the vertebrae, vertebral joints, intervertebral discs and ligamentous apparatus, that begin suddenly and progress rapidly and which are caused by the altered static load on the segments.

Idiopathic scoliosis are classified in the following subgroups according to the patient’s age at initial onset:

  1. Infantile idiopathic scoliosis (initial manifestation of scoliosis up to 3 years of age)
  2. Juvenile idiopathic scoliosis (initial manifestation from 3 to 9 years of age)
  3. Adolescent idiopathic scoliosis (initial manifestation between 10 years of age and the end of adolescence)

Congenital scoliosis

Congenital scoliosis is a spinal deformity with lateral deviation and rotation of the spinal column caused by birth defects in the embryonal development of the vertebrae leading to the formation of one or more deformed vertebrae. The incomplete formation of the vertebrae results in asymmetrical growth of the spinal column. Congenitally anomalous vertebrae can occur in any part of the spinal column. Formation defects, segmentation defects, or combined forms of vertebral anomalies disturb the normal growth pattern of the spinal column, so that a scoliosis may develop as the spinal column develops. Congenital scolioses are rare, but may require early surgery due to the severity of the spinal deformity.

Neuromuscular scoliosis

This term describes a clinical picture resulting primarily from neurological or muscular diseases and characterized by a wide variety of symptoms of varying degrees of severity (for example disorders affecting posture and the locomotor system, mental disability, or damage to sensory perception functions). Many of

these diseases have their onset in childhood and may, in addition to the many individual primary symptoms observed, also lead to the formation of a scoliosis due to the neuromuscular disturbance of the postural apparatus with local or generalized muscular dysfunctions.

This text is taken from
Prof. Dr. med. Jürgen Harms • Klinikum Karlsbad-Langensteinbach • Guttmannstraße 1 • 76307 Karlsbad
© www.harms-spinesurgery.com 2007.