Informational & Position Statements | Scoliosis Research Society
Skip to Content

Informational & Position Statements

As approved by the SRS Board of Directors

Main Content

SRS Statements

Open AllClose All
Response to FDA Med Watch

Scoliosis Research Society Response to FDA Med Watch

December 14, 2016

The United States Food and Drug Administration has released a warning that “repeated or lengthy use of general anesthesia and sedation drugs during surgeries or procedures in children younger than 3 years... may affect the development of children’s brains” (1). Warnings will be added to the labels of anesthetic drugs (inhaled anesthetics, ketamine, propofol, midazolam, and lorazepam) and apply specifically to patients undergoing 3 or more hours of anesthesia. For the SRS membership, this development has the greatest potential impact on the treatment of patients with early onset scoliosis. Young children with severe spinal and thoracic deformity may require procedures under sedation/anesthesia including MRI, serial Mehta casting, hemivertebra resection, or growing spine instrumentation for example. These procedures and the anesthetic exposure may be multiple and at times prolonged.

Initial concerns regarding early childhood exposure to anesthetic agents were based on animal studies with multiple classes of drugs, including both IV and inhaled anesthetics. Observational clinical studies have shown a higher rate of learning delays in school children who had two or more anesthetics compared to patients with one or no anesthetic exposure (2,3). One short anesthetic likely is safe(4,5) and a prospective randomized controlled trial showed no learning differences in children undergoing regional vs. inhaled anesthesia for one-time inguinal hernia repair(5). One study found that patients with 2 or more anesthetic exposures had a 18% rate of attention-deficit/hyperactivity disorder compared to 7-11% in patients with one or fewer exposures with an adjusted hazard ratio of 1.95(3). Longer anesthetic exposure is associated with a higher rate of learning disorders. This association has held up in multiple studies that have controlled for associated comorbidities and other exposures that may contribute to learning delay.

Infantile scoliosis is a life-threatening condition associated with higher than expected mortality(6,7). Early intervention is thought to prevent severe deformity and worsening pulmonary function, which may compromise lifetime health-related quality of life(8,9). For infantile idiopathic scoliosis, Mehta casting has found to be curative in up to ½ the cases, eliminating or delaying the need for spinal surgery. Casting at a younger age (<18 months) is associated with a higher cure rate. If intervention is delayed until over age 3, larger curves may require more aggressive procedures such as vertebral column osteotomy which hold higher neurologic risk or prolonged treatments such as halo gravity traction. Thus, we know young children with severe spinal deformity benefit from early treatment with casting and surgery. These benefits must be weighed against the FDA warning and potential risk of early childhood exposure to anesthetics.

We are supportive of future work on this topic to identify protocols in children 3 and under to reduce potential anesthetic effects on the developing brain. Early onset scoliosis patients are at high risk for pulmonary compromise and lifetime disability without appropriate and early treatment. Thus, surgeons must take a balanced approach and discuss with families both the known and unknown risks as well as benefits of a procedure requiring repeated or lengthy anesthesia prior to age 3 years.

1) FDA Med Watch December 14, 2016 (
2) Wilder RT, Flick RP, Sprung J, et al. Early exposure to anesthesia and learning disabilities in a population-based birth cohort. Anesthesiology. 2009;110:796–804.
3) Sprung J, Flick RP, Katusic SK, et al. Attention-deficit/hyperactivity disorder after early exposure to procedures requiring general anesthesia. Mayo Clin Proc. 2012;87:120–129.
4) Sun LS, Li G, Miller TKL, et al. Association Between a Single General Anesthesia Exposure Before Age 36 Months and Neurocognitive Outcomes in Later Childhood. JAMA. 2016;315(21):2312-2320.
5) Davidson AJ, Disma N, de Graaff JC, et al. Neurodevelopmental outcome at 2 years of age after general anaesthesia and awake regional anaesthesia in infancy (GAS): an international multicentre, randomised controlled trial. Lancet. 2016;387:239–250.
6) Pehrsson K, Larsson S, Oden A, Nachemson A. Long-term follow-up of patients with untreated scoliosis. A study of mortality, causes of death, and symptoms. Spine (Phila Pa 1976). 1992 Sep;17(9):1091-6.
7) Pehrsson K, Nachemson A, Olofson J, Ström K, Larsson S. Respiratory failure in scoliosis and other thoracic deformities. A survey of patients with home oxygen or ventilator therapy in Sweden. Spine (Phila Pa 1976). 1992 Jun;17(6):714-8.
8) Goldberg CJ, Gillic I, Connaughton O, Moore DP, Fogarty EE, Canny GJ, Dowling FE. Respiratory function and cosmesis at maturity in infantile-onset scoliosis. Spine (Phila Pa 1976). 2003 Oct 15;28(20):2397-406.
9) Karol LA, Johnston C, Mladenov K, Schochet P, Walters P, Browne RH. Pulmonary function following early thoracic fusion in non-neuromuscular scoliosis. J Bone Joint Surg Am. 2008 Jun;90(6):1272-81.

