LSDA: Experiment - NNX16AP89G

EXPERIMENT INFORMATION

Quantitative CT and MRI-based Modeling Assessment of Dynamic Vertebral Strength and Injury Risk Following Long-Duration Spaceflight (NNX16AP89G)

Principal Investigator

+ Weaver, Ashley

Species Studied

Scientific Name: Homo sapiens Species: Human

Study Type

+ International Space Station (ISS)

Description

OBJECTIVES:
Astronauts exposed to microgravity for extended periods have incurred damage to their musculoskeletal systems. There is concern that the changes observed may lead to reduced performance and an increased risk of injury, including fractures, when dynamic loads are experienced. This experiment is a flight definition investigation in which the investigators hypothesize that crewmembers exposed to long-duration microgravity will exhibit profound degradation in cervical, thoracic, and lumbar vertebrae and spinal musculature. It is further hypothesized that spaceflight-induced changes to crewmember vertebrae and spinal musculature will result in reduced vertebral strength and increased fracture risk from dynamic loading.

The central objective of this investigation is to quantify the dynamic strength changes in the cervical, thoracic, and lumbar vertebrae incurred following long-duration microgravity exposure. Specific objectives are to:

Quantify vertebral geometry, volume, cortical thickness, and volumetric bone mineral density (vBMD) changes and spinal muscle volume changes in pre- and postflight medical images of crewmembers on long-duration ISS missions.
Quantify vertebral strength and assess injury risk in dynamic simulations with a human body model (HBM) altered to represent long-duration ISS crewmembers’ pre- and postflight vertebrae and spinal musculature.

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APPROACH:
In this study, a unique engineering approach will be used for determining musculoskeletal strength and injury risk under dynamic loading conditions. Quantitative computed tomography (qCT) scans will be used to measure bone morphology, vBMD, and cortical thickness of the spine. Magnetic resonance imaging (MRI) will be used to measure the volume of spinal musculature. Results derived from pre- and postflight scans will be integrated and applied in dynamic simulations.

Subjects for this study will be ISS crewmembers who have previously flown as well as nine crewmembers who have yet to fly.

Retrospective data will include pre- and postflight qCT scans and MRI scans archived with NASA’s Life Sciences Data Archive. The lumbar spine (L1 and L2) were the focus of the qCT scans. MRIs focused on the cervical and lumbar areas.

Data collection from prospective subjects is planned to occur once preflight between L-180 and L-45 days and once postflight between R+0 and R+14 days. Each data collection will include a qCT scan of the C3, T3, and L1 vertebrae. Each data collection will also include MRI scans of the cervical, thoracic, and lumbar spine regions. qCT scanning and MRI scanning need not occur on the same day, but must occur within 30 days of each other. There will be no inflight data collection.

Tissue degradation will be measured from retrospective and prospective qCT and MRI pre- and postflight scans. Image segmentation, registration, cortical thickness, and vBMD analysis techniques will be applied to quantify morphological and material property changes that occur in the vertebrae (cervical, thoracic, and lumbar) and spinal musculature when exposed to long-duration microgravity.

Geometric, volumetric, cortical thickness, and vBMD data will be used to morph and scale a finite element (FE) HBM to represent the pre- versus postflight spinal anatomy of individual crewmembers. Dynamic loads representing launch, pad or launch abort, and landing will be simulated with each altered HBM to assess individual and group strength decrement and injury risk with stress, strain, force, moment, and acceleration-based metrics.

RESULTS:
This investigation is in progress and results are not yet available. However, this study is expected to provide a greater understanding of spaceflight-induced bone and muscle degradation of the vertebral column and the resulting risk of vertebral fracture. Knowledge gained will inform the development and evaluation of countermeasures to prevent or reduce the effects of microgravity.

Keywords

Spine

Spinal fractures

Bone mineral density

Data Information

Data Availability

Archiving in progress. Data is not yet available for this experiment.

Parameters

Blood pressure

Bone mineral content (BMC)

Bone volume (BV)

Cortical thickness

Muscle cross-sectional area - CSA

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Mission/Study Information

Mission	Launch/Start Date	Landing/End Date	Duration
Expedition 58	12/18/2018	03/14/2019	85 days
Expedition 59	03/14/2019	06/24/2019	102 days
Expedition 60	06/24/2019	10/03/2019	101 days
Expedition 61	10/03/2019	02/06/2020	126 days
Expedition 62	02/06/2020	04/17/2020	70 days
Expedition 63	04/17/2020	10/21/2020	187 days
Expedition 64	10/21/2020		In progress
Ground	05/01/2009		In Progress

Human Research Program (HRP) Human Research Roadmap (HRR) Information

Crew health and performance is critical to successful human exploration beyond low Earth orbit. The Human Research Program (HRP) investigates and mitigates the highest risks to human health and performance, providing essential countermeasures and technologies for human space exploration. Risks include physiological and performance effects from hazards such as radiation, altered gravity, and hostile environments, as well as unique challenges in medical support, human factors, and behavioral health support. The HRP utilizes an Integrated Research Plan (IRP) to identify the approach and research activities planned to address these risks, which are assigned to specific Elements within the program. The Human Research Roadmap is the web-based tool for communicating the IRP content.

The Human Research Roadmap is located at: https://humanresearchroadmap.nasa.gov/

+ Click here for information of how this experiment is contributing to the HRP's path for risk reduction.

Additional Information

Co-Investigators

+ Stitzel , Joel

+ Tooze, Janet

Managing NASA Center

Johnson Space Center (JSC)

Responsible NASA Representative

Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri

Institutional Support

National Aeronautics and Space Administration (NASA)

Proposal Date

10/01/2016

Proposal Source

2015-16 HERO NNJ15ZSA001N

Similar Experiments or Analyses

+Vertebral Strength and Fracture Risk Following Long Duration Spaceflight (Vertebral_Strength)