3D printed templates improve the accuracy and safety of pedicle screw placement in the treatment of pediatric congenital scoliosis

Abstract

Background: Three-dimensional (3-D) printed guidance templates are being increasingly used in spine surgery. The purpose of this study was to determine if 3D printed navigation templates can improve the accuracy of pedicle screw placement and decrease the complication rate compared to freehand screw placement in the treatment of children with congenital scoliosis.

Methods: The records of pediatric patients with congenital scoliosis treated at our hospital from January 2017 to January 2019 were retrospectively reviewed. Patients were divided into those where a 3D printed guidance templated was used and those in which the freehand method was used for pedicle screw placement. The accuracy rate of pedicle screw placement, surgical outcomes, and complications were compared between groups.

Results: A total of 67 children with congenital scoliosis were included (43 males and 24 females; mean age of 4.13 ± 2.66 years; range, 2-15 years). There were 34 children in the template-assisted group and 33 in the freehand group. The excellent accuracy rate of pedicle screw placement was significantly higher in the template-assisted group (96.10% vs. 88.64%, P = 0.007). The main Cobb angle and kyphosis angle were similar between the 2 groups preoperatively and postoperatively (all, P > 0.05), and in both groups both angles were significantly decreased after surgery as compared to the preoperative values (all, P < 0.001). The degree of change of the Cobb angle of the main curve and kyphosis angle were not significantly different between the 2 groups. There were no postoperative complications in the template group and 4 in the freehand group (0% vs. 12.12%; P = 0.009). All 4 patients with complications required revision surgery.

Keywords: 3D printed template; Computer-assisted surgery; Pediatric congenital scoliosis; Screw placement.

Fig. 1

A 7-year-old male was seen due to worsening neck skew. A, B X-rays showed congenital scoliosis and multiple vertebral deformities in the cervical and upper thoracic spine. The angle of scoliosis was about 72°, and the trunk was offset by 2.7 cm. C-E Computed tomography (CT) showed multiple vertebral malformations in the upper thoracic spine. CT angiography (CTA) was performed to determine the position of the carotid artery. F-J The spine was exposed during the operation, and a premade 3D printed navigation template was placed on the spine. The spinous processes and transverse processes were used as anatomical landmarks to confirm the fixation position. Using the navigation template Kirschner wires were placed, followed by placement of pedicle screws. K-L Postoperative anterolateral radiographs of the spine showed correction of scoliosis to 26°. M) Postoperative CT showed that all of the screws were placed in the center of the pedicles

Fig. 2

A 9-year-old female patient with a bulging back. A-C X-ray showed congenital scoliosis and a thoracolumbar hemi-vertebral deformity. The scoliosis angle was about 53° and kyphosis angle was 68°. D, E Postoperatively, the scoliosis angle was corrected to 5° and the kyphosis angle to 23°. After the operation, the patient’s lower limb muscle strength decreased but returned to normal after 1 month. F, G Computed tomography (CT) showed that the left L1 and L2 pedicle screws were offset into the spinal canal