SRS Statement on Physiotherapy Scoliosis Specific Exercises - May 2014

Physiotherapy Scoliosis Specific Exercises: Scoliosis Research Society

M. Timothy Hresko, MD: Chair, SRS Non-operative committee

May 19, 2014

Physiotherapy Scoliosis Specific Exercises (PSSE) have been proposed as a supplemental treatment to orthotic management of scoliosis to prevent progressive deformity in children and adolescents. PSSE have also been applied for adult patients with pain associated with scoliosis deformities. The common principles of PSSE involve auto correction, elongation, and chest wall expansion with integration of the “corrected” posture into daily life activities. Several programs have been proposed for scoliosis treatment throughout Europe. One of the initial proponents was Katharina Schroth of Germany who established a clinic for treatment of scoliosis based on a spa-like concept. The Schroth technique evolved into an intensive initial evaluation and treatment regimen to include a residential program of several weeks duration with group and individual therapy sessions followed by daily home exercises and periodic physical therapy sessions. Other “schools” of scoliosis physiotherapy have evolved from the Schroth concept including the Schroth-Barcelona School (BSPTS), where the exercises are learned in an outpatient regimen. Different approaches also developed in Europe like SEAS in Italy, Dobomed and FITS of Poland, and “side shift” of England to name a few. A therapist may incorporate principles from several of these “schools” in their treatment of the individual patient with scoliosis while working with a rehabilitation team formed by physiotherapists, orthotists and medical doctors.

Physiotherapy Scoliosis Specific Exercises have been used with spinal orthotic management in the treatment of progressive idiopathic scoliosis. The combination of the two modalities may offer advantages over more simplified treatment plans. At the present time, there is no evidence supporting PSSE to be offered in substitution of bracing in treating progressive idiopathic scoliosis.  Although some evidence has shown the superiority of some PSSE programs in comparison with non-specific exercises and/or controls, it is still too soon to make a general statement about their applicability. Most studies in the literature are based on case series of selected patients who are managed at specialized scoliosis clinics. It is uncertain if the results of treatment can be expanded to the general population. In addition, further follow up assessments are needed to ascertain if the effects of PSSE can be maintained and that the scoliosis does not deteriorate with time.  Treatment programs that emphasize the same principles of the PSSE are being investigated for their potential application in a community setting which is typical for North America.

At the present time, there is strong evidence to support the use of brace treatment for moderate scoliosis and for surgical treatment for progressive scoliosis in adolescents or painful scoliosis in adults. Early detection of scoliosis is paramount to optimize the care of patients with spinal deformities. Early detection involves physical examination of the spine for at-risk population of adolescents by all healthcare providers. Subsequently, individualized treatment programs can be established for patients who have been detected to have a deformity.

Scoliosis Research Society (SRS) and its members actively support optimal treatment for each patient which may include non-operative, operative and combined treatment methods. SRS has supported and will continue to support pilot research studies for the role of exercises in the treatment of scoliosis. SRS in conjunction with Society On Scoliosis Orthopedic & Rehabilitative Treatment (SOSORT) is in the process of development of research guidelines for the study of treatment method for scoliosis to include bracing, physiotherapeutic scoliosis exercises, and other fusion less treatments.

Position Statements

Payor Coverage for Anterior Fusionless Scoliosis Technologies for Immature Patients with Idiopathic Scoliosis - April 2020

Joint SRS / POSNA Position Statement


An anterior instrumentation system designed to correct idiopathic scoliosis without spinal fusion (The Tether™ - Vertebral Body Tethering System by Zimmer Biomet) was approved by the FDA for use on August 16, 2019.

