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Body mass index affects outcomes after vertebral body tethering surgery



To compare the outcomes of anterior Vertebral Body Tethering (AVBT) surgery between overweight and non-overweight patients.


AIS/JIS patients with AVBT with 2-year follow-up from a multi-center pediatric spine database were evaluated pre-operatively, 1st post-operative erect, and 2 years post-operatively. ANOVA was used to compare 3 categories of BMI with significance as per Tukey–Kramer HSD post hoc test. Risk of scoliosis progression was analysed with Mid-P exact test.


121 patients (51 underweight, 58 normal, 12 overweight; mean age 12.5 ± 1.6 yr; BMI 18.8 ± 4.6 kg/m2) were identified. Comparing underweight, normal, and overweight groups: mean pre-operative age (13 yr, 13 yr, 12 yr), scoliosis (52°, 50°, 52°), pre-operative kyphosis (29°, 28°, 33°), peri-operative scoliosis correction (44%, 42%, 46%), and complications by 2-year follow-up (23%, 24%, 17%) were similar between groups. There was one broken tether in each of the underweight and normal weight groups. Change in percent scoliosis correction from 1st erect to 2-year post-operative (i.e., growth modulation phase) was not significantly different between groups; however, the risk ratio for scoliosis progression during this period was 4.74 (1.02–22.02; p = 0.04) for overweight patients.


Our findings demonstrate that, as compared to normal weight and underweight patients, overweight patients did not have a statistically significant difference in intra-operative scoliosis correction or in risk of experiencing complication; however, overweight patients had a risk ratio of 4.74 for progression of scoliosis during the growth modulation phase of treatment from first erect radiographs to minimum 2-year follow-up.

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Data availability

Registry data are available to member institutions. Measurements and analysis done at the IWK Health Centre are on a password protected server. Access may be arranged through application to the REB.

Code availability

Statistical analysis was conducted using SPSS v25 (IBM Corporation, Armonk, NY, USA).


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Pediatric Spine Study Group: Abdullah Saad Abdulfattah Abdullah, Edward Ahn, Behrooz Akbarnia, Harry Akoto, Stephen Albanese, Jason Anari, John Anderson, Richard Anderson, Lindsay Andras, Jennifer Bauer, Laura Bellaire, Randy Betz, Craig Birch, Laurel Blakemore, Oheneba Boachie-Adjei, Chris Bonfield, Daniel Bouton, Felix Brassard, Douglas Brockmeyer, Jaysson Brooks, David Bumpass, Pat Cahill, Olivier Chemaly, Jason Cheung, Kenneth Cheung, Robert Cho, Tyler Christman, Eduardo Colom Beauchamp, Daniel Couture, Haemish Crawford, Alvin Crawford, Benny Dahl, Gokhan Demirkiran, Dennis Devito, Mohammad Diab, Hazem El Sebaie, Ron El-Hawary, John Emans, Mark Erickson, Jorge Fabregas, Frances Farley, David Farrington, Graham Fedorak, Ryan Fitzgerald, Nicholas Fletcher, Lorena Floccari, Jack Flynn, Peter Gabos, Adrian Gardner, Sumeet Garg, Frank Gerow, Michael Glotzbecker, Jaime Gomez, David Gonda, Tenner Guillaume, Purnendu Gupta, Kyle Halvorson, Kim Hammerberg, Christina Hardesty, Daniel Hedequist, Michael Heffernan, John Heflin, Ilkka Helenius, Jose Herrera, Grant Hogue, Josh Holt, Jason Howard, Michael Timothy Hresko, Steven Hwang, Stephanie Ihnow, Brice Ilharreborde, Kenneth Illingworth, Viral Jain, Andrew Jea, Megan Johnson, Charles Johnston, Morgan Jones, Judson Karlen, Lawrence Karlin, Danielle Katz, Noriaki Kawakami, Brian Kelly, Derek Kelly, Raymond Knapp, Paul Koljonen, Kenny Kwan, Hubert Labelle, Robert Lark, A. Noelle Larson, William Lavelle, Lawrence Lenke, Sean Lew, Gertrude Li, Craig Louer, Scott Luhmann, Jean-Marc Mac-Thiong, Stuart Mackenzie, Erin MacKintosh, Francesco Mangano, David Marks, Sanchez Marquez, Jonathan Martin, Jeffrey Martus, Antonia Matamalas, Oscar Mayer, Richard McCarthy, Amy McIntosh, Jessica McQuerry, Jwalant Mehta, Lionel Metz, Daniel Miller, Firoz Miyanji, Greg Mundis, Josh Murphy, Robert Murphy, Karen Myung, Susan Nelson, Peter Newton, Matthew Newton Ede, Cynthia Nguyen, Susana Nunez, Matthew Oetgen, Timothy Oswald, Jean Ouellet, Josh Pahys, Kathryn Palomino, Stefan Parent, Alejandro Peiro Garcia, Ferran Pellise, Joseph Perra, Jonathan Phillips, Javier Pizones, Selina Poon, Nigel Price, Norman Ramirez-Lluch, Brandon Ramo, Gregory Redding, Todd Ritzman, Luis Rodriguez, Juan Carlos Rodriguez-Olaverri, David Roye, Benjamin Roye, Lisa Saiman, Amer Samdani, Francisco Sanchez Perez-Grueso, James Sanders, Jeffrey Sawyer, Christina Sayama, Michael Schmitz, Jacob Schulz, Richard Schwend, Suken Shah, Jay Shapiro, Harry Shufflebarger, David Skaggs, Kevin Smit, John Smith, Brian Snyder, Paul Sponseller, George Stephen, Joe Stone, Peter Sturm, Hamdi Sukkarieh, Ishaan Swarup, Michal Szczodry, John Thometz, George Thompson, Tanaka Tomoko, Walter Truong, Raphael Vialle, Michael Vitale, John Vorhies, Eric Wall, Shengru Wang, Bill Warner, Stuart Weinstein, Michelle Welborn, Klane White, David Wrubel, Nan Wu, Kwadwo Yankey, Burt Yaszay, Muharrem Yazici, Terry Jianguo Zhang.


