Patient selection
The patients were retrospectively identified from our surgical database using the following inclusion criteria: Lenke type 1 to 4 scoliosis, based on preoperative imaging (radiographs, computed tomography, and magnetic resonance); corrective surgery using either the multilevel Ponte osteotomy procedure combined with posterior selective segmental pedicle screw constructs or posterior selective segmental pedicle screw constructs only; and availability of complete clinical data throughout the follow-up period. Sixty-five patients met the inclusion criteria and were enrolled in the study. Among these, 32 had been treated using multilevel Ponte osteotomy (group A) and 33 using soft tissue release only (group B).
Group A included 10 males and 22 females, 13 to 18 years of age (mean, 15.1 ± 1.9 years), with a disease course of 2–6 years (mean, 3.5 ± 1.1 years) and a Risser sign of 3.3 ± 0.9. After corrective surgery, thoracic kyphosis was decreased in 11 cases, within normal limits in 18 cases and increased in 3 cases. All patients were followed-up, on average, for 24.2 months (range, 18–30 months).
Group B included 10 males and 23 females, 13 to 19 years of age (mean, 15.7 ± 1.9 years), with a disease course of 2–6 years (mean, 3.3 ± 1.3 years) and a Risser sign of 3.1 ± 1.0. Thoracic kyphosis was decreased in 11 cases, normal in 19 cases, and increased in 4 cases. All patients were followed-up, on average, for 23.9 months (range, 18–30 months).
Prior to surgery, full-length spinal radiographs (standing anterior-posterior and lateral views), computed tomography (CT) and magnetic resonance (MR) images of the spinal region of interest for correction, echocardiography, B-mode ultrasonography of the urinary system, and pulmonary function testing were routinely obtained. No evidence of pathology or structural abnormalities of the spinal canal and neural structures were identified in any patient, and all patients had unremarkable assessments of the cardiorespiratory, urinary, and renal systems.
The distribution of sex, age, disease course, Risser sign, number of segments fused, postoperative coronal Cobb angle, and thoracic kyphosis were comparable between the two groups (
P > 0.05; Table
1).
Table 1
Basic information of patients in two groups
A
| 32 | 22 | 16.1 ± 1.9 | 3.5 ± 1.1 | 3.3 ± 0.9 | 34.7 ± 7.9 | 66.1 ± 7.7 | 10.3 ± 2.0 |
B
| 33 | 23 | 15.7 ± 1.9 | 3.3 ± 1.3 | 3.1 ± 1.0 | 47.5 ± 6.8 | 66.4 ± 7.3 | 9.6 ± 2.3 |
| | ×2 = 0.007 | t = 0.703 | t = 0.766 | t = 0.830 | t = −6.998 | t = −0.128 | t = 1.416 |
| | P = 0.934 | P = 0.484 | P = 0.447 | P = 0.410 | P = 0.000 | P = 0.898 | P = 0.162 |
Surgical procedure
For group A, after administration of general anesthesia and intubation, the patients were placed in the prone position with the abdomen suspended. A midline posterior incision was performed to expose the posterior structures of the spine. Subperiostial tissues were dissected to expose the laminae, articular processes, and transverse processes. A pedicle screw was manually inserted into the appropriate vertebrae based on the flexibility of the scoliosis and the number of interval vertebrae: upper vertebral body of the top vertebra of the scoliosis and the adjacent stable vertebra or between the two top vertebrae of the scoliosis and the adjacent stable vertebra. A C-arm was used to visualize the length of penetration and location of the pedicle screw.
We subsequently proceeded with the release of the posterior structures of the spine using a rongeur to remove the spinous processes, interspinous ligaments, and supraspinous ligaments along the root. The yellow ligament was also completely removed using a gun-like rongeur up to the anterior surface of the facet joints. Subsequently, the facet joints and inferior articular processes were completely resected bilaterally until the intervertebral opening was completely open to retain the integrity of the pedicle. We also resected the edge of the upper and lower lamina to achieve a uniform width of the lamina window. A Ponte osteotomy was then performed at each segment of the thoracic curvature. The spinal rod, which had been prebent according to the degree of curvature of the scoliosis and the sagittal physiological curve, was placed on the concave side of the thoracic curve, with the length and orientation adjusted to achieve appropriate distraction up to the top vertebra. A second spinal rod was then inserted on the convex side and tightened. After adequate correction of the spinal alignment was confirmed, the surgical field was rinsed using a flushing gun. The cortical bone of the posterior laminae was then grounded and treated with a mixture of autogenic and allogeneic bone. A drainage tube was placed in situ, and the incision was closed. All surgeries were performed under monitoring of the spinal cord function, and only autologous blood transfusion was used, as needed.
For group B, the same surgical procedure as for group A was performed, with the exception that the interspinal and intertransverse ligaments and joint capsules were completely resected by cauterization and using a rongeur, but without performing a posterior column osteotomy.