Spinal osteotomy is a procedure where a cut is made into one of the bones of the spine, usually removing a portion of the bone in a wedge shape to allow for correction of spinal alignment. There are a number of different types of osteotomy. The specific osteotomy used in any case depends on the location of the spinal deformity to be corrected as well as the amount of correction that is needed. Spinal osteotomies are used as part of a spinal reconstructive procedure in order to achieve spinal balance and stability.
Spinal instrumentation (rods and screws) are used as part of a spinal realignment procedure to hold the spine in correct alignment while spinal fusion occurs. Spinal fusion is a process where the bones of the spine heal together or mend into one solid piece. Once this occurs the spine will be stable in that area and further curvature or progression is unlikely.
Patients who have had previous spinal surgery in which previous instrumentation was placed may require partial or complete removal of the preexisting implants and placement of additional implants as part of the spinal deformity reconstruction.
TYPES OF SPINAL OSTEOTOMIES:
Smith-Peterson osteotomy (posterior column osteotomy) [Figure 1] is a procedure where a portion of the bone in the back portion of the spine may be removed. When this bone is removed it creates a space and when this space is closed down it allows the bones in the back of the spine come closer together, therefore "leaning" the spine more toward the back. Smith-Peterson osteotomy may be performed at one location or multiple locations along the spine to allow the surgeon to restore lordosis in the area of the osteotomy. SPO refers to an osteotomy where the posterior ligament and facet joints are removed to allow for correction through this area. This procedure requires motion through the mobile anterior portion of the spine or the discs for correction.
A pedicle subtraction osteotomy (PSO) [Figure 2] is also known as a transpedicular wedge osteotomy. A PSO is performed by removing the posterior element and facet joints similar to a Smith-Peterson osteotomy. The PSO then involves removing the remaining posterior elements and pedicles of the vertebral body then working around the nerves of the spine into the front portion of the spine and a portion of the vertebral body is removed, usually in a wedge [Figure 3]. This osteotomy involves all three columns of the spine (posterior, middle, and anterior). During a posterior subtraction osteotomy (PSO) resection of a great deal more bone is performed than a single Smith-Peterson osteotomy. Therefore, the correction of the lordosis with this osteotomy is greater.
Figure 2: A pedicle subtraction osteotomy (PSO)
Vertebral column resection (VCR) [Figure 4] allows the largest correction of any spinal osteotomy. During the vertebral column resection, one entire segment of the spine is removed. This procedure was initially described through an anterior and posterior combined approach. More recently the VCR has been performed through a posterior only approach and is shown to be safe and effective for many patients [Figure 5].
Figure 4: Vertebral column resection (VCR)
Figure 5: An x-ray from taken from the side (lateral) of a patient who has undergone a thoracic VCR. The spine is supported in the front by a cage which restored the height of the spine and pedicle screws and rods in the back. Spinal fusion is performed over these levels.
Spinal deformity correction surgery with osteotomy is an option for the patient if the nonsurgical treatments do not relieve their pain or symptoms. Surgery is also needed for patients whose deformity is getting worse over time or who have curvatures that are leading to nerve compression causing symptoms such as numbness, weakness, or pain. Surgical reconstruction involves some correction of the curvature, with the goal of the surgery being to relieve pain and to prevent the curvature from getting worse in the future [Figures 6, 7, 8].
Caption for Figures 6,7,8: This patient is a 64 year old female who had lumbar fusion surgery in the past. She did well for years, but then she began leaning forward and to her left side. She developed severe pain that kept her from walking or even standing. Her x-rays revealed flat back deformity with a loss of normal lumbar lordosis and also a new scoliosis. She underwent spinal reconstruction surgery with Dr. Good over 2 years ago. During her surgery, a portion of bone was removed (osteotomy) to allow for realignment of her spine and the spine was held in the new alignment using pedicle screw implants. Her X-rays and clinical photographs show excellent correction of her flat back deformity and she has returned to activities including working at a greenhouse.
Determining if an osteotomy is needed and which type for any given patient depends on multiple factors as well as the location of the spinal deformity to be corrected. The surgeons at Virginia Spine Institute will perform x-rays to determine the magnitude of the spinal deformity as well as the flexibility of the spine to determine the extent of the correction that may be necessary. Once the spinal deformity reconstruction surgery is indicated, careful preoperative assessment of the curve is needed to help determine the optimal spinal alignment of the spine after surgery.
Spinal deformity surgery with vertebral osteotomy is a challenging but safe procedure and can be performed with relatively low complication rate; however, complication rates are higher with more complicated surgeries. Published studies how shown good results following spinal osteotomy surgery. The decision to perform surgery to correct spinal deformity with an osteotomy should be made carefully after a thorough discussion with your spine surgeon.