Pain and Vertebral Dysfunction in Dry Immersion: A Model of Microgravity Simulation Different from Bed Rest Studies

Area of Science:

• Space medicine
• Musculoskeletal research
• Osteopathic manipulative medicine

Background:

• Astronauts commonly report back pain during and after spaceflight missions.
• Understanding the physiological changes contributing to back pain in microgravity is crucial for astronaut health.
• Dry immersion (DI) serves as a valuable ground-based model for simulating microgravity effects.

Purpose of the Study:

• To investigate potential vertebral somatic dysfunction (VD) in individuals undergoing simulated microgravity.
• To correlate pre-existing VD with the incidence and severity of back pain during dry immersion.
• To explore the utility of osteopathic clinical methods in assessing spaceflight-related musculoskeletal issues.

Main Methods:

• Eleven subjects participated in a three-day dry immersion protocol in a specialized space research clinic.
• Clinical assessments included manual palpation for vertebral somatic dysfunction (VD) and measurement of spine height.
• Back pain and global discomfort were evaluated before and after the dry immersion period.

Main Results:

• Back pain and significant global discomfort were reported by subjects throughout the dry immersion protocol.
• A statistically significant, low positive correlation (Pearson r = 0.44; P < 0.001) was observed between pre-existing VD and pain experienced during DI.
• Specific pain locations were identified, suggesting distinct patterns related to simulated microgravity exposure.

Conclusions:

• The study provides initial evidence for a link between vertebral somatic dysfunction and back pain in a simulated microgravity environment.
• Manual palpation of the spine emerged as a novel assessment tool in this space research context.
• An osteopathic perspective may aid in identifying astronauts at higher risk for developing back pain during space missions.