This technique has several benefits compared to spinal fusion with instrumentation

  1. Growth modulation.
    Anterior instrumentation without fusion was first reported to change vertebral growth in an immature patient by Drs. Crawford and Lenke in 2010, followed by subsequent larger retrospective series by other centers 7-10.
  2. Motion preservation.
    Significant progress has also been achieved in the treatment of spinal deformity in the past 50 years, allowing deformity to be corrected safely in all three planes. However, the standard of care currently requires that spinal instrumentation results in spinal fusion. It is known that if the sagittal plane is restored according to physiologic contour and the instrumentation is limited to the upper lumbar vertebral levels, excellent functional capacity is preserved for many years and quality of life is comparable to healthy individuals. However, this does not change the fact that fusion surgery is against the nature of human biomechanics and that it does cause some limitation of motion. The loss of motion may not affect daily activities of living, but still negatively impacts neighboring spinal segments over the long term. Undoubtedly, an alternative treatment that corrects deformity without the need for spinal fusion, preserving motion and not increasing the stress on neighboring segments, has created great excitement. In this context, VBT is a newly FDA approved treatment method that has great potential to correct scoliosis without the negative impacts of spinal fusion.
  3. Less morbidity and costs.
    Reported evidence is summarized below.  Clinical reports indicate a potential for 1) decreased length of stay 2) decreased narcotic use, 3) decreased blood loss, and 4) decreased operative time compared to fusion surgery.  Revision rates are reported at 5-40% at 1 to 3 years of follow-up7-10.  A wide variety of centers and surgeons across North America have reproduced clinical results demonstrating safety and efficacy of Anterior Vertebral Body Tethering (AVBT). Additionally, there are four surgeon-sponsored IDE studies (NCT03506334, NCT03194568, NCT04119284, NCT03802656).

Based on physician directed use of the Dynesys System and an industry sponsored FDA IDE retrospective study, The Tether™ - Vertebral Body Tethering System by Zimmer Biomet received Humanitarian Device Exemption (HDE) approval by the FDA in August 2019. 

The potential for anterior non-fusion devices to improve scoliosis patient outcomes under the principles of beneficence means that this device needs to be made available to those patients that meet FDA approved treatment indications and show interest in a new technology.

The Position of SRS / POSNA

The FDA approved Anterior Vertebral Body Tethering (AVBT) system is appropriately restricted under the terms of the HDE approval as being indicated for curves between 30 to 65 degrees in skeletally immature patients with idiopathic scoliosis and limited to use by surgeons with active IRB approval.  Although the FDA did not require a more specific definition of “skeletal immaturity”, we believe the definition should be similar to those used for bracing indications. Scoliosis Research Society defines skeletally immature as patients Risser 2 and under OR Sanders 5 and less, as under current understanding, growth modulation depends on meaningful remaining skeletal growth.  AVBT is NOT indicated in the following circumstances: Skeletally mature patients, Congenital scoliosis or cases with vertebral or chest malformations, Non-ambulatory patients or patients with altered muscle function or control.

Due to lack of appropriate descriptive billing codes, billing this procedure as “anterior spinal fusion and instrumentation surgery with reduced services” is a reasonable coding approach as this best describes the amount of work, skill, and RVUs associated with this procedure. Current CPT code for spinal instrumentation are listed and valued as “add-on” procedures to be listed in addition to the spinal fusion CPT codes. As such the RVU values of the instrumentation codes are not subject to multiple procedure modifiers as the reductions in value have are been taken into account. We believe the fusion codes should receive a “reduced services” modifier and the instrumentation codes should be valued normally.

Functional benefit:
Clinical reports (below) indicate a potential for 1) decreased length of stay 2) decreased narcotic use, 3) decreased blood loss, and 4) decreased operative time compared to fusion surgery.  Revision rates are reported at 5-40% at 1 to 3 years of follow-up7-10. Additionally, POSNA and the SRS believe that non-fusion technology provides significant functional promise. It is difficult to put a price on spinal motion, but many patients and families place a high value on retaining spinal motion to support their wide variety of sports, activities, and everyday movements.

