The Spine Journal Outstanding Papers
The Spine Journal and NASS presented the 2017 Outstanding Paper Awards (OPAs) Thursday, October 27th during the NASS Annual Meeting. Up to four OPAs are presented annually by TSJ and NASS to recognize excellence in Basic Science, Surgical Science,
Medical Interventional Science and Value in Spine Care. Winning papers are published
in The Spine Journal and receive a monetary prize. This year’s award winners are:
Outstanding Paper: Medical Interventional Science
From the International Space Station to the clinic: how prolonged unloading may
elevate risk for low back pain and lumbar instability
Jeannie F. Bailey, PhD, Stephanie L. Miller, MS, Kristine Khieu, Conor W. O’Neill , MD, Robert M.
Healey , MBA, Dezba G. Couglin, PhD, Jojo V. Sayson, PT, DMT, Douglas G. Chang, MD, PhD, Alan
R. Hargens, PhD, Jeffrey C. Lotz, PhD
BACKGROUND CONTEXT: Prolonged microgravity exposure is associated with localized low back
pain and an elevated risk of postflight disc herniation. Though the mechanisms by which microgravity impairs the spine are unclear, they should be foundational for developing inflight countermeasures for maintaining astronaut spine health. Because human spine anatomy has adapted to
upright posture on Earth, observations of how spaceflight affects the spine should also provide new
and potentially important information on spine biomechanics that benefit the general population.
PURPOSE: This study compares quantitative measures of lumbar spine anatomy, health and
biomechanics in astronauts before and after six months of microgravity exposure on board the
International Space Station (ISS).
STUDY DESIGN: Prospective longitudinal study.
SAMPLE: Six astronaut crewmember volunteers from the National Aeronautics and Space Administration (NASA) with six-month missions aboard the ISS.
OUTCOME MEASURES: For multifidus and erector spinae at L3-L4, measures include: cross-sectional area (CSA), functional cross-sectional area (FCSA), and FCSA/CSA. Other measures include:
supine lumbar lordosis (L1-S1), active (standing) and passive (lying) flexion-extension range of
motion (FE ROM) for each lumbar disc segment, disc water content from T2-weighted intensity,
Pfirrmann grade, vertebral endplate pathology, and subject-reported incidence of chronic low back
pain or disc injuries at one-year follow-up.
ME THODS: 3 T MRI and dynamic fluoroscopy of the lumbar spine were collected for each subject at
two time points: approximately 30 days before launch (preflight) and one day following six months
of spaceflight on the ISS (postflight). Outcome measures were compared between time points using
paired t-tests and regression analyses.
RESULTS: Supine lumbar lordosis decreased (flattened) by an average of 11% (p=0.019). Active FE
ROM decreased for the middle three lumbar discs (L2-L3: - 22.1%, p=0.049; L3-L4: - 17.3%, p=0.016;
L4-L5: - 30.3%, p=0.004). By contrast, no significant passive FE ROM changes in these discs were
observed (p>0.05). Disc water content did not differ systematically from pre- to postflight. Multifidus and erector spinae changed variably between subjects, with five of six subjects experiencing
an average decrease 20% for FCSA and 8%-9% for CSA in both muscles. For all subjects, changes
in multifidus FCSA strongly correlated with changes in lordosis (r2=0.86, p=0.008) and active FE
ROM at L4-L5 (r2=0.94, p=0.007). Additionally, changes in multifidus FCSA/CSA correlated with
changes in lordosis (r2=0.69, p=0.03). While multifidus-associated changes in lordosis and ROM
were present amongst all subjects, only those with severe, preflight endplate irregularities ( 2 of 6