Deformity: Kyphosis/ Scoliosis
Of the many conditions or diseases that can affect the spine, one of the simplest to understand is spinal deformity. Simply defined as a deviation from the normal shape of the spine, it can be caused by trauma, infection, tumor, degeneration, neuromuscular disease, or possibly most commonly by reasons unknown or not fully understood (idiopathic, meaning we have no clue why). In idiopathic conditions we have some working knowledge of certain attributes, such as genetic predisposition or normal history, just from careful observation of patients over decades and centuries, but without an understanding of the true basic underlying cause. Our treatment is designed to lessen the effects that we expect will occur from having seen the process follow its natural path in patients in the past.
- The most common spine deformity is scoliosis, complex enough to be discussed in a separate paper. Suffice to say in this context, in relatively simplistic terms, this is a deformity that occurs for the most part in the coronal plane (frontal plane, observed by viewing from front or back). This is to be distinguished from sagittal plane deformities (those viewed from the side). The third plane to be aware of is the transverse plane (viewed from above or below). By understanding that we can describe the spine shape in these three planes (coronal, sagittal, transverse) you understand that we can virtually define and quantify any deformity precisely in X, Y, Z axes.
- The second most common spinal deformity is kyphosis. Like scoliosis it can be congenital, traumatic, infectious (think tuberculosis or Pott’s disease), neoplastic (as in metastatic cancer destroying the vertebral body), degenerative (due to disc degeneration, multiple compression fractures, etc.), and like scoliosis, idiopathic. This latter version, frequently referred to as Scheuermann’s kyphosis, is defined as a kyphotic deformity characterized by three adjacent or consecutive wedged/kyphotic vertebrae, typically in the thoracic spine causing thoracic kyphosis in excess of normal (generally more than 40-50˚). This frequently occurs in adolescents and, like scoliosis, can progress during growth or even past skeletal maturity, to cause deformity, pain and dysfunction. The treatment is similar to scoliosis with careful observation of mild cases, bracing for moderate cases in select individuals (skeletally immature and with documented progression) and surgery for severe cases. The surgery is similar to scoliosis as well, with spinal fusion being the main objective, and use of rods and internal fixation to correct the deformity as much as possible. Unlike scoliosis, severe kyphosis can cause spinal cord injury due to stretch of the cord over the apex of the curve.
Another unfortunate cause of kyphosis is iatrogenic (or doctor-caused). This can occur when insufficient attention is paid to sagittal alignment during fusion surgery. Fortunately this cause is waning as a result of increased awareness and better surgical training. Unfortunately it can be the most painful variety of kyphosis and the most difficult to treat, or correct.