The FDA has deemed the device to be safe and of probable benefit. Thus, the Pediatric Orthopaedic Society of North America (POSNA) and the Scoliosis Research Society (SRS) firmly concur that payors should provide coverage for any FDA approved devices under FDA stated clinical indications and requirements (limited to surgeons with active IRB approval) at the same level as traditional spinal instrumentation/fusion and growing rod procedures for management of skeletally immature patients  (Risser ≤  2 or Sanders ≤ 5) with idiopathic scoliosis (as defined above, 30 to 65 degrees Cobb angle).  For those patients who meet criteria for use of The Tether™ or other similarly FDA approved growth modulation systems, the decision for fusion versus growth modulation is best made between the patient, guardians, and treating physician - accounting for individual needs, values, and perspectives.

Detailed Review of Scientific Evidence on Anterior Vertebral Growth Modulation

Scientific Theory

Growth modulation operates under the principles of the Hueter-Volkmann Law, which describes the physiological response of growing bones under mechanical compression11. Compressive instrumentation of only the convex side of a scoliotic curvature inhibits growth on the convex side while permitting the concave side to lengthen with growth. As the patient approaches skeletal maturity, the lengthening of the concave side of the curve progressively straightens the spine in accordance with the Hueter-Volkmann Law12,13.

Pre-Clinical Research on Anterior Vertebral Body Tethering

AVBT is a surgical technique that utilizes an implant system consisting of flexible tethers anchors to the anterolateral vertebral body that apply compressive force across the vertebral endplates (growth area) and discs without fully arresting spine mobility.

Early research on AVBT was conducted in skeletally immature non-scoliotic animal models. In 2002, Newton et al. showed that asymmetric flexible tethering was able to induce a spinal curve at the tethered levels in a rapidly growing bovine model14.  This landmark study was followed in 2008 by a study utilizing an immature porcine model15. The investigators found that mechanical tethering during growth altered spinal morphology in the coronal and sagittal planes and produced vertebral and disc wedging proportional to the duration of tethering15.  The generation of scoliotic curves in non-scoliotic animals was evidence that AVBT had the ability to modify spinal growth and curvature.

In 2013, Moal et al.16 modified the design of the prior animal studies to further substantiate the findings that tethering can affect the instrumented spine in the coronal, sagittal, and axial planes. They conducted a biphasic study where they first used AVBT to induce scoliosis in a non-scoliotic animal16. They then removed the AVBT in the now scoliotic spines and switched the tethers from the concave side to the convex side to test if AVBT could treat the tethering-induced scoliotic curve16. The secondary corrective tether successfully created 3D realignment of the scoliotic curves and the observed corrective process was not only a product of the mechanical tether, but also altered bone growth secondary to Hueter-Volkmann principles16.    

Subsequent animal studies were then conducted to examine the impacts of tethering on the cellular and structural integrity of spines post-treatment with AVBT17,18. Newton et al.17 followed up on their bovine study and observed that tethering decreased spine motion by approximately 50% in lateral bending, flexion, and extension.  Following the removal of the tether, motion returned to normal control values17.  Biochemical and histologic analysis showed no change in gross morphologic disc health or disc water content17. Proteoglycan synthesis was significantly greater in the tethered discs and there was a trend toward increased type 2 collagen on the tethered side of the disc17. This was further substantiated in a more recent study that found these changes likely represent metabolic responses to the compressive loads generated by the flexible tether18.

Additional histological studies have been performed evaluating the effects of growth modulation on the physis19,20.  Chay et al.19 conducted a comparative histological study of immature Yorkshire pigs that had only scoliosis-inducing AVBT versus pigs that had biphasic tethering with scoliosis-inducing AVBT followed by corrective AVBT. Between the two groups, they found no difference in hypertrophic zone height and cell height in the hypertrophic zone, concluding that growth potential is preserved with growth modulation.19 These findings were substantiated in a more recent study that showed thinner physes on the tethered side without notable physeal closure20.

Clinical Data

In 2010, Crawford and Lenke9 published the first human trial of AVBT in a case report of an 8 year, 6 month old male with juvenile idiopathic scoliosis that underwent treatment by AVBT.  The patient’s preoperative curve improved from 40° to 6° at most recent follow-up, 48 months after the index procedure9.  The patient’s thoracic kyphosis changed from 26° preoperatively to 18° at most recent follow-up9.  Furthermore, the patient grew 33.1 cm during this time.9  Although this patient was without complication 4 years post-tethering, he remained skeletally immature at most recent follow-up in this report9.

