715: Longitudinal Evaluation of Cervical Spine Structure, Function, and Disc Herniation in Astronauts

Topic: Experimental (Non-clinical) Human Studies
Subtopic: Non -specific to any diagnosis, Developing methodology/technology, Electrophysiology/Clinical neurophysiology (e.g. microneurography, EEG, MEG, OPMs, TMS), Imaging (e.g. fMRI, PET, MRS)

Background and Aims: Astronauts have 21 times higher risk of cervical intervertebral disc (IVD) herniation [1], yet there is limited data on potential causes and existing data predominately focus on the lumbar spine [2]. We aimed to examine alterations in the cervical spine after spaceflight that may be associated with the risk for disc herniation development [3].

Methods: In this prospective, longitudinal, observational cohort study, five astronauts undertaking space missions to the International Space Station were included and analysed to date. The participants were assessed at two pre-flight (Launch-210 to -30 days) and four post-flight time points (Return+1 to +190 days). We collected the following data: (a) magnetic resonance imaging (MRI) for cervical intervertebral disc, vertebral, and muscle morphology, (b) cervical spine kinematics, (c) electromyography and hand-held dynamometry measures (d) neck muscle oxygenation (Near-Infrared Spectroscopy (NIRS)), (e) dual-energy X-ray absorptiometry (DXA) for cervical bone mineral density and (f) questionnaires on pain and fighter-pilot experience.

Results: Cervical IVD T2 relaxation time showed a post-flight increase followed by a long-term decrease, while IVD height showed no change. Vertebral fat fraction increased post-flight and decreased long-term. Muscle volume (deep cervical extensors and flexors) increased post-flight with inconsistent long-term changes whereas muscle fat infiltration increased post-flight and further increased long-term. Cervical spine range of motion reduced and aberrant motions increased post-flight. Shoulder shrug peak force and neck flexor force steadiness reduced at immediate post-flight timepoint (~5d). Baseline and contraction muscle oxygenation reduced post-flight but recovered at long-term timepoints. Cervical bone density slightly decreased early post-flight and increased thereafter.

Conclusions: This novel dataset investigates the cervical spine for the first time in an astronaut cohort. The early post-flight reductions in muscle oxygenation, bone density, range of motion and short-lasting neuromuscular changes indicate physiological changes that may precede or interact with disc injury mechanisms. The changes observed in cervical disc, vertebral, muscle and kinematic measures were relatively small in magnitude. Further data collection with five subsequent astronauts will give insight into the clinical and statistical significance of the effects observed.

References: 1. Johnston SL, Campbell MR, Scheuring R, Feiveson AH. Risk of herniated nucleus pulposus among U.S. astronauts. Aviat Space Environ Med. 2010;81:566–74.
2. Belavy DL, Adams M, Brisby H, Cagnie B, Danneels L, Fairbank J, et al. Disc herniations in astronauts: What causes them, and what does it tell us about herniation on earth? Eur Spine J. 2016;25:144–54.
3. Belavy DL, Armbrecht G, Albracht K, Brisby H, Falla D, Scheuring R, et al. Cervical spine and muscle adaptation after spaceflight and relationship to herniation risk: protocol from 'Cervical in Space' trial. BMC Musculoskelet Disord. 2022;23:772.

Presenting Author: Nitin Kumar Arora
Submitting Author: Nitin Kumar Arora

Senior Author: Daniel L. Belavy

IASP 2026 Global Year theme of Neuropathic Pain: No

• Daniel L. Belavy: PhD - Bochum University of Applied Sciences, Department of Nursing, Midwifery and Therapeutic Sciences, Division of Physiotherapy, Bochum, Germany
• Kirsten Albracht: PhD - Institute of Movement and Neuroscience, Center for Health and Integrative Physiology in Space, German Sport University, Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany; Aachen University of Applied Sciences, Department of Medical Engineering and Technomathematics, Aachen, Heinrich-Mußmann-Straße 1, 52428 Juelich, Germany
• Helena Brisby: PhD - Dept. of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University,of Gothenburg, Gothenburg, Sweden
• Deborah Falla: PhD - Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom
• Richard Scheuring: MS - Constellation Medical Operations Specialist; Flight Surgeon, Johnson Space Center, 2101 NASA Parkway SD4, Houston, TX 77058, USA
• Roope Sovelius: MD - Aeromedical Centre, Finnish Defence Force, Tukholmankatu 8 A, Helsinki, Finland
• Hans-Joachim Wilke: PhD - Ulm University Medical Centre, Institute of Orthopaedic Research and Biomechanics, Helmholtzstrasse 14, 89081 Ulm, Germany
• Kajsa Rennerfelt - Dept. of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University,of Gothenburg, Gothenburg, Sweden
• Michail Arvanitidis: PhD - Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston B15 2TT, United Kingdom
• Nitin Kumar Arora: MPT - Bochum University of Applied Sciences, Department of Nursing, Midwifery and Therapeutic Sciences, Division of Physiotherapy, Bochum, Germany
• Bjoern Braunstein: PhD - Institute of Movement and Neuroscience, Center for Health and Integrative Physiology in Space, German Sport University, Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany; Institute of Biomechanics and Orthopaedics, German Research Centre of Elite Sport, German Sport University, Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany
• Fabian Göll: Doctoral student - Institute of Movement and Neuroscience, Center for Health and Integrative Physiology in Space, German Sport University, Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany; Aachen University of Applied Sciences, Department of Medical Engineering and Technomathematics, Aachen, Heinrich-Mußmann-Straße 1, 52428 Juelich, Germany
• Svenja Kaczorowski: Doctoral student - Bochum University of Applied Sciences, Department of Nursing, Midwifery and Therapeutic Sciences, Division of Physiotherapy, Bochum, Germany
• Eva Moreira: MSc Physiotherapy - Bochum University of Applied Sciences, Department of Nursing, Midwifery and Therapeutic Sciences, Division of Physiotherapy, Bochum, Germany
• Florian Teichert: Doctoral student - Bochum University of Applied Sciences, Department of Nursing, Midwifery and Therapeutic Sciences, Division of Physiotherapy, Bochum, Germany
• Gabriele Armbrecht: PhD - Charité – University Medicine Berlin, Center for Muscle and Bone Research, Hindenburgdamm 30, 12203 Berlin, Germany