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Authors and Affiliations




AM, SP, FM, KS, JM, RB, NAK, Pediatric Spine Study Group, RE-H contributed on design or the acquisition, analysis, or interpretation of data, drafted the work or revised it critically, approved, accountable.

Corresponding author

Correspondence to Ron El-Hawary.

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Conflict of interest

Amir Mishreky has nothing to disclose. Stefan Parent reports personal fees from EOS-imaging, personal fees from Spinologics, personal fees from K2M, personal fees from EOS-imaging, personal fees from Medtronic, personal fees from DePuy Synthes Spine, other from Academic Research chair in spine deformities of the CHU Sainte-Justine (DePuy), grants from DePuy Synthes Spine, grants from Canadian Institutes of Health Research, grants from Pediatric Orthopaedic Society of North America, grants from Scoliosis Research Society, grants from Medtronic, grants from EOS imaging, grants from Canadian Foundation for Innovation, grants from Setting Scoliosis Straight Foundation, grants from Natural Sciences and Engineering Council of Canada, grants from Fonds de recherche Québec—Santé, grants and other from Orthopaedic Research and Education Foundation, other from DePuy Synthes, other from Medtronic, other from Orthopaediatrics, from null, outside the submitted work. Firoz Miyanji consults for Zimmer Biomet. Kevin Smit receives grant from Zimmer Biomet. Joshua Murphy consults for OrthoPediatrics, Depuy Synthes Spine and is a member of the physician advisory board. Riley Bowker has nothing to disclose. Nedal Al Khatib has nothing to disclose. Pediatric Spine Study Group reports grants from Pediatric Orthopaedic Society of North America, grants from Food and Drug Administration, grants from NuVasive, grants from DePuy Synthes Spine, grants from Children’s Spine Foundation, and grants from Growing Spine Foundation. Ron El-Hawary reports grants and personal fees from Depuy Synthes Spine, grants and personal fees from Medtronic Spine, personal fees and other from Orthopediatrics, other from Pediatric Spine Foundation, other from Scoliosis Research Society, personal fees from Wishbone Medical, personal fees from Globus Medical, outside the submitted work.

Ethical approval

This work is a sub-study of the Pediatric Spine Study Group Registry which was approved by the Research Ethics Board at the IWK Health Centre (#1002256) in accordance with the ethical standards outlined in the Tri-Council Policy Statement and the 1964 Declaration of Helsinki and its later amendments.

Consent to participate

All research participants or their legal guardians provided written consent to be a part of the registry and have the data collected be used in ongoing research on scoliosis.

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Not applicable.

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Mishreky, A., Parent, S., Miyanji, F. et al. Body mass index affects outcomes after vertebral body tethering surgery. Spine Deform 10, 563–571 (2022).

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  • Vertebral body tethering
  • VBT
  • Growth modulation
  • Scoliosis
  • BMI
  • Obesity