All-terrain vehicles (ATVs)This Position Statement was developed as an educational tool based on the opinion of the authors. It is not a product of a systematic review. Readers are encouraged to consider the information presented and reach their own conclusions.
All-terrain vehicles (ATVs) are three- or four-wheeled motorized vehicles with large, soft tires and a relatively high center of gravity. Used primarily for off-road activities, ATVs have handlebars like a motorcycle and are designed for a single operator to straddle the body of the vehicle. Some can reach speeds of 50 mph and weigh up to 600 lbs.
Very few states require a license to operate an ATV, most of which are used for recreational purposes. There are no mandatory national safety standards for their construction, and only some states have issued regulations for their use. ATVs are often operated by children, some as young as age five.
ATVs have been involved in an alarming number of injuries and deaths, particularly among young people. Because of this, in 1998 the Consumer Public Safety Commission (CPSC) replaced its initial consent decree with ATV manufacturers with an updated ATV Action Plan agreement. The agreement included not marketing or selling adult-sized ATVs for use by children younger than 16, not marketing or selling three-wheeled ATVs, and providing information and safety education.1
The American Academy of Orthopaedic Surgeons (AAOS), the Orthopaedic Trauma Association (OTA), and the Pediatric Orthopaedic Society of North America (POSNA) support the Consumer Product Safety Commission consent agreement placing restrictions on the sale of four-wheeled ATVs to children. In addition, we support efforts to pass state laws mandating licensing for operation on public roadways, and we strongly urge governmental agencies to educate the public about the dangers of these vehicles, including requiring ATV retailers to provide purchasers with educational safety materials.
The three-wheeled ATV is inherently unstable. When the operator executes a sharp turn at even moderate rates of speed, the high center of gravity of the vehicle, short wheel base and short turning radius, can cause the vehicle to turn over. The rider may also be thrown from the vehicle or crushed beneath it as it rolls.
Four-wheeled ATVs have some of the same design features as the three-wheeled models, including a high center of gravity, short wheel-base, short turning radius and high-powered engine. They are difficult machines to operate, even if somewhat less likely to roll over than the three-wheeled versions. Moreover, as off-road vehicles, they are generally used on rough or uneven ground. Uneven surfaces can cause them to turn over, largely due to the high center of gravity. When used on hills, they are capable of flipping over from front to back, as the rear wheels can lift the front wheels off the ground when excessive power is applied. Studies have shown that almost 60 percent of accidents involving four-wheeled ATVs result from tipping and overturning. Drivers can be thrown from these ATVs or can be crushed beneath them, just as with three-wheeled models.
Many other risk factors, such as the use of alcohol and the lack of safety equipment, can contribute to accidents on ATVs. However, the basic design of the three-and four-wheeled models makes them hazardous to anyone who rides them.
Although perceived as recreational toys, ATVs can be extremely unsafe. According to the US Consumer Product Safety Commission, more than 368,000 ATV-related injuries were treated in hospitals, doctors’ offices and clinics in 2009. Of those injuries, over 117,000 were to riders under the age of eighteen.
In 2007, at least 107 children younger than 16 were killed on ATVs. This accounts for 20 percent of fatalities.4 The most common mechanisms of injury include striking the ground, hitting fixed objects such as trees, and rolling backwards. The majority of injuries are cranial or spinal. Although the relative incidence of these injuries is declining, the consequences remain severe.
In light of statistics that show an inordinate number of injuries and deaths resulting from the use of ATVs, the AAOS, OTA and POSNA consider ATVs to be a significant public risk.
The three orthopaedic societies provide the following recommendations and safety tips for those choosing to ride ATVs:
- ATV operators should be licensed on the basis of demonstrated competence in handling the vehicle and knowledge of the safety hazards. With few existing laws governing the use of these vehicles, almost anyone of any age or level of skill or training can legally operate an ATV. No person should operate such a machine without some demonstration of training, knowledge and maturity.
- ATVs should never be driven by a child younger than age of 12. Children younger the age of 12 generally possess neither the body size and strength, nor the motor skills and coordination necessary for the safe handling of an ATV.
- Children between the age of 12 and 16 should have limitations on their use of ATVs. Children under age 16 generally have not yet developed the perceptual abilities or the judgment required for the safe use of highly powered vehicles. ATVs with a 90 cc or greater engine size should not be used by children under the age of 16. The child should be of a size appropriate to operate the particular ATV. Children should be supervised by a responsible adult. Children, in particular, should receive hands on safety training and certification.
