New Surgical Treatments for Scoliosis: Vertebral Body Stapling and Wedge Osteotomies
As an alternative to bracing or spinal fusion for treatment of progressive scoliosis, surgeons at the Philadelphia Hospital are investigating several methods for fusionless stabilization or correction of spine deformity. By not having to fuse the spine to correct the curvature, movement and flexibility can be maintained, allowing for preserved motion and less chance for back pain in adulthood.
For patients with progressive moderate scoliosis (less than 45°) who are still growing (girls up to age 14 and boys up to age 16), intervertebral body stapling of the convex (outer) side of the anterior spine may keep the curve from progressing. With the convex growth plates held in check, continued development of the concave (inner) growth plates should stabilize the progression and may allow some slight correction of deformity as the child grows. This concept has been used in children with bowlegs and knock-knees for some time. Using staples in the spine for stabilization of scoliosis was actually conceived 20 years ago but failed because the staples would dislodge and fall into the chest. Improvements in technology have led to development of a staple made of a memory-shaped alloy (nickel and titanium). The staple is shaped like a clamp at room temperature. When placed in an ice bath, the staple can be bent straight for insertion. After inserting the staple into the spine, upon heating to body temperature the staple returns to its original clamp shape, which prevents it from dislodging. This technologic advancement has allowed physicians to reconsider its use for correction of spine deformity.
At the Philadelphia Hospital, staples have been used in 12 patients with adolescent idiopathic scoliosis (AIS) who didn't want to wear a brace. All but one patient had the staples inserted through a thoracoscopic approach. The other patient had mini-incisions because the curve was in the lumbar spine instead of in the chest area. The follow-up on many of these patients is short, but so far all curves have been maintained and none have progressed. The curves of the first several patients, who had their stapling over one year ago, have actually improved. In the first patient, a 12-year-old boy whose curve had progressed from 20° to 38° despite bracing, the curve has improved from 38° to 30°. In the second patient, a 12-year-old girl, her curve improved from 35° to 27° one year after stapling. The patients are braced for one month after surgery to stabilize the staples, but then the brace is removed and there are no restrictions on activity.
Three additional young patients (each 5 years old) with severe curves have had staples inserted. These patients' curves were progressing despite brace treatment. Two of these patients with very severe curves required a posterior growing rod system in addition to the stapling. Their rods will be extended every six months until their spine has finished growing.
A new concept in scoliosis treatment is that of maintaining spine mobility following correction. The ability of the spine to move freely may allow the patient to participate more fully in sports and other activities and may decrease the chance of back pain, as he or she gets older. For skeletally mature adolescents with scoliosis, surgeons at the Philadelphia Hospital are investigating use of wedge osteotomies of the vertebral bodies to correct the curve. In this procedure, the surgeons remove a wedge-shaped section of vertebra on the concave side of the curve, straighten the spine by bringing the two sections together, and maintain the correction with a temporary rod system. While the patient has the rod, a brace is worn and all activity is restricted. After 12 weeks, when the osteotomies are healed and the rod is removed, the spine can move normally again and the patient can resume normal activity. This procedure is an alternative to a spinal fusion, in which motion can never be regained in the section that was fused.
Under a protocol approved by the Institutional Review Board (IRB) at Temple University, we are currently investigating the safety and utility of the wedge-rod system in patients with spinal cord injury (SCI) and spina bifida. In the 9 patients who have undergone the procedure, the deformity has been corrected, paralysis has not worsened, and none of the patients with SCI have lost spasticity. These results suggest that the vertebral body osteotomies can be performed safely. Because of this safety and early success with correction, the surgeons at the Philadelphia Hospital plan to submit an IRB protocol for application of the vertebral body osteotomy for application in mature adolescents with idiopathic scoliosis.
Exciting advances in scoliosis correction are emerging, and the Philadelphia Hospital is employing this new technology with the hope that these new and better procedures will soon become effective treatment options for children with spine deformities.