In 2014, Samdani et al.7 conducted the first multiple patient study of AVBT in a case series of 11 patients with thoracic idiopathic scoliosis and a mean age of 12.3 years.  All patients underwent tethering over an average of 7.8 levels7.  Preoperative thoracic Cobb angle and compensatory lumbar curves corrected on average from 44.2° to 13.5° and 25.1° to 7.2°, respectively, at 2 year follow-up with approximately 70% correction on average for both curves7. Furthermore, scoliometer measurements improved from 12.4° to 6.9°7.  No major complications were observed7.

In 2015, Samdani et al.8 expanded their sample size and reported results on their first 32 patients that underwent AVBT. The mean age was 12 years, mean Sanders score was 3.2, and all patients had minimum 1 year follow-up8.  Thoracic curve correction improved from mean preoperative magnitude of 42.8° to 17.9° at most recent follow-up8.  The mean compensatory lumbar curve also showed correction from 25.2° to 12.6°8.

In 2017, Boudissa et al.21 reported similar positive results and published their early outcomes of AVBT with minimum 1 year follow-up.  Six patients underwent tethering of the thoracic curve at a mean age of 11.2 years and mean thoracic Cobb 45° and lumbar Cobb 33°21.  At 1 year follow-up, the average thoracic Cobb corrected to 38° and lumbar Cobb 25° with no patients requiring fusion21. Additionally, no complications were recorded in this small series of patients21. These early human trials demonstrated the potential efficacy and safety of AVBT for the treatment of juvenile and adolescent socliosis7-9,21, but were limited by small sample sizes and short follow-up timelines.

In 2018, Newton et al.10 published a retrospective case series of 17 patients with 2-4 years follow-up.  All patients underwent thoracoscopic tethering of the thoracic curve and mean age at surgery was 11.2 years10. Average preoperative thoracic curve was 52° and corrected to 27° at most recent follow-up10

In February of 2020, Newton et al. published a comparison of vertebral tethering and posterior spinal fusion22. They compared 23 VBT patients to 26 PSF patients at 2 and 5 years post-operative. They reported similar patient reported outcomes and a higher re-operation rate. However, they also found that VBT was successful at avoiding or delaying the need for fusion surgery in the majority of patients 22

Ongoing AVBT research has demonstrated some additional patient selection criteria that may help refine surgical indications. At the SRS 2018 Annual Meeting, Yilgor et al. presented their results of a single surgeon experience of 19 thoracoscopic AVBT cases with minimum 1-year follow-up23.  The average age at time of surgery was 12.5 years with mean follow-up of 17.6 months.  Patients were divided into Rapid Growing (Sanders <5; mean height gain 8.1 cm) and Steady Growing (Sanders 5-7; mean height gain 2.6 cm).  The average preoperative main thoracic Cobb was 45° and thoracolumbar/lumbar Cobb of 30° in the Rapid Growing cohort, and 44° and 30°, respectively, in the Steady Growing cohort.  At most recent follow-up, the Rapid Growing cohort achieved 75% total correction and the Steady Growing cohort achieved 62% total correction.  In the Rapid Growing Cohort, 2 patients developed atelectasis, 1 patient had a screw loosen, 1 tether release due to over-correction, and 2 more patients are candidates for tether release, but have yet to undergo surgery. No complications were reported in the Steady Growing cohort. Based upon these findings, the authors concluded this is a promising technique and may be safely performed in Steady Growing patients, but longer follow-up is needed.

At the POSNA 2019 Annual Meeting, Hoernschemeyer et al. presented their results on which curves may respond to AVBT with 2 years of follow-up24.  All patients were diagnosed with adolescent idiopathic scoliosis and categorized into 5 groups:  main thoracic (Lenke 1A), thoracolumbar, long thoracolumbar, Lenke 1B/1C, and Lenke 3 curves.  31 skeletally immature patients (mean Sanders 4.2; Risser 1.8) were reviewed:  11 main thoracic curves (mean preoperative Cobb 48°; mean post-operative Cobb 22°), 8 Lenke 1B/1C curves (mean preoperative Cobb 48°; mean post-operative Cobb 24°), 4 long thoracolumbar curves (mean preoperative Cobb 54°; mean post-operative Cobb 27°).  There were 4 patients with Lenke 5 curves and 2 patients with double tethers that showed no significant change at most recent follow-up.  The authors concluded Lenke 1A, 1B, 1C, and long thoracolumbar curves appear to be effectively treated with AVBT with low complication rate and low rate of revision surgery at 2 years post-operative.

