Kaiying Shen1, R Carter Clement2, Burt Yaszay3,4, Tracey Bastrom3, Vidyadhar V Upasani3,4, Peter O Newton5,6. 1. Department of Orthopedics, Shanghai Children's Medical Center, Shanghai, China. 2. Department of Pediatric Orthopedic Surgery, Children's Hospital of New Orleans, New Orleans, LA, USA. 3. Department of Orthopedics, Rady Children's Hospital San Diego, 3030 Children's Way, San Diego, CA, 92123, USA. 4. Department of Orthopaedics, University of California, San Diego, CA, USA. 5. Department of Orthopedics, Rady Children's Hospital San Diego, 3030 Children's Way, San Diego, CA, 92123, USA. pnewton.rady@gmail.com. 6. Department of Orthopaedics, University of California, San Diego, CA, USA. pnewton.rady@gmail.com.
Abstract
STUDY DESIGN: Retrospective. OBJECTIVES: To determine how the pre- and postoperative three-dimensional (3D) sagittal profiles of Lenke 5 curves in idiopathic scoliosis patients compare to unaffected controls. Prior research evaluating the sagittal plane of Lenke 5 (thoracolumbar/lumbar) curves in 2D suggests that the major curve is hypolordotic. METHODS: Patients with Lenke 5 curves treated with thoracolumbar/lumbar posterior fusion who had biplanar radiography (with 3D reconstruction) preoperatively (Pre) and 2+ years postoperatively (PO2Y) were included. A cohort of similarly aged controls (C) without spinal pathology was identified. The following 3D sagittal measurements were compared both pre- and postoperatively to controls: T1-T10, T10-L3, L3-S1, and pelvic incidence (PI). Kyphosis is designated by positive values, and lordosis by negative values. RESULTS: Nineteen Lenke 5 patients and 125 controls were included. Preoperatively, Lenke 5 patients were hypokyphotic relative to controls from T1 to T10 (30° ± 13° vs. 42° ± 9°, p < 0.001) and hyperlordotic from T10 to L3 (- 26° ± 15° vs. - 13° ± 12°, p < 0.001). Lenke 5 spines were less lordotic from L3 to S1 (- 41° ± 9° vs. - 47° ± 7°, p = 0.004). PI was similar between groups (Lenke 5 Pre: 48° ± 13°, C: 46° ± 10°, p = 0.49). Postoperatively, the area of principal deformity (T10-L3) remained hyperlordotic (PO2Y: - 23° ± 10° vs. C: - 13° ± 12°, p < 0.001). The proximal and distal uninstrumented segments demonstrated spontaneous sagittal correction, becoming similar to controls: T1-T10 (PO2Y: 41° ± 12° vs. C: 42° ± 9°, p = 0.421) and L3-S1 (PO2Y: - 48° ± 9° vs. C: - 47° ± 7°, p = 0.56). CONCLUSION: When measured in 3D, Lenke 5 curves were more lordotic than controls in the periapical region of the major coronal curve. Posterior correction improved sagittal alignment, including spontaneous sagittal correction of the unfused segments. However, ~ 10° of hyperlordosis persisted in the instrumented/fused T12-L3 segment. Intraoperative correction strategies should take this preoperative increase in 3D sagittal deformity into account during rod contouring as well as compression/distraction to restore more normal sagittal alignment. LEVEL OF EVIDENCE: III.
STUDY DESIGN: Retrospective. OBJECTIVES: To determine how the pre- and postoperative three-dimensional (3D) sagittal profiles of Lenke 5 curves in idiopathic scoliosispatients compare to unaffected controls. Prior research evaluating the sagittal plane of Lenke 5 (thoracolumbar/lumbar) curves in 2D suggests that the major curve is hypolordotic. METHODS:Patients with Lenke 5 curves treated with thoracolumbar/lumbar posterior fusion who had biplanar radiography (with 3D reconstruction) preoperatively (Pre) and 2+ years postoperatively (PO2Y) were included. A cohort of similarly aged controls (C) without spinal pathology was identified. The following 3D sagittal measurements were compared both pre- and postoperatively to controls: T1-T10, T10-L3, L3-S1, and pelvic incidence (PI). Kyphosis is designated by positive values, and lordosis by negative values. RESULTS: Nineteen Lenke 5 patients and 125 controls were included. Preoperatively, Lenke 5 patients were hypokyphotic relative to controls from T1 to T10 (30° ± 13° vs. 42° ± 9°, p < 0.001) and hyperlordotic from T10 to L3 (- 26° ± 15° vs. - 13° ± 12°, p < 0.001). Lenke 5 spines were less lordotic from L3 to S1 (- 41° ± 9° vs. - 47° ± 7°, p = 0.004). PI was similar between groups (Lenke 5 Pre: 48° ± 13°, C: 46° ± 10°, p = 0.49). Postoperatively, the area of principal deformity (T10-L3) remained hyperlordotic (PO2Y: - 23° ± 10° vs. C: - 13° ± 12°, p < 0.001). The proximal and distal uninstrumented segments demonstrated spontaneous sagittal correction, becoming similar to controls: T1-T10 (PO2Y: 41° ± 12° vs. C: 42° ± 9°, p = 0.421) and L3-S1 (PO2Y: - 48° ± 9° vs. C: - 47° ± 7°, p = 0.56). CONCLUSION: When measured in 3D, Lenke 5 curves were more lordotic than controls in the periapical region of the major coronal curve. Posterior correction improved sagittal alignment, including spontaneous sagittal correction of the unfused segments. However, ~ 10° of hyperlordosis persisted in the instrumented/fused T12-L3 segment. Intraoperative correction strategies should take this preoperative increase in 3D sagittal deformity into account during rod contouring as well as compression/distraction to restore more normal sagittal alignment. LEVEL OF EVIDENCE: III.