- Operators should wear safety equipment. The key piece of safety equipment is a safety helmet that meets standards set for helmets used by motorcycle riders. As with motorcycle riders, the helmet provides the best protection available against death or serious disabling injury. In 80 percent of the deaths from accidents involving ATVs, the driver was not wearing a helmet. Proper clothing includes eye protection, gloves with padded knuckles, work boots or motorcycle racing boots, long pants and a long sleeved shirt or jacket. The minimum can help to prevent or mitigate injuries associated with falls from the vehicle. Even better is to use specific riding gear that includes padding over shoulders, elbows and knees.
- ATVs should be used only during daylight hours. Most ATVs are marketed and used as off-road recreational vehicles. In the varied terrain in which they are most commonly used, good visibility is required. Riding after dark is especially dangerous because lights attached to a vehicle cannot provide enough properly directed illumination when the vehicle is bouncing or turning.
- Only one person at a time should ride an ATV which is intended for single person use. Adding a passenger to the ATV increases the propensity of the vehicle to tip or turn over. In almost a third of ATV accidents (31 percent), more than one person was riding the vehicle. The safety of two person or multirider ATVs is not well known. Recent research has shown that there is a much greater likelihood of primary limb amputation or open fracture on multirider ATVs versus single rider ATVs.
- ATVs should not be operated if you are under the influence of drugs or alcohol. According to the CPSC, approximately 30 percent of all fatal ATV accidents involved alcohol use.5
- All-Terrain Vehicle Safety. U.S. Consumer Product Safety Commission. Washington, DC. Available at: http://www.cpsc.gov/cpscpub/pubs/540.html
- All-Terrain Vehicle Safety. Your Orthopaedic Connection. AAOS, Rosemont, IL, March 2002.
- All-terrain vehicle injury prevention: Two-, three-, and four-wheeled unlicensed motor vehicles. Pediatrics, 2000;105(6):1352-4.
- Warda L, Klassen TP, Buchan N, Zierler A: All-terrain vehicle ownership, use and self reported safety behaviors in rural children. Inj Prev 1998;4:44-9.
- Rodgers GB, Adler P: Risk factors for all-terrain vehicle injuries: A national case-control study. Am J Epidemiol 2001;153:1112-8.
- US Consumer Product Safety Commission: Annual Report of ATV Deaths and Injuries (2000). Washington, DC: CPSC, 2001.
- Upperman JS, Shultz B, Gaines BA, et al: All-terrain vehicle rules and regulations: Impact on pediatric mortality. J Pediatr Surg 2003;38:1284-6.
October 1987 American Academy of Orthopaedic Surgeons.
Revised June 2005 and September 2010.
Consensus Statement on the Use of Anesthetic and Sedative Drugs in Infants and Toddlers
This statement represents many months of deliberation, and urges further research to determine more definitively if the use of anesthesia and sedative use in very young children has the potential to cause learning deficits or other problems involving the developing brain. The working group involved in writing the statement cites growing evidence that these drugs cause harm in very young animals, and clinical research results that are mixed but suggest this harm may extend to humans.
While the statement does not recommend postponing needed surgeries or procedures for infants and toddlers, it does urge providers and parents to consider the risks, benefits and timing of any such surgery or procedure. In addition, it suggests exploring alternatives to anesthetics and sedatives when pain management is not an issue.
SmartTots has created FAQ sheets for both health care professionals and for parents and caregivers. You can find more information on the SmartTots website, or by viewing the press release announcing the statement, issued by SmartTots, a public-private partnership of the International Anesthesia Research Society and the U.S. Food and Drug Administration.
Consensus Statement Supplement
Spondylolisthesis and Spondylolysis
Diagnosis and Clinical Evaluation
Spondylolysis is relatively common in children and adolescents. The term spondylolysis is derived from the Greek words for vertebra (spondylo) and defect (lysis). The anatomic feature of spondylolysis is a defect in the pars interarticularis, and alone implies that there is no forward slippage of the superior vertebra. The term spondylolisthesis describes the forward displacement of the superior vertebra. Both conditions can coexist, thus they are intertwined when assessing the literature.
Spondylolysis and spondylolisthesis occur in both children and adults. While the anatomy is similar, the clinical presentation, physical exam findings, pathophysiology, natural history, and treatments are different in children and adolescents compared to older adults.
This position statement focuses on spondylolysis and spondylolisthesis in children, adolescents and young adults (<21 years old).
Spondylolysis is often described as secondary to trauma, and has not been found in non-ambulatory adults. It is more common in athletes involved in sports which require repetitive loading, twisting, flexion, and extension of the spine. Spondylolysis is cited as the most common identifiable cause of low back pain in the teenage athlete.