At SRS 2018, Turcot et al. presented their results of a prospective developmental study of 23 patients with 2 years follow-up25.  The average age at time of surgery was 11.8 years. Mean thoracic Cobb 53° improved to 27° at most recent follow-up.  Thoracic kyphosis was found to be unchanged from preoperative radiographs and most recent follow-up.  Apical vertebral rotation corrected on average from 14° to 11° at most recent follow-up.  This abstract showed there is progressive improvement of coronal and rotational deformity.

At POSNA 2019, Miyanji et al. presented an AVBT study with the largest patient cohort to date26. They conducted a prospective multicenter database study of AVBT with minimum 2-year follow-up in 57 patients who underwent a total of 63 procedures. The mean age at time of surgery was 12.7 years and mean follow-up was 29.2 months. Mean preoperative curve improved from 51° to 23° and mean compensatory curve improved a mean 31% at most recent follow-up. In this review of 57 patients from 2 centers, the authors concluded AVBT is an acceptable treatment option being effective at preventing and obtaining curve correction in most patients.


In summary, a wide variety of centers and surgeons across the US, Canada, and outside North America have reproduced clinical results demonstrating acceptable safety and efficacy of anterior vertebral body tethering (AVBT) in skeletally immature patients. The FDA has judged this treatment as ‘safe’ and with ‘probable benefit’, and given this FDA approval the SRS and POSNA support insurance payor coverage for FDA approved usage of such devices. There have been no published scientific reports to support the use of vertebral tethering or other non-fusion anterior instrumentation in treating scoliosis in skeletally mature individuals. The SRS and POSNA do not support the use or reimbursement for anterior non-fusion instrumentation in skeletally mature individuals for the management of scoliosis or other spinal deformities.  For skeletally immature patients with idiopathic scoliosis who, with their parents/guardians, have selected this approach via shared decision making with their health care professionals considering the risks (including higher rate of reoperation) and the motion preserving benefits, the SRS and POSNA recommend such treatment as an insured covered benefit.


