Quan T, Matsumoto H, Bonsignore-Opp L, Ramo B, Murphy RF, Brooks JT, Welborn MC, Emans JB, Anari JB, Johnston CE, Akbarnia BA, McCarthy R, Flynn J, Sawyer JR, Vitale MG, and Roye BD
Background: The term "Tweener" is colloquially used to refer to early-onset scoliosis (EOS) patients whose age and development make them candidates for multiple surgical options. The purpose of this study was to establish expert consensus on a definition to formally characterize the Tweener population., Methods: A 3-round survey of surgeons in an international EOS study group was conducted. Surgeons were provided with various patient characteristics and asked if each was part of their definition for Tweener patients. Responses were analyzed for consensus (≥70%), near-consensus (60% to 69%), and no consensus (<60%)., Results: Consensus was reached (89% of respondents) for including chronological age in the Tweener definition; 8 to 10 years for females and 9 to 11 years for males. Surgeons agreed for inclusion of Sanders score, particularly Sanders 2 (86.0%). Patients who have reached Sanders 4, postmenarche, or have closed triradiate cartilage should not be considered Tweeners. Bone age range of 8 years and 10 months to 10 years and 10 months for females (12 y for males) could be part of the Tweener definition., Conclusions: This study suggests that the Tweener definition could be the following: patients with open triradiate cartilage who are not postmenarche and have not reached Sanders 4, and if they have one of the following: Sanders 2 or chronological age 8 to 10 years for females (9 to 11 y for males) or bone age 8 years and 10 months to 10 years and 10 months for females (12 y for males). This definition will allow for more focused and comparative research on this population., Level of Evidence: Level V-expert opinion., Competing Interests: B.A.A. reports personal fees from DePuy Spine, NuVasive, and Stryker Spine outside the submitted work. J.B.A. reports personal fees from Johnson and Johnson outside the submitted work. J.T.B. reports grants from POSNA and personal fees from Orthopediatrics and Depuy Synthes outside the submitted work. J.B.E. reports personal fees from Zimmer/Biomet outside the submitted work. J.R.S. reports personal fees from Elsevier, Orthopediatrics, Medtronic Spine, and Depuy Synthes outside the submitted work. J.F. reports personal fees from The Research Grants Council of Hong Kong, American Society for Bone and Mineral Research, Biomet, Wolters Kluwer Health-Lippincott Williams and Wilkins, and leadership in American Board of Orthopaedic Surgery outside the submitted work. C.E.J. reports personal fees from Medtronic, Elsevier, and Shriners Hospital Montreal PQ outside the submitted work. R.F.M. reports personal fees from Globus Medical and Stryker outside the submitted work. R.M. reports personal fees from Medtronic and Orthopediatrics outside the submitted work. B.R. reports personal fees from Elsevier Publishing, grants from Pediatric Orthopaedic Society of North America and Orthopaedic Research and Education Foundation outside the submitted work. M.C.W. reports grants or contracts from Zimmer Biomet, POSNA, and Shriners Hospital for Children, personal fees from Zimmer Biomet Spine, Depuy Synthes Spine, Nuvasive Spine, Stryker/K2M Spine, CHOP FDA course, Samaritan Health Services Grand Rounds, Saint Alphonsus Grand Rounds, and Peace Health Grand Rounds, leadership in PSSG, SRS, POSNA, and Shriners Spine Surgeon Study Group outside the submitted work. H.M. reports personal fees from Pediatric Spine Foundation, grants from Scoliosis Research Society, grants from Pediatric Orthopaedic Society of North America outside the submitted work. M.G.V. reports nonfinancial support from Pediatric Spine Foundation, during the conduct of the study; grants from Setting Scoliosis Straight Foundation, grants and other from Children’s Spine Foundation, grants from Orthopaedic Scientific Research Foundation, grants and other from POSNA, other from OMeGA, personal fees from Stryker, personal fees from Biomet, personal fees from Nuvasive outside of the submitted work. B.D.R. reports grants from Pediatric Orthopaedic Society of North America, Orthopaedic Scientific Research Foundation, and Scoliosis Research Society outside the submitted work. Pediatric Spine Study Group reports support from Zimmer Biomet, DePuy Synthes Spine, Pediatric Spine Foundation, OrthoPediatrics, Nuvasive, Medtronic, Globus Medical Inc., and Stryker during the conduct of the study. The remaining authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)