Spondylolisthesis is a relatively common condition of the lower lumbar spine. The term listhesis describes a slip as being an integral part of the condition. In children, the amount of slip can be low grade, in which the upper vertebra is slipped forward less than 50%, or high grade, in which the amount of upper vertebral slip is greater than 50% or associated with kyphotic angulation. Low grade slips can be asymptomatic or painful, and in rare cases can progress to a higher grade of slip. High grade slips can also be asymptomatic, but frequently are painful, and associated with hamstring tightness, pelvic and spine imbalance, and neural dysfunction. High grade slips are likely to progress, even to the point where the slipped vertebra is 100% displaced, which is known as spondyloptosis. The most dreaded complication of a high grade slip is cauda equina syndrome, which results in paralysis and/or bowel and bladder dysfunction.
Both spondylolysis and spondylolisthesis can cause disabling low back pain. Often symptoms are exacerbated by hyperextension movements of the lower back. Hamstring spasm/contractures and neurologic findings of radiculopathy may be present on physical exam.
Radiographic Evaluation of Spondylolysis and Spondylolisthesis
The defect of the lumbar pars may or may not be visible on the lateral and/or oblique radiographs. MRI is useful for ruling out other pathology, diagnosing occult or stress fractures of the pars, localizing neural compression in symptomatic patients, and offer essential anatomical detail for preoperative planning in high grade spondylolisthesis. Bone scan with SPECT imaging is a sensitive tool for diagnosis. CT scanning is also implemented to detail the bony anatomy of spondylolysis and spondylolisthesis, however, it requires radiation and does not illuminate soft-tissue or neural elements well.
Non-operative treatment is successful in relieving symptoms in the majority of cases of acute symptomatic spondylolysis and mild spondylolisthesis. Conservative measures include activity modification, physical therapy, immobilization with a brace, and pharmacologic interventions for pain control.
- Klein G, Mehlman CT, McCarty M. Nonoperative treatment of spondylolysis and grade I spondylolisthesis in children and young adults: a meta-analysis of observational studies. J Pediatr Orthop. 2009 Mar;29(2):146-56. Level of Evidence: IV
- Kurd MF, Patel D, Norton R, Picetti G, Friel B, Vaccaro AR. Nonoperative treatment of symptomatic spondylolysis. J Spinal Disord Tech. 2007 Dec;20(8):560-4. Level of Evidence: IV
- Debnath UK, Freeman BJ, Grevitt MP, Sithole J, Scammell BE, Webb JK. Clinical outcome of symptomatic unilateral stress injuries of the lumbar pars interarticularis. Spine (Phila Pa 1976). 2007 Apr 20;32(9):995-1000. Level of Evidence: II
- Miller SF, Congeni J, Swanson K. Long-term functional and anatomical follow-up of early detected spondylolysis in young athletes. Am J Sports Med. 2004 Jun;32(4):928-33. Level of Evidence: IV
chronic spondylolytic lesion. If there is documentation of an acute or recent injury, a
brace may be tried to facilitate healing of the lesion/fracture. A brace does not improve or
correct forward slippage of the vertebra.
- Sairyo K, Sakai T, Yasui N, Dezawa A. Conservative treatment for pediatric lumbar spondylolysis to achieve bone healing using a hardbrace: what type and how long? J Neurosurg Spine. 2012 Jun;16(6):610-4. Epub 2012 Apr 20. Level of Evidence: I
- Sairyo K, Sakai T, Yasui N. Conservative treatment of lumbar spondylolysis in childhood and adolescence: the radiological signs which predict healing. J Bone Joint Surg Br. 2009 Feb;91(2):206-9. Level of Evidence: IV
- Kurd MF, Patel D, Norton R, Picetti G, Friel B, Vaccaro AR. Nonoperative treatment of symptomatic spondylolysis. J Spinal Disord Tech. 2007 Dec;20(8):560-4. Level of Evidence: IV
- Sys J, Michielsen J, Bracke P, Martens M, Verstreken J. Nonoperative treatment of active spondylolysis in elite athletes with normal X-ray findings: literature review and results of conservative treatment. Eur Spine J. 2001 Dec;10(6):498-504. Level of Evidence: IV
Indications for Surgery: SpondylolysisSurgical treatment for spondylolysis (without significant spondylolisthesis) is indicated for the patient with significant pain and disability who is not responsive to a comprehensive conservative treatment program.
