You may be referring to Dr. X-F Li at the University School of Shanghai in China who recently reported on the use of pedicle subtraction osteotomy to correct congenital spinal deformity in children. The results of that study were published in The Spine Journal (February 2011).
In that same journal Dr. M. N. Imrie from Children’s Hospital at Stanford University wrote a commentary on the study and the procedure. She also offers a nice review of congenital scoliosis including what it is and how it is treated.
Anything “congenital” means it is present at birth. In the case of congenital scoliosis, there is a curvature of the spine caused by a defect in the vertebral (spinal) bone. There are several different types of spinal defects that can cause this type of congenital scoliosis.
The pedicle subtraction osteotomy for the treatment of mild to moderate congenital scoliosis was reported to be safe and “simple.” It’s that word “simple” that Dr. Imrie takes some exception to.
In this procedure, the surgeon removes a pie-shaped piece from the deformed hemivertebra. Along with the piece of vertebral bone, they also remove the transverse process — that’s the bony bump you feel along the back of your spine. The effect is to allow the remaining edges of bone to collapse toward each other.
The surgeon guides either side of the remaining bone fragments to move together — enough to close the gap formed by removing the piece of bone. The end result is correction of the curve. It’s called a subtraction osteotomy because only a portion of the deformed vertebra is removed or taken away (subtracted).
But there are several limitations to this procedure. First, the hemivertebra has to be large enough to allow a chunk of it to be removed. Some are too small for that. Second, since only part of the bone is removed, the curve correction is less than if it were removed completely. And third, this method won’t work if there is a rigid bar of bone present because of a segmentation deformity.
Dr. Imrie agrees that the reduced operative time and smaller blood loss are important advantages of the subtraction osteotomy. But the surgical technique described with this approach is not simple. Highly skilled spine surgeons with the right kind of experience and expertise are needed to perform such procedures.
In addition, the patient must be monitored carefully for any damage to the spinal cord or spinal nerve roots. This type of neural injury could result in sensory and/or motor loss that could even be serious enough to cause permanent paralysis.
Only 12 patients were included in the study. And only those with a defect at the T12 vertebra were operated on with this new technique. Despite the positive outcomes, Dr. Imrie urges caution before adding this procedure as a confirmed, safe treatment option.
Further comparative studies are needed with children of different ages, with different types of deformities, and comparing results to other more tried and true surgical approaches. The first report of pedicle subtraction osteotomy is important but not the final word.