Title: Cervical spine and muscle adaptation after spaceflight and relationship to herniation risk
Funder: UK Space Agency

Abstract: Astronauts are at increased risk of neck injury and pain upon returning to Earth. In particular, the incidence of cervical intervertebral disc (IVD) herniation in astronauts is over 21 times higher than that of the general population. IVD herniation can lead to severe and disabling pain which inevitably compromises quality of life. However, despite the documented increased risk of cervical IVD post spaceflight, the mechanisms underlying this increased risk remains unknown. Muscle function is known to be impaired after spaceflight and is expected to be a relevant factor associated with an increased risk of cervical IVD herniation. Changes in muscle function do not appear to be solely attributed to atrophy of the cervical muscles during spaceflight, but rather may be due to changes in the neural control of neck muscles, which so far have not been investigated in any detail in this population or in people with cervical IVD on Earth. Therefore, to date, no study has attempted to understand whether these factors are present in people who have cervical IVD herniation or whether changes in the neural control of the neck could contribute to the increased risk of IVD herniation experienced by astronauts when they return to Earth. In a combined effort with other research centres, this European Space Agency (ESA) approved project (CerISS), studies the causes that contribute to an increased risk of cervical IVD herniation in astronauts. Collectively, the project includes magnetic resonance imaging of cervical IVD morphology and composition, 3D cervical spine kinematics, blood-flow and O2-saturation in the cervical muscles, examination of neck muscle force, endurance and neuromuscular control and self_x0002_reported outcome measures prior to and after spaceflight. Three out of the required 14 astronauts for the project have consented to participate and data collection commenced in March 2022

Lay abstract: Astronauts are at increased risk of neck injury and pain upon returning to Earth. In particular, the incidence of cervical intervertebral disc (IVD) herniation in astronauts is over 21 times higher than that of the general population. IVD herniation can lead to severe and disabling pain which inevitably compromises quality of life. However, despite the documented increased risk of cervical IVD post spaceflight, the mechanisms underlying this increased risk remains unknown. Muscle function is known to be impaired after spaceflight and is expected to be a relevant factor associated with an increased risk of cervical IVD herniation. Changes in muscle function do not appear to be solely attributed to atrophy of the cervical muscles during spaceflight, but rather may be due to changes in the neural control of neck muscles, which so far have not been investigated in any detail in this population or in people with cervical IVD on Earth. Therefore, to date, no study has attempted to understand whether these factors are present in people who have cervical IVD herniation or whether changes in the neural control of the neck could contribute to the increased risk of IVD herniation experienced by astronauts when they return to Earth. In a combined effort with other research centres, this European Space Agency (ESA) approved project (CerISS), studies the causes that contribute to an increased risk of cervical IVD herniation in astronauts. Collectively, the project includes magnetic resonance imaging of cervical IVD morphology and composition, 3D cervical spine kinematics, blood-flow and O2-saturation in the cervical muscles, examination of neck muscle force, endurance and neuromuscular control and self_x0002_reported outcome measures prior to and after spaceflight. Three out of the required 14 astronauts for the project have consented to participate and data collection commenced in March 2022

Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING;2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: MUSCULOSKELETAL