- Schlenzka D, Seitsalo S, Poussa M, Osterman K. Operative treatment of symptomatic lumbar spondylolysis and mild isthmic spondylolisthesis in young patients: direct repair of the defect or segmental spinal fusion? ) Eur Spine J. 1993 Aug;2(2):104-12. Level of Evidence: IV
- Schlenzka D, Remes V, Helenius I, Lamberg T, Tervahartiala P, Yrjnen T, Tallroth K, Osterman K, Seitsalo S, Poussa M. Direct repair for treatment of symptomatic spondylolysis and low-grade isthmic spondylolisthesis in young patients: no benefit in comparison to segmental fusion after a mean follow-up of 14.8 years. Spine J. 2006 Oct;15(10):1437-47. Epub 2006 Feb 7. Level of Evidence: IV
- Frennered AK, Danielson BI, Nachemson AL, Nordwall AB: Midterm follow-up of young patientsfused in situ for spondylolisthesis. Spine 1991;16:409-416. Level of Evidence: IV
- Cheung EV, Herman MJ, Cavalier R, Pizzutillo PD. Spondylolysis and spondylolisthesis in children and adolescents: II. J Am Acad Orthop Surg. 2006 Aug;14(8):488-98. Level of Evidence: V
Surgical options for symptomatic spondylolysis (without significant spondylolisthesis), which has failed conservative intervention, are an instrumented spondylolysis repair or a single level fusion.
- Westacott DJ, Cooke SJ. Functional outcome following direct repair or intervertebral fusion for adolescent spondylolysis: a systematic review. J Pediatr Orthop B. Jun 1 2012. Systematic review of 9 studies comparing pars repair (80 pts) vs fusion (108 pts) found no significant different between groups. Level of Evidence: IV
- Hioki A, Miyamoto K, Sadamasu A, et al. Repair of pars defects by segmental transverse wiring for athletes with symptomatic spondylolysis: relationship between bony union and postoperative symptoms. Spine (Phila Pa 1976). Apr 20 2012;37(9):802-807. Case series of 44 patients treated for spondylolysis found that bilateral fusion based on CT was associated with improved ODI compared to unilateral union or non union. Level of Evidence: IV
- Debnath UK, Freeman BJ, Grevitt MP, Sithole J, Scammell BE, Webb JK. Clinical outcome of symptomatic unilateral stress injuries of the lumbar pars interarticularis. Spine (Phila Pa 1976). Apr 20 2007;32(9):995-1000. 42 patients with unilateral spondy were followed prospectively with initial conservative care x 6 months. 8 patients failed conservative care and required surgery with one patient with spina bifida having a persistent nonunion. ODI scores improved in all patients after surgery. Level of Evidence: III
- Schlenzka D, Remes V, Helenius I, et al. Direct repair for treatment of symptomatic spondylolysis and low-grade isthmic spondylolisthesis in young patients: no benefit in comparison to segmental fusion after a mean follow-up of 14.8 years. Eur Spine J. Oct 2006;15(10):1437-1447. Long term follow up of 25 pts after repair and 23 pts after fusion at 14.8 years found no difference in functional outcomes with a slightly WORSE outcome in repaired patients vs fusion patients. Level of Evidence: IV
- Ivanic GM, Pink TP, Achatz W, Ward JC, Homann NC, May M. Direct stabilization of lumbar spondylolysis with a hook screw: mean 11-year follow-up period for 113 patients. Spine (Phila Pa 1976). Feb 1 2003;28(3):255-259. 113 patients followed up at 11 years after direct repair for spondy/grade I spondylolisthesis found a 13% nonunion rate with older patients faring poorer than younger ones. No functional outcomes assessed. Level of Evidence: IV
- Pellise F, Toribio J, Rivas A, Garcia-Gontecha C, Bago J, Villanueva C. Clinical and CT scan evaluation after direct defect repair in spondylolysis using segmental pedicular screw hook fixation. J Spinal Disord. Oct 1999;12(5):363-367. Small group of 7 patients - performed CT after pars repair and found only 2 had bilateral fusion but all patients had some improvement in pain scores. Level of Evidence: IV
Indications for Surgery: SpondylolisthesisIndications for surgical treatment for spondylolisthesis include patients with significant pain and disability not responsive to a comprehensive conservative treatment program, patients (including asymptomatic patients) who show progression of the slip, and those with greater than a 50% slip.
- Seitsalo S. Operative and conservative treatment of moderate spondylolisthesis in young patients. J Bone Joint Surg Br. 1990 Sep;72(5):908-13. Level of Evidence: III
- Bourassa-Moreau E, Labelle H, Mac-Thiong JM. Radiological and clinical outcome of non-surgical management for pediatric high grade spondylolisthesis. Studies in Health Technology & Informatics. 158:177-81, 2010 Level of Evidence: III (Conflicts in part with recommendation: Findings included similar quality of life scores in subjects with high grade spondylolisthesis who were treated operatively and non-operatively. While, the non-operative group was less functionally impaired initially, there was no worsening quality of life observed with follow-up.)
- Harris IE, Weinstein SL. Long-term follow-up of patients with grade III and IV spondylolisthesis, treatment with and without posterior fusion. The Journal of Bone and Joint Surgery. Vol 69-A, No. 7, Sept 1987 Level of Evidence: III (Conflicts in part with recommendation: Subjects with grade III and IV slips at presentation were found to have similar long-term outcomes with non-operative and operative management.)
