# Intraoperative Optimization and Validation of Musculoskeletal Reconstruction

> **NIH VA I01** · EDWARD HINES JR VA HOSPITAL · 2022 · —

## Abstract

The long-term goal of this project is to improve the outcome of surgical procedures
involving skeletal muscle transfer, whether muscle transposition or transplantation. Under
previous support from V.A. Rehab R&D, we characterized the design of muscles involved in
tendon transfer surgery and developed high-resolution tools with which to study them. In this
proposal, we exploit a relatively rare surgical procedure for brachial plexus injury, in which the
gracilis muscle is surgically isolated and then transplanted into the arm to act as an elbow
flexor. The key idea is that this surgical procedure allows us, for the first time, to completely
characterize a single human skeletal muscle intraoperatively and then to predict and
subsequently test its function in vivo. Further, because gracilis is the only muscle acting at the
elbow we can explicitly test our model to optimize this and related types of surgery since no
other muscles are involved in the elbow flexion movement. Our three aims are (1), to measure
gracilis muscle sarcomere length and active and passive mechanical properties intraoperatively
during surgical transplantation in 30 patients, (2) to compare predicted and actual function of the
transferred gracilis muscle one- and two-years postoperatively, and (3) to develop a practical
tool to train surgeons to perform these complex procedures.
 This proposal consists of three aims. The first two aims are interconnected. Aim 1
presents a sophisticated intraoperative experiment in which gracilis muscles are measured in
vivo, in isolation, and then after transplantation into the arm. This aim is based on our previous
intraoperative experience with tendon transfer surgery and biomechanical testing of muscle.
The novelty of this experiment is that, for the first time, a complete structural and functional data
set will be obtained from a single human muscle. In aim 2, using a deterministic model of
muscle function (rather than current models which are indeterminate and must be solved by
optimization), we will determine whether the typical biomechanical modeling approaches used in
the field can accurately predict elbow flexion torque given the most detailed set of tissue-level
parameters ever directly collected from a human muscle. If it is, this will be the first explicit
validation of such an approach. If it is not, we will be able to identify and isolate the factor(s)
that are obstacles to simulation validity.
 Aim 3 came directly out of our discussions with surgeons at the Mayo Clinic. We have
spent a tremendous amount of time training them regarding muscle active and passive
mechanical and functional properties as we perform these procedures. However, they
encouraged us to create a training tool that would allow other surgeons across the country to be
trained using the same concepts but not in the actual operating room. Aim 3 does just that by
programming an ergometer to “feel” just like a muscle in the operating room and then to practice
“trans...

## Key facts

- **NIH application ID:** 10309386
- **Project number:** 2I01RX002462-05
- **Recipient organization:** EDWARD HINES JR VA HOSPITAL
- **Principal Investigator:** Richard L. Lieber
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2022
- **Award amount:** —
- **Award type:** 2
- **Project period:** 2018-01-01 → 2025-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10309386

## Citation

> US National Institutes of Health, RePORTER application 10309386, Intraoperative Optimization and Validation of Musculoskeletal Reconstruction (2I01RX002462-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10309386. Licensed CC0.

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