  1. Ledonio CL, Larson AN, Polly DW, Yaszemski MJ. Minimum 20-Year Radiographic Outcomes for Treatment of Adolescent Idiopathic Scoliosis:Preliminary Results from a Novel Cohort of US Patients. The Spine Journal. 2014;14(11):S36.
  2. Larson AN, Baky F, Ashraf A, et al. Minimum 20-Year Health-Related Quality of Life and Surgical Rates After the Treatment of Adolescent Idiopathic Scoliosis. Spine Deform. 2019;7(3):417-427.
  3. Weinstein SL, Ponseti IV. Curve progression in idiopathic scoliosis. J Bone Joint Surg Am. 1983;65(4):447-455.
  4. Burton DC, Carlson BB, Place HM, et al. Results of the Scoliosis Research Society Morbidity and Mortality Database 2009-2012: A Report From the Morbidity and Mortality Committee. Spine Deform. 2016;4(5):338-343.
  5. Martin CT, Pugely AJ, Gao Y, Weinstein SL. Causes and risk factors for 30-day unplanned readmissions after pediatric spinal deformity surgery. Spine (Phila Pa 1976). 2015;40(4):238-246.
  6. Pugely AJ, Martin CT, Gao Y, Ilgenfritz R, Weinstein SL. The incidence and risk factors for short-term morbidity and mortality in pediatric deformity spinal surgery: an analysis of the NSQIP pediatric database. Spine (Phila Pa 1976). 2014;39(15):1225-1234.
  7. Samdani AF, Ames RJ, Kimball JS, et al. Anterior vertebral body tethering for idiopathic scoliosis: two-year results. Spine (Phila Pa 1976). 2014;39(20):1688-1693.
  8. Samdani AF, Ames RJ, Kimball JS, et al. Anterior vertebral body tethering for immature adolescent idiopathic scoliosis: one-year results on the first 32 patients. Eur Spine J. 2015;24(7):1533-1539.
  9. Crawford CH, 3rd, Lenke LG. Growth modulation by means of anterior tethering resulting in progressive correction of juvenile idiopathic scoliosis: a case report. J Bone Joint Surg Am. 2010;92(1):202-209.
  10. Newton PO, Kluck DG, Saito W, Yaszay B, Bartley CE, Bastrom TP. Anterior Spinal Growth Tethering for Skeletally Immature Patients with Scoliosis: A Retrospective Look Two to Four Years Postoperatively. J Bone Joint Surg Am. 2018;100(19):1691-1697.
  11. Mehlman CT, Araghi A, Roy DR. Hyphenated history: the Hueter-Volkmann law. Am J Orthop (Belle Mead NJ). 1997;26(11):798-800.
  12. Stokes IA, Spence H, Aronsson DD, Kilmer N. Mechanical modulation of vertebral body growth. Implications for scoliosis progression. Spine (Phila Pa 1976). 1996;21(10):1162-1167.
  13. Akel I, Yazici M. Growth modulation in the management of growing spine deformities. J Child Orthop. 2009;3(1):1-9.
  14. Newton PO, Fricka KB, Lee SS, Farnsworth CL, Cox TG, Mahar AT. Asymmetrical flexible tethering of spine growth in an immature bovine model. Spine (Phila Pa 1976). 2002;27(7):689-693.
  15. Newton PO, Upasani VV, Farnsworth CL, et al. Spinal growth modulation with use of a tether in an immature porcine model. J Bone Joint Surg Am. 2008;90(12):2695-2706.
  16. Moal B, Schwab F, Demakakos J, et al. The impact of a corrective tether on a scoliosis porcine model: a detailed 3D analysis with a 20 weeks follow-up. Eur Spine J. 2013;22(8):1800-1809.
  17. Newton PO, Farnsworth CL, Faro FD, et al. Spinal growth modulation with an anterolateral flexible tether in an immature bovine model: disc health and motion preservation. Spine (Phila Pa 1976). 2008;33(7):724-733.
  18. Upasani VV, Farnsworth CL, Chambers RC, et al. Intervertebral disc health preservation after six months of spinal growth modulation. J Bone Joint Surg Am. 2011;93(15):1408-1416.
  19. Chay E, Patel A, Ungar B, et al. Impact of unilateral corrective tethering on the histology of the growth plate in an established porcine model for thoracic scoliosis. Spine (Phila Pa 1976). 2012;37(15):E883-889.
  20. Newton PO, Glaser DA, Doan JD, Farnsworth CL. 3D Visualization of Vertebral Growth Plates and Disc: The Effects of Growth Modulation. Spine Deform. 2013;1(5):313-320.
  21. Boudissa M, Eid A, Bourgeois E, Griffet J, Courvoisier A. Early outcomes of spinal growth tethering for idiopathic scoliosis with a novel device: a prospective study with 2 years of follow-up. Childs Nerv Syst. 2017;33(5):813-818.
  22. Newton PO, Bartley CE, Bastrom TP, Kluck DG, Saito W, & Yaszay B. Anterior Spinal Growth Modulation in Skeletally Immature Patients with Idiopathic Scoliosis: A Comparison with Posterior Spinal Fusion at 2 to 5 Years Postoperatively. J Bone Joint Surg Am. 2020.
  23. Yilgor C, Cebeci B,  Abul K. Non-fusion thoracoscopic anterior vertebral body tethering for adolescent idiopathic scoliosis: preliminary results of a single European center. Scoliosis Research Society Annual Meeting; 2018; Bologna, Italy.
  24. Hoernschemeyer D, Worley J, Loftis C. Two year follow-up of vertebral body tethering for adolescent idiopathic scoliosis – which curve types are responding to growth modulation? Pediatric Orthopaedic Society of North America Annual Meeting; 2019; Charlotte, NC.
  25. Turcot O, Roy-Beaudry M, Turgeon I. Tridimensional changes following anterior vertebral growth modulation after two years of follow-up. Scoliosis Research Society Annual Meeting; 2018; Bologna, Italy.
  26. Miyanji F, Pawelek J, Nasto L. A prospective, multicenter analysis of the efficacy of anterior vertebral body tethering in the treatment of idiopathic scoliosis. Pediatric Orthopaedic Society of North America; 2019; Charlotte, NC.

Approved by the POSNA Board of Directors - April 2, 2020
Approved by the SRS Board of Directors - April 1, 2020

*To be reviewed and updated based on relevant evidence in 2021