- Seitsalo S, Oosterman K, Hyvãrinen H, Tallroth K, Schlenzka D, Poussa M. Progression of spondylolisthesis in children and adolescents. A long-term follow-up of 272 patients. Spine. Vol 16, No. 4, 1991. Level of Evidence: III (Conflicts with recommendations: Findings were that risk of slip progression increased with worse slip percentage at initial presentation but risk of slip progression was not different between subjects receiving non-operative therapy and those receiving surgery. However, notable differences in slip percentage between the two groups existed at presentation.)
- Pizzutillo PD, Hummer CD 3rd. Nonoperative treatment for painful adolescent spondylosis or spondylolisthesis. J Pediatr Orthop 1989 Sep-Oct; 9(5):538-40 Level of Evidence: IV
- Blackburne JS, Velikas EP. Spondylolisthesis in children and adolescents. The Journal of Bone & Joint Surgery. Volume 59-B, No. 4, November 1977 Level of Evidence: IV
- Pizzutillo PD, Hummer CD. Nonoperative treatment for painful adolescent spondylosis or spondylolisthesis. Journal of Pediatric Orthopaedics. Vol 9, No. 5, 1989. Level of Evidence: IV
- Wiltse LL, Jackson DW. Treatment of spondylolisthesis and spondylolysis in children. Clin Orthop Relat Res. 1976 Jun;(117):92-100. Level of Evidence: V
- Mardjetko S, Albert T, Andersson G, Bridwell K, DeWald C, Gaines R, Geck M, Hammerberg K, Herkowitz H, Kwon B, Labelle H, Lubicky J, McAfee P, Ogilvie J, Shufflebarger H, Whitesides T. Spine/SRS Spondylolisthesis Summary Statement. Spine Volume 30(6S) Supplement, 15 Mar 2005, p S3 Level of Evidence: V
- Agabegi SS, Fischgrund JS. Contemporary management of isthmic spondylolisthesis: pediatric and adult. The Spine Journal 10 (2010) 530-543 Level of Evidence: V
- Herman MJ, Pizzutillo, PD. Spondylosis and spondylolisthesis in the child and adolescent. Clinical Orthopaedics and Related Research. Number 434, pp. 46-54. Level of Evidence: V
- Smith, JA, Hu SS. Management of spondylosis and spondylolisthesis in the pediatric and adolescent population. Disorders of the Pediatric and Adolescent Spine. Volume 30 - Number 3 – July 1999. Level of Evidence: V
- Lonstein JE. Spondylolisthesis in children. Cause, natural history, and management. Spine. Volume 24, No. 24, pp 2640-2648 Level of Evidence: V
- Herman MJ, Pizzutillo PD, Cavalier R. Spondylosis and spondylolisthesis in the child and adolescent athlete. Orthop Clin N Am 34 (2003) 461-467. Level of Evidence: V
- Cavalier R, Herman MJ, Cheung EV, Pizzutillo PD. Spondylosis and spondylolisthesis in children and adolescents: I. Diagnosis, natural history, and nonsurgical management. J Am Acad Orthop Surg 2006; 14:417-424. Level of Evidence: V
- Cheung EV, Herman MJ, Cavalier R, Pizzutillo PD. Spondylosis and spondylolisthesis in children and adolescents: II. Surgical management. J Am Acad Orthop Surg 2006; 14:488-498. Level of Evidence: V
- Radcliff KE, Kalantar SB, Reitman CA. Surgical Management of spondylosis and spondylolisthesis in athletes: Indications and return to play. Spine conditions Vol 8, No. 1, Jan/Feb 2009 Level of Evidence: V
- McTimoney CA, Micheli LJ. Current evaluation and management of spondylosis and spondylolisthesis. Curr Sports Med Rep. 2003 Feb 2(1):41-6. Level of Evidence: V
- Boxall D, Bradford DS, Winter RB, Moe JH. Management of severe spondylolisthesis in children and adolescents. J Bone Joint Surg Am. 1979 Jun;61(4):479-95. Level of Evidence: V
Outcomes of Spondylolysis and Spondylolisthesis SurgeryCommonly used tools to assess the efficacy of spine surgery include clinical outcome measures and postoperative radiographic images to assess fusion, alignment, and surgical instrumentation. Numerous studies in the medical literature report good clinical and radiographic success with surgical intervention, as high as 95%. Patients with high grade, severe spondylolisthesis are the group with the highest complication rate. Complications can include nerve root injury, dural tears, loss of fixation, implant breakage or failure, non union, progression of the deformity, need for revision surgery, pelvic or spinal imbalance, or infection.
