Barrow Neurological Institute
Researchers from the Spinal Biomechanics Lab at Barrow Neurological Institute (BNI) in Phoenix, Arizona, walked away with the Best Basic Science Award at the recent meeting of the International Society for the Advancement of Spine Surgery.

With an eye toward expanding the existing kinematic data, the scientists set out to explore the relationship between things such as subject’s height, bone mineral density, flexibility, etc.

Anna Newcomb, M.S. is a research engineer at Barrow and a co-author on the unpublished work, “Variations among Human Spine Segments and their Relationships to in vitro Kinematics: A Retrospective Analysis of Experimental Data Including 282 Lumbar Motion Segments from 85 Donor Spines.” Newcomb’s collaborators on the project were Jennifer Lehrman, M.S., Brian Kelly, Ph.D., and Neil Crawford, Ph.D.

The authors told OTW, “The Spinal Biomechanics lab at BNI has produced and published data from a large number of in vitro studies over the past 20+ years. Each study has had a unique focus, but all have involved the same test methodology (which originated in the lab) and testing of intact cadaveric spine segments obtained from tissue banks to generate baseline values of normal spine flexibility. The setup phase of this retrospective analysis involved the creation and management of baseline information that was collected from these studies.”

Newcomb commented to OTW, “This study was actually conceived while gathering information from published studies involving finite element (FE) models of the spine. Some published studies have configured their computer model’s behavior to mimic experimental behavior seen in limited data sets or matching averages behavior from meta-data collected using a large number of samples but inconsistent methods. We realized we have an unusually large store of data with very well controlled methods. Our experimental data set, which has been collected from a large number of ‘normal’ cadaveric spines and over a long period of time, provides valuable information to the field of spinal biomechanics, including computational modeling.”

The authors wrote, “General spine tissue donor information (age, gender, height) was obtained from medical histories provided by tissue banks. Vertebral body heights, disc heights, and bone mineral densities (BMD) were obtained from X-rays and DEXA scans of the dissected spines. Kinematic data was retrieved from studies involving intact testing of the fresh frozen lumbar spine segments (L1 through S), with all tests performed in the same lab and using the same methods…”

“There were significant negative correlations between ROM [range of motion] and subject height and ROM and disc height. Other significant correlations with ROM include: donor age [Ax Rot: R=0.243, P< 0.001], BMD [all directions: R< -0.16, P< 0.007], and vertebral body height [FL-EX: R=0.186, P=0.006, and Lat Bend: R=0.136, P=0.046]. There were no relationships between ROM and donor age during FL-EX (R=-0.016, P=0.791) or Lat Bend (R=0.023, P=0.700). Similarly, there was no correlation between ROM and body height during Ax Rot (R=0.094, P=0.170).”

Newcomb told OTW, “The main message to spine surgeons is that this study revealed that differences in areas such as gender, age, bone mineral density, disc height and vertebral body height can lead to significant differences in kinematic behaviors of the spine, and computational models that don’t take this into account may be limited.”

SOURCE RRY Publications

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