2023 Undergraduate Research Showcase

Document Type

Student Presentation

Presentation Date


Faculty Sponsor

Dr. Erin Mannen


The gold standard surgical treatment for children with adolescent idiopathic scoliosis is deformity correction with spinal instrumentation and fusion. However, there is associated significant, long-term morbidity in fusing multiple motion segments in a child. Pain, inflexibility, and degenerative arthritis are often sequelae of the surgery due to fusion sites being immobile [1], and longevity of the metal rods and screws is a long-term concern. However, an innovative approach, vertebral body tethering (VBT), was recently approved by the FDA and has since provided an alternate treatment option. VBT takes advantage of the natural growth of a child's spine to modulate spinal growth and correct the deformity over time without spinal fusion. A flexible polyethylene tether is affixed to multiple spinal segments to apply compressive forces on the vertebral growth plates. Using a tensioner device, the amount of tension in the tether at each vertebral level is controlled, eventually correcting spinal curvature as the patient grows. Recent data shows 74% of patients treated with VBT achieve clinical success [2]. The tensioner device has tension settings of 0 to 5, though no data is available to correlate with the amount of tension generated in the tether at each setting. Furthermore, there are two different tensioner device designs that can be used in this medical device set (methods A and B), and it is unknown whether these different tensioners produce similar tension. Therefore, the purpose of this study was to quantify the forces generated with the two tensioner methods (A and B) at six categorical tension levels using current VBT instrumentation.


  1. Hoernschemeyer DG et al. J Bone Joint Surg Am. 2020 Jul 1;102(13):1169-1176.
  2. Newton PO et al. Spine Deform. 2022 May;10(3):553-561.


The Scoliosis Research Society Biedermann Innovation Award supported this research. We thank ZimVie for use of the set.