Adults who need spinal deformities corrected can present a problem for surgeons because of the inflexibility of most of the deformities. There are many deformities that need this type of correction, ranging scoliosis (curvature of the spine, side to side) and different types of arthritis in the spine. that can result in hyperkyphosis (humped back or rounded back). To be able to treat these though, surgeons must understand the advantages and disadvantages of major spinal osteotomies, surgery where bone is cut, and which is best for which deformity.
The authors of this article reviewed the different types of osteotomies and how they affect the patients’ horizontal gaze. The horizontal gaze is how the patient can look straight out in front, parallel (in line with) the floor. If a patient’s back is too hunched, they may be unable to look out that way and always have a downcast view.
Patients who have sagittal or coronal imbalances. Sagittal imbalances refer to the spine as you see it from the side while coronal is when you look at the spine from the front or the back. These can be stage I, where they are still balanced if a plumb line was held from their neck and hung down along the back, or stage II when this plumb line doesn’t fall straight along the back. A patient who has a kyphosis is unbalanced along the side, but if you look at it straight from the back, it could be stage I. On the other hand, if the back is curved in such a way that the patient has to adjust the stance to balance, this is stage II.
To correct these imbalances, surgeons have to manipulate how the spine is by either cutting bone or lengthening it. The different types of osteomies available all offer different approaches and outcomes. These are picked by the surgeons after taking into account the location of the deformity, the type of deformity, the angles to be corrected, and if bone needs to be removed or lengthened. These, of course, also all lead to how well the patient will be able to look out straight, the horizontal gaze.
As with all surgeries, there are complications associated with osteotomies. Spinal surgery, because of how long it can take and how complicated it is, has several risks that are common to all surgeries and some that are only for spinal surgery. The more common complications are infection and bleeding. The spinal complications include nerve damage. In osteotomies that shorten the bones, there are other issues. For example, one procedure, called the Smith-Peterson osteotomy is one that shortens the posterior column (back) while lengthening the anterior column (front). But, this can cause a injury to the main artery of the heart, the aorta, among others.
Some types of surgery have a higher rate of complications. For example, the Pedicle subtraction osteotomies are done for patients who aren’t candidates for the Smith-Peterson procedure. Bone is removed to help straighten the spine. However, this is a technically difficult procedure. A study that examined 46 patients who had the pedicle subtraction found that they were seven times more likely to have a major complication than patients who had different spinal surgeries. These complications included neurological problems, infections, pulmonary embolus (clot that entered the lungs), pneumonia, and heart attacks.
The authors concluded by writing that it’s “important to be able to recognize the type and underlying cause of the deformity so that the most appropriate osteotomy can be chosen.” While some procedures are more simple than others, they may be not be the best choice given the correction needed.