Surgery for Kyphosis correction is indicated for one or more reasons like progressive curve, severe curve, unrelenting backache, and neural deficit or paraplegia. The decision process for surgery depends on a number of factors: the type of sagittal imbalance, a history of prior surgeries, the degree and location of neural compression, the age and health of the patient, among other things. Surgery may involve one of the various types of osteotomies (removal of a part of bone/vertebra) to correct the deformity and spinal instrumentation for achieving a spinal fusion in desired position.
Common causes of kyphosis include:
Postural kyphosis, or “round back”
Inflammatory (Ankylosing Spondylitis)
Kyphosis correction is done with the use of implants and is called Spinal Instrumentation. Spinal instrumentation commonly involves insertion of pedicle screws in the required vertebrae and connecting them by a rod posteriorly in the desired position.
Decision regarding the type of osteotomy in a particular case is taken based on magnitude of the kyphosis, cause of kyphosis among others. Types of spinal osteotomies commonly done are
1. Posterior osteotomy (also called “Smith-Peterson” or “Ponte” osteotomies): This procedure involves removing the facet joints and interspinous ligaments to tilt the bones posteriorly through a mobile disc space. The facet joints typically limit extension of the spine, so their removal allows the surgeon to accentuate lordosis. Over multiple levels, 5-15o of lordosis per level is possible.
2. Pedicle subtraction osteotomy (also called closing wedge osteotomy): This procedure is used to cut through kyphotic segments. A triangle of bone is removed so the bone can be angled backwards. The procedure is particularly powerful, especially in the lumbar spine where the bones are bigger, and small corrections can lead to large improvements in posture. It is similar to placing a wedge between bricks – creating a sudden backward bend in the spine. The surgery requires the support of instrumentation above and below the osteotomy.
3. Vertebral column resection: This is the most powerful procedure of all spinal osteotomies. It is necessary when there is a severe bend in a small area. It involves essentially dislocating the spine in a controlled manner and realigning it in the proper direction
4. Anterior-posterior osteotomy: At times there is a failed fusion whose motion can be used to restore alignment. This may require an anterior and posterior surgery to take advantage of the motion through the failed fusion or mobile segment.