Abstract
Study designRetrospective study.ObjectiveTo evaluate the radiological results of fusion with segmental pedicle screw fixation in juvenile idiopathic scoliosis with a minimum 5-year follow-up.Summary of background dataProgression of spinal deformity after posterior instrumentation and fusion in immature patients has been reported by several authors. Segmental pedicle screw fixation has been shown to be effective in controlling both coronal and sagittal plane deformities. However, there is no long term study of fusion with segmental pedicle screw fixation in these group of patients.MethodsSeven patients with juvenile idiopathic scoliosis treated by segmental pedicle screw fixation and fusion were analyzed. The average age of the patients was 7.4 years (range 5–9 years) at the time of the operation. All the patients were followed up 5 years or more (range 5–8 years) and were all Risser V at the most recent follow up. Three dimensional reconstruction of the radiographs was obtained and 3DStudio Max software was used for combining, evaluating and modifying the technical data derived from both 2d and 3d scan data.ResultsThe preoperative thoracic curve of 56 ± 15° was corrected to 24 ± 17° (57% correction) at the latest follow-up. The lumbar curve of 43 ± 14° was corrected to 23 ± 6° (46% correction) at the latest follow-up. The preoperative thoracic kyphosis of 37 ± 13° and the lumbar lordosis of 33 ± 13° were changed to 27 ± 13° and 42 ± 21°, respectively at the latest follow-up. None of the patients showed coronal decompensation at the latest follow-up. Four patients had no evidence of crankshaft phenomenon. In two patients slight increase in Cobb angle at the instrumented segments with a significant increase in AVR suggesting crankshaft phenomenon was seen. One patient had a curve increase in both instrumented and non instrumented segments due to incorrect strategy.ConclusionIn juvenile idiopathic curves of Risser 0 patients with open triradiate cartilages, routine combined anterior fusion to prevent crankshaft may not be warranted by posterior segmental pedicle screw instrumentation.
Highlights
Children diagnosed with scoliosis after 3 years and before 10 years constitute 8–21 % of those with scoliosis and present a distinct clinical entity
In juvenile idiopathic curves of Risser 0 patients with open triradiate cartilages, routine combined anterior fusion to prevent crankshaft may not be warranted by posterior segmental pedicle screw instrumentation
Deformity progression after posterior fusion for idiopathic scoliosis have been addressed across all Risser groups but Risser 0 patients with open triradiate cartilage are at most risk for crankshaft [1,2]
Summary
Children diagnosed with scoliosis after 3 years and before 10 years constitute 8–21 % of those with scoliosis and present a distinct clinical entity. Deformity progression after posterior fusion for idiopathic scoliosis have been addressed across all Risser groups but Risser 0 patients with open triradiate cartilage are at most risk for crankshaft [1,2]. The incidence of crankshaft phenomenon in Risser 0 patients with open triradiate cartilage treated with segmental pedicle screw instrumentation – posterior fusion followed till maturity; have not been reported in English speaking literature to our knowledge. The same scanner was used to obtain a 3D virtual model of the spine and pelvis. With the calibration of the virtual model's vertebral heights; the model was equalized to the real spine. The virtual model was set to be transparent in order to visualize the radiographs lying on the back font
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