# Analysis of the rib construct for treatment of early-onset spinal deformity with hyperkyphosis

> **NIH NIH F31** · MEDICAL UNIVERSITY OF SOUTH CAROLINA · 2021 · $46,036

## Abstract

Project Summary/Abstract
Early-onset spinal deformity (EOSD) is a common affliction of early childhood in which the spine curves
abnormally. This spinal curvature can induce debilitating deformity and secondary medical problems. Thus,
EOSD is an important pediatric problem. Spinal deformity in the lateral direction is scoliosis, while deformity in
the anterior direction is kyphosis. EOSD can be treated with surgery. There are two widely-used growth-sparing
surgical methods for EOSD: 1) growing rods and 2) VEPTR (Vertical Expandable Prosthetic Titanium Rib).
These methods provide some immediate correction of spinal deformity by realigning vertebral bodies, and they
may provide additional gradual correction of the deformity via growth modulation of the spine over time.
However, the presence of hyperkyphosis complicates the surgical treatment of EOSD, as currently available
growth-sparing instrumentation does not provide ideal control of the deformity in the sagittal plane. Furthermore,
hyperkyphosis increases mechanical failure rates in the existing surgical approaches. Thus, a new surgical
method of treating hyperkyphosis is needed. We are developing a novel method, called the “rib construct,” which
utilizes a series of laminar hooks to anchor extendable rods to the ribs. The merits of the rib construct have been
validated anecdotally in a small series of patients and with ex vivo biomechanical testing at our institution.
However, to date, there have been no large animal studies that have examined the performance and mechanism
of the rib construct for correcting hyperkyphosis under controlled laboratory conditions. The central hypothesis
of this proposal is that the rib construct will correct hyperkyphosis in a pediatric porcine animal model.
Aim 1 will assess the ability of the rib construct to correct hyperkyphosis via growth modulation in a pediatric
porcine animal model. We will implant the rib construct in juvenile pigs with hyperkyphosis and assess its ability
to correct the curvature, compared to standard treatment with pedicle screws. Aim 2 will evaluate the biological
mechanism of spinal growth modulation with the rib construct at the tissue and cellular level. We will examine
the biological mechanism by which the rib construct works by quantifying chondrocyte number and density and
by measuring changes in marker genes and proteins related to chondrogenesis and osteogenesis. Aim 3 will
evaluate the biomechanics of the rib construct. Utilizing a computer model simulation program, we will analyze
the stress and strain distributions on the instrumentation, bone, and soft tissues, then compare them to those of
conventional surgical approaches. We will validate these findings by conducting normal pull-out force, bending,
and torsional biomechanical testing on human and porcine cadaver spines. Finally, we will report our clinical
data on the use of the rib construct in a retrospective study of human patients. Success in this project could
revol...

## Key facts

- **NIH application ID:** 10251070
- **Project number:** 5F31AR076917-02
- **Recipient organization:** MEDICAL UNIVERSITY OF SOUTH CAROLINA
- **Principal Investigator:** Daniel James Bonthius
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $46,036
- **Award type:** 5
- **Project period:** 2020-07-09 → 2022-07-08

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10251070

## Citation

> US National Institutes of Health, RePORTER application 10251070, Analysis of the rib construct for treatment of early-onset spinal deformity with hyperkyphosis (5F31AR076917-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10251070. Licensed CC0.

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