SummaryThe majority of patients with spondylolysis and mild spondylolisthesis do not require surgery.
The current standard of care for surgical intervention includes symptomatic spondylolysis not responsive to non-operative therapies, spondylolisthesis not responsive to non-operative therapies, documented progression of spondylolisthesis slippage (with or without symptoms), and high grade spondylolisthesis (with or without symptoms).
The Management of Pediatric TraumaThe Pediatric Orthopedic Society of North America, recognizes full well the major implications of trauma on the physical, psychological socioeconomic well being of children in North America. Of children admitted to the hospital for the treatment of multiple trauma, over 50% of them will have persistent limitations of physical function six months after discharge.1,2 Injured children are frequently left with behavioural disturbances which are even more common with persistent physical limitations. It is only in the past decade that the full impact of life threatening and multi system injuries on children and their families has been recognized as requiring long term follow-up and the provision of multiple pediatric support systems. It must also be appreciated that residual deficits in children ultimately add up to more significant costs during the life of the individual then similar deficits in older individuals. The personal loss in adults may be as severe as in children, but the financial impact to society of similar trauma in children adds up over a longer lifespan. Therefore, it is cost effective to devote a disproportionate amount of funds and effort towards reducing pediatric morbidity.
POSNA recognizes that the management of the pediatric patient sustaining the traumatic injury is influenced by patient size, surface area to body mass ratio, thermo-regulation and fluid requirements. A predetermined and systematic approach to the injured child is essential and is best delivered in a pediatric environment. This guarantees the early recognition of life threatening injuries and provides a method for rapid stabilization of the immature child. 3 There are major differences in pathophysiology, injury patterns and treatment of the traumatized child as compared with the traumatized adult. Multiple trauma remains the leading cause of death among children. Insufficient training of medical personnel in pediatrics and hence the lack of expertise in the management of injured children are factors contributing to disability and death in such children.4 Although the principles of resuscitation of injured children are similar to those for adults, appreciation of the differences in cardiorespiratory variables, airway anatomy, response to blood loss, thermo regulation and equipment required is essential for successful initial resuscitation. Cerebral, abdominal and thoracic injuries account for most of the disability and death among injured children. Cerebral damage may be due to secondary injuries to the brain and is potentially preventable. The need to preserve the spleen in children complicates the management of abdominal trauma. Although children usually have large cardiorespiratory reserves, they are likely to need airway control and ventilation with thoracic injuries. The psychological effect of trauma often poses long term problems and needs close follow-up . POSNA endorses the view that the care of seriously injured pediatric patients falls within the purview of surgical and medical specialists with special training in pediatrics. In analysing children with multiple trauma, a pediatric trauma score should be applied. This assists in the identification of the more critically injured child and those who are most likely to utilize pediatric hospital resources as evidenced by the need for surgery, intensive care and hospital stay. We would agree with the recommendations to triage children with pediatric trauma scores of 8 or less to a Level 1 Pediatric Trauma Centre.5
The Trauma Committee of the American Pediatric Surgical Association and the Pediatric Trauma Committee of the New England Medical Centre in Boston have developed a group of standards for care of critically injured pediatric patients. These standards have been endorsed by the Board of Governors of the American Pediatric Surgical Association and were modelled after the American College of Surgeons 1976 report, “Optimal Hospital Resources for the Care of the Seriously Injured”.6 The most important reason for specialized care of injured children is that children have special needs. The child is truly not “a little man”. Not only does he or she react differently to stress - the young child will compensate well for blood loss , for example, until it is extensive and then suddenly go into shock, but also has different reactions to drugs, suffers different types of injuries, and is a growing organism in whom injury can result in long term crippling if growth is interfered with. Because the acute management of injured children poses a number of specific problems; difficulty of vascular access, difficulty of airway access, peculiarities of ventilation, both in rate and volume, and the need for accuracy and fluid administration, the care of these multiple traumatized children is best delivered at a Pediatric Emergency Centre.
The need for specialized equipment and instrumentation for pediatric care is essential. Micro techniques eliminate the need to draw large quantities of blood from the small host. Smaller equipment for intubation and resuscitation, monitoring, etc. are essential to the care of children. All of the specialized equipment and techniques are found in a facility that is orientated specifically toward care of the pediatric patient. The few outcome studies performed regarding pediatric trauma at a Pediatric Trauma Centre indicates that there is reduced mortality and morbidity resulting from such care.7,8,9,10,11,12,13
In summary, it is the position of the Pediatric Orthopedic Society of North America that the delivery of care for the traumatized child is best given at a Level 1 Pediatric Trauma Centre, staffed by pediatric medical and surgical specialists with the resources to deal with the multifaceted requirements of such traumatized children including pediatric surgical operating theatres, pediatric intensive care units and pediatric rehabilitation services.
