Hargens AR, Hutchinson KJ, Murthy G, Watenpaugh DE, Convertino VA, Wing PC.

Aviat Space Environ Med. 1993 May; 64: 435.

Life Science Division, NASA Ames Research Center, Moffett Field, CA 94035-1000.

INTRODUCTION. In a recent retrospective study, 68% of 58 Shuttle crew members complained of back pain during exposure to microgravity (Wing et al, Orthop. Clinics N. Amer. 22:255, 1991). Of 19 crew members who completed a pain questionnaire, pain was localized to the lower back (50%), and consisted of dull pain (62%) with an intensity averaging 2 on a 5 point scale. Flight data from IML-1 and Skylab indicate that the spine lengthens 4-7 cm in microgravity. Our objective in the present study was to compare back pain and spinal lengthening (height increase) during simulated microgravity (6 degrees head-down tilt: HDT) with those during actual microgravity. METHODS. After informed consent, 8 healthy male volunteers (38 +/- 2 years in age, 80.8 +/- 3.7 kg) were tilted head-down at 6 degrees for 16 days. All subjects completed the pain questionnaire with pain levels graded from zero (no pain) to 5 (intense and incapacitating pain) at 7:00 pm each day during the 2d pre-tilt control, 16d HDT, and 1d post-tilt recovery period. Each day the subjects' heights were measured in a supine position (control and recovery) or HDT position. RESULTS. Back pain increased from zero (baseline control period) to 2.3 +/- 0.4 at days 1-3 of HDT. During this time, all subjects experienced lower back pain and categorized this as dull and/or burning. By day 4 of HDT, the pain level decreased to 1.1 +/- 0.2 with 88% of the subjects (7 of 8) still experiencing pain. Only 2 subjects reported any pain at the end of HDT and during recovery. Subjects' heights increased by 2-3 cm within 3d of HDT and remained at that level until recovery. CONCLUSION. Although spinal lengthening in space is twice that during HDT, the HDT model of microgravity provides a good simulation of the type, level, distribution, and time course of back pain associated with actual microgravity. Lower back pain in these conditions appears to be associated with spinal lengthening, and pain subsides in intensity when lengthening stops.

Publication Types:

• Meeting Abstracts

Keywords:

• Animals
• Back Pain
• Body Height
• Head
• Head-Down Tilt
• Low Back Pain
• Male
• Retrospective Studies
• Skin
• Weightlessness
• Weightlessness Simulation
• NASA Center ARC
• NASA Center KSC
• NASA Discipline Musculoskeletal
• NASA Discipline Number 26-10
• NASA Program Space Physiology and Countermeasures

Other ID:

• 95607632

UI: 102212606

From Meeting Abstracts