Study design: Retrospective review of anterior and posterior fusions for treatment of Lenke5C adolescent idiopathic scoliosis (AIS).
Objective: To compare the clinical and radiographic results of anterior versus posterior pedicle screw instrumentation in Lenke5C AIS.
Summary of background data: Anterior and posterior pedicle screw instrumentations are 2 established methods of correcting Lenke5C AIS. However, there are few reports that compare the 2 methods.
Methods: Forty-six consecutive patients with Lenke5C AIS curves underwent selective lumbar or thoracolumbar fusion (1999-2005). Twenty-two patients had anterior surgery, and 24 patients had posterior surgery. Patients were evaluated at a minimum 2-year follow-up.
Results: No complications occurred in either group. The number of levels involved in the major curve was similar for the anterior and posterior groups (5.5 vs. 5.7). Preoperative thoracic (24.13 degrees +/- 4.9 degrees vs. 22.88 degrees +/- 5.14 degrees) and lumbar/thoracolumbar (50.2 degrees +/- 7.52 degrees vs. 52.2 degrees +/- 6.40 degrees). Cobb values for the 2 groups were also similar. The percent correction of the lumbar curve was similar between the 2 groups at all stages of follow-up (56% vs. 57.7%), as was the percent of spontaneous correction of the unfused thoracic curve (25% vs. 27.2%). However, fusion levels were significantly shorter in the anterior group (mean, 5.09 vs. 6.13), and there were 8 patients (4 in the anterior group and 4 in the posterior group) whose thoracic curve became greater at the latest follow-up. The thoracolumbar/lumbar-thoracic Cobb ratio for these 8 patients was less than that for the other patients (1.34 vs. 2.43), and their curve flexibility was worse.
Conclusion: Selective anterior and posterior screw instrumentation both achieved good surgical lumbar and subsequent spontaneous thoracic correction. There was no statistically significant difference between the 2 groups in lumbar correction or thoracic correction, but fusion levels were shorter in the anterior group. Patients with late thoracic curve decompensation had smaller thoracolumbar/lumbar-thoracic Cobb ratios and less preoperative flexibility than those who did not decompensate.