- Wesson, DE., Williams, JI., Spence, LJ., et al: Functional outcome in pediatric trauma. J of Trauma 29:589, 1989
- Wesson, DE., Scorpio, RJ., Spence, LJ., Kenny, BD., et al.: The physical psychological and socioenconomic costs of pediatric trauma. J of Trauma 33:252, 1991
- Eichelberger, MR., Randolph, JG.: Pediatric Trauma; An algorithm for Diagnosis and Therapy. J of Trauma 23:91, 1983.
- Kisoon, N., Dreyer, J., Wallia, M.: Pediatric Trauma: Differences in pathophysiology, injury patterns and treatment compared with adult trauma. Can Med Ass J., 142:27, 1990
- Aprahamian, C., Cattey, RP., Walker, AP., et al: Archives of Surgery, 125:1128, 1990.
- Ramenofski, NL., Morris, TS.: Standards of care for the critically injured pediatric patients. J of Trauma, 22:921, 1982.
- Cooper, A., Barlow, B., DiScala, C., et al: Efficacy of pediatric trauma care: Results of a population based study. J Ped surg 28:299, 1993.
- Hulka, F., Mullens, RJ., Mann, NC., et al: Influence of a state wide trauma system onpediatric hospitalization and outcome. J Trauma, 42:514, 1997.
- Hulka, F.: Pediatric Trauma systems: Critical distinctions. J Trauma, 47:585, 1999.
- Phillips, S., Rond, PC, Kelly, SM., Swartz, PD.: The Need for Pediatric Specific Triage Criteria; Results from the Florida Trauma Triage Study. Ped Emerg Care 12:394, 1996.
- Wesson, DE., Spence, LJ., Williams, JI., Armstrong, P.: Trauma Prevention and Treatment - the Odd Couple: Injury Scoring Sytems in Children. Can J Surg 30:398, 1987
- Tepas, J.J.; Mollitt, DL., Talbert, JL., et al: The Pediatric Trauma Score as a Predictor of Injury Severity in the Injured Child. J of Ped. Surg. 22: 14-18, 1987.
- Yian, EH., Gullahorn, LJ., Loder, RT., : Scoring of Pediatric Orthopedic Polytrauma: Correlations of Different Injury Scoring Systems and Prognosis for Hospital Course. J Pediatr Orthop, 20: 2, 203-208, 2000.
In-office Diagnostic Ultrasonography by Pediatric Orthopaedic Surgeons
IntroductionUltrasonographic examination enhances the diagnostic capabilities of pediatric orthopaedic surgeons and improves their therapeutic capabilities . By virtue of their education and training, pediatric orthopaedic surgeons are highly qualified to perform and supervise diagnostic imaging studies that are integral to high quality, efficient and cost-conscious pediatric musculoskeletal care. The American Board of Orthopaedic Surgery mandates training in musculoskeletal imaging during residency as a requirement for certification. While radiologists are trained to interpret musculoskeletal ultrasounds in descriptive terms, pediatric orthopaedic surgeons add functional, anatomical and clinical assessments resulting in patient-specific information not typically available to or provided for the radiologist. It is the pediatric orthopaedic interpretation of the ultrasonographic study, in conjunction with the history, and physical examination that guides the treatment instituted by the pediatric orthopaedist—the professional ultimately responsible for the care of the child.
TimelinessOptimal patient care is dependent upon diagnostic imaging that can be performed and interpreted in a timely manner. Ideally, orthopaedic imaging, including ultrasound studies, are performed in the pediatric orthopaedic office so that critical judgements can be made at the same time that other clinical decision-making is occurring. When children are required to leave the pediatric orthopaedic surgeon’s office to obtain diagnostic ultrasound imaging, there is a potential for significant delay in the initiation of therapy. This is especially problematic in the setting of an acute septic arthritis of the hip or in a subperiosteal abscess in a child.
Quality of CarePediatric orthopaedic surgeons are experts in the utilization and interpretation of imaging studies of the musculoskeletal system including ultrasonograms. Children undergoing musculoskeletal ultrasonography may benefit from the presence of the pediatric orthopaedic surgeon to position the child, stress the joint or palpate the bone over the area of concern. In most instances, the pediatric orthopaedist is the only qualified and knowledgeable caregiver who can perform these maneuvers. The ability of the pediatric orthopaedist to correlate the ultrasonographic images with the real-time physical examination findings plays a critical role in the correct interpretation of the sonographic images and guides the proper treatment for the child.
