Osteotomies
Osteotomies are bone-cutting procedures. In the spine, their goal is to produce lordosis. They can also correct rigid or angular scoliosis that occurs over a short segment.
Pedicle Subtraction Osteotomy
The goal of a pedicle subtraction osteotomy procedure is to create a normal amount of lumbar lordosis (approximately 50 degrees). In this type of osteotomy, the “pedicle” (a bony tube going from the back and front of the vertebra) is “subtracted” (removed). A wedge is taken from the bone, and the whole vertebra is bent backwards. This allows 20-40 degrees of lordosis to be restored at a single level. It is not dependent on the flexibility of the discs like the Smith-Peterson osteotomy does.
Posterior Osteotomy
TH required multiple posterior osteotomies (called “Smith-Peterson” or “Ponte Osteotomies”) to straighten her spine to normal degrees of kyphosis. Normally the vertebra contact each other through 3 joints at each level: one disc in the front, and two sliding facets in the back. In the thoracic spine, the facets look like shingles on a roof, and will only allow you to bend backward so far. In this osteotomy, we remove the facets and bend the spine backward further than normal. Over one level, only a little bit of correction will occur (5-15 degrees). However, over many levels, large amounts of correction can be achieved.