Cost EffectivenessWhen children are required to leave the pediatric orthopaedic surgeon’s office to obtain ultrasounds, more than one visit may be required to appropriately assess the situation when all of the data is available and initiate the appropriate therapy. This is especially onerous on the patient’s family. Pediatric orthopaedists can provide these services in office in a more cost-efficient manner furthering the goals of healthcare cost containment. The POSNA believes that pediatric orthopaedic surgeons are entitled to adequate compensation for the cost and work involved in performing and interpreting diagnostic ultrasonographic studies in their offices.
ConclusionThe POSNA believes that the onus of care and the ultimate responsibility for the pediatric orthopaedic patient rests with the treating surgeon. The immediate performance and interpretation of sonograpic imaging plays an integral role in diagnosing and treating these infants and children. Pediatric orthopaedic surgeons, as a matter of practice, are required to interpret diagnostic imaging studies. They are held accountable by their patients, families and society to correctly interpret radiologic studies including ultrasounds, even when the studies are performed by other specialists. Pediatric orthopaedic surgeons are highly qualified to supervise, perform and interpret these sonographic studies. The POSNA believes that pediatric orthopaedists can provide these services in a more cost-effective manner in their offices and are entitled to adequate compensation for the cost and work involved in providing these services. Any policy that prohibits pediatric orthopaedic surgeons from performing and interpreting ultrasound images in their offices interferes with the child’s ability to receive optimal care. Such a policy is likely to increase the cost of providing those services, and adds a potential risk to those children requiring comprehensive care for developmental hip dysplasia, possible septic arthritis, suspected subperiosteal abscesses, sports injuries, fractures, sprains and other pediatric orthopaedic conditions.
POSNA Advocacy Committee December, 2013
Screening for the Early Detection of Idiopathic Scoliosis in Adolescents
The Scoliosis Research Society (SRS), American Academy of Orthopaedic Surgeons (AAOS), Pediatric Orthopaedic Society of North America (POSNA), and American Academy of Pediatrics (AAP) believe that there has been additional useful research in the early detection and management of adolescent idiopathic scoliosis (AIS) since the review performed by the United States Preventive Services Task Force (USPSTF) in 2004. This information should be abailable for use by patients, treating health care providers, and policy makers in assessing the releative risks and benefits of the early identification and management of AIS.
The AAOS, SRS, POSNA, and AAP believe that there are documented benefits of earlier detection and non-operative management of AIS, earlier identification of severe deformities that are surgically treated, and incorporation of screening of children for AIS by knowledgeable health care providers as a part of their care.
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Swaddling and Developmental Hip Dysplasia
The Pediatric Orthopaedic Society of North America (POSNA), International Hip Dysplasia Institute (IHDI), American Academy of Orthopaedic Suregons (AAOS), United States Bone and Joint Initiative (USBJI) and Shriners Hospitals for Children have come to together to promote "hip-healthy swaddling" when parents decide to swaddle their infant.
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Payor Coverage for Anterior Fusionless Scoliosis Technologies for Immature Patients with Idiopathic ScoliosisI. Background
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-up (7-10). 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.
II. The Position of SRS/POSNA
Indication: 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.
Billing/coding: 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-up(7-10). 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.
Conclusion: 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.
III. 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 compression(11).
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 Law (12, 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 model (14). This landmark study was followed in 2008 by a study utilizing an immature porcine model (15). 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 tethering (15). 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 animal (16). 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 curve (16). 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 principles (16).
Subsequent animal studies were then conducted to examine the impacts of tethering on the cellular and structural integrity of spines post-treatment with AVBT (17, 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 values (17). . Biochemical and histologic analysis showed no change in gross morphologic disc health or disc water content (17). 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 disc (17). 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 tether (18).
Additional histological studies have been performed evaluating the effects of growth modulation on the physis (19, 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 closure (20).
Clinical Data: In 2010, Crawford and Lenke (9) 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 procedure (9). The patient’s thoracic kyphosis changed from 26° preoperatively to 18° at most recent follow-up (9). 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 report (9).
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 levels (7). 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 curves (7). Furthermore, scoliometer measurements improved from 12.4° to 6.9° (7). No major complications were observed (7).
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-up (8). Thoracic curve correction improved from mean preoperative magnitude of 42.8° to 17.9° at most recent follow-up (8). 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 fusion (21). Additionally, no complications were recorded in this small series of patients (21). . These early human trials demonstrated the potential efficacy and safety of AVBT for the treatment of juvenile and adolescent socliosis (7-9, 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 years (10). Average preoperative thoracic curve was 52° and corrected to 27° at most recent follow-up (10).
In February of 2020, Newton et al. published a comparison of vertebral tethering and posterior spinal fusion (22). 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-up (23). 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-up (24). . 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-up (25). 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 date (26). 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.
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- 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.
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- 